40 results on '"Halder, S"'
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2. Cesium ion-guided detection of trichloroethylene in air.
- Author
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Adhihetty PK, Halder S, Abu UO, Fu XA, and Nantz MH
- Abstract
Whereas the close associations of cesium ion with organochlorine compounds have been previously documented, the present report is the first attempt to exploit these interactions to create a trichloroethylene (TCE)-selective sensor. Gold monolayer-protected clusters peripherally functionalized with Cs
+ ions were used to prepare a chemiresistance film on MEMS-fabricated interdigitated electrodes. Vapor sensing properties of the cesium-rich chemiresistor were determined using a panel of chlorinated hydrocarbons including TCE as well as polar and non-polar VOCs for comparison. The sensor was selective and highly sensitive toward VOCs containing a 1,2-dichloro group at concentrations as low as 0.1 ppm. The results suggest the key interaction contributing to sensor response is a bidentate, metallocycle-like coordination of the 1,2-dichloro group to the cesium cations at the sensor surface., Competing Interests: Declaration of competing interest The authors report no declarations of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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3. Long non-coding intergenic RNA, LINC00273 induces cancer metastasis and stemness via miRNA sponging in triple negative breast cancer.
- Author
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Sengupta P, Roy A, Roy L, Bose D, Halder S, Jana K, Mukherjee G, and Chatterjee S
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- Animals, Female, Humans, Mice, Cell Line, Tumor, Neoplastic Stem Cells metabolism, Neoplastic Stem Cells pathology, Gene Expression Regulation, Neoplastic, MicroRNAs genetics, Neoplasm Metastasis, RNA, Long Noncoding genetics, Triple Negative Breast Neoplasms genetics, Triple Negative Breast Neoplasms pathology
- Abstract
LncRNAs and miRNAs, being the master regulators of gene expression, are crucial functional mediators in cancer. Our study unveils the critical regulatory role of the metastatic long non-coding RNA LINC00273 as the master regulator of oncogenes involved in cancer metastasis, stemness, and chemoresistance via its miRNA sponging mechanism. M2 (a salt of bis-Schiff base) mediated G quadruplex (G4) stabilization at the LINC00273 gene promoter remarkably inhibits LINC00273 transcription. Therefore, low-level LINC00273 transcripts are unable to efficiently sponge the miRNAs, which subsequently become available to bind and downregulate their target oncogenes. We have observed significantly different global transcriptomic scenarios in LINC00273 upregulated and downregulated circumstances in MDA-MB-231 triple-negative breast cancer model. Additionally, we have found the G4 sequence in the LINC00273 RNA to play a critical role in miRNA sequestration. miRNAs (miR-6789-5p, miR200b, miR-125b-5p, miR-4268, miR3978) have base pairing complementarity within the G4 region of LINC00273 RNA and the 3'-UTR (untranslated region) of MAPK12, TGF-β1, and SIX-1 transcripts. We have reported TGF-β1, SIX-1, and MAPK12 to be the direct downstream targets of LINC00273. The correlation between abnormal expression of lncRNA LINC00273 and TNBC aggressiveness strongly evidenced in our study shall accelerate the development of lncRNA-based anti-metastatic therapeutics., Competing Interests: Declaration of competing interest The authors declared no sign of conflict., (Copyright © 2024. Published by Elsevier B.V.)
- Published
- 2024
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4. Disposable graphene-oxide screen-printed electrode integrated with portable device for detection of SARS-CoV-2 in clinical samples.
- Author
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Ramya PR, Halder S, Nagamani K, Singh Chouhan R, and Gandhi S
- Subjects
- Humans, Immunoassay methods, Immunoassay instrumentation, Electrochemical Techniques methods, Electrochemical Techniques instrumentation, Spike Glycoprotein, Coronavirus immunology, Spike Glycoprotein, Coronavirus analysis, Limit of Detection, Graphite chemistry, SARS-CoV-2 immunology, SARS-CoV-2 isolation & purification, SARS-CoV-2 genetics, COVID-19 diagnosis, COVID-19 virology, Electrodes, Biosensing Techniques instrumentation, Biosensing Techniques methods
- Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis is the need of the hour, as cases are persistently increasing, and new variants are constantly emerging. The ever-changing nature of the virus leading to multiple variants, has brought an imminent need for early, accurate and rapid detection methods. Herein, we have reported the design and fabrication of Screen-Printed Electrodes (SPEs) with graphene oxide (GO) as working electrode and modified with specific antibodies for SARS-CoV-2 Receptor Binding Domain (RBD). Flexibility of design, and portable nature has made SPEs the superior choice for electrochemical analysis. The developed immunosensor can detect RBD as low as 0.83 fM with long-term storage capacity. The fabricated SPEs immunosensor was tested using a miniaturized portable device and potentiostat on 100 patient nasopharyngeal samples and corroborated with RT-PCR data, displayed 94 % sensitivity. Additionally, the in-house developed polyclonal antibodies detected RBD antigen of the mutated Omicron variant of SARS-CoV-2 successfully. We have not observed any cross-reactivity/binding of the fabricated immunosensor with MERS (cross-reactive antigen) and Influenza A H1N1 (antigen sharing common symptoms). Hence, the developed SPEs sensor may be applied for bedside point-of-care diagnosis of SARS-CoV-2 using miniaturized portable device, in clinical samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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5. Synthesis of chiral functional polyhydroxylated arenes via Mukaiyama aldol reaction from Perlin aldehydes.
- Author
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Halder S, Moktan S, Sreeram V, and Kancharla PK
- Subjects
- Molecular Structure, Stereoisomerism, Ethyl Ethers, Aldehydes, Ethers
- Abstract
Functionalized aryl polyhydroxylated compounds could be of great synthetic value for natural product synthesis. However, the synthesis of such compounds usually requires multi-step synthesis or the usage of sensitive reagents. We present here a practically simple route for the synthesis of such functionalized arylpolyols from glycal derived α,β-unsaturated 2,3-dideoxy aldehyde as well as α,β-saturated 2,3-dideoxy aldehyde (Perlin aldehydes) via Mukaiyama cross aldol condensation in the presence of silyl enol ether and TiCl
4. It was observed that the nature of the electronic substitution of the silyl enol ether does not play any role in the yield of the desired products. Further functionalization of the products has also been shown., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)- Published
- 2024
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6. Harnessing the cation-π interactions of metalated gold monolayer-protected clusters to detect aromatic volatile organic compounds.
- Author
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Adhihetty PK, Halder S, Jasinski JB, Fu XA, and Nantz MH
- Subjects
- Cations, Gold, Volatile Organic Compounds
- Abstract
The strong, non-covalent interactions between π-systems and cations have been the focus of numerous studies on biomolecule structure and catalysis. These interactions, however, have yet to be explored as a sensing mechanism for detecting trace levels of volatile organic compounds (VOCs). In this article, we provide evidence that cation-π interactions can be used to elicit sensitive and selective chemiresistor responses to aromatic VOCs. The chemiresistors are fitted with carboxylate-linked alkali metals bound to the surface of gold monolayer-protected clusters formulated on microfabricated interdigitated electrodes. Sensor responses to aromatic and non-aromatic VOCs are consistent with a model for cation-π interactions arising from association of electron-rich aromatic π-systems to metal ions with the relative strength of attraction following the order K
+ > Na+ > Li+ . The results point toward cation-π interactions as a promising research avenue to explore for developing aromatic VOC-selective sensors., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Michael H. Nantz and Xiao-An Fu reports financial support was provided by National Institutes of Health., (Copyright © 2022 Elsevier B.V. All rights reserved.)- Published
- 2023
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7. Understanding noise in cell signalling in the prospect of drug-targets.
- Author
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Halder S, Ghosh S, Chattopadhyay J, and Chatterjee S
- Subjects
- Humans, Models, Theoretical, Signal Transduction, Neoplasms
- Abstract
The introduction of noise to signals can alter central regulatory switches of cellular processes leading to diseases. Noise is inherently present in the cellular signalling system and plays a decisive role in the input-output (I/O) relation. The current study aims to understand the noise tolerance of motif structures in the cell signalling processes. The vulnerability of a node to noise could be a significant factor in causing signalling error and need to be controlled. We developed stochastic differential equation (SDE) based mathematical models for different network motifs with two nodes and studied the association between motif structure and signal-noise relation. A two-dimensional parameter space analysis on motif sensitivity with noise and input signal variation was performed to classify and rank the motifs. Identifying sensitive motifs and their high druggability infers their significance in screening potential drug-target candidates. Finally, we proposed a theoretical framework to identify nodes from a network as potential drug targets. We applied this mathematical formalism to three cancer networks to identify drug-targets and validated them with existing databases., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
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8. The Pleiotropic role, functions and targeted therapies of LIF/LIFR axis in cancer: Old spectacles with new insights.
- Author
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Halder S, Parte S, Kshirsagar P, Muniyan S, Nair HB, Batra SK, and Seshacharyulu P
- Subjects
- Humans, Interleukin-6 metabolism, Leukemia Inhibitory Factor genetics, Leukemia Inhibitory Factor Receptor alpha Subunit genetics, Neoplasms drug therapy, Neoplasms genetics, Phosphatidylinositol 3-Kinases
- Abstract
The dysregulation of leukemia inhibitory factor (LIF) and its cognate receptor (LIFR) has been associated with multiple cancer initiation, progression, and metastasis. LIF plays a significant tumor-promoting role in cancer, while LIFR functions as a tumor promoter and suppressor. Epithelial and stromal cells secrete LIF via autocrine and paracrine signaling mechanism(s) that bind with LIFR and subsequently with co-receptor glycoprotein 130 (gp130) to activate JAK/STAT1/3, PI3K/AKT, mTORC1/p70s6K, Hippo/YAP, and MAPK signaling pathways. Clinically, activating the LIF/LIFR axis is associated with poor survival and anti-cancer therapy resistance. This review article provides an overview of the structure and ligands of LIFR, LIF/LIFR signaling in developmental biology, stem cells, cancer stem cells, genetics and epigenetics of LIFR, LIFR regulation by long non-coding RNAs and miRNAs, and LIF/LIFR signaling in cancers. Finally, neutralizing antibodies and small molecule inhibitors preferentially blocking LIF interaction with LIFR and antagonists against LIFR under pre-clinical and early-phase pre-clinical trials were discussed., (Published by Elsevier B.V.)
- Published
- 2022
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9. Integration of a micropreconcentrator with solid-phase microextraction for analysis of trace volatile organic compounds by gas chromatography-mass spectrometry.
- Author
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Halder S, Xie Z, Nantz MH, and Fu XA
- Subjects
- Gas Chromatography-Mass Spectrometry methods, Humans, Toluene analysis, Xylenes analysis, Solid Phase Microextraction methods, Volatile Organic Compounds analysis
- Abstract
The analysis of toxic volatile organic compounds (VOCs) in environmental air is important because toxic VOCs induce adverse effects on human health. Although gas chromatography- mass spectrometry (GC-MS) is the standard instrument for analysis of trace VOCs in air, this mode of analysis requires preconcentration and cryogenic processes. The preconcentration and subsequent thermal desorption of VOCs require special instruments and a long time of processing sample that significantly limit applications of GC-MS for monitoring indoor and outdoor VOC levels. Using a microfabricated preconcentrator for VOC analysis also has the challenge of a large sample volume for concentration. Using solid-phase microextraction (SPME) for VOC analysis by GC-MS often approaches the limit of detection of the GC-MS instrument for trace VOCs in air. This work reports a simple method to integrate microfabricated preconcentrators with commercial SPME fibers in a two-stage concentration processes to achieve rapid and reliable measurement of trace VOCs in air by GC-MS. We designed and fabricated a preconcentrator with micropillars in a microfluidic chamber to support sorbents and to increase the heat transfer rate to the sorbents for rapid thermal desorption. The effects of air flow rates through the preconcentrator on VOCs adsorption and thermal desorption were optimized for increasing analytical accuracy of VOCs measurements. The integration of a micropreconcentrator with SPME enabled measurements of sub-ppb levels of benzene, toluene, ethylbenzene, and xylene (BTEX), and trichloroethylene (TCE) in environmental air by GC-MS., Competing Interests: Declaration of Competing Interest The authors declare no competing interest for this work., (Copyright © 2022. Published by Elsevier B.V.)
- Published
- 2022
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10. A fully resolved multiphysics model of gastric peristalsis and bolus emptying in the upper gastrointestinal tract.
- Author
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Acharya S, Halder S, Kou W, Kahrilas PJ, Pandolfino JE, and Patankar NA
- Abstract
Over the past few decades, in silico modeling of organ systems has significantly furthered our understanding of their physiology and biomechanical function. In spite of the relative importance of the digestive system in normal functioning of the human body, there is a scarcity of high-fidelity models for the upper gastrointestinal tract including the esophagus and the stomach. In this work, we present a detailed numerical model of the upper gastrointestinal tract that not only accounts for the fiber architecture of the muscle walls, but also the multiphasic components they help transport during normal digestive function. Construction details for 3D models of representative stomach geometry are presented along with a simple strategy for assigning circular and longitudinal muscle fiber orientations for each layer. We developed a fully resolved model of the stomach to simulate gastric peristalsis by systematically activating muscle fibers embedded in the stomach. Following this, for the first time, we simulate gravity-driven bolus emptying into the stomach due to density differences between ingested contents and fluid contents of the stomach. Finally, we present a case of retrograde flow of fluid from the stomach into the esophagus, resembling the phenomenon of acid reflux. This detailed computational model of the upper gastrointestinal tract provides a foundation for future models to investigate the biomechanics of acid reflux and probe various strategies for gastric bypass surgeries to address the growing problem of obesity., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2022
- Full Text
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11. Benefits of satellite XCO 2 and newly proposed atmospheric CO 2 observation network over India in constraining regional CO 2 fluxes.
- Author
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Halder S, Tiwari YK, Valsala V, Sijikumar S, Janardanan R, and Maksyutov S
- Subjects
- Asia, India, Seasons, Carbon Dioxide analysis, Ecosystem
- Abstract
Top-down modeling estimates are among the most reliable information available on the CO
2 fluxes of the earth system. The inadequate coverage of CO2 observing stations over the tropical regions adds a limitation to this estimate, especially when the satellite XCO2 is strictly screened for cloud contamination, aerosol, dust, etc. In this study, we investigated the potential benefit of a global ground-based observing station network, 17 newly proposed stations over India, and global satellite XCO2 in reducing the uncertainty of terrestrial biospheric fluxes of Tropical Asia-Eurasia in TransCom cyclo-stationary inversion. The data from selected 80 global ground-based CO2 observation stations, together with two additional stations from India (i.e., Cape Rama and Sinhagad) and satellite XCO2 , helps to reduce the temperate Eurasian terrestrial flux uncertainty by 23.8%, 26.4%, and 36.2%, respectively. This further improved to 54.7% by adding the newly proposed stations over India into the inversion. By separating the Indian sub-continent from temperate Eurasia (as inspired by the heterogeneity in the terrestrial ecosystems, prevailing meteorological conditions, and the orography of this vast region), the inversion evinces the capacity of existing CO2 observations to reduce the Indian terrestrial flux uncertainty by 20.5%. The largest benefit (70% reduction of annual mean uncertainty) for estimating Indian terrestrial fluxes could be achieved by combining these global observations with data from the newly proposed stations over India. The existing two stations from India suggest Temperate Eurasia as a mild source of CO2 (0.33 ± 0.57 Pg C yr-1 ), albeit with prominent anthropogenic influences visible in these two stations during the dry seasons. This implies that the proposed new stations should be cautiously placed to avoid such effects. The study also finds that the newly proposed stations over India also have an impact in constraining nearby oceanic CO2 fluxes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)- Published
- 2022
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12. Filarial thioredoxin reductase exerts anti-inflammatory effects upon lipopolysaccharide induced inflammation in macrophages.
- Author
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Joardar N, Bhattacharya R, Halder S, Sen A, Biswas SR, Jana K, and Babu SPS
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- Animals, Cell Line, Down-Regulation drug effects, Helminth Proteins metabolism, Inflammation chemically induced, Lipopolysaccharides pharmacology, Mice, NF-kappa B metabolism, Protein Conformation, alpha-Helical drug effects, Protein Conformation, beta-Strand drug effects, RAW 264.7 Cells, Setaria Nematode drug effects, Toll-Like Receptor 4 metabolism, Anti-Inflammatory Agents metabolism, Anti-Inflammatory Agents pharmacology, Inflammation drug therapy, Inflammation metabolism, Macrophages metabolism, Thioredoxin-Disulfide Reductase metabolism, Thioredoxin-Disulfide Reductase pharmacology
- Abstract
Lymphatic filariasis and its associated health hazards have taken enormous tolls especially in the tropical and sub-tropical countries round the globe. Our present work contemplates the immunomodulatory role of filarial Thioredoxin reductase (TrxR) for the survival of the parasite inside the human host. For this, the protein TrxR was purified from the filarial parasite Setaria cervi and further substantiated through specific anti-TrxR antibody raised in mice. Both commercially available anti-TrxR antibody and laboratory raised antibody produced a single band with a molecular mass of ~80 kDa on western blot. The protein is optimally active at pH 7.0 and at temperature 37 °C. This protein contains both alpha helix and beta pleated sheet with selenocysteine at its active site. The Km was found to be 2.75 ± 0.49 mM. TrxR was found to downregulate lipopolysaccharide (LPS)-induced inflammation in macrophages due to inhibition of TLR4-NF-κB pathway. The result was further supported by the downregulation of inflammasome pathway and activation of alternatively activated macrophages upon TrxR treatment. Hence this study projects insights into the importance of filarial TrxR in host-parasite interface as well as it illustrates novel therapeutic strategy towards anti-filarial drug development., (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Published
- 2021
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13. 3-D printed electrode integrated sensing chip and a PoC device for enzyme free electrochemical detection of blood urea.
- Author
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Roy D, Singh P, Halder S, Chanda N, and Mandal S
- Subjects
- Humans, Electrochemical Techniques methods, Graphite chemistry, Nanocomposites chemistry, Urea blood
- Abstract
Herein we report a novel electrochemical sensing chip and a point-of-care device (PoC) for enzyme-free electrochemical detection of urea in human blood. The electrochemical sensing chip was developed by 3-D printing of conductive Ag ink and subsequent electrodeposition of AuNP-rGO nanocomposite. Material characterization of the sensing chip was conducted to find a plausible mechanism for the electrochemical reaction with urea. Subsequently, the response with varying concentrations of urea in solution and human blood samples was tested. High peak response current (~5 times than that of the highest reported value), low impedance, rapid sensor fabrication procedure, high selectivity towards urea, excellent linear response (R
2 = 0.99), high sensitivity of 183 μA mM-1 cm-2 , the fast response indicated by high diffusion coefficient, the limit of detection of 0.1 µM, tested shelf life of more than 6 months and recovery rate of >99% ensured the application of the developed sensor chip towards PoC urea detection test kit. A PoC device housing an electronic circuitry following the principles of linear sweep voltammetry and compatible with a sensing chip was developed. A maximum percentage error of 4.86% and maximum RSD of 3.63% confirmed the use of the PoC device for rapid urea measurements in human blood., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)- Published
- 2021
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14. The modified radical peripartum cesarean hysterectomy (Soleymani-Alazzam-Collins technique): a systematic, safe procedure for the management of severe placenta accreta spectrum.
- Author
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Soleymani Majd H, Collins SL, Addley S, Weeks E, Chakravarti S, Halder S, and Alazzam M
- Subjects
- Adult, Female, Humans, Postoperative Complications epidemiology, Pregnancy, Retrospective Studies, Severity of Illness Index, Surgical Oncology, Blood Loss, Surgical, Cesarean Section methods, Hysterectomy methods, Intensive Care Units statistics & numerical data, Operative Time, Placenta Accreta surgery
- Abstract
Background: The prevalence of placenta accreta spectrum is rising worldwide. The severe end of the spectrum where the placenta has invaded other organs is fortunately rare, however, few surgical techniques for such a complex hysterectomy have been described in the literature., Objective: This study aimed to describe a stepwise, systematic technique for radical cesarean hysterectomy for placenta accreta spectrum to investigate outcomes for women with severe, invasive placenta accreta spectrum who were hysterectomized using this technique., Study Design: This was a retrospective cohort study undertaken at a large UK tertiary referral center. A total of 24 cases of elective primary cesarean hysterectomy with a confirmed intrapartum diagnosis of severe percreta (Federation of Gynecology and Obstetrics grades 3b and 3c) were identified between 2011 and 2020. Among those cases, 16 had standard care (surgical technique dependent on surgeon's preference), and 8 had a radical peripartum hysterectomy using the Soleymani-Alazzam-Collins technique as described. Nonparametric testing was used because of sample size., Results: The Soleymani-Alazzam-Collins technique resulted in significantly less blood loss (P=.032), more transverse incisions (P=.009), and less intensive care unit admissions (P=.046). Furthermore, there was no significant difference in theater time., Conclusion: The Soleymani-Alazzam-Collins technique demonstrated a significant improvement in outcomes for women with severe placenta accreta spectrum, without increasing surgical time., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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15. Triggering the downstream apoptotic signal inside human parasitic organisms demonstrates a promising approach for anti-parasitic drug development: A mechanistic perspective.
- Author
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Joardar N, Mukherjee N, Halder S, Jana K, and Sinha Babu SP
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- Humans, Antiparasitic Agents therapeutic use, Apoptosis drug effects, Apoptosis immunology, Drug Development, Parasitic Diseases drug therapy, Parasitic Diseases immunology, Parasitic Diseases parasitology, Signal Transduction drug effects, Signal Transduction immunology
- Abstract
Parasitic organisms of various genera have threatened humankind. Although they are not always fatal but can damage the well-being of an individual in terms of both economic and societal crisis. Marked progress has been made toward eliminating those pathogenic organisms, however, complete removal is still not possible. Several antiparasitic drug moieties have been largely commercialized and are routinely used at the same time novel drug candidates are still required. Programmed cell death (PCD) is a vital biological phenomenon inside every organism. Particularly, induction of the death signaling inside the parasitic species through selective targeting of effective drug candidates is one of the major strategies to combat these infectious organisms. In this chapter significance of apoptosis induction to eliminate the parasitic disease has been illustrated with suitable references. Moreover, we have shared our own experiences of apoptosis induction in eliminating a World Health Organization enlisted Neglected Tropical Disease, lymphatic filariasis. On the other hand, we have also tried to put some light on the mechanism of apoptosis in different parasites., Competing Interests: Conflict of interest None., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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16. Generalized phase compensator of continuous time plants.
- Author
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Dey J, Mondal R, and Halder S
- Abstract
This work proposes a novel design method for generalized order lead/lag compensators. With respect to the traditional lead/lag compensator, it introduces a new parameter, β, which is a non-integer number. A new design method of the compensator is introduced in order to quantify its design parameters. Compared to its integer order counterpart, the generalized order lead compensator facilitates with the unique solution of desired design specifications with maximum phase at the desired gain cross-over frequency to achieve reshaping of the loop frequency domain characteristics. On the other hand, generalized order lag compensator is designed so as to allow minimum phase lag at the new gain crossover frequency. Examples with simulation and real-time results are presented to validate the efficacy of the proposed approach., (Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2018
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17. Dynamics simulation of soybean agglutinin (SBA) dimer reveals the impact of glycosylation on its enhanced structural stability.
- Author
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Halder S, Surolia A, and Mukhopadhyay C
- Subjects
- Glycosylation, Hydrogen Bonding, Models, Molecular, Molecular Dynamics Simulation, Protein Folding, Protein Multimerization, Protein Structure, Secondary, Protein Structure, Tertiary, Thermodynamics, Plant Lectins chemistry, Soybean Proteins chemistry
- Abstract
The legume lectins are widely used as a model system for studying protein-carbohydrate and protein-protein interactions. They exhibit a fascinating quaternary structure variation. Recently, it has become clear that lectins exist as oligomers. Soybean agglutinin is a tetrameric legume lectin, each of whose subunits are glycosylated. In the present study we explore the main origin for the stability of soybean agglutinin dimer. In order to understand the role of glycosylation on the dimeric interface, we have carried out normal (298K), high temperatures (380K, 500K) long explicit solvent molecular dynamics (MD) simulations and compared the structural and conformational changes between the glycosylated and non-glycosylated dimers. The study reveals that the high degree of stability at normal temperature is mostly contributed by interfacial ionic interactions (~200 kcal/mol) between polar residues like Lys, Arg, Asp, Thr, Ser, Asn and Gln (62%). It maintains its overall folded conformation due to high subunit interactions at the non-canonical interface. Mainly five important hydrogen bonds between CO of one β sheet of one subunit with the N-H of other β strand of the other subunit help to maintain the structural integrity. Ten inter subunit salt-bridge interactions between Arg 185-Asṕ192, Lys 163-Asṕ169, Asp 169-Lyś 163 and Asp 192-Arǵ 185 at non-canonical interface appear to be important to maintain the three dimensional structure of SBA dimer. Moreover, our simulation results revealed that increase in vibrational entropy could decrease the free energy and contribute to the glycan-induced stabilization by ~45 kcal/mol at normal temperature., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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18. Training leads to increased auditory brain-computer interface performance of end-users with motor impairments.
- Author
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Halder S, Käthner I, and Kübler A
- Subjects
- Aged, Female, Humans, Male, Middle Aged, Motor Skills Disorders diagnosis, Motor Skills Disorders psychology, Acoustic Stimulation methods, Brain-Computer Interfaces, Event-Related Potentials, P300 physiology, Evoked Potentials, Auditory physiology, Motor Skills Disorders physiopathology, Practice, Psychological
- Abstract
Objective: Auditory brain-computer interfaces are an assistive technology that can restore communication for motor impaired end-users. Such non-visual brain-computer interface paradigms are of particular importance for end-users that may lose or have lost gaze control. We attempted to show that motor impaired end-users can learn to control an auditory speller on the basis of event-related potentials., Methods: Five end-users with motor impairments, two of whom with additional visual impairments, participated in five sessions. We applied a newly developed auditory brain-computer interface paradigm with natural sounds and directional cues., Results: Three of five end-users learned to select symbols using this method. Averaged over all five end-users the information transfer rate increased by more than 1800% from the first session (0.17 bits/min) to the last session (3.08 bits/min). The two best end-users achieved information transfer rates of 5.78 bits/min and accuracies of 92%., Conclusions: Our results show that an auditory BCI with a combination of natural sounds and directional cues, can be controlled by end-users with motor impairment. Training improves the performance of end-users to the level of healthy controls., Significance: To our knowledge, this is the first time end-users with motor impairments controlled an auditory brain-computer interface speller with such high accuracy and information transfer rates. Further, our results demonstrate that operating a BCI with event-related potentials benefits from training and specifically end-users may require more than one session to develop their full potential., (Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2016
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19. Effects of training and motivation on auditory P300 brain-computer interface performance.
- Author
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Baykara E, Ruf CA, Fioravanti C, Käthner I, Simon N, Kleih SC, Kübler A, and Halder S
- Subjects
- Adult, Female, Humans, Male, Young Adult, Acoustic Stimulation methods, Auditory Cortex physiology, Brain-Computer Interfaces, Electroencephalography methods, Event-Related Potentials, P300 physiology, Motivation physiology
- Abstract
Objectives: Brain-computer interface (BCI) technology aims at helping end-users with severe motor paralysis to communicate with their environment without using the natural output pathways of the brain. For end-users in complete paralysis, loss of gaze control may necessitate non-visual BCI systems. The present study investigated the effect of training on performance with an auditory P300 multi-class speller paradigm. For half of the participants, spatial cues were added to the auditory stimuli to see whether performance can be further optimized. The influence of motivation, mood and workload on performance and P300 component was also examined., Methods: In five sessions, 16 healthy participants were instructed to spell several words by attending to animal sounds representing the rows and columns of a 5 × 5 letter matrix., Results: 81% of the participants achieved an average online accuracy of ⩾ 70%. From the first to the fifth session information transfer rates increased from 3.72 bits/min to 5.63 bits/min. Motivation significantly influenced P300 amplitude and online ITR. No significant facilitative effect of spatial cues on performance was observed., Conclusions: Training improves performance in an auditory BCI paradigm. Motivation influences performance and P300 amplitude., Significance: The described auditory BCI system may help end-users to communicate independently of gaze control with their environment., (Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2016
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20. Differential regulation of urine proteins in urothelial neoplasm.
- Author
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Halder S, Dey RK, Chowdhury AR, Bhattacharyya P, and Chakrabarti A
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Urinary Bladder Neoplasms pathology, Urothelium pathology, Biomarkers, Tumor urine, Neoplasm Proteins urine, Proteinuria urine, Urinary Bladder Neoplasms urine, Urothelium metabolism
- Abstract
Urothelial neoplasm of the urinary bladder has a high rate of multifocality and recurrence. To understand this we first need to understand the changes in the molecular level that distinguishes a normal individual from a patient and also a low grade neoplasm from a high grade. In this work we aim to study the urine proteome of Indian patients with urothelial neoplasm categorised on the basis of their p53 immunohistochemistry. The urine samples of pre-operative patients were subjected to two dimensional gel electrophoresis followed by densitometric analysis and spot identification using MALDI mass spectrometry. Our study shows that few proteins such as albumin, alpha 1 antitrypsin, apolipoprotein A1, transferrin, transthyretin, haptoglobin and haemoglobin β chain were upregulated and inter alpha trypsin inhibitor heavy chain was downregulated in the disease samples. Further we have reported that some of these proteins show an association with disease severity. The present study marks the first step in the identification of new diagnostic markers as well as therapeutic targets., Biological Significance: Bladder carcinoma is the ninth most common cancer worldwide. It has gained attention within both clinicians and cancer biologists because of its recurrence and mortality rate. Identifying the prognostic factors of progression is a challenge, so that high risk patients who may be a candidate for a radical cystectomy may be identified. In this study we have attempted to study the changes observed in the urinary protein levels of urothelial neoplasm patients. The samples were graded based on p53 immunohistochemistry staining. We have reported eight (8) proteins, mostly highly abundant; those have exhibited differential regulation in case of diseased samples. This study is first of its kind that associates the changes in the urinary protein levels to that of the severity of the disease. We believe that the findings can be used as a stepping stone in the development of a noninvasive prognostic tool for the disease. This article is part of a Special Issue entitled: Proteomics in India., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
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21. Codeine and breast-feeding mothers.
- Author
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Halder S, Russell R, and Quinlan J
- Subjects
- Female, Humans, Infant, Practice Guidelines as Topic, Analgesics, Opioid, Breast Feeding, Codeine, Mothers
- Published
- 2015
- Full Text
- View/download PDF
22. Parvovirus glycan interactions.
- Author
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Huang LY, Halder S, and Agbandje-McKenna M
- Subjects
- Animals, Capsid Proteins genetics, Capsid Proteins metabolism, Humans, Parvoviridae Infections virology, Parvovirus genetics, Parvoviridae Infections metabolism, Parvovirus metabolism, Polysaccharides metabolism, Receptors, Virus metabolism
- Abstract
Members of the Parvoviridae utilize glycan receptors for cellular attachment and subsequent interactions determine transduction efficiency or pathogenic outcome. This review focuses on the identity of the glycan receptors utilized, their capsid binding footprints, and a discussion of the overlap of these sites with tropism, transduction, and pathogenicity determinants. Despite high sequence diversity between the different genera, most parvoviruses bind to negatively charged glycans, such as sialic acid and heparan sulfate, abundant on cell surface membranes. The capsid structure of these viruses exhibit high structural homology enabling common regions to be utilized for glycan binding. At the same time the sequence diversity at the common footprints allows for binding of different glycans or differential binding of the same glycan., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
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23. Determinants of prakriti, the human constitution types of Indian traditional medicine and its correlation with contemporary science.
- Author
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Rotti H, Raval R, Anchan S, Bellampalli R, Bhale S, Bharadwaj R, Bhat BK, Dedge AP, Dhumal VR, Gangadharan GG, Girijakumari TK, Gopinath PM, Govindaraj P, Halder S, Joshi KS, Kabekkodu SP, Kamath A, Kondaiah P, Kukreja H, Kumar KL, Nair S, Nair SN, Nayak J, Prasanna BV, Rashmishree M, Sharanprasad K, Thangaraj K, Patwardhan B, Satyamoorthy K, and Valiathan MV
- Abstract
Background: Constitutional type of an individual or prakriti is the basic clinical denominator in Ayurveda, which defines physical, physiological, and psychological traits of an individual and is the template for individualized diet, lifestyle counseling, and treatment. The large number of phenotype description by prakriti determination is based on the knowledge and experience of the assessor, and hence subject to inherent variations and interpretations., Objective: In this study we have attempted to relate dominant prakriti attribute to body mass index (BMI) of individuals by assessing an acceptable tool to provide the quantitative measure to the currently qualitative ayurvedic prakriti determination., Materials and Methods: The study is cross sectional, multicentered, and prakriti assessment of a total of 3416 subjects was undertaken. Healthy male, nonsmoking, nonalcoholic volunteers between the age group of 20-30 were screened for their prakriti after obtaining written consent to participate in the study. The prakriti was determined on the phenotype description of ayurvedic texts and simultaneously by the use of a computer-aided prakriti assessment tool. Kappa statistical analysis was employed to validate the prakriti assessment and Chi-square, Cramer's V test to determine the relatedness in the dominant prakriti to various attributes., Results: We found 80% concordance between ayurvedic physician and software in predicting the prakriti of an individual. The kappa value of 0.77 showed moderate agreement in prakriti assessment. We observed a significant correlations of dominant prakriti to place of birth and BMI with Chi-square, P < 0.01 (Cramer's V-value of 0.156 and 0.368, respectively)., Conclusion: The present study attempts to integrate knowledge of traditional ayurvedic concepts with the contemporary science. We have demonstrated analysis of prakriti classification and its association with BMI and place of birth with the implications to one of the ways for human classification.
- Published
- 2014
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24. Bulk growth of ninhydrin single crystals by solvent evaporation method and its characterization for SHG and THG applications.
- Author
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Vijayan N, Philip J, Haranath D, Rathi B, Bhagavannarayana G, Halder SK, Roy N, Jayalakshmy MS, and Verma S
- Subjects
- Birefringence, Electricity, Hot Temperature, Time Factors, Volatilization, X-Ray Diffraction, Crystallization methods, Ninhydrin chemistry, Solvents chemistry
- Abstract
Ninhydrin is a well-known compound generally used in amino acid synthesis and also for detecting the latent fingerprints on porous surfaces. Single crystals can be grown by dissolving the compound in double distilled water at ambient temperature, and can be used as a potential material for second and third harmonic generation applications. The grown specimen was subjected to different characterization techniques in order to find out its suitability for device fabrication. Its lattice dimensions have been confirmed by X-ray powder diffraction and its crystalline quality has been assessed by high resolution X-ray diffraction and X-ray topography methods. The presence of functional groups was identified from HETCOR analysis and confirmed the absence of impurities during crystallization. Its optical properties have been examined by photoluminescence and birefringence analyses. Its thermal parameters such as thermal diffusivity, thermal conductivity and specific capacity have been carried out by following photopyroelectric method. Third order nonlinear optical measurements have been carried out using Z-scan technique and its nonlinear optical absorption coefficient has been determined., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2014
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25. Mutual prodrugs containing bio-cleavable and drug releasable disulfide linkers.
- Author
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Jain AK, Gund MG, Desai DC, Borhade N, Senthilkumar SP, Dhiman M, Mangu NK, Mali SV, Dubash NP, Halder S, and Satyam A
- Subjects
- Body Fluids chemistry, Disulfides chemistry, Drug Design, Humans, Molecular Structure, Prodrugs chemical synthesis, Body Fluids metabolism, Disulfides metabolism, Prodrugs chemistry, Prodrugs metabolism
- Abstract
We report herein the design and synthesis of several representative examples of novel mutual prodrugs containing nine distinct types of self-immolative drug-releasable disulfide linkers with urethane, ester, carbonate, or imide linkages between the linker and any two amine/amide/urea (primary or secondary) or carboxyl or hydroxyl (including phenolic)-containing drugs. We also report drug release profiles of a few representative mutual prodrugs in biological fluids such as simulated gastric fluid and human plasma. We also propose plausible mechanisms of drug release from these mutual prodrugs. We have also conducted a few mechanistic studies based on suggested sulfhydryl-assisted cleavage of mutual prodrugs and characterized a few important metabolites to give support to the proposed mechanism of drug release from the reported mutual prodrugs., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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26. A portable auditory P300 brain-computer interface with directional cues.
- Author
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Käthner I, Ruf CA, Pasqualotto E, Braun C, Birbaumer N, and Halder S
- Subjects
- Adolescent, Adult, Affect physiology, Communication, Electroencephalography, Feasibility Studies, Female, Humans, Male, Models, Neurological, Motivation physiology, Photic Stimulation, Young Adult, Acoustic Stimulation, Brain-Computer Interfaces, Communication Aids for Disabled, Cues, Event-Related Potentials, P300 physiology, Task Performance and Analysis
- Abstract
Objectives: The main objective of the current study was to implement and evaluate a P300 based brain-computer interface (BCI) speller that uses directional cues of auditory stimuli, which are presented over headphones. The interstimulus interval (ISI) was successively reduced to determine the optimal combination of speed and accuracy. The study further aimed at quantifying the differences in subjective workload between the auditory and the visual P300 spelling application. The influence of workload, mood and motivation on BCI performance and P300 amplitude was investigated., Methods: Twenty healthy participants performed auditory and visual spelling tasks in an EEG experiment with online feedback., Results: Sixteen of twenty participants performed at or above a level necessary for satisfactory communication (≥70% spelling accuracy) with the auditory BCI. Average bit rates of up to 2.76 bits/min (best subject 7.43 bits/min) were achieved. A significantly higher workload was reported for the auditory speller compared to the visual paradigm. Motivation significantly influenced P300 amplitude at Pz in the auditory condition., Conclusions: The results of the online study suggest that the proposed paradigm offers a means of communication for most healthy users., Significance: The described auditory BCI can serve as a communication channel for completely paralyzed patients., (Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
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27. Probing command following in patients with disorders of consciousness using a brain-computer interface.
- Author
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Lulé D, Noirhomme Q, Kleih SC, Chatelle C, Halder S, Demertzi A, Bruno MA, Gosseries O, Vanhaudenhuyse A, Schnakers C, Thonnard M, Soddu A, Kübler A, and Laureys S
- Subjects
- Adult, Aged, Arousal, Consciousness Disorders diagnosis, Data Interpretation, Statistical, Electroencephalography, Event-Related Potentials, P300, Evoked Potentials, Auditory, Female, Humans, Male, Middle Aged, Persistent Vegetative State physiopathology, Persistent Vegetative State psychology, Quadriplegia physiopathology, Quadriplegia psychology, Brain-Computer Interfaces, Consciousness Disorders physiopathology, Consciousness Disorders psychology
- Abstract
Objective: To determine if brain-computer interfaces (BCIs) could serve as supportive tools for detecting consciousness in patients with disorders of consciousness by detecting response to command and communication., Methods: We tested a 4-choice auditory oddball EEG-BCI paradigm on 16 healthy subjects and 18 patients in a vegetative state/unresponsive wakefulness syndrome, in a minimally conscious state (MCS), and in locked-in syndrome (LIS). Subjects were exposed to 4 training trials and 10 -12 questions., Results: Thirteen healthy subjects and one LIS patient were able to communicate using the BCI. Four of those did not present with a P3. One MCS patient showed command following with the BCI while no behavioral response could be detected at bedside. All other patients did not show any response to command and could not communicate with the BCI., Conclusion: The present study provides evidence that EEG based BCI can detect command following in patients with altered states of consciousness and functional communication in patients with locked-in syndrome. However, BCI approaches have to be simplified to increase sensitivity., Significance: For some patients without any clinical sign of consciousness, a BCI might bear the potential to employ a "yes-no" spelling device offering the hope of functional interactive communication., (Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
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28. Transition from the locked in to the completely locked-in state: a physiological analysis.
- Author
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Murguialday AR, Hill J, Bensch M, Martens S, Halder S, Nijboer F, Schoelkopf B, Birbaumer N, and Gharabaghi A
- Subjects
- Adult, Area Under Curve, Communication Aids for Disabled, Electroencephalography, Electromyography, Humans, Male, Signal Processing, Computer-Assisted, User-Computer Interface, Amyotrophic Lateral Sclerosis physiopathology, Brain physiopathology, Disease Progression
- Abstract
Objective: To clarify the physiological and behavioral boundaries between locked-in (LIS) and the completely locked-in state (CLIS) (no voluntary eye movements, no communication possible) through electrophysiological data and to secure brain-computer-interface (BCI) communication., Methods: Electromyography from facial muscles, external anal sphincter (EAS), electrooculography and electrocorticographic data during different psychophysiological tests were acquired to define electrophysiological differences in an amyotrophic lateral sclerosis (ALS) patient with an intracranially implanted grid of 112 electrodes for nine months while the patient passed from the LIS to the CLIS., Results: At the very end of the LIS there was no facial muscle activity, nor external anal sphincter but eye control. Eye movements were slow and lasted for short periods only. During CLIS event related brain potentials (ERP) to passive limb movements and auditory stimuli were recorded, vibrotactile stimulation of different body parts resulted in no ERP response., Conclusions: The results presented contradict the commonly accepted assumption that the EAS is the last remaining muscle under voluntary control and demonstrate complete loss of eye movements in CLIS. The eye muscle was shown to be the last muscle group under voluntary control. The findings suggest ALS as a multisystem disorder, even affecting afferent sensory pathways., Significance: Auditory and proprioceptive brain-computer-interface (BCI) systems are the only remaining communication channels in CLIS., (Copyright © 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2011
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29. Out of the frying pan into the fire--the P300-based BCI faces real-world challenges.
- Author
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Kleih SC, Kaufmann T, Zickler C, Halder S, Leotta F, Cincotti F, Aloise F, Riccio A, Herbert C, Mattia D, and Kübler A
- Subjects
- Humans, Internet, Signal Processing, Computer-Assisted, Communication Aids for Disabled, Event-Related Potentials, P300 physiology, User-Computer Interface
- Abstract
Brain-computer interfaces (BCIs) have been investigated for more than 20 years. Many BCIs use noninvasive electroencephalography as a measurement technique and the P300 event-related potential as an input signal (P300 BCI). Since the first experiment with a P300 BCI system in 1988 by Farwell and Donchin, not only data processing has improved but also stimuli presentation has been varied and a plethora of applications was developed and refined. Nowadays, these applications are facing the challenge of being transferred from the research laboratory into real-life situations to serve motor-impaired people in their homes as assistive technology., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2011
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30. Motivation modulates the P300 amplitude during brain-computer interface use.
- Author
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Kleih SC, Nijboer F, Halder S, and Kübler A
- Subjects
- Adult, Humans, Photic Stimulation methods, Psychomotor Performance physiology, Reaction Time physiology, Brain physiology, Event-Related Potentials, P300 physiology, Motivation physiology, User-Computer Interface
- Abstract
Objective: This study examined the effect of motivation as a possible psychological influencing variable on P300 amplitude and performance in a brain-computer interface (BCI) controlled by event-related potentials (ERP)., Methods: Participants were instructed to copy spell a sentence by attending to cells of a randomly flashing 7*7 matrix. Motivation was manipulated by monetary reward. In two experimental groups participants received 25 (N=11) or 50 (N=11) Euro cent for each correctly selected character; the control group (N=11) was not rewarded. BCI performance was defined as the overall percentage of correctly selected characters (correct response rate=CRR)., Results: Participants performed at an average of 99%. At electrode location Cz the P300 amplitude was positively correlated to self-rated motivation. The P300 amplitude of the most motivated participants was significantly higher than that of the least motivated participants. Highly motivated participants were able to communicate correctly faster with the ERP-BCI than less motivated participants., Conclusions: Motivation modulates the P300 amplitude in an ERP-BCI., Significance: Motivation may contribute to variance in BCI performance and should be monitored in BCI settings., (Copyright 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2010
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31. An auditory oddball brain-computer interface for binary choices.
- Author
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Halder S, Rea M, Andreoni R, Nijboer F, Hammer EM, Kleih SC, Birbaumer N, and Kübler A
- Subjects
- Acoustic Stimulation methods, Adult, Electroencephalography, Female, Humans, Male, Middle Aged, Neuropsychological Tests, Reaction Time physiology, Signal Processing, Computer-Assisted, Young Adult, Brain physiology, Brain Mapping, Choice Behavior physiology, Discrimination, Psychological physiology, Evoked Potentials, Auditory physiology, User-Computer Interface
- Abstract
Objective: Brain-computer interfaces (BCIs) provide non-muscular communication for individuals diagnosed with late-stage motoneuron disease (e.g., amyotrophic lateral sclerosis (ALS)). In the final stages of the disease, a BCI cannot rely on the visual modality. This study examined a method to achieve high accuracies using auditory stimuli only., Methods: We propose an auditory BCI based on a three-stimulus paradigm. This paradigm is similar to the standard oddball but includes an additional target (i.e. two target stimuli, one frequent stimulus). Three versions of the task were evaluated in which the target stimuli differed in loudness, pitch or direction., Results: Twenty healthy participants achieved an average information transfer rate (ITR) of up to 2.46 bits/min and accuracies of 78.5%. Most subjects (14 of 20) achieved their best performance with targets differing in pitch., Conclusions: With this study, the viability of the paradigm was shown for healthy participants and will next be evaluated with individuals diagnosed with ALS or locked-in syndrome (LIS) after stroke., Significance: The here presented BCI offers communication with binary choices (yes/no) independent of vision. As it requires only little time per selection, it may constitute a reliable means of communication for patients who lost all motor function and have a short attention span., (2009 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2010
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32. A P300-based brain-computer interface for people with amyotrophic lateral sclerosis.
- Author
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Nijboer F, Sellers EW, Mellinger J, Jordan MA, Matuz T, Furdea A, Halder S, Mochty U, Krusienski DJ, Vaughan TM, Wolpaw JR, Birbaumer N, and Kübler A
- Subjects
- Adult, Aged, Discriminant Analysis, Electroencephalography methods, Feedback, Psychological, Female, Humans, Male, Middle Aged, Pattern Recognition, Visual physiology, Photic Stimulation, Reaction Time, Amyotrophic Lateral Sclerosis pathology, Amyotrophic Lateral Sclerosis physiopathology, Brain physiopathology, Event-Related Potentials, P300 physiology, User-Computer Interface
- Abstract
Objective: The current study evaluates the efficacy of a P300-based brain-computer interface (BCI) communication device for individuals with advanced ALS., Methods: Participants attended to one cell of a N x N matrix while the N rows and N columns flashed randomly. Each cell of the matrix contained one character. Every flash of an attended character served as a rare event in an oddball sequence and elicited a P300 response. Classification coefficients derived using a stepwise linear discriminant function were applied to the data after each set of flashes. The character receiving the highest discriminant score was presented as feedback., Results: In Phase I, six participants used a 6 x 6 matrix on 12 separate days with a mean rate of 1.2 selections/min and mean online and offline accuracies of 62% and 82%, respectively. In Phase II, four participants used either a 6 x 6 or a 7 x 7 matrix to produce novel and spontaneous statements with a mean online rate of 2.1 selections/min and online accuracy of 79%. The amplitude and latency of the P300 remained stable over 40 weeks., Conclusions: Participants could communicate with the P300-based BCI and performance was stable over many months., Significance: BCIs could provide an alternative communication and control technology in the daily lives of people severely disabled by ALS.
- Published
- 2008
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33. Copper(II) complexes of lipophilic aminoglycoside derivatives for the amino acid enantiomeric separation by ligand-exchange liquid chromatography.
- Author
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Zaher M, Baussanne I, Ravelet C, Halder S, Haroun M, Fize J, Décout JL, and Peyrin E
- Subjects
- Aminoglycosides chemistry, Copper chemistry, Stereoisomerism, Amino Acids analysis, Aminoglycosides analysis, Chromatography, Liquid methods
- Abstract
In this paper, a new class of ligand-exchange chiral stationary phase (LE-CSP) based on the copper complexes of lipophilic aminoglycoside derivatives was reported. Different stationary phases were developed by coating reversed-phase liquid chromatography supports with three neamine derivatives carrying a lipophilic octadecyl chain at the 4', 5 and 6 positions, respectively. The enantioselective ability of these LE neamine-based CSPs was evaluated and the 4'-derivative coated column was found to be the most interesting one for the amino acid resolution. The effects of the variation of several chromatographic parameters on the enantioseparation were evaluated in order to identify the analysis optimal conditions.
- Published
- 2008
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34. A panel of monoclonal antibodies recognizing GPI-anchored ADP-ribosyltransferase ART4, the carrier of the Dombrock blood group antigens.
- Author
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Parusel I, Kahl S, Braasch F, Glowacki G, Halverson GR, Reid ME, Schawalder A, Ortolan E, Funaro A, Malavasi F, Hardie D, Halder S, Buckley CD, Haag F, and Koch-Nolte F
- Subjects
- ADP Ribose Transferases genetics, ADP Ribose Transferases metabolism, Amino Acid Sequence, Animals, Antibodies, Monoclonal biosynthesis, Antibodies, Monoclonal immunology, Cell Cycle Proteins genetics, Cell Cycle Proteins metabolism, Cross Reactions, Endothelium, Vascular immunology, Erythrocytes immunology, GPI-Linked Proteins, Humans, Macrophages immunology, Membrane Proteins genetics, Membrane Proteins metabolism, Mice, Mice, Inbred BALB C, Molecular Sequence Data, Monocytes immunology, Neoplasm Proteins genetics, Neoplasm Proteins metabolism, Palatine Tonsil metabolism, Rats, Sequence Alignment, Spleen immunology, Umbilical Veins immunology, ADP Ribose Transferases immunology, Cell Cycle Proteins immunology, Membrane Proteins immunology, Neoplasm Proteins immunology
- Abstract
ART4 (CD297) is a member of the family of toxin-related ADP-ribosyltransferases (ARTs) and is the carrier of the Dombrock blood group alloantigens (Do). Two mouse monoclonal antibodies (MIMA-52 and MIMA-53), and two rat monoclonal antibodies (N0NI-B4 and NONI-B63) were obtained following immunization of mice with human Do/ART4-transfected cells and of rats with human Do/ART4 cDNA, respectively. All four mAbs recognize Do/ART4-transfected Jurkat cells but not untransfected cells by FACS analysis. Staining of Do/ART4-transfected cells by these mAbs was reduced following treatment of cells with PI-PLC, confirming that Do/ART4 is anchored in the cell membrane by linkage to glycosylphosphatidylinositol as predicted from its amino acid sequence. The four mAbs did not react with Gy(a-) (Dombrock null) erythrocytes but agglutinated other red blood cells. By flow cytometric analysis, all mAbs reacted prominently with erythrocytes, and weakly with peripheral blood monocytes and splenic macrophages, but not with B-lymphocytes or T-lymphocytes. The mAbs reacted weakly also with human umbilical vein endothelial cells and the basophilic leukemia KU-812. Immunohistology revealed staining of epithelia and endothelia on sections of tonsils. In FACS analyses NONI-B4 competed with MIMA-52 for binding to Do/ART4-transfected cells and erythrocytes, whereas NONI-B63 competed with MIMA-53. Neither of the mAbs reacted with mouse ART4-transfected cells, but NONI-B63 and MIMA-53 did react with a mouse/human ART4 chimera, indicating that the epitope recognized by these mAbs lies in the C-terminal half of the protein.
- Published
- 2005
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35. Report on antibodies submitted to the stromal cell section of HLDA8.
- Author
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Buckley CD, Halder S, Hardie D, Reynolds G, Torensma R, De Villeroche VJ, Brouty-Boye D, and Isacke CM
- Subjects
- Antibodies, Monoclonal immunology, Antibody Specificity, Antigens, CD analysis, Endothelial Cells immunology, Flow Cytometry, Humans, Immunohistochemistry, Neoplasms immunology, Stem Cells immunology, Stromal Cells immunology
- Abstract
The paradigm for tissue specific homing of leukocytes is the "area code" hypothesis, which predicts that a specific combination of adhesive interactions and chemokine signals from the endothelium directs leukocyte migration into specific tissue sites. This area code hypothesis has been supported by studies from previous HLDA workshops where endothelial specific cell antigens have been studied. Similarly, a clear haematopoietic "stem cell code" comprising the chemokine SDF-1 (CXCL12) and the adhesion receptor VCAM-1 (CD106) has been shown to contribute to the stem cell niche within bone marrow [K. Tokoyoda, T. Egawa, T. Sugiyama, B.I. Chai, T. Nagasawa, Cellular niches controlling B lymphocyte behaviour within bone marrow during development, Immunity 20 (2004) 707-718]. HLDA 7 included a section devoted to stem cell antigens, which began to define additional antigens important in these processes. During the course of HLDA 8 we have extended these observations to determine whether a more global stromal address code defined by fibroblasts, exists in variety of different tissues [G. Parsonage, A.D. Filer, O. Haworth, G.B. Nash, G.E. Rainger, M. Salmon, C.D. Buckley, A stromal area postcode defined by fibroblasts, Trends Immunol. 26 (2005) 150-156]. The stromal cell section in HLDA 8 was designed to complement the malignant cell, endothelial cell, and stem cell/progenitor cell sections. Seven new CD numbers were assigned to antibodies included in this section at the HLDA 8 Workshop meeting held during December 2004.
- Published
- 2005
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36. Meta-analysis of randomized controlled trials on hydrocolloid occlusive dressing versus conventional gauze dressing in the healing of chronic wounds.
- Author
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Singh A, Halder S, Menon GR, Chumber S, Misra MC, Sharma LK, and Srivastava A
- Subjects
- Cost-Benefit Analysis, Humans, Odds Ratio, Randomized Controlled Trials as Topic, Risk, Bandages, Colloids, Occlusive Dressings, Wound Healing
- Abstract
Chronic wound management is a difficult area in surgical practice. A wide range of dressings have been recommended for the management of chronic wounds. The present meta-analysis was undertaken to determine the effectiveness of hydrocolloid dressing (HCD) in the healing of chronic wounds compared with conventional gauze dressing. All available controlled clinical trials published before December 2001 that compared HCD to conventional gauze dressing in the healing of chronic wounds were systematically reviewed. We identified and analysed 12 randomized trials (11 published; 1 unpublished) comprising 693 patients with 819 ulcers. The overall odds ratio under the fixed effect model was 1.72, that is, 72% more ulcers healed completely with HCD than with conventional gauze dressing. This result was both clinically and statistically significant.
- Published
- 2004
- Full Text
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37. Retrograde fixation of fractures of the neck and shaft of the humerus with the 'Halder humeral nail'.
- Author
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Halder SC, Chapman JA, Choudhury G, and Wallace WA
- Subjects
- Adult, Aged, Aged, 80 and over, Equipment Design, Female, Follow-Up Studies, Fracture Fixation, Intramedullary adverse effects, Fracture Healing, Humans, Humeral Fractures diagnostic imaging, Humeral Fractures rehabilitation, Humerus diagnostic imaging, Male, Middle Aged, Radiography, Shoulder Fractures rehabilitation, Bone Nails, Fracture Fixation, Intramedullary methods, Humeral Fractures surgery, Humerus surgery, Shoulder Fractures surgery
- Abstract
The Halder humeral nail is a new intramedullary device designed for displaced two part humeral neck and shaft fractures. It is inserted retrograde from the olecranon fossa and a unique trio wire is inserted through the nail to provide good proximal fixation. This avoids the use of proximal screws and damage to the rotator cuff thereby ensuring good rotator cuff function. The results of 100 cases are presented. At 6 weeks, 95 patients could perform the majority of daily tasks. There were four non-unions, one following a deep infection.
- Published
- 2001
- Full Text
- View/download PDF
38. Nosocomial influenza infection.
- Author
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Halder S, Benons L, Dey P, Woodman C, and Snee K
- Subjects
- Health Personnel, Humans, Infectious Disease Transmission, Professional-to-Patient prevention & control, Influenza, Human transmission, Vaccination statistics & numerical data, Cross Infection prevention & control, Influenza Vaccines, Influenza, Human prevention & control
- Published
- 2000
- Full Text
- View/download PDF
39. Zona glomerulosa-specific factor: cloning and function.
- Author
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Okamoto M, Takemori H, Halder SK, and Hatano O
- Subjects
- Adrenal Cortex anatomy & histology, Adrenal Cortex metabolism, Animals, Binding Sites, Blotting, Northern, Cholesterol Side-Chain Cleavage Enzyme genetics, Cloning, Molecular, Cytochrome P-450 CYP11B2 genetics, Epidermal Growth Factor chemistry, Epidermal Growth Factor metabolism, Humans, Immunohistochemistry, Intercellular Signaling Peptides and Proteins, Membrane Proteins immunology, Rats, Recombinant Proteins genetics, Recombinant Proteins immunology, Recombinant Proteins metabolism, Sequence Homology, Amino Acid, Zona Glomerulosa chemistry, Zona Glomerulosa physiology, Membrane Proteins genetics, Membrane Proteins metabolism, Zona Glomerulosa metabolism
- Abstract
The rat adrenal cortex is composed of three zones: the zona glomerulosa, the zona fasciculata, and the zona reticularis. Several investigators have claimed the presence of a zona intermedia between the zonae glomerulosa and fasciculata. The cells of zona glomerulosa, a few layers of cells just beneath the adrenal capsule, synthesize and secrete aldosterone, whereas those of zonae fasciculata and reticularis secrete glucocorticoids and androgens, respectively. The function of the cells in zona intermedia is unclear, because they express neither aldosterone synthase nor 11 beta-hydroxylase. To investigate the mechanism underlying the zonal differentiation of adrenocortical steroidogenesis, attempts have been made to isolate and characterize zone-specifically expressed proteins such as steroidogenic enzymes and putative regulatory factors. Having subtracted the mRNAs present in the decapsulated adrenal gland from those in the adrenal capsule, we successfully isolated three distinct clones, each specifically expressed in the zona glomerulosa. One clone encoded a protein named zona glomerulosa-specific factor (ZOG), which had a putative signal peptide at the N-terminus, six tandem epidermal growth factor (EGF)-like repeats, and a transmembrane domain in the central portion and a short cytosolic stretch at the C-terminus. Immunohistochemical studies using the antibody raised against ZOG confirmed the presence of the protein in all layers of cells in the zona glomerulosa. In contrast, cells possessing aldosterone synthase were present only in the periphery of zona glomerulosa, just beneath the capsule. These findings suggest that there are at least two kinds of zona glomerulosa cells in the rat adrenal cortex, one expressing aldosterone synthase as well as ZOG, and another expressing only ZOG. The cells in the zona intermedia did not express ZOG, aldosterone synthase, or 11 beta-hydroxylase, but did express Ad4BP. ZOG was not detected in zonae fasciculata and reticularis where 11 beta-hydroxylase was present.
- Published
- 1997
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40. Human interleukin-3 receptor modulates bcl-2 mRNA and protein levels through protein kinase C in TF-1 cells.
- Author
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Rinaudo MS, Su K, Falk LA, Halder S, and Mufson RA
- Subjects
- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine, Base Sequence, Dactinomycin pharmacology, Humans, Isoquinolines pharmacology, Leukemia, Erythroblastic, Acute metabolism, Leukemia, Erythroblastic, Acute pathology, Molecular Sequence Data, Naphthalenes pharmacology, Neoplasm Proteins biosynthesis, Piperazines pharmacology, Protein Kinase C antagonists & inhibitors, Proto-Oncogene Proteins biosynthesis, Proto-Oncogene Proteins c-bcl-2, RNA, Messenger genetics, Tetradecanoylphorbol Acetate pharmacology, Transcription, Genetic drug effects, Apoptosis drug effects, Gene Expression Regulation, Leukemic drug effects, Interleukin-3 pharmacology, Leukemia, Erythroblastic, Acute genetics, Neoplasm Proteins genetics, Protein Kinase C physiology, Proto-Oncogene Proteins genetics, RNA, Messenger biosynthesis, Receptors, Interleukin-3 physiology, Signal Transduction drug effects, Sulfonamides
- Abstract
Upon withdrawal of interleukin-3 (IL-3) from human factor-dependent erythroleukemic cell line TF-1, bcl-2 mRNA and protein levels decrease within 8 to 24 hours. Accompanying this decrease is the onset of apoptosis as determined by flow cytometric analysis of DNA degradation. By 8 to 18 hours of deprivation approximately 70% to 80% of the cells have entered apoptosis. Downregulation of protein kinase (PK) by a 24-hour incubation in 100 nmol/L 12-O-tetradecanoyl-phorbol-13-acetate (TPA) in the presence of IL-3 dramatically reduced bcl-2 mRNA levels, and induced apoptosis in the presence of IL-3. We have also found that even in the presence of IL-3, two inhibitors of PKC, light-activated calphostin and H-7, substantially reduced the levels of bcl-2 mRNA between 8 and 24 hours as measured by a semi-quantitative reverse transcriptase/polymerase chain reaction assay method; however, the cyclic nucleotide-dependent PK inhibitor HA 1004, that is a structural analog of H-7 but a poor inhibitor of PKC, did not reduce bcl-2 levels in the presence of IL-3. This decrease in bcl-2 mRNA was accompanied by a decline in bcl-2 protein levels by 8 to 24 hours after addition of light-activated calphostin. In addition to interfering with the maintenance of bcl-2 mRNA levels, inhibition of PKC with H-7 inhibited the induction of bcl-2 mRNA in factor-deprived TF-1 cells restimulated with IL-3. The cyclic nucleotide-dependent PK inhibitor HA 1004 did not inhibit IL-3-induced bcl-2 mRNA. Studies with actinomycin D showed that transcription plays a major role in maintaining bcl-2 levels in TF-1 cells, and it is therefore likely that IL-3 plays a role in maintaining bcl-2 transcription through activation of PKC in these cells.
- Published
- 1995
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