166 results on '"Ong, TA"'
Search Results
2. Engineering synthetic breath biomarkers for respiratory disease
- Author
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Chan, Leslie W., Anahtar, Melodi N., Ong, Ta-Hsuan, Hern, Kelsey E., Kunz, Roderick R., and Bhatia, Sangeeta N.
- Published
- 2020
- Full Text
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3. Mass Spectrometry Imaging and Identification of Peptides Associated with Cephalic Ganglia Regeneration in Schmidtea mediterranea
- Author
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Ong, Ta-Hsuan, Romanova, Elena V., Roberts-Galbraith, Rachel H., Yang, Ning, Zimmerman, Tyler A., Collins, James J., III, Lee, Ji Eun, Kelleher, Neil L., Newmark, Phillip A., and Sweedler, Jonathan V.
- Published
- 2016
- Full Text
- View/download PDF
4. Mass spectrometry-based characterization of endogenous peptides and metabolites in small volume samples
- Author
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Ong, Ta-Hsuan, Tillmaand, Emily G., Makurath, Monika, Rubakhin, Stanislav S., and Sweedler, Jonathan V.
- Published
- 2015
- Full Text
- View/download PDF
5. Zeolite Y adsorbents with high vapor uptake capacity and robust cycling stability for potential applications in advanced adsorption heat pumps
- Author
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Li, Xiansen, Narayanan, Shankar, Michaelis, Vladimir K., Ong, Ta-Chung, Keeler, Eric G., Kim, Hyunho, McKay, Ian S., Griffin, Robert G., and Wang, Evelyn N.
- Published
- 2015
- Full Text
- View/download PDF
6. Controversy and Consensus on Indications for Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations
- Author
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Agarwal, A, Farkouh, A, Saleh, R, Abdel-Meguid Hamoda, TA-A, Harraz, AM, Kavoussi, P, Arafa, M, Salvio, G, Rambhatla, A, Toprak, T, Gül, M, Phuoc, NHV, Boitrelle, F, Birowo, P, Ghayda, RA, Cannarella, R, Kuroda, S, Durairajanayagam, D, Zini, A, Wyns, C, Sarikaya, S, Tremellen, K, Mostafa, T, Sokolakis, I, Evenson, DP, Henkel, R, Zohdy, W, Chung, E, Ziouziou, I, Falcone, M, Russo, GI, Al-Hashimi, M, Calogero, AE, Ko, E, Colpi, G, Lewis, S, Serefoglu, EC, Bahar, F, Martinez, M, Nguyen, Q, Ambar, RF, Bakircioglu, ME, Kandil, H, Mogharabian, N, Sabbaghian, M, Taniguchi, H, Tsujimura, A, Sajadi, H, Ibrahim, W, Atmoko, W, Vogiatzi, P, Gunes, S, Gilani, MAS, Roychoudhury, S, Güngör, ND, Hakim, L, Adriansjah, R, Kothari, P, Jindal, S, Amar, E, Park, HJ, Long, TQT, Homa, S, Karthikeyan, VS, Zilaitiene, B, Rosas, IM, Marino, A, Pescatori, E, Ozer, C, Akhavizadegan, H, Garrido, N, Busetto, GM, Adamyan, A, Al-Marhoon, M, Elbardisi, H, Dolati, P, Darbandi, M, Darbandi, S, Balercia, G, Pinggera, G-M, Micic, S, Ho, CCK, Moussa, M, Preto, M, Zenoaga-Barbăroșie, C, Smith, RP, Kosgi, R, Rosette, JDL, El-Sakka, AI, Abumelha, SM, Mierzwa, TC, Ong, TA, Banihani, SA, Bowa, K, Fukuhara, S, Boeri, L, Danacıoğlu, YO, Gokalp, F, Selim, OM, Cho, C-L, Tadros, NN, Ugur, MR, Ozkent, MS, Chiu, P, Kalkanli, A, Khalafalla, K, Vishwakarma, RB, Finocchi, F, Andreadakis, S, Giulioni, C, Çeker, G, Ceyhan, E, Malhotra, V, Yilmaz, M, Timpano, M, Barrett, TL, Kim, SHK, Ahn, S-T, Giacone, F, Palani, A, Duarsa, GWK, Kadioglu, A, Gadda, F, Zylbersztejn, DS, Aydos, K, Kulaksız, D, Gupte, D, Calik, G, Karna, KK, Drakopoulos, P, Baser, A, Kumar, V, Molina, JMC, Rajmil, O, Ferreira, RH, Leonardi, S, Avoyan, A, Sogutdelen, E, Franco, G, Ramsay, J, Ramirez, L, Shah, R, Global Andrology Forum, Agarwal, Ashok, Farkouh, Ala'A, Saleh, Ramadan, Abdel-Meguid Hamoda, Taha Abo-Almagd, Harraz, Ahmed M, Kavoussi, Parviz, Arafa, Mohamed, Salvio, Gianmaria, Rambhatla, Amarnath, Toprak, Tuncay, Gül, Murat, Phuoc, Nguyen Ho Vinh, Boitrelle, Florence, Birowo, Ponco, Ghayda, Ramy Abou, Cannarella, Rossella, Kuroda, Shinnosuke, Durairajanayagam, Damayanthi, Zini, Armand, Wyns, Christine, Sarikaya, Selcuk, Tremellen, Kelton, Mostafa, Taymour, Sokolakis, Ioanni, Evenson, Donald P, Henkel, Ralf, Zohdy, Wael, Chung, Eric, Ziouziou, Imad, Falcone, Marco, Russo, Giorgio I, Al-Hashimi, Manaf, Calogero, Aldo E, Ko, Edmund, Colpi, Giovanni, Lewis, Sheena, Serefoglu, Ege Can, Bahar, Fahmi, Martinez, Marlon, Nguyen, Quang, Ambar, Rafael F, Bakircioglu, Mustafa Emre, Kandil, Hussein, Mogharabian, Nasser, Sabbaghian, Marjan, Taniguchi, Hisanori, Tsujimura, Akira, Sajadi, Hesamoddin, Ibrahim, Wael, Atmoko, Widi, Vogiatzi, Paraskevi, Gunes, Sezgin, Gilani, Mohammad Ali Sadighi, Roychoudhury, Shubhadeep, Güngör, Nur Dokuzeylül, Hakim, Lukman, Adriansjah, Ricky, Kothari, Priyank, Jindal, Sunil, Amar, Edouard, Park, Hyun Jun, Long, Tran Quang Tien, Homa, Sheryl, Karthikeyan, Vilvapathy Senguttuvan, Zilaitiene, Birute, Rosas, Israel Maldonado, Marino, Angelo, Pescatori, Edoardo, Ozer, Cevahir, Akhavizadegan, Hamed, Garrido, Nicola, Busetto, Gian Maria, Adamyan, Aram, Al-Marhoon, Mohamed, Elbardisi, Haitham, Dolati, Parisa, Darbandi, Mahsa, Darbandi, Sara, Balercia, Giancarlo, Pinggera, Germar-Michael, Micic, Sava, Ho, Christopher Chee Kong, Moussa, Mohamad, Preto, Mirko, Zenoaga-Barbăroșie, Cătălina, Smith, Ryan P, Kosgi, Raghavender, Rosette, Jean de la, El-Sakka, Ahmed I, Abumelha, Saad Mohammed, Mierzwa, Tiago Cesar, Ong, Teng Aik, Banihani, Saleem A, Bowa, Kasonde, Fukuhara, Shinichiro, Boeri, Luca, Danacıoğlu, Yavuz Onur, Gokalp, Fatih, Selim, Osama Mohamed, Cho, Chak-Lam, Tadros, Nicholas N, Ugur, Muhammet Rasit, Ozkent, Mehmet Serkan, Chiu, Peter, Kalkanli, Arif, Khalafalla, Kareim, Vishwakarma, Ranjit B, Finocchi, Federica, Andreadakis, Sotiri, Giulioni, Carlo, Çeker, Gökhan, Ceyhan, Erman, Malhotra, Vineet, Yilmaz, Mehmet, Timpano, Massimiliano, Barrett, Trenton L, Kim, Shannon Hee Kyung, Ahn, Sun-Tae, Giacone, Filippo, Palani, Ayad, Duarsa, Gede Wirya Kusuma, Kadioglu, Ate, Gadda, Franco, Zylbersztejn, Daniel Suslik, Aydos, Kaan, Kulaksız, Deniz, Gupte, Deepak, Calik, Gokhan, Karna, Keshab Kumar, Drakopoulos, Panagioti, Baser, Aykut, Kumar, Vijay, Molina, Juan Manuel Corral, Rajmil, Osvaldo, Ferreira, Raphael H, Leonardi, Sofia, Avoyan, Armen, Sogutdelen, Emrullah, Franco, Giorgio, Ramsay, Jonathan, Ramirez, Liliana, Shah, Rupin, and Rocco, Lucia
- Subjects
Male infertility ,Practice guideline ,Delphi method ,DNA fragmentation ,Survey ,Sperm - Abstract
PURPOSE: Sperm DNA fragmentation (SDF) testing was recently added to the sixth edition of the World Health Organization laboratory manual for the examination and processing of human semen. Many conditions and risk factors have been associated with elevated SDF; therefore, it is important to identify the population of infertile men who might benefit from this test. The purpose of this study was to investigate global practices related to indications for SDF testing, compare the relevant professional society guideline recommendations, and provide expert recommendations. MATERIALS AND METHODS: Clinicians managing male infertility were invited to take part in a global online survey on SDF clinical practices. This was conducted following the CHERRIES checklist criteria. The responses were compared to professional society guideline recommendations related to SDF and the appropriate available evidence. Expert recommendations on indications for SDF testing were then formulated, and the Delphi method was used to reach consensus. RESULTS: The survey was completed by 436 experts from 55 countries. Almost 75% of respondents test for SDF in all or some men with unexplained or idiopathic infertility, 39% order it routinely in the work-up of recurrent pregnancy loss (RPL), and 62.2% investigate SDF in smokers. While 47% of reproductive urologists test SDF to support the decision for varicocele repair surgery when conventional semen parameters are normal, significantly fewer general urologists (23%; p=0.008) do the same. Nearly 70% would assess SDF before assisted reproductive technologies (ART), either always or for certain conditions. Recurrent ART failure is a common indication for SDF testing. Very few society recommendations were found regarding SDF testing. CONCLUSIONS: This article presents the largest global survey on the indications for SDF testing in infertile men, and demonstrates diverse practices. Furthermore, it highlights the paucity of professional society guideline recommendations. Expert recommendations are proposed to help guide clinicians.
- Published
- 2023
7. Protein–nucleotide contacts in motor proteins detected by DNP-enhanced solid-state NMR
- Author
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Wiegand, Thomas, Liao, Wei-Chih, Ong, Ta Chung, Däpp, Alexander, Cadalbert, Riccardo, Copéret, Christophe, Böckmann, Anja, and Meier, Beat H.
- Published
- 2017
- Full Text
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8. Thiophene-based covalent organic frameworks
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Bertrand, Guillaume H. V., Michaelis, Vladimir K., Ong, Ta-Chung, Griffin, Robert G., and Dincă, Mircea
- Published
- 2013
9. STREET KETAMINE-ASSOCIATED BLADDER DYSFUNCTION: AN EMERGING HEALTH PROBLEM
- Author
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TEH GC, CCM Lei, CHUA CB, ONG TA, and LEE PY
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Ketamine ,lower urinary tract symptoms ,bladder dysfunction. ,Medicine - Abstract
Introduction: Ketamine is frequently abused nowadays as a recreational drug. Case reports are emerging since 2007 to describe a new clinical entity of severe bladder dysfunction associated with chronic abuse of street ketamine. Clinical presentation: Severe lower urinary tract symptoms of urinary frequency and urgency which are refractory to conventional treatment. Quality of life is adversely affected as a consequence. Chronic kidney disease will develop in advanced cases. Investigation findings: The urine is sterile on culture. Ultrasound will show reduced bladder capacity with thickened bladder wall. In advanced stage, hydronephrosis and renal impairment will develop. Treatment: Patients should be advised to stop street ketamine use immediately. Anticholinergic medication could be tried to alleviate the symptoms. Refractory cases with dilatation of the upper urinary tract might need urinary diversion. Conclusion: Awareness of this new condition is essential in diagnosis. Early intervention offers better treatment outcome.
- Published
- 2009
10. TUBERCULOUS PROSTATIC ABSCESS IN AN IMMUNOCOMPROMISED PATIENT
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DAYANGKU NORLIDA AO, ONG TA, and LEE PY
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Medicine - Published
- 2010
11. DO UNIVERSITY STUDENTS HAVE HIGH CARDIOVASCULAR RISK? A PILOT STUDY FROM UNIVERSITI MALAYSIA SARAWAK (UNIMAS)
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KAMARUDIN K, SYED ALWI SAR, MUNA S, ONG TA, and LEE PY
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Cardiovascular risk factors ,university students ,undergraduate. ,Medicine - Abstract
A health screening was done in UNIMAS in August 2008 for 237 undergraduate students. Body mass index (BMI), waist circumference (WC) and blood pressure (BP) were measured for all subjects. Total cholesterol and glucose levels were checked for those who fulfilled the screening criteria. The proportion of participants with cardiovascular (CVD) risk factors was high. The strategies for health promotion should not only be targeted to the older community but also to the younger community.
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- 2010
12. Biradical Polarizing Agents at High Fields.
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Michaelis, Vladimir K., Keeler, Eric G., Bahri, Salima, Ong, Ta-Chung, Daviso, Eugenio, Colvin, Michael T., and Griffin, Robert G.
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- 2022
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13. Vapor Signatures of Double-Base Smokeless Powders and Gunshot Residues for Supporting Canine Odor Imprinting.
- Author
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Ong, Ta-Hsuan, Ljunggren, James, Mendum, Ted, Geurtsen, Geoff, and Kunz, Roderick Russell
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- 2022
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14. Icosahedral m-Carboranes Containing Exopolyhedral B-Se and B-Te Bonds.
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Mills, Harrison A., Alsarhan, Fadi, Ong, Ta-Chung, Gembicky, Milan, Rheingold, Arnold L., and Spokoyny, Alexander M.
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- 2021
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15. Dendritic polarizing agents for DNP SENS† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6sc03139k Click here for additional data file
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Liao, Wei-Chih, Ong, Ta-Chung, Gajan, David, Bernada, Florian, Sauvée, Claire, Yulikov, Maxim, Pucino, Margherita, Schowner, Roman, Schwarzwälder, Martin, Buchmeiser, Michael R., Jeschke, Gunnar, Tordo, Paul, Ouari, Olivier, Lesage, Anne, Emsley, Lyndon, and Copéret, Christophe
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Chemistry - Abstract
Dendrimer-shielded polarizing agents for the application of DNP SENS to reactive surfaces., Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an effective method to significantly improve solid-state NMR investigation of solid surfaces. The presence of unpaired electrons (polarizing agents) is crucial for DNP, but it has drawbacks such as leading to faster nuclear spin relaxation, or even reaction with the substrate under investigation. The latter can be a particular problem for heterogeneous catalysts. Here, we present a series of carbosilane-based dendritic polarizing agents, in which the bulky dendrimer can reduce the interaction between the solid surface and the free radical. We thereby preserve long nuclear T′2 of the surface species, and even successfully enhance a reactive heterogeneous metathesis catalyst.
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- 2016
16. Case report: A rare case of extravesical, extraperitoneal metastasis after transuretheral resection of urothelial carcinoma
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Lim, HC, Khong, TL, Ong, TA, Roslani, AC, and Ang, CW
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- 2020
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17. DNP Enhanced Solid-State NMR Spectroscopy of Heterogeneous Catalysts
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Gajan, David, Berruyer, Pierrick, Ong, Ta-Chung, Liao, Wei-Chih, Mougel, Victor, Conley, Matthew P, Silverio, Daniel L, Widdifield, Cory, Lelli, Moreno, Thieuleux, Chloé, Lesage, Anne, Copéret, Christophe, Emsley, Lyndon, Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry and Applied Biosciences [ETH Zürich] (D-CHAB), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Chemistry, Durham University, Center for Magnetic Resonance, Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences et ingénierie chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), American Chemical Society - Colorado section, and Society for Applied Spectroscopy
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[CHIM.ANAL]Chemical Sciences/Analytical chemistry - Abstract
International audience; Heterogeneous catalysts are key to efficient processes in the chemical industry. However, they are difficult to improve because of the lack of access to their active-site structures. Although solid-state NMR is the method of choice to describe at atomic level the structure of catalysts, it is plagued by its intrinsic low sensitivity. This limitation is further exacerbated by the small fraction of active sites on the materials and by their often disordered and multi-site nature. Recently it has been demonstrated that this limit can be overcome by using dynamic nuclear polarization (DNP) which allows enhancement factors of up to 250 in solutions, at a magnetic field of 9.4 T and sample temperatures of ca. 100 K. Key to transposing the high enhancement factors observed for bulk frozen solutions to materials is the use of incipient wetness impregnation. In this approach, the materials are wetted by a minimal amount of radical solution. If the first proof of concepts was reported on model mesoporous silica materials, recent applications by our group and others concern a diverse range of chemical systems such as nanoparticles, mixed oxides, cementitious materials or microcrystalline solids. Here we will present new applications of DNP SENS in heterogeneous catalysis. We will show that DNP SENS allows to directly measure structural information of surface reaction intermediates in alkene metathesis catalysts, namely by obtaining C-C connectivities and bond distances. We will also show how the gain in sensitivity provided by DNP allows us to determine the full three-dimensional atomic-scale structure of a catalytically relevant organometallic complex anchored on a silica surface. This is done through a series of multi-dimensional and multi-nuclear NMR experiments producing several inter-nuclear distance constraints and the implementation of sophisticated NMR structure determination protocols.
- Published
- 2016
18. One-pot solvothermal synthesis of a well-ordered layered sodium aluminoalcoholate complex: a useful precursor for the preparation of porous Al[subscript 2]O[subscript 3] particles
- Author
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Li, Xiansen, Michaelis, Vladimir K., Ong, Ta-Chung, Smith, Stacey J., McKay, Ian, Griffin, Robert Guy, Wang, Evelyn, Mueller, Peter, Massachusetts Institute of Technology. Department of Chemistry, Massachusetts Institute of Technology. Department of Mechanical Engineering, Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology), Li, Xiansen, Michaelis, Vladimir K., Ong, Ta-Chung, Smith, Stacey J., McKay, Ian, Muller, Peter, Griffin, Robert Guy, and Wang, Evelyn N.
- Abstract
One-pot solvothermal synthesis of a robust tetranuclear sodium hexakis(glycolato)tris(methanolato)aluminate complex Na[subscript 3][Al[subscript 4](OCH[subscript 3])[subscript 3](OCH[subscript 2]CH[subscript 2]O)[subscript 6]] via a modified yet rigorous base-catalyzed transesterification mechanism is presented here. Single crystal X-ray diffraction (SCXRD) studies indicate that this unique Al complex contains three pentacoordinate Al[superscript 3+] ions, each bound to two bidentate ethylene glycolate chelators and one monodentate methanolate ligand. The remaining fourth Al[superscript 3+] ion is octahedrally coordinated to one oxygen atom from each of the six surrounding glycolate chelators, effectively stitching the three pentacoordinate Al moieties together into a novel tetranuclear Al complex. This aluminate complex is periodically self-assembled into well-ordered layers normal to the [110] axis with the intra-/inter-layer bonding involving extensive ionic bonds from the three charge-counterbalancing Na[superscript +] cations rather than the more typical hydrogen bonding interactions as a result of fewer free hydroxyl groups present in its structure. It can also serve as a valuable precursor toward the facile synthesis of high-surface-area alumina powders using a very efficient rapid pyrolysis technique., United States. Advanced Research Projects Agency-Energy (0471-1627), National Institutes of Health (U.S.) (Grant EB-001960), National Institutes of Health (U.S.) (Grant EB-002026), National Science Foundation (U.S.) (Grant CHE-0946721), Natural Sciences and Engineering Research Council of Canada (Postdoctoral Fellowship)
- Published
- 2013
19. Rapid Quantitative Analysis of Multiple Explosive Compound Classes on a Single Instrument via Flow‐Injection Analysis Tandem Mass Spectrometry.
- Author
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Ostrinskaya, Alla, Kunz, Roderick R., Clark, Michelle, Kingsborough, Richard P., Ong, Ta‐Hsuan, and Deneault, Sandra
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TNT (Chemical) ,QUANTITATIVE research ,FLOW injection analysis ,TANDEM mass spectrometry ,FORENSIC sciences ,TETRYL - Abstract
A flow‐injection analysis tandem mass spectrometry (FIA MSMS) method was developed for rapid quantitative analysis of 10 different inorganic and organic explosives. Performance is optimized by tailoring the ionization method (APCI/ESI), de‐clustering potentials, and collision energies for each specific analyte. In doing so, a single instrument can be used to detect urea nitrate, potassium chlorate, 2,4,6‐trinitrotoluene, 2,4,6‐trinitrophenylmethylnitramine, triacetone triperoxide, hexamethylene triperoxide diamine, pentaerythritol tetranitrate, 1,3,5‐trinitroperhydro‐1,3,5‐triazine, nitroglycerin, and octohy‐dro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine with sensitivities all in the picogram per milliliter range. In conclusion, FIA APCI/ESI MSMS is a fast (<1 min/sample), sensitive (~pg/mL LOQ), and precise (intraday RSD < 10%) method for trace explosive detection that can play an important role in criminal and attributional forensics, counterterrorism, and environmental protection areas, and has the potential to augment or replace several of the existing explosive detection methods. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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20. The β‐Agostic Structure in (C5Me5)2Sc(CH2CH3): Solid‐State NMR Studies of (C5Me5)2Sc−R (R=Me, Ph, Et).
- Author
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Culver, Damien B., Huynh, Winn, Tafazolian, Hosein, Ong, Ta‐Chung, and Conley, Matthew P.
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NUCLEAR magnetic resonance ,DENSITY functional theory ,COUPLING constants ,CHEMICAL shift (Nuclear magnetic resonance) ,PHENYL compounds - Abstract
Abstract: Multinuclear solid‐state NMR studies of Cp*
2 Sc−R (Cp*=pentamethylcyclopentadienyl; R=Me, Ph, Et) and DFT calculations show that the Sc−Et complex contains a β‐CH agostic interaction. The static central transition45 Sc NMR spectra show that the quadrupolar coupling constants (Cq ) follow the trend of Ph≈Me>Et, indicating that the Sc−R bond is different in Cp*2 Sc−Et compared to the methyl and phenyl complexes. Analysis of the chemical shift tensor (CST) shows that the deshielding experienced by Cβ in Sc−CH2 CH3 is related to coupling between the filled σC‐C orbital and the vacant π S c ⋯ H C * orbital. [ABSTRACT FROM AUTHOR]- Published
- 2018
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21. Tailored Polarizing Hybrid Solids with Nitroxide Radicals Localized in Mesostructured Silica Walls.
- Author
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Silverio, Daniel L., Kalkeren, Henri A., Ong, Ta‐Chung, Baudin, Mathieu, Yulikov, Maxim, Veyre, Laurent, Berruyer, Pierrick, Chaudhari, Sachin, Gajan, David, Baudouin, David, Cavaillès, Matthieu, Vuichoud, Basile, Bornet, Aurélien, Jeschke, Gunnar, Bodenhausen, Geoffrey, Lesage, Anne, Emsley, Lyndon, Jannin, Sami, Thieuleux, Chloé, and Copéret, Christophe
- Abstract
Hyperpolarization by dynamic nuclear polarization relies on the microwave irradiation of paramagnetic radicals dispersed in molecular glasses to enhance the nuclear magnetic resonance ( NMR) signals of target molecules. However, magnetic or chemical interactions between the radicals and the target molecules can lead to attenuation of the NMR signal through paramagnetic quenching and/or radical decomposition. Here we describe polarizing materials incorporating nitroxide radicals within the walls of the solids to minimize interactions between the radicals and the solute. These materials can hyperpolarize pure pyruvic acid, a particularly important substrate of clinical interest, while nitroxide radicals cannot be used, even when incorporated in the pores of silica, because of reactions between pyruvic acid and the radicals. The properties of these materials can be engineered by tuning the composition of the wall by introducing organic functionalities. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
22. Dendritic polarizing agents for DNP SENS.
- Author
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Liao, Wei-Chih, Ong, Ta-Chung, Gajan, David, Bernada, Florian, Sauvée, Claire, Yulikov, Maxim, Pucino, Margherita, Schowner, Roman, Schwarzwälder, Martin, Buchmeiser, Michael R., Jeschke, Gunnar, Tordo, Paul, Ouari, Olivier, Lesage, Anne, Emsley, Lyndon, and Copéret, Christophe
- Published
- 2017
- Full Text
- View/download PDF
23. Identifying Sn Site Heterogeneities Prevalent Among Sn-Beta Zeolites.
- Author
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Wolf, Patrick, Liao, Wei‐Chih, Ong, Ta‐Chung, Valla, Maxence, Harris, James W., Gounder, Rajamani, Graaff, William N. P., Pidko, Evgeny A., Hensen, Emiel J. M., Ferrini, Paola, Dijkmans, Jan, Sels, Bert, Hermans, Ive, and Copéret, Christophe
- Abstract
In recent years, various protocols on preparing Lewis acidic Sn- β zeolite hydrothermally and postsynthetically have been reported. However, very little is known about the effects of different synthesis protocols on the Sn( IV) speciation in the final material. Even the effects of individual synthesis parameters within a certain preparation method have not been studied systematically. Here, we demonstrate that hydrothermally synthesized Sn- β zeolites prepared via very similar recipes show significantly different
119 Sn- NMR spectra, suggesting different Sn site speciation. Among postsynthetically prepared Sn- β zeolites, less variation in the resulting119 Sn- NMR spectra have been observed, indicating a more reproducible synthesis procedure compared to hydrothermal synthesis in fluoride media. This work highlights the importance of119 Sn- NMR measurements to elucidate the precise local geometry of the Sn heteroatoms in Sn- β, and the need to quantify the number of reactive Sn sites on each sample that participate in a given catalytic reaction, in order to accurately compare materials prepared by different routes. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
24. Atomistic Description of Reaction Intermediates for Supported Metathesis Catalysts Enabled by DNP SENS.
- Author
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Ong, Ta ‐ Chung, Liao, Wei ‐ Chih, Mougel, Victor, Gajan, David, Lesage, Anne, Emsley, Lyndon, and Copéret, Christophe
- Subjects
- *
INTERMEDIATES (Chemistry) , *METATHESIS reactions , *CHEMICAL reactions , *CATALYSTS , *DYNAMIC nuclear polarisation , *SOLID state chemistry , *NUCLEAR magnetic resonance spectroscopy - Abstract
Obtaining detailed structural information of reaction intermediates remains a key challenge in heterogeneous catalysis because of the amorphous nature of the support and/or the support interface that prohibits the use of diffraction-based techniques. Combining isotopic labeling and dynamic nuclear polarization (DNP) increases the sensitivity of surface enhanced solid-state NMR spectroscopy (SENS) towards surface species in heterogeneous alkene metathesis catalysts; this in turn allows direct determination of the bond connectivity and measurement of the carbon-carbon bond distance in metallacycles, which are the cycloaddition intermediates in the alkene metathesis catalytic cycle. Furthermore, this approach makes possible the understanding of the slow initiation and deactivation steps in these heterogeneous metathesis catalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
25. Biosilica-Entrapped Enzymes Studied by Using Dynamic Nuclear-Polarization-Enhanced High-Field NMR Spectroscopy.
- Author
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Ravera, Enrico, Michaelis, Vladimir K., Ong, Ta‐Chung, Keeler, Eric G., Martelli, Tommaso, Fragai, Marco, Griffin, Robert G., and Luchinat, Claudio
- Published
- 2015
- Full Text
- View/download PDF
26. Formation of organic molecular nanocrystals under soft confinement.
- Author
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Yang, Xiaochuan, Ong, Ta-Chung, Michaelis, Vladimir K., Heng, Scott, Griffin, Robert G., and Myerson, Allan S.
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- *
NANOCRYSTALS , *MOLECULAR shapes , *PHARMACEUTICAL industry , *THIN films , *SOLUBILITY , *CRYSTALLIZATION - Abstract
Methods to produce nano-sized organic molecular crystals in thin films are of great interest in the pharmaceutical industry due to the potential benefit of increased solubility of poorly soluble drugs and the advantages of film-based dosage forms over traditional tablet/capsule-based dosage forms. One method to directly form organic nanocrystals is by crystallization in confined environments where the overall crystallization volume is constrained. We report the use of a novel solution impregnation method to form nanocrystals in polymer matrices with various microstructures in order to study the structure of the confined nanocrystals and the role of soft confinement and polymer chemistry on the nucleation process of nano-sized crystals. The particle diameter correlates with the microstructure of the polymer matrices and the nucleation kinetics. In addition, by carefully choosing the experimental conditions and the polymer matrix, polymorph control of nanocrystals can be achieved. Solid-state nuclear magnetic resonance (ssNMR) was used to examine the local structure of nanocrystals inside the polymer matrices and crystal polymer interactions. This method may serve as a novel formulation method to obtain nanocrystals of poorly soluble active pharmaceutical ingredients (APIs) for pharmaceutical industry. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
27. Structural Insights into Bound Water in CrystallineAmino Acids: Experimental and Theoretical 17O NMR.
- Author
-
Michaelis, Vladimir K., Keeler, Eric G., Ong, Ta-Chung, Craigen, Kimberley N., Penzel, Susanne, Wren, John E.C., Kroeker, Scott, and Griffin, Robert G.
- Published
- 2015
- Full Text
- View/download PDF
28. Designed Single-Step Synthesis, Structure, and Derivative Textural Properties of Well-Ordered Layered Penta-coordinate Silicon Alcoholate Complexes.
- Author
-
Li, Xiansen, Michaelis , Vladimir K., Ong , Ta‐Chung, Smith, Stacey J., Griffin , Robert G., and Wang, Evelyn N.
- Subjects
CRYSTAL structure ,POLYCRYSTALS ,ALCOHOLYSIS ,TRANSESTERIFICATION ,SINGLE crystals - Abstract
The controllable synthesis of well-ordered layered materials with specific nanoarchitecture poses a grand challenge in materials chemistry. Here the solvothermal synthesis of two structurally analogous 5-coordinate organosilicate complexes through a novel transesterification mechanism is reported. Since the polycrystalline nature of the intrinsic hypervalent Si complex thwarts the endeavor in determining its structure, a novel strategy concerning the elegant addition of a small fraction of B species as an effective crystal growth mediator and a sacrificial agent is proposed to directly prepare diffraction-quality single crystals without disrupting the intrinsic elemental type. In the determined crystal structure, two monomeric primary building units (PBUs) self-assemble into a dimeric asymmetric secondary BU via strong Na
+ O2− ionic bonds. The designed one-pot synthesis is straightforward, robust, and efficient, leading to a well-ordered (10ī)-parallel layered Si complex with its principal interlayers intercalated with extensive van der Waals gaps in spite of the presence of substantial Na+ counter-ions as a result of unique atomic arrangement in its structure. However, upon fast pyrolysis, followed by acid leaching, both complexes are converted into two SiO2 composites bearing BET surface areas of 163.3 and 254.7 m2 g−1 for the pyrolyzed intrinsic and B-assisted Si complexes, respectively. The transesterification methodology merely involving alcoholysis but without any hydrolysis side reaction is designed to have generalized applicability for use in synthesizing new layered metal-organic compounds with tailored PBUs and corresponding metal oxide particles with hierarchical porosity. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
29. Topical Developments in High-Field Dynamic Nuclear Polarization.
- Author
-
Michaelis, Vladimir K., Ong, Ta‐Chung, Kiesewetter, Matthew K., Frantz, Derik K., Walish, Joseph J., Ravera, Enrico, Luchinat, Claudio, Swager, Timothy M., and Griffin, Robert G.
- Subjects
- *
POLARIZATION (Nuclear physics) , *THIOUREA , *NITROXIDES , *PERFORMANCE evaluation , *NUCLEAR magnetic resonance spectroscopy , *RADICALS , *MOLECULAR structure - Abstract
We report our recent efforts directed at improving high-field dynamic nuclear polarization (DNP) experiments. We investigated a series of thiourea nitroxide radicals and the associated DNP enhancements ranging from ε=25 to 82, which demonstrate the impact of molecular structure on performance. We directly polarized low-gamma nuclei, including 13C, 2H, and 17O, by the cross effect mechanism using trityl radicals as a polarization agent. We discuss a variety of sample preparation techniques for DNP with emphasis on the benefits of methods that do not use a glass-forming cryoprotecting matrix. Lastly, we describe a corrugated waveguide for use in a 700 MHz/460 GHz DNP system that improves microwave delivery and increases enhancements up to 50 %. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
30. Phenyl Ring Dynamics in a Tetraphenylethylene-Bridged Metal-Organic Framework: Implications for the Mechanism of Aggregation-Induced Emission.
- Author
-
Shustova, Natalia B., Ong, Ta-Chung, Cozzolino, Anthony F., Michaelis, Vladimir K., Griffin, Robert G., and Dinca, Mircea
- Subjects
- *
MOLECULAR structure of metal-organic frameworks , *CHROMOPHORES , *STYRENE , *FLUORESCENCE , *DEFORMATIONS (Mechanics) , *LIGHT emitting diodes - Abstract
Molecules that exhibit emission in the solid state, especially those known as aggregation-induced emission (AIE) chromophores, have found applications in areas as varied as light-emitting diodes and biological sensors. Despite numerous studies, the mechanism of fluorescence quenching in AIE chromophores is still not completely understood. To this end, much interest has focused on understanding the low-frequency vibrational dynamics of prototypical systems, such as tetraphenylethylene (TPE), in the hope that such studies would provide more general principles toward the design of new sensors and electronic materials. We hereby show that a perdeuterated TPE-based metal-organic framework (MOF) serves as an excellent platform for studying the low-energy vibrational modes of AIE-type chromophores. In particular, we use solid-state 2H and 13C NMR experiments to investigate the phenyl ring dynamics of TPE cores that are coordinatively trapped inside a MOF and find a phenyl ring flipping energy barrier of 43(6) kJ/mol. DFT calculations are then used to deconvolute the electronic and steric contributions to this flipping barrier. Finally, we couple the NMR and DFT studies with variable-temperature X-ray diffraction experiments to propose that both the ethylenic C═C bond twist and the torsion of the phenyl rings are important for quenching emission in TPE, but that the former may gate the latter. To conclude, we use these findings to propose a set of design criteria for the development of tunable turn-on porous sensors constructed from AIE-type molecules, particularly as applied to the design of new multifunctional MOFs. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
31. Human aldehyde dehydrogenase-catalyzed oxidation of ethylene glycol ether aldehydes
- Author
-
Gross, Aaron, Ong, Ta Ren, Grant, Rainer, Hoffmann, Todd, Gregory, Daniel D., and Sreerama, Lakshmaiah
- Subjects
- *
OXIDATION , *ETHYLENE glycol , *ALDEHYDES , *ETHERS , *ALDEHYDE dehydrogenase , *BIOTRANSFORMATION (Metabolism) , *TERATOGENESIS - Abstract
Abstract: Ethylene glycol ethers (EGEs) are primary alcohols commonly used as solvents in numerous household and industrial products. Exposure to EGEs has been correlated with delayed encephalopathy, metabolic acidosis, sub-fertility and spermatotoxicity in humans. In addition, they also cause teratogenesis, carcinogenesis, hemolysis, etc., in various animal models. Metabolism EGEs parallels ethanol metabolism, i.e., EGEs are first converted to 2-alkoxy acetaldehydes (EGE aldehydes) by alcohol dehydrogenases, and then to alkoxyacetic acids by aldehyde dehydrogenases (ALDHs). The acid metabolite of EGEs is considered responsible for toxicities associated with EGEs. The role of human ALDHs in EGE metabolism is not clear; accordingly, we have investigated the ability of five different human ALDHs (ALDH1A1, ALDH2, ALDH3A1, ALDH5A1 and ALDH9A1) to catalyze the oxidation of various EGE aldehydes. The EGE aldehydes used in this study were synthesized via Swern oxidation. All of the human ALDHs were purified from human cDNA clones over-expressing these enzymes in E. coli. The ALDHs tested, so far, differentially catalyze the oxidation of EGE aldehydes to their corresponding acids (K m values range from ∼10μM to ∼20.0mM). As judged by V max/K m ratios, short-chain alkyl-group containing EGE aldehydes are oxidized to their acids more efficiently by ALDH2, whereas aryl- and long-chain alkyl-group containing EGE aldehydes are oxidized to their acid more efficiently by ALDH3A1. Given the product of ALDH-catalyzed reaction is toxic, this process should be considered as a bio-activation (toxification) process. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
32. Protein–nucleotide contacts in motor proteins detected by DNP-enhanced solid-state NMR
- Author
-
Wiegand, Thomas, Liao, Wei-Chih, Ong, Ta-Chung, Däpp, Alexander, Cadalbert, Riccardo, Copéret, Christophe, Böckmann, Anja, and Meier, Beat H.
- Subjects
Protein–DNA ,Protein ,DNP ,DNA ,Solid-state NMR ,3. Good health ,Helicase - Abstract
Journal of Biomolecular NMR, 69 (3), ISSN:0925-2738, ISSN:1573-5001
33. Atomistic Description of Reaction Intermediates for Supported Metathesis Catalysts Enabled by DNP SENS
- Author
-
Ong, Ta-Chung, Liao, Wei-Chih, Mougel, Victor, Gajan, David, Lesage, Anne, Emsley, Lyndon, and Copéret, Christophe
- Subjects
3. Good health - Abstract
Angewandte Chemie. International Edition, 55 (15), ISSN:1433-7851, ISSN:1521-3773, ISSN:0570-0833
34. Resolving the Core and the Surface of CdSe Quantum Dots and Nanoplatelets Using Dynamic Nuclear Polarization Enhanced PASS–PIETA NMR Spectroscopy
- Author
-
Piveteau, Laura, Ong, Ta-Chung, Walder, Brennan J., Dirin, Dmitry N., Moscheni, Daniele, Schneider, Barbara, Bär, Janine, Protesescu, Loredana, Masciocchi, Norberto, Guagliardi, Antonietta, Emsley, Lyndon, Copéret, Christophe, and Kovalenko, Maksym V.
- Subjects
7. Clean energy - Abstract
Understanding the surface of semiconductor nanocrystals (NCs) prepared using colloidal methods is a long-standing goal of paramount importance for all their potential optoelectronic applications, which remains unsolved largely because of the lack of site-specific physical techniques. Here, we show that multidimensional 113Cd dynamic nuclear polarization (DNP) enhanced NMR spectroscopy allows the resolution of signals originating from different atomic and magnetic surroundings in the NC cores and at the surfaces. This enables the determination of the structural perfection, and differentiation between the surface and core atoms in all major forms of size- and shape-engineered CdSe NCs: irregularly faceted quantum dots (QDs) and atomically flat nanoplatelets, including both dominant polymorphs (zinc-blende and wurtzite) and their epitaxial nanoheterostructures (CdSe/CdS core/shell quantum dots and CdSe/CdS core/crown nanoplatelets), as well as magic-sized CdSe clusters. Assignments of the NMR signals to specific crystal facets of oleate-terminated ZB structured CdSe NCs are proposed. Significantly, we discover far greater atomistic complexity of the surface structure and the species distribution in wurtzite as compared to zinc-blende CdSe QDs, despite an apparently identical optical quality of both QD polymorphs., ACS Central Science, 4 (9), ISSN:2374-7951
35. Colloidal-ALD-Grown Core/Shell CdSe/CdS Nanoplatelets as Seen by DNP Enhanced PASS–PIETA NMR Spectroscopy
- Author
-
Piveteau, Laura, Dirin, Dmitry N., Gordon, Christopher, Walder, Brennan J., Ong, Ta-Chung, Emsley, Lyndon, Copéret, Christophe, and Kovalenko, Maksym V.
- Subjects
c-ALD ,dynamic nuclear polarization ,nanocrystals ,nanoplatelets ,solid-state NMR ,PASS−PIETA ,3. Good health - Abstract
Ligand exchange and CdS shell growth onto colloidal CdSe nanoplatelets (NPLs) using colloidal atomic layer deposition (c-ALD) were investigated by solid-state nuclear magnetic resonance (NMR) experiments, in particular, dynamic nuclear polarization (DNP) enhanced phase adjusted spinning sidebands–phase incremented echo-train acquisition (PASS–PIETA). The improved sensitivity and resolution of DNP enhanced PASS–PIETA permits the identification and study of the core, shell, and surface species of CdSe and CdSe/CdS core/shell NPLs heterostructures at all stages of c-ALD. The cadmium chemical shielding was found to be proportionally dependent on the number and nature of coordinating chalcogen-based ligands. DFT calculations permitted the separation of the the 111/113Cd chemical shielding into its different components, revealing that the varying strength of paramagnetic and spin–orbit shielding contributions are responsible for the chemical shielding trend of cadmium chalcogenides. Overall, this study points to the roughening and increased chemical disorder at the surface during the shell growth process, which is not readily captured by the conventional characterization tools such as electron microscopy., Nano Letters, 20 (5), ISSN:1530-6984, ISSN:1530-6992
36. Sensitivity-Enhanced NMR Reveals Alterations in Protein Structure by Cellular Milieus.
- Author
-
Frederick, Kendra K., Michaelis, Vladimir K., Corzilius, Björn, Ong, Ta-Chung, Jacavone, Angela C., Griffin, Robert G., and Lindquist, Susan
- Subjects
- *
PROTEIN structure , *DYNAMIC nuclear polarisation , *PRIONS , *RADIOLABELING , *NUCLEAR magnetic resonance spectroscopy , *BIOPHYSICS - Abstract
Summary Biological processes occur in complex environments containing a myriad of potential interactors. Unfortunately, limitations on the sensitivity of biophysical techniques normally restrict structural investigations to purified systems, at concentrations that are orders of magnitude above endogenous levels. Dynamic nuclear polarization (DNP) can dramatically enhance the sensitivity of nuclear magnetic resonance (NMR) spectroscopy and enable structural studies in biologically complex environments. Here, we applied DNP NMR to investigate the structure of a protein containing both an environmentally sensitive folding pathway and an intrinsically disordered region, the yeast prion protein Sup35. We added an exogenously prepared isotopically labeled protein to deuterated lysates, rendering the biological environment “invisible” and enabling highly efficient polarization transfer for DNP. In this environment, structural changes occurred in a region known to influence biological activity but intrinsically disordered in purified samples. Thus, DNP makes structural studies of proteins at endogenous levels in biological contexts possible, and such contexts can influence protein structure. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
37. Biomimetic Sniffing Improves the Detection Performance of a 3D Printed Nose of a Dog and a Commercial Trace Vapor Detector
- Author
-
Jessica L. Staymates, Ta-Hsuan Ong, Matthew E. Staymates, William A. MacCrehan, Thomas H.e. Mendum, Brent A. Craven, Geoffrey P. Geurtsen, Greg Gillen, Roderick R. Kunz, Lincoln Laboratory, Kunz, Roderick R, Mendum, Thomas H.e., Ong, Ta-Hsuan, and Geurtsen, Geoffrey P.
- Subjects
3d printed ,Multidisciplinary ,Electronic nose ,Acoustics ,010401 analytical chemistry ,Detector ,02 engineering and technology ,Nose ,021001 nanoscience & nanotechnology ,01 natural sciences ,Article ,0104 chemical sciences ,Smell ,Expired air ,Dogs ,Odor ,Sniffing ,Biomimetics ,Printing, Three-Dimensional ,Detection performance ,Environmental science ,Animals ,0210 nano-technology ,Electronic Nose - Abstract
Unlike current chemical trace detection technology, dogs actively sniff to acquire an odor sample. Flow visualization experiments with an anatomically-similar 3D printed dog’s nose revealed the external aerodynamics during canine sniffing, where ventral-laterally expired air jets entrain odorant-laden air toward the nose, thereby extending the “aerodynamic reach” for inspiration of otherwise inaccessible odors. Chemical sampling and detection experiments quantified two modes of operation with the artificial nose-active sniffing and continuous inspiration-and demonstrated an increase in odorant detection by a factor of up to 18 for active sniffing. A 16-fold improvement in detection was demonstrated with a commercially-available explosives detector by applying this bio-inspired design principle and making the device “sniff” like a dog. These lessons learned from the dog may benefit the next-generation of vapor samplers for explosives, narcotics, pathogens, or even cancer, and could inform future bio-inspired designs for optimized sampling of odor plumes., United States. Department of Homeland Security. Advanced Research Projects Agency (Interagency Agreement HSHQPM-13-X-00107), United States. Air Force (Contract FA8721-05-C-0002), United States. Air Force (Contract FA8702-15-D-0001)
- Published
- 2016
38. Formation of organic molecular nanocrystals under soft confinement
- Author
-
Robert G. Griffin, Allan S. Myerson, Xiaochuan Yang, Ta-Chung Ong, Scott N. Heng, Vladimir K. Michaelis, Novartis-MIT Center for Continuous Manufacturing, Massachusetts Institute of Technology. Department of Chemical Engineering, Massachusetts Institute of Technology. Department of Chemistry, Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology), Yang, Xiaochuan, Ong, Ta-Chung, Michaelis, Vladimir K., Heng, Scott N., Griffin, Robert Guy, and Myerson, Allan S.
- Subjects
chemistry.chemical_classification ,Nucleation ,Nanotechnology ,General Chemistry ,Polymer ,Condensed Matter Physics ,Microstructure ,Dosage form ,Article ,law.invention ,Crystal ,chemistry ,Nanocrystal ,law ,General Materials Science ,Thin film ,Crystallization - Abstract
Methods to produce nano-sized organic molecular crystals in thin films are of great interest in the pharmaceutical industry due to the potential benefit of increased solubility of poorly soluble drugs and the advantages of film-based dosage forms over traditional tablet/capsule-based dosage forms. One method to directly form organic nanocrystals is by crystallization in confined environments where the overall crystallization volume is constrained. We report the use of a novel solution impregnation method to form nanocrystals in polymer matrices with various microstructures in order to study the structure of the confined nanocrystals and the role of soft confinement and polymer chemistry on the nucleation process of nano-sized crystals. The particle diameter correlates with the microstructure of the polymer matrices and the nucleation kinetics. In addition, by carefully choosing the experimental conditions and the polymer matrix, polymorph control of nanocrystals can be achieved. Solid-state nuclear magnetic resonance (ssNMR) was used to examine the local structure of nanocrystals inside the polymer matrices and crystal polymer interactions. This method may serve as a novel formulation method to obtain nanocrystals of poorly soluble active pharmaceutical ingredients (APIs) for pharmaceutical industry., Novartis-MIT Center for Continuous Manufacturing, National Institutes of Health (U.S.) (grant no. EB-002026), Natural Sciences and Engineering Research Council of Canada, Government of Canada (Banting Postdoctoral Fellowship)
- Published
- 2016
39. Designed Single-Step Synthesis, Structure, and Derivative Textural Properties of Well-Ordered Layered Penta-Coordinate Silicon Alcoholate Complexes
- Author
-
Ta-Chung Ong, Evelyn N. Wang, Vladimir K. Michaelis, Xiansen Li, Stacey J. Smith, Robert G. Griffin, Massachusetts Institute of Technology. Department of Chemistry, Massachusetts Institute of Technology. Department of Mechanical Engineering, Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology), Li, Xiansen, Wang, Evelyn N., Michaelis, Vladimir K., Ong, Ta-Chung, Griffin, Robert Guy, and Smith, Stacey J.
- Subjects
Models, Molecular ,Solid-state chemistry ,Silicon ,Solvothermal synthesis ,Side reaction ,Ionic bonding ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,Article ,symbols.namesake ,chemistry.chemical_compound ,Organometallic Compounds ,Molecule ,Organic chemistry ,Group 2 organometallic chemistry ,Molecular Structure ,Organic Chemistry ,Oxides ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,3. Good health ,Crystallography ,chemistry ,symbols ,van der Waals force ,0210 nano-technology ,Derivative (chemistry) - Abstract
The controllable synthesis of well-ordered layered materials with specific nanoarchitecture poses a grand challenge in materials chemistry. Here the solvothermal synthesis of two structurally analogous 5-coordinate organosilicate complexes through a novel transesterification mechanism is reported. Since the polycrystalline nature of the intrinsic hypervalent Si complex thwarts the endeavor in determining its structure, a novel strategy concerning the elegant addition of a small fraction of B species as an effective crystal growth mediator and a sacrificial agent is proposed to directly prepare diffraction-quality single crystals without disrupting the intrinsic elemental type. In the determined crystal structure, two monomeric primary building units (PBUs) self-assemble into a dimeric asymmetric secondary BU via strong Na+[BOND]O2− ionic bonds. The designed one-pot synthesis is straightforward, robust, and efficient, leading to a well-ordered (10ī)-parallel layered Si complex with its principal interlayers intercalated with extensive van der Waals gaps in spite of the presence of substantial Na+ counter-ions as a result of unique atomic arrangement in its structure. However, upon fast pyrolysis, followed by acid leaching, both complexes are converted into two SiO2 composites bearing BET surface areas of 163.3 and 254.7 m2 g−1 for the pyrolyzed intrinsic and B-assisted Si complexes, respectively. The transesterification methodology merely involving alcoholysis but without any hydrolysis side reaction is designed to have generalized applicability for use in synthesizing new layered metal–organic compounds with tailored PBUs and corresponding metal oxide particles with hierarchical porosity., United States. Defense Advanced Research Projects Agency (control No. 0471-1627), National Institute for Biomedical Imaging and Bioengineering (U.S.) (award No. EB-001960), National Institutes of Health (U.S.) (NIBIB award No. EB-002026), National Science Foundation (U.S.) (Grant No. CHE-0946721)
- Published
- 2014
40. Management of advanced prostate cancer in the Asia-Pacific region: Summary of the Asia-Pacific Advanced Prostate Cancer Consensus Conference 2023.
- Author
-
Chiong E, Murphy DG, Buchan N, Chen K, Chen SS, Chua MLK, Hamid AR, Kanesvaran R, Khochikar M, Letran J, Lojanapiwat B, Mallik I, Ng CF, Ong TA, Poon DMC, Pu YS, Saad M, Schubach K, Takahara K, Tey J, Thang SP, Toh PC, Türkeri L, Vinh NT, Williams S, Ye D, and Davis ID
- Subjects
- Male, Humans, Asia epidemiology, Prostatic Neoplasms, Castration-Resistant therapy, Prostatic Neoplasms, Castration-Resistant pathology, Prostatic Neoplasms therapy, Prostatic Neoplasms pathology
- Abstract
Aim: The aim of the third Asia-Pacific Advanced Prostate Cancer Consensus Conference (APAC APCCC 2023) was to discuss the application in the Asia-Pacific (APAC) region of consensus statements from the 4th Advanced Prostate Cancer Consensus Conference (APCCC 2022)., Methods: The one-day meeting in July 2023 brought together 27 experts from 14 APAC countries. The meeting covered five topics: (1) Intermediate- and high-risk and locally advanced prostate cancer; (2) Management of newly diagnosed metastatic hormone-sensitive prostate cancer; (3) Management of non-metastatic castration-resistant prostate cancer; (4) Homologous recombination repair mutation testing; (5) Management of metastatic castration-resistant prostate cancer. Pre- and post-symposium polling gathered APAC-specific responses to APCCC consensus questions and insights on current practices and challenges in the APAC region., Results: APAC APCCC highlights APAC-specific considerations in an evolving landscape of diagnostic technologies and treatment innovations for advanced prostate cancer. While new technologies are available in the region, cost and reimbursement continue to influence practice significantly. Individual patient considerations, including the impact of chemophobia on Asian patients, also influence decision-making., Conclusion: The use of next-generation imaging, genetic testing, and new treatment combinations is increasing the complexity and duration of prostate cancer management. Familiarity with new diagnostic and treatment options is growing in the APAC region. Insights highlight the continued importance of a multidisciplinary approach that includes nuclear medicine, genetic counseling, and quality-of-life expertise. The APAC APCCC meeting provides an important opportunity to share practice and identify APAC-specific issues and considerations in areas of low evidence where clinical experience is growing., (© 2024 The Authors. Asia‐Pacific Journal of Clinical Oncology published by John Wiley & Sons Australia, Ltd.)
- Published
- 2024
- Full Text
- View/download PDF
41. Performance in the Fundamentals of Laparoscopic Surgery: Does it reflect global rating scales in the Objective Structured Assessment of Technical Skills in porcine laparoscopic surgery?
- Author
-
Tiong HY, So WZ, Yuen-Chun Teoh J, Isotani S, Zhu G, Ong TA, Shu-Yin Chan E, Sau-Kwan Chu P, Kijvikai K, Liu M, Lojanapiwat B, Wong M, and Chi-Fai Ng A
- Abstract
Objective: To correlate the utility of the Fundamentals of Laparoscopic Surgery (FLS) manual skills program with the Objective Structured Assessment of Technical Skills (OSATS) global rating scale in evaluating operative performance., Methods: The Asian Urological Surgery Training and Educational Group (AUSTEG) Laparoscopic Upper Tract Surgery Course implemented and validated the FLS program for its usage in laparoscopic surgical training. Delegates' basic laparoscopic skills were assessed using three different training models (peg transfer, precision cutting, and intra-corporeal suturing). They also performed live porcine laparoscopic surgery at the same workshop. Live surgery skills were assessed by blinded faculty using the OSATS rating scale., Results: From March 2016 to March 2019, a total of 81 certified urologists participated in the course, with a median of 5 years of post-residency experience. Although differences in task time did not reach statistical significance, those with more surgical experience were visibly faster at completing the peg transfer and intra-corporeal suturing FLS tasks. However, they took longer to complete the precision cutting task than participants with less experience. Overall OSATS scores correlated weakly with all three FLS tasks (peg transfer time: r =-0.331, r
2 =0.110; precision cutting time: r =-0.240, r2 =0.058; suturing with intra-corporeal knot time: r =-0.451, r2 =0.203)., Conclusion: FLS task parameters did not correlate strongly with OSATS globing rating scale performance. Although FLS task models demonstrated strong validity, it is important to assimilate the inconsistencies when benchmarking technical proficiency against real-life operative competence, as evaluated by FLS and OSATS, respectively., Competing Interests: The authors declare no conflict of interest., (© 2024 Editorial Office of Asian Journal of Urology. Production and hosting by Elsevier B.V.)- Published
- 2024
- Full Text
- View/download PDF
42. Health-Related Quality of Life Assessment in Prostate Cancer Patient Undergoing Androgen Deprivation Therapy: Real-World Experience in the READT Study.
- Author
-
Lim J, Ng CF, Wei Y, Ong TA, Chu PS, Chan WKW, Huang CY, Feng KK, Teoh JY, Xu N, Low JW, Yeoh WS, Chiu PK, Yee CH, and Leung SCH
- Abstract
Purpose: To investigate the effect of androgen deprivation therapy (ADT) on health-related quality of life (HRQOL) in Asian men with all stages of prostate cancer., Materials and Methods: READT (real-life evaluation of the effect of ADT in prostate cancer patients in Asia) was a multi-center, prospective observational study involving six sites across four Asian populations. We enrolled eligible prostate cancer patients, who opted for ADT alone or in combination without prior neoadjuvant or adjuvant ADT within 12 months. The EuroQoL-5 dimensions, 5 level scale (EQ-5D-5L) utility index scores and visual analog scale (VAS) were evaluated at baseline, month 6 and month 12., Results: A total of 504 patients were recruited into READT between September 2016 and May 2020 with 52.9% diagnosed with metastatic prostate cancer. The EQ-5D-5L was evaluable in 442/504 (87.7%) of patients. Overall baseline EQ-5D-5L utility index score was 0.924 (interquartile range [IQR] 0.876-1.000). We observed a statistically significant difference in baseline EQ-5D-5L utility index score among different populations with a median EQ-5D-5L utility index score of 1 for Taiwan & Hong Kong, 0.897 for China and 0.838 for Malaysia. Similar trend was observed throughout multiple treatment time-points. Stage IV prostate cancer were significantly associated with a lower baseline EQ-5D-5L utility index score compared to stage I-III prostate cancer, producing a median disutility value of -0.080. Participants had a high median VAS (80, IQR 70-90), indicating good overall health on average during ADT initiation., Conclusions: The study highlights the differences in health state utility index scores among various Asian prostate cancer patients receiving ADT at real-world setting. Our findings will be informative and useful in cost-effectiveness evaluation and policy decision making., Competing Interests: The authors have nothing to disclose., (Copyright © 2024 Korean Society for Sexual Medicine and Andrology.)
- Published
- 2024
- Full Text
- View/download PDF
43. Cardiovascular disease risk assessment and multidisciplinary care in prostate cancer treatment with ADT: recommendations from the APMA PCCV expert network.
- Author
-
Merseburger AS, Bakshi G, Chen DY, Chiong E, Jabbour M, Joung JY, Lai AY, Lawrentschuk N, Le TA, Ng CF, Ng CT, Ong TA, Pang JS, Rabah DM, Ragavan N, Sase K, Suzuki H, Teo MMH, Uemura H, and Woo HH
- Subjects
- Male, Humans, Androgen Antagonists adverse effects, Risk Assessment, Gonadotropin-Releasing Hormone, Prostatic Neoplasms drug therapy, Prostatic Neoplasms chemically induced, Cardiovascular Diseases chemically induced, Cardiovascular Diseases epidemiology
- Abstract
Purpose: Androgen deprivation therapy (ADT) is the mainstay approach for prostate cancer (PCa) management. However, the most commonly used ADT modality, gonadotropin-releasing hormone (GnRH) agonists, has been associated with an increased risk of cardiovascular disease (CVD)., Methods: The PCa Cardiovascular (PCCV) Expert Network, consisting of multinational urologists, cardiologists and oncologists with expertise in managing PCa, convened to discuss challenges to routine cardiovascular risk assessment in PCa management, as well as how to mitigate such risks in the current treatment landscape., Results: The experts identified several barriers, including lack of awareness, time constraints, challenges in implementing risk assessment tools and difficulties in establishing multidisciplinary teams that include cardiologists. The experts subsequently provided practical recommendations to improve cardio-oncology care for patients with PCa receiving ADT, such as simplifying cardiovascular risk assessment, individualising treatment based on CVD risk categories, establishing multidisciplinary teams and referral networks and fostering active patient engagement. A streamlined cardiovascular risk-stratification tool and a referral/management guide were developed for seamless integration into urologists' practices and presented herein. The PCCV Expert Network agreed that currently available evidence indicates that GnRH antagonists are associated with a lower risk of CVD than that of GnRH agonists and that GnRH antagonists are preferred for patients with PCa and a high CVD risk., Conclusion: In summary, this article provides insights and guidance to improve management for patients with PCa undergoing ADT., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
44. Dielectric properties of urine in relation to bladder cancer.
- Author
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Zhu CZ, Ting HN, Ng KH, Mun KS, and Ong TA
- Subjects
- Humans, ROC Curve, Urinalysis, Epithelial Cells pathology, Cytodiagnosis, Urinary Bladder Neoplasms diagnosis, Urinary Bladder Neoplasms pathology, Urinary Bladder Neoplasms urine
- Abstract
Many studies have investigated the dielectric properties of human and animal tissues, particularly to differentiate between normal cells and tumors. However, these studies are invasive as tissue samples have to be excised to measure the properties. This study aims to investigate the dielectric properties of urine in relation to bladder cancer, which is safe and non-invasive to patients. 30 healthy subjects and 30 bladder cancer patients were recruited. Their urine samples were subjected to urinalysis and cytology assessment. A vector network analyzer was used to measure the dielectric constant (Ɛ') and loss factor (Ɛ″) at microwave frequencies of between 0.2 and 50 GHz at 25 °C, 30 °C and 37 °C. Significant differences in Ɛ' and Ɛ″ were observed between healthy subjects and patients, especially at frequencies of between 25 and 40 GHz at 25 °C. Bladder cancer patients had significant lower Ɛ' and higher Ɛ″ compared with healthy subjects. The Ɛ' was negatively correlated with urinary exfoliated urothelial cell number, and Ɛ″ was positively correlated. The study achieved a receiver operating characteristic area under curve (ROC-AUC) score of 0.69099 and an optimum accuracy of 75% with a sensitivity of 80% and a specificity of 70%. The number of exfoliated urothelial cell had significant effect on the dielectric properties, especially in bladder cancer patients. Urinary dielectric properties could potentially be used as a tool to detect bladder cancer., (© 2023. Australasian College of Physical Scientists and Engineers in Medicine.)
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- 2024
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45. Artificial intelligence-aided detection for prostate cancer with multimodal routine health check-up data: an Asian multi-center study.
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Song Z, Zhang W, Jiang Q, Deng L, Du L, Mou W, Lai Y, Zhang W, Yang Y, Lim J, Liu K, Park JY, Ng CF, Ong TA, Wei Q, Li L, Wei X, Chen M, Cao Z, Wang F, and Chen R
- Subjects
- Male, Humans, Artificial Intelligence, Neoplasm Grading, Risk Assessment methods, Biopsy, ROC Curve, Prostate-Specific Antigen, Prostatic Neoplasms diagnosis
- Abstract
Background: The early detection of high-grade prostate cancer (HGPCa) is of great importance. However, the current detection strategies result in a high rate of negative biopsies and high medical costs. In this study, the authors aimed to establish an Asian Prostate Cancer Artificial intelligence (APCA) score with no extra cost other than routine health check-ups to predict the risk of HGPCa., Patients and Methods: A total of 7476 patients with routine health check-up data who underwent prostate biopsies from January 2008 to December 2021 in eight referral centres in Asia were screened. After data pre-processing and cleaning, 5037 patients and 117 features were analyzed. Seven AI-based algorithms were tested for feature selection and seven AI-based algorithms were tested for classification, with the best combination applied for model construction. The APAC score was established in the CH cohort and validated in a multi-centre cohort and in each validation cohort to evaluate its generalizability in different Asian regions. The performance of the models was evaluated using area under the receiver operating characteristic curve (ROC), calibration plot, and decision curve analyses., Results: Eighteen features were involved in the APCA score predicting HGPCa, with some of these markers not previously used in prostate cancer diagnosis. The area under the curve (AUC) was 0.76 (95% CI:0.74-0.78) in the multi-centre validation cohort and the increment of AUC (APCA vs. PSA) was 0.16 (95% CI:0.13-0.20). The calibration plots yielded a high degree of coherence and the decision curve analysis yielded a higher net clinical benefit. Applying the APCA score could reduce unnecessary biopsies by 20.2% and 38.4%, at the risk of missing 5.0% and 10.0% of HGPCa cases in the multi-centre validation cohort, respectively., Conclusions: The APCA score based on routine health check-ups could reduce unnecessary prostate biopsies without additional examinations in Asian populations. Further prospective population-based studies are warranted to confirm these results., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)
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- 2023
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46. Controversy and Consensus on the Management of Elevated Sperm DNA Fragmentation in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations.
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Farkouh A, Agarwal A, Hamoda TAA, Kavoussi P, Saleh R, Zini A, Arafa M, Harraz AM, Gul M, Karthikeyan VS, Durairajanayagam D, Rambhatla A, Boitrelle F, Chung E, Birowo P, Toprak T, Ghayda RA, Cannarella R, Phuoc NHV, Dimitriadis F, Russo GI, Sokolakis I, Mostafa T, Makarounis K, Ziouziou I, Kuroda S, Bendayan M, Kaiyal RS, Japari A, Simopoulou M, Rocco L, Garrido N, Gherabi N, Bocu K, Kahraman O, Le TV, Wyns C, Tremellen K, Sarikaya S, Lewis S, Evenson DP, Ko E, Calogero AE, Bahar F, Martinez M, Crafa A, Nguyen Q, Ambar RF, Colpi G, Bakircioglu ME, Henkel R, Kandil H, Serefoglu EC, Alarbid A, Tsujimura A, Kheradmand A, Anagnostopoulou C, Marino A, Adamyan A, Zilaitiene B, Ozer C, Pescatori E, Vogiatzi P, Busetto GM, Balercia G, Elbardisi H, Akhavizadegan H, Sajadi H, Taniguchi H, Park HJ, Maldonado Rosas I, Al-Marhoon M, Sadighi Gilani MA, Alhathal N, Pinggera GM, Kothari P, Mogharabian N, Micic S, Homa S, Darbandi S, Long TQT, Zohdy W, Atmoko W, Sabbaghian M, Ibrahim W, Smith RP, Ho CCK, de la Rosette J, El-Sakka AI, Preto M, Zenoaga-Barbăroșie C, Abumelha SM, Baser A, Aydos K, Ramirez-Dominguez L, Kumar V, Ong TA, Mierzwa TC, Adriansjah R, Banihani SA, Bowa K, Fukuhara S, Rodriguez Peña M, Moussa M, Ari UÇ, Cho CL, Tadros NN, Ugur MR, Amar E, Falcone M, Santer FR, Kalkanli A, Karna KK, Khalafalla K, Vishwakarma RB, Finocchi F, Giulioni C, Ceyhan E, Çeker G, Yazbeck C, Rajmil O, Yilmaz M, Altay B, Barrett TL, Ngoo KS, Roychoudhury S, Salvio G, Lin H, Kadioglu A, Timpano M, Avidor-Reiss T, Hakim L, Sindhwani P, Franco G, Singh R, Giacone F, Ruzaev M, Kosgi R, Sofikitis N, Palani A, Calik G, Kulaksız D, Jezek D, Al Hashmi M, Drakopoulos P, Omran H, Leonardi S, Celik-Ozenci C, Güngör ND, Ramsay J, Amano T, Sogutdelen E, Duarsa GWK, Chiba K, Jindal S, Savira M, Boeri L, Borges E, Gupte D, Gokalp F, Hebrard GH, Minhas S, and Shah R
- Abstract
Purpose: Sperm DNA fragmentation (SDF) has been associated with male infertility and poor outcomes of assisted reproductive technology (ART). The purpose of this study was to investigate global practices related to the management of elevated SDF in infertile men, summarize the relevant professional society recommendations, and provide expert recommendations for managing this condition., Materials and Methods: An online global survey on clinical practices related to SDF was disseminated to reproductive clinicians, according to the CHERRIES checklist criteria. Management protocols for various conditions associated with SDF were captured and compared to the relevant recommendations in professional society guidelines and the appropriate available evidence. Expert recommendations and consensus on the management of infertile men with elevated SDF were then formulated and adapted using the Delphi method., Results: A total of 436 experts from 55 different countries submitted responses. As an initial approach, 79.1% of reproductive experts recommend lifestyle modifications for infertile men with elevated SDF, and 76.9% prescribe empiric antioxidants. Regarding antioxidant duration, 39.3% recommend 4-6 months and 38.1% recommend 3 months. For men with unexplained or idiopathic infertility, and couples experiencing recurrent miscarriages associated with elevated SDF, most respondents refer to ART 6 months after failure of conservative and empiric medical management. Infertile men with clinical varicocele, normal conventional semen parameters, and elevated SDF are offered varicocele repair immediately after diagnosis by 31.4%, and after failure of antioxidants and conservative measures by 40.9%. Sperm selection techniques and testicular sperm extraction are also management options for couples undergoing ART. For most questions, heterogenous practices were demonstrated., Conclusions: This paper presents the results of a large global survey on the management of infertile men with elevated SDF and reveals a lack of consensus among clinicians. Furthermore, it demonstrates the scarcity of professional society guidelines in this regard and attempts to highlight the relevant evidence. Expert recommendations are proposed to help guide clinicians., Competing Interests: The authors have nothing to disclose., (Copyright © 2023 Korean Society for Sexual Medicine and Andrology.)
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- 2023
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47. Differential Protein Expression Patterns of HOXA13 and HOXB13 Are Associated with Bladder Cancer Progression.
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Chin FW, Hussin H, Chau DM, Ong TA, Yunus R, Abdul Razack AH, Yusoff K, Chan SC, and Veerakumarasivam A
- Abstract
Bladder cancer is a common urological cancer and has the highest recurrence rate of any cancer. The aim of our study was to profile and characterize the protein expression of homeobox A13 ( HOXA13 ) and homeobox B13 ( HOXB13 ) genes in Malaysian bladder cancer patients. The protein expression of HOXA13 and HOXB13 in formalin-fixed paraffin-embedded (FFPE) bladder cancer tissues was determined by immunohistochemistry (IHC) analysis. The association between HOXA13/HOXB13 protein expression and demographic/clinicopathological characteristics of the bladder cancer patients was determined by chi-square analysis. Approximately 63.6% of the bladder cancer tissues harbored high HOXA13 expression. High HOXA13 expression was significantly associated with non-muscle invasive bladder cancer, lower tumor grade, higher number of lymph node metastases, and recurrence risk. In contrast, low HOXB13 expression (including those with negative expression) was observed in 71.6% of the bladder cancer tissues analyzed. Low HOXB13 expression was significantly associated with muscle-invasive bladder cancer, higher tumor stage, tumor grade, and metastatic risk. Both HOXA13 and HOXB13 protein expression were found to be associated with bladder tumorigenesis. The putative oncogenic and tumor suppressive roles of HOXA13 and HOXB13 , respectively, suggest their potential utility as biomarkers in bladder cancer.
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- 2023
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48. Classification and assessment techniques of breast ptosis: A systematic review.
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See MH, Yip KC, Teh MS, Teoh LY, Lai LL, Wong LK, Hisham Shunmugam R, Ong TA, and Ng KH
- Subjects
- Female, Humans, Nipples, Breast pathology
- Abstract
Background: Breast ptosis is characterized by the inferolateral descent of the glandular area and nipple-areola complex. A high degree of ptosis may negatively impact a woman's attractiveness and self-confidence. There are various classifications and measurement techniques for breast ptosis used as references in the medical and garment industry. A practical and comprehensive classification will provide accurate standardized definitions of the degrees of ptosis to facilitate the development of corrective surgeries and well-fitting undergarments for women in need., Methods: A systematic review on the classification and assessment techniques to measure breast ptosis was carried out based on the Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias was assessed using the modified Newcastle-Ottawa scale for observational studies, whereas the Revised Cochrane risk-of-bias tool for randomized trials (RoB2) was used to evaluate randomized studies., Results: Of 2550 articles identified in the literature search, 16 observational and 2 randomized studies describing the classification and assessment techniques of breast ptosis were included in the review. A total of 2033 subjects were involved. Half of the total observational studies had a Newcastle-Ottawa scale score of 5 and above. In addition, all randomized trials recorded a low overall bias., Conclusion: A total of 7 classifications and 4 measurement techniques for breast ptosis were identified. However, most studies did not demonstrate a clear derivation of sample size beside lacking robust statistical analysis. Hence, further studies that apply the latest technology to combine the strength of previous assessment techniques are needed to develop better classification system that is applicable to all affected women., Competing Interests: Declaration of Competing Interest None declared., (Copyright © 2023 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2023
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49. Controversy and Consensus on Indications for Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations.
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Agarwal A, Farkouh A, Saleh R, Abdel-Meguid Hamoda TA, Harraz AM, Kavoussi P, Arafa M, Salvio G, Rambhatla A, Toprak T, Gül M, Phuoc NHV, Boitrelle F, Birowo P, Ghayda RA, Cannarella R, Kuroda S, Durairajanayagam D, Zini A, Wyns C, Sarikaya S, Tremellen K, Mostafa T, Sokolakis I, Evenson DP, Henkel R, Zohdy W, Chung E, Ziouziou I, Falcone M, Russo GI, Al-Hashimi M, Calogero AE, Ko E, Colpi G, Lewis S, Serefoglu EC, Bahar F, Martinez M, Nguyen Q, Ambar RF, Bakircioglu ME, Kandil H, Mogharabian N, Sabbaghian M, Taniguchi H, Tsujimura A, Sajadi H, Ibrahim W, Atmoko W, Vogiatzi P, Gunes S, Sadighi Gilani MA, Roychoudhury S, Güngör ND, Hakim L, Adriansjah R, Kothari P, Jindal S, Amar E, Park HJ, Long TQT, Homa S, Karthikeyan VS, Zilaitiene B, Maldonado Rosas I, Marino A, Pescatori E, Ozer C, Akhavizadegan H, Garrido N, Busetto GM, Adamyan A, Al-Marhoon M, Elbardisi H, Dolati P, Darbandi M, Darbandi S, Balercia G, Pinggera GM, Micic S, Ho CCK, Moussa M, Preto M, Zenoaga-Barbăroșie C, Smith RP, Kosgi R, de la Rosette J, El-Sakka AI, Abumelha SM, Mierzwa TC, Ong TA, Banihani SA, Bowa K, Fukuhara S, Boeri L, Danacıoğlu YO, Gokalp F, Selim OM, Cho CL, Tadros NN, Ugur MR, Ozkent MS, Chiu P, Kalkanli A, Khalafalla K, Vishwakarma RB, Finocchi F, Andreadakis S, Giulioni C, Çeker G, Ceyhan E, Malhotra V, Yilmaz M, Timpano M, Barrett TL, Kim SHK, Ahn ST, Giacone F, Palani A, Duarsa GWK, Kadioglu A, Gadda F, Zylbersztejn DS, Aydos K, Kulaksız D, Gupte D, Calik G, Karna KK, Drakopoulos P, Baser A, Kumar V, Molina JMC, Rajmil O, Ferreira RH, Leonardi S, Avoyan A, Sogutdelen E, Franco G, Ramsay J, Ramirez L, and Shah R
- Abstract
Purpose: Sperm DNA fragmentation (SDF) testing was recently added to the sixth edition of the World Health Organization laboratory manual for the examination and processing of human semen. Many conditions and risk factors have been associated with elevated SDF; therefore, it is important to identify the population of infertile men who might benefit from this test. The purpose of this study was to investigate global practices related to indications for SDF testing, compare the relevant professional society guideline recommendations, and provide expert recommendations., Materials and Methods: Clinicians managing male infertility were invited to take part in a global online survey on SDF clinical practices. This was conducted following the CHERRIES checklist criteria. The responses were compared to professional society guideline recommendations related to SDF and the appropriate available evidence. Expert recommendations on indications for SDF testing were then formulated, and the Delphi method was used to reach consensus., Results: The survey was completed by 436 experts from 55 countries. Almost 75% of respondents test for SDF in all or some men with unexplained or idiopathic infertility, 39% order it routinely in the work-up of recurrent pregnancy loss (RPL), and 62.2% investigate SDF in smokers. While 47% of reproductive urologists test SDF to support the decision for varicocele repair surgery when conventional semen parameters are normal, significantly fewer general urologists (23%; p=0.008) do the same. Nearly 70% would assess SDF before assisted reproductive technologies (ART), either always or for certain conditions. Recurrent ART failure is a common indication for SDF testing. Very few society recommendations were found regarding SDF testing., Conclusions: This article presents the largest global survey on the indications for SDF testing in infertile men, and demonstrates diverse practices. Furthermore, it highlights the paucity of professional society guideline recommendations. Expert recommendations are proposed to help guide clinicians., Competing Interests: The authors have nothing to disclose., (Copyright © 2023 Korean Society for Sexual Medicine and Andrology.)
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- 2023
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50. Genotypic characteristics of Uropathogenic Escherichia coli isolated from complicated urinary tract infection (cUTI) and asymptomatic bacteriuria-a relational analysis.
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Maniam L, Vellasamy KM, Ong TA, Teh CSJ, Jabar KA, Mariappan V, Narayanan V, Vadivelu J, and Pallath V
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- Humans, Virulence Factors genetics, Anti-Bacterial Agents pharmacology, Bacteriuria drug therapy, Uropathogenic Escherichia coli genetics, Urinary Tract Infections drug therapy
- Abstract
Background: Uropathogenic Escherichia coli (UPEC) is the predominant agent causing various categories of complicated urinary tract infections (cUTI). Although existing data reveals that UPEC harboured numerous virulence determinants to aid its survival in the urinary tract, the reason behind the occurrence of differences in the clinical severity of uninary tract infections (UTI) demonstrated by the UPEC infection is poorly understood. Therefore, the present study aims to determine the distribution of virulence determinants and antimicrobial resistance among different phylogroups of UPEC isolated from various clinical categories of cUTI and asymptomatic bacteriuria (ASB) E. coli isolates. The study will also attempt a relational analysis of the genotypic characteristics of cUTI UPEC and ASB E. coli isolates., Methods: A total of 141 UPEC isolates from cUTI and 160 ASB E. coli isolates were obtained from Universiti Malaya Medical Centre (UMMC). Phylogrouping and the occurrence of virulence genes were investigated using polymerase chain reaction (PCR). Antimicrobial susceptibility of the isolates to different classes of antibiotics was determined using the Kirby Bauer Disc Diffusion method., Results: The cUTI isolates were distributed differentially among both Extraintestinal Pathogenic E. coli (ExPEC) and non-ExPEC phylogroups. Phylogroup B2 isolates were observed to possess the highest average aggregative virulence score (7.17), a probable representation of the capability to cause severe disease. Approximately 50% of the cUTI isolates tested in this study were multidrug resistant against common antibiotics used to treat UTI. Analysis of the occurrence of virulence genes among different cUTI categories demonstrated that UPEC isolates of pyelonephritis and urosepsis were highly virulent and had the highest average aggregative virulence scores of 7.80 and 6.89 respectively, compared to other clinical categories. Relational analysis of the occurrence of phylogroups and virulence determinants of UPEC and ASB E. coli isolates showed that 46.1% of UPEC and 34.3% of ASB E. coli from both categories were distributed in phylogroup B2 and had the highest average aggregative virulence score of 7.17 and 5.37, respectively. The data suggest that UPEC isolates which carry virulence genes from all four virulence genes groups studied (adhesions, iron uptake systems, toxins and capsule synthesis) and isolates from phylogroup B2 specifically could predispose to severe UTI involving the upper urinary tract. Therefore, specific analysis of the genotypic characteristics of UPEC could be further explored by incorporating the combination of virulence genes as a prognostic marker for predicting disease severity, in an attempt to propose a more evidence driven treatment decision-making for all UTI patients. This will go a long way in enhancing favourable therapeutic outcomes and reducing the antimicrobial resistance burden among UTI patients., Competing Interests: Cindy Shuan Ju Teh is an Academic Editor for PeerJ., (©2023 Maniam et al.)
- Published
- 2023
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