21 results on '"Kim, Joshua P."'
Search Results
2. The Atacama Cosmology Telescope: Cosmology from Cross-correlations of unWISE Galaxies and ACT DR6 CMB Lensing
- Author
-
Farren, Gerrit S, Krolewski, Alex, MacCrann, Niall, Ferraro, Simone, Abril-Cabezas, Irene, An, Rui, Atkins, Zachary, Battaglia, Nicholas, Bond, J Richard, Calabrese, Erminia, Choi, Steve K, Darwish, Omar, Devlin, Mark J, Duivenvoorden, Adriaan J, Dunkley, Jo, Hill, J Colin, Hilton, Matt, Huffenberger, Kevin M, Kim, Joshua, Louis, Thibaut, Madhavacheril, Mathew S, Marques, Gabriela A, McMahon, Jeff, Moodley, Kavilan, Page, Lyman A, Partridge, Bruce, Qu, Frank J, Schaan, Emmanuel, Sehgal, Neelima, Sherwin, Blake D, Sifón, Cristóbal, Staggs, Suzanne T, Van Engelen, Alexander, Vargas, Cristian, Wenzl, Lukas, White, Martin, and Wollack, Edward J
- Subjects
Particle and High Energy Physics ,Physical Sciences ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry (incl. Structural) ,Astronomy & Astrophysics ,Astronomical sciences ,Particle and high energy physics ,Space sciences - Abstract
We present tomographic measurements of structure growth using cross-correlations of Atacama Cosmology Telescope (ACT) DR6 and Planck cosmic microwave background (CMB) lensing maps with the unWISE Blue and Green galaxy samples, which span the redshift ranges 0.2 ≲ z ≲ 1.1 and 0.3 ≲ z ≲ 1.8, respectively. We improve on prior unWISE cross-correlations not just by making use of the new, high-precision ACT DR6 lensing maps, but also by including additional spectroscopic data for redshift calibration and by analyzing our measurements with a more flexible theoretical model. We determine the amplitude of matter fluctuations at low redshifts (z ≃ 0.2-1.6), finding S 8 ≡ σ 8 ( Ω m / 0.3 ) 0.5 = 0.813 ± 0.021 using the ACT cross-correlation alone and S 8 = 0.810 ± 0.015 with a combination of Planck and ACT cross-correlations; these measurements are fully consistent with the predictions from primary CMB measurements assuming standard structure growth. The addition of baryon acoustic oscillation data breaks the degeneracy between σ 8 and Ωm , allowing us to measure σ 8 = 0.813 ± 0.020 from the cross-correlation of unWISE with ACT and σ 8 = 0.813 ± 0.015 from the combination of cross-correlations with ACT and Planck. These results also agree with the expectations from primary CMB extrapolations in ΛCDM cosmology; the consistency of σ 8 derived from our two redshift samples at z ∼ 0.6 and 1.1 provides a further check of our cosmological model. Our results suggest that structure formation on linear scales is well described by ΛCDM even down to low redshifts z ≲ 1.
- Published
- 2024
3. Google Trends Analysis of Otologic Symptom Searches Following COVID-19
- Author
-
Kim, Joshua K, Tawk, Karen, Kim, Jonathan M, Djalilian, Hamid R, and Abouzari, Mehdi
- Subjects
Biomedical and Clinical Sciences ,Clinical Sciences ,Clinical Research ,Infectious Diseases ,Pain Research ,Emerging Infectious Diseases ,Brain Disorders ,Coronaviruses ,Neurosciences ,Chronic Pain ,Headaches ,2.1 Biological and endogenous factors ,Google Trends ,Otologic Symptoms ,Pandemic ,Search Interest ,Search Trends ,Clinical sciences - Abstract
IntroductionCOVID-19 infection was accompanied by otologic symptoms, a pattern that was captured early by Google Trends. The objective of this study is to investigate searches for otologic symptoms and identify correlations with the pandemic onset.Materials and methodsSearch interest for otologic symptoms was gathered using Google Trends from two years before and two years following the pandemic start date. A two-tailed Mann-Whitney U test was used to identify significant changes and effect size.ResultsIn total, search interest for 14 terms was collected, with significant changes identified in 11. Six terms showed increased search interest, with the most significant rises observed for headache (r=0.589, p
- Published
- 2024
4. Correlation Between Laterality of Hearing Loss and Migraine Features in Menière's Disease
- Author
-
Tawk, Karen, Kim, Joshua K, Frank, Madelyn, Goshtasbi, Khodayar, Abouzari, Mehdi, and Djalilian, Hamid R
- Subjects
Allied Health and Rehabilitation Science ,Biomedical and Clinical Sciences ,Clinical Sciences ,Health Sciences ,Dental/Oral and Craniofacial Disease ,Migraines ,Brain Disorders ,Headaches ,Pain Research ,Chronic Pain ,Neurosciences ,Neurological ,Ear ,Humans ,Male ,Female ,Middle Aged ,Aged ,Meniere Disease ,Earache ,Hearing Loss ,Migraine Disorders ,Deafness ,Headache ,Hearing loss ,Meniere's disease ,Migraine ,Otalgia ,Otologic migraine ,Zoology ,Public Health and Health Services ,Otorhinolaryngology ,Clinical sciences ,Allied health and rehabilitation science - Abstract
ObjectivesThe objective of this study is to understand whether the hearing loss laterality in Menière's disease (MD) correlates with migraine symptoms laterality such as headache, neck stiffness, and otalgia.MethodsWe performed a retrospective review of prospectively obtained data on patients presenting between September 2015 and October 2021 with definite or probable MD. A custom-designed, comprehensive questionnaire was used to identify patients' migraine-related symptoms. The clinical and audiometric data were used to diagnose patients with definite or probable MD using criteria set by the American Academy of Otolaryngology-Head and Neck Surgery.ResultsIn total, 113 patients with definite or probable MD were included in the study. The mean age of the patients was 60 ± 15 years with no gender predominance (49.6% male and 50.4% female). A total of 57 (50%) patients were presented with headaches. Among the migraine headache cohort, headache and otalgia were on the same side as the MD ear affected by hearing loss. In addition, in patients who present with otalgia as the primary feature of headache, otalgia was more likely to be on the same side as the ear affected by the hearing loss.ConclusionsThe high prevalence of migraine symptoms on the same side of the ear affected by MD among this cohort could suggest a shared pathophysiology in both MD and migraine, possibly involving migraine-related changes in both the cochlea and vestibule.
- Published
- 2023
5. Microsurgical Needle Retention Does Not Cause Pain or Neurovascular Injury in a Rat Model.
- Author
-
Arora, Jagmeet, Kim, Joshua, Pakvasa, Mikhail, Sayadi, Lohrasb, Leis, Amber, Widgerow, Alan, and Lem, Melinda
- Abstract
UNLABELLED: Approximately 20% of retained foreign bodies are surgical needles. Retained macro-needles may become symptomatic, but the effect of microsurgical needles is uncertain. We present the first animal model to simulate microsurgical needle retention. Given a lack of reported adverse outcomes associated with macro-needles and a smaller cutting area of microsurgical needles, we hypothesized that microsurgical needles in rats would not cause changes in health or neurovascular compromise. METHODS: Male Sprague-Dawley rats (x̄ weight: 288.9 g) were implanted with a single, 9.0 needle (n = 8) or 8.0 needle (n = 8) orthogonal to the right femoral vessels and sutured in place. A control group (n = 8) underwent sham surgery. Weekly, a cumulative health score evaluating body weight, body condition score, physical appearance, and behavior for each rat was determined. Infrared thermography (°C, FLIR one) of each hindlimb and the difference was obtained on postoperative days 15, 30, 60, and 90. On day 90, animals were euthanatized, hindlimbs were imaged via fluoroscopy, and needles were explanted. RESULTS: The mean, cumulative health score for all cohorts at each weekly timepoint was 0. The mean temperature difference was not significantly different on postoperative days 15 (P = 0.54), 30 (P = 0.97), 60 (P = 0.29), or 90 (P = 0.09). In seven of eight rats, 8.0 needles were recovered and visualized on fluoroscopy. In six of eight rats, 9.0 needles were recovered, but 0/8 needles were visualized on fluoroscopy. CONCLUSIONS: Microsurgical needle retention near neurovascular structures may be benign, and imaging for needles smaller than 8.0 may be futile. Further studies should explore microsurgical needle retention potentially through larger animal models.
- Published
- 2023
6. One hundred most‐cited articles in head and neck surgery and analysis of female authorship
- Author
-
Trent, Monica S, Michelle, Lauren, Roman, Kelsey, Kim, Joshua K, Haidar, Yarah M, Tjoa, Tjoson, and Abouzari, Mehdi
- Subjects
Biomedical and Clinical Sciences ,Clinical Sciences ,Dentistry ,Dental/Oral and Craniofacial Disease ,Female ,Humans ,Authorship ,Bibliometrics ,female authorship ,head and neck surgery ,impact ,otolaryngology ,top cited ,Otorhinolaryngology ,Clinical sciences - Abstract
BackgroundWhile female head and neck surgeons have made significant contributions to the field, women's achievements in scientific communication have traditionally been underreported.MethodsA search of high-impact journals in the field of head and neck surgery was performed in the Elsevier's Scopus database to identify the top 100 most-cited articles.ResultsThe top 100 most-cited articles (during the span of 1953 and 2016) had the highest total number of citations between 2005 and 2009. Women accounted for 36% of first authors and 25% of corresponding authors. Change in the relative number of first female authors in these top 100 articles did not increase significantly between 1950 and 2019.ConclusionThe proportion of female first authors in head and neck surgery has not significantly increased over the past several decades, despite greater numbers of female trainees. Our findings support the need for additional research on female representation in head and neck surgery.
- Published
- 2023
7. Single-molecule Taq DNA polymerase dynamics
- Author
-
Turvey, Mackenzie W, Gabriel, Kristin N, Lee, Wonbae, Taulbee, Jeffrey J, Kim, Joshua K, Chen, Silu, Lau, Calvin J, Kattan, Rebecca E, Pham, Jenifer T, Majumdar, Sudipta, Garcia, Davil, Weiss, Gregory A, and Collins, Philip G
- Subjects
Biochemistry and Cell Biology ,Biological Sciences ,Nanotechnology ,Bioengineering ,Generic health relevance ,Catalysis ,DNA Replication ,Kinetics ,Nucleotides ,Taq Polymerase - Abstract
Taq DNA polymerase functions at elevated temperatures with fast conformational dynamics-regimes previously inaccessible to mechanistic, single-molecule studies. Here, single-walled carbon nanotube transistors recorded the motions of Taq molecules processing matched or mismatched template-deoxynucleotide triphosphate pairs from 22° to 85°C. By using four enzyme orientations, the whole-enzyme closures of nucleotide incorporations were distinguished from more rapid, 20-μs closures of Taq's fingers domain testing complementarity and orientation. On average, one transient closure was observed for every nucleotide binding event; even complementary substrate pairs averaged five transient closures between each catalytic incorporation at 72°C. The rate and duration of the transient closures and the catalytic events had almost no temperature dependence, leaving all of Taq's temperature sensitivity to its rate-determining open state.
- Published
- 2022
8. Pyrocinchonimides Conjugate to Amine Groups on Proteins via Imide Transfer
- Author
-
Richardson, Mark B, Gabriel, Kristin N, Garcia, Joseph A, Ashby, Shareen N, Dyer, Rebekah P, Kim, Joshua K, Lau, Calvin J, Hong, John, Le Tourneau, Ryan J, Sen, Sanjana, Narel, David L, Katz, Benjamin B, Ziller, Joseph W, Majumdar, Sudipta, Collins, Philip G, and Weiss, Gregory A
- Subjects
Organic Chemistry ,Chemical Sciences ,Generic health relevance ,Amines ,Hydrogen-Ion Concentration ,Imides ,Kinetics ,Lysine ,Proteins ,Solvents ,Sulfhydryl Compounds ,Thermodynamics ,Medicinal and Biomolecular Chemistry ,Biochemistry and Cell Biology ,Biochemistry and cell biology ,Medicinal and biomolecular chemistry - Abstract
Advances in bioconjugation, the ability to link biomolecules to each other, small molecules, surfaces, and more, can spur the development of advanced materials and therapeutics. We have discovered that pyrocinchonimide, the dimethylated analogue of maleimide, undergoes a surprising transformation with biomolecules. The reaction targets amines and involves an imide transfer, which has not been previously reported for bioconjugation purposes. Despite their similarity to maleimides, pyrocinchonimides do not react with free thiols. Though both lysine residues and the N-termini of proteins can receive the transferred imide, the reaction also exhibits a marked preference for certain amines that cannot solely be ascribed to solvent accessibility. This property is peculiar among amine-targeting reactions and can reduce combinatorial diversity when many available reactive amines are available, such as in the formation of antibody-drug conjugates. Unlike amides, the modification undergoes very slow reversion under high pH conditions. The reaction offers a thermodynamically controlled route to single or multiple modifications of proteins for a wide range of applications.
- Published
- 2020
9. Pyrocinchonimides Conjugate to Amine Groups on Proteins via Imide Transfer
- Author
-
Richardson, Mark B, Gabriel, Kristin N, Garcia, Joseph A, Ashby, Shareen N, Dyer, Rebekah P, Kim, Joshua K, Lau, Calvin J, Hong, John, Le Tourneau, Ryan J, Sen, Sanjana, Narel, David L, Katz, Benjamin B, Ziller, Joseph W, Majumdar, Sudipta, Collins, Philip G, and Weiss, Gregory A
- Subjects
Generic health relevance ,Amines ,Hydrogen-Ion Concentration ,Imides ,Kinetics ,Lysine ,Proteins ,Solvents ,Sulfhydryl Compounds ,Thermodynamics ,Medicinal and Biomolecular Chemistry ,Organic Chemistry ,Biochemistry and Cell Biology - Abstract
Advances in bioconjugation, the ability to link biomolecules to each other, small molecules, surfaces, and more, can spur the development of advanced materials and therapeutics. We have discovered that pyrocinchonimide, the dimethylated analogue of maleimide, undergoes a surprising transformation with biomolecules. The reaction targets amines and involves an imide transfer, which has not been previously reported for bioconjugation purposes. Despite their similarity to maleimides, pyrocinchonimides do not react with free thiols. Though both lysine residues and the N-termini of proteins can receive the transferred imide, the reaction also exhibits a marked preference for certain amines that cannot solely be ascribed to solvent accessibility. This property is peculiar among amine-targeting reactions and can reduce combinatorial diversity when many available reactive amines are available, such as in the formation of antibody-drug conjugates. Unlike amides, the modification undergoes very slow reversion under high pH conditions. The reaction offers a thermodynamically controlled route to single or multiple modifications of proteins for a wide range of applications.
- Published
- 2020
10. The Crystallinity and Aspect Ratio of Cellulose Nanomaterials Determine Their Pro‐Inflammatory and Immune Adjuvant Effects In Vitro and In Vivo
- Author
-
Wang, Xiang, Chang, Chong Hyun, Jiang, Jinhong, Liu, Qi, Liao, Yu‐Pei, Lu, Jianqin, Li, Linjiang, Liu, Xiangsheng, Kim, Joshua, Ahmed, Ayman, Nel, André E, and Xia, Tian
- Subjects
Medical Biotechnology ,Engineering ,Biomedical and Clinical Sciences ,Nanotechnology ,Bioengineering ,Inflammatory and immune system ,Adjuvants ,Immunologic ,Animals ,Cell Survival ,Cellulose ,Crystallization ,Dendritic Cells ,Glutathione ,Humans ,Hydrodynamics ,Immunity ,Humoral ,Immunoglobulin G ,Inflammasomes ,Inflammation ,Interleukin-1beta ,Lysosomes ,Mice ,Inbred C57BL ,NLR Family ,Pyrin Domain-Containing 3 Protein ,Nanoparticles ,Nanostructures ,Ovalbumin ,Oxidative Stress ,Particle Size ,Reactive Oxygen Species ,Static Electricity ,Subcellular Fractions ,THP-1 Cells ,aspect ratio ,cellulose nanocrystals ,cellulose nanofibrils ,crystallinity ,humoral immune effects ,Nanoscience & Nanotechnology - Abstract
Nanocellulose is increasingly considered for applications; however, the fibrillar nature, crystalline phase, and surface reactivity of these high aspect ratio nanomaterials need to be considered for safe biomedical use. Here a comprehensive analysis of the impact of cellulose nanofibrils (CNF) and nanocrystals (CNC) is performed using materials provided by the Nanomaterial Health Implications Research Consortium of the National Institute of Environmental Health Sciences. An intermediary length of nanocrystals is also derived by acid hydrolysis. While all CNFs and CNCs are devoid of cytotoxicity, 210 and 280 nm fluorescein isothiocyanate (FITC)-labeled CNCs show higher cellular uptake than longer and shorter CNCs or CNFs. Moreover, CNCs in the 200-300 nm length scale are more likely to induce lysosomal damage, NLRP3 inflammasome activation, and IL-1β production than CNFs. The pro-inflammatory effects of CNCs are correlated with higher crystallinity index, surface hydroxyl density, and reactive oxygen species generation. In addition, CNFs and CNCs can induce maturation of bone marrow-derived dendritic cells and CNCs (and to a lesser extent CNFs) are found to exert adjuvant effects in ovalbumin (OVA)-injected mice, particularly for 210 and 280 nm CNCs. All considered, the data demonstrate the importance of length scale, crystallinity, and surface reactivity in shaping the innate immune response to nanocellulose.
- Published
- 2019
11. Skin-mountable stretch sensor for wearable health monitoring
- Author
-
Pegan, Jonathan D, Zhang, Jasmine, Chu, Michael, Nguyen, Thao, Park, Sun-Jun, Paul, Akshay, Kim, Joshua, Bachman, Mark, and Khine, Michelle
- Subjects
Lung ,Equipment Design ,Humans ,Monitoring ,Physiologic ,Movement ,Respiration ,Wearable Electronic Devices ,Physical Sciences ,Chemical Sciences ,Technology ,Nanoscience & Nanotechnology - Abstract
This work presents a wrinkled Platinum (wPt) strain sensor with tunable strain sensitivity for applications in wearable health monitoring. These stretchable sensors show a dynamic range of up to 185% strain and gauge factor (GF) of 42. This is believed to be the highest reported GF of any metal thin film strain sensor over a physiologically relevant dynamic range to date. Importantly, sensitivity and dynamic range are tunable to the application by adjusting wPt film thickness. Performance is reliable over 1000 cycles with low hysteresis after sensor conditioning. The possibility of using such a sensor for real-time respiratory monitoring by measuring chest wall displacement and correlating with lung volume is demonstrated.
- Published
- 2016
12. Highly stretchable wrinkled gold thin film wires.
- Author
-
Kim, Joshua, Park, Sun-Jun, Nguyen, Thao, Chu, Michael, Pegan, Jonathan, and Khine, Michelle
- Abstract
With the growing prominence of wearable electronic technology, there is a need to improve the mechanical reliability of electronics for more demanding applications. Conductive wires represent a vital component present in all electronics. Unlike traditional planar and rigid electronics, these new wearable electrical components must conform to curvilinear surfaces, stretch with the body, and remain unobtrusive and low profile. In this paper, the piezoresistive response of shrink induced wrinkled gold thin films under strain demonstrates robust conductive performance in excess of 200% strain. Importantly, the wrinkled metallic thin films displayed negligible change in resistance of up to 100% strain. The wrinkled metallic wires exhibited consistent performance after repetitive strain. Importantly, these wrinkled thin films are inexpensive to fabricate and are compatible with roll to roll manufacturing processes. We propose that these wrinkled metal thin film wires are an attractive alternative to conventional wires for wearable applications.
- Published
- 2016
13. Maïssa Bey and Senja L. Djelouah, Above All, Don’t Look Back (Charlottesville, Virginia: University of Virginia Press, 2009). pp. 190.
- Author
-
Kim, Joshua
- Published
- 2016
14. Impaired GABAB Receptor Signaling Dramatically Up-Regulates Kiss1 Expression Selectively in Nonhypothalamic Brain Regions of Adult but Not Prepubertal Mice
- Author
-
Di Giorgio, Noelia P, Semaan, Sheila J, Kim, Joshua, López, Paula V, Bettler, Bernhard, Libertun, Carlos, Lux-Lantos, Victoria A, and Kauffman, Alexander S
- Subjects
Pharmacology and Pharmaceutical Sciences ,Biomedical and Clinical Sciences ,Contraception/Reproduction ,Women's Health ,Neurosciences ,1.1 Normal biological development and functioning ,Neurological ,Amygdala ,Animals ,Arcuate Nucleus of Hypothalamus ,Brain Mapping ,Estradiol ,Female ,Gene Expression Regulation ,Genotype ,Hypothalamus ,Immunohistochemistry ,Kisspeptins ,Male ,Mice ,Mice ,Knockout ,Midline Thalamic Nuclei ,Neurons ,Phenotype ,Receptors ,GABA-B ,Septal Nuclei ,Signal Transduction ,Testosterone ,Time Factors ,Up-Regulation ,gamma-Aminobutyric Acid ,Biological Sciences ,Agricultural and Veterinary Sciences ,Medical and Health Sciences ,Endocrinology & Metabolism ,Clinical sciences - Abstract
Kisspeptin, encoded by Kiss1, stimulates reproduction and is synthesized in the hypothalamic anteroventral periventricular and arcuate nuclei. Kiss1 is also expressed at lower levels in the medial amygdala (MeA) and bed nucleus of the stria terminalis (BNST), but the regulation and function of Kiss1 there is poorly understood. γ-Aminobutyric acid (GABA) also regulates reproduction, and female GABAB1 receptor knockout (KO) mice have compromised fertility. However, the interaction between GABAB receptors and Kiss1 neurons is unknown. Here, using double-label in situ hybridization, we first demonstrated that a majority of hypothalamic Kiss1 neurons coexpress GABAB1 subunit, a finding also confirmed for most MeA Kiss1 neurons. Yet, despite known reproductive impairments in GABAB1KO mice, Kiss1 expression in the anteroventral periventricular and arcuate nuclei, assessed by both in situ hybridization and real-time PCR, was identical between adult wild-type and GABAB1KO mice. Surprisingly, however, Kiss1 levels in the BNST and MeA, as well as the lateral septum (a region normally lacking Kiss1 expression), were dramatically increased in both GABAB1KO males and females. The increased Kiss1 levels in extrahypothalamic regions were not caused by elevated sex steroids (which can increase Kiss1 expression), because circulating estradiol and testosterone were equivalent between genotypes. Interestingly, increased Kiss1 expression was not detected in the MeA or BNST in prepubertal KO mice of either sex, indicating that the enhancements in extrahypothalamic Kiss1 levels initiate during/after puberty. These findings suggest that GABAB signaling may normally directly or indirectly inhibit Kiss1 expression, particularly in the BNST and MeA, and highlight the importance of studying kisspeptin populations outside the hypothalamus.
- Published
- 2014
15. Impaired GABAB receptor signaling dramatically up-regulates Kiss1 expression selectively in nonhypothalamic brain regions of adult but not prepubertal mice.
- Author
-
Di Giorgio, Noelia P, Semaan, Sheila J, Kim, Joshua, López, Paula V, Bettler, Bernhard, Libertun, Carlos, Lux-Lantos, Victoria A, and Kauffman, Alexander S
- Subjects
Amygdala ,Hypothalamus ,Septal Nuclei ,Midline Thalamic Nuclei ,Neurons ,Animals ,Mice ,Knockout ,Mice ,gamma-Aminobutyric Acid ,Testosterone ,Estradiol ,Receptors ,GABA-B ,Brain Mapping ,Immunohistochemistry ,Signal Transduction ,Gene Expression Regulation ,Up-Regulation ,Genotype ,Phenotype ,Time Factors ,Female ,Male ,Kisspeptins ,Arcuate Nucleus of Hypothalamus ,Endocrinology & Metabolism ,Agricultural and Veterinary Sciences ,Medical and Health Sciences ,Biological Sciences - Abstract
Kisspeptin, encoded by Kiss1, stimulates reproduction and is synthesized in the hypothalamic anteroventral periventricular and arcuate nuclei. Kiss1 is also expressed at lower levels in the medial amygdala (MeA) and bed nucleus of the stria terminalis (BNST), but the regulation and function of Kiss1 there is poorly understood. γ-Aminobutyric acid (GABA) also regulates reproduction, and female GABAB1 receptor knockout (KO) mice have compromised fertility. However, the interaction between GABAB receptors and Kiss1 neurons is unknown. Here, using double-label in situ hybridization, we first demonstrated that a majority of hypothalamic Kiss1 neurons coexpress GABAB1 subunit, a finding also confirmed for most MeA Kiss1 neurons. Yet, despite known reproductive impairments in GABAB1KO mice, Kiss1 expression in the anteroventral periventricular and arcuate nuclei, assessed by both in situ hybridization and real-time PCR, was identical between adult wild-type and GABAB1KO mice. Surprisingly, however, Kiss1 levels in the BNST and MeA, as well as the lateral septum (a region normally lacking Kiss1 expression), were dramatically increased in both GABAB1KO males and females. The increased Kiss1 levels in extrahypothalamic regions were not caused by elevated sex steroids (which can increase Kiss1 expression), because circulating estradiol and testosterone were equivalent between genotypes. Interestingly, increased Kiss1 expression was not detected in the MeA or BNST in prepubertal KO mice of either sex, indicating that the enhancements in extrahypothalamic Kiss1 levels initiate during/after puberty. These findings suggest that GABAB signaling may normally directly or indirectly inhibit Kiss1 expression, particularly in the BNST and MeA, and highlight the importance of studying kisspeptin populations outside the hypothalamus.
- Published
- 2014
16. Developmental GnRH Signaling Is Not Required for Sexual Differentiation of Kisspeptin Neurons but Is Needed for Maximal Kiss1 Gene Expression in Adult Females
- Author
-
Kim, Joshua, Tolson, Kristen P, Dhamija, Sangeeta, and Kauffman, Alexander S
- Subjects
Biomedical and Clinical Sciences ,Clinical Sciences ,Contraception/Reproduction ,Neurosciences ,Pediatric ,Underpinning research ,1.1 Normal biological development and functioning ,Reproductive health and childbirth ,Animals ,Anterior Thalamic Nuclei ,Estradiol ,Estrogen Receptor alpha ,Estrogen Replacement Therapy ,Estrogens ,Female ,Gonadotropin-Releasing Hormone ,Hypogonadism ,Intralaminar Thalamic Nuclei ,Kisspeptins ,Mice ,Mice ,Inbred C57BL ,Mice ,Mutant Strains ,Nerve Tissue Proteins ,Neurons ,Ovariectomy ,Sex Differentiation ,Sexual Development ,Signal Transduction ,Thalamic Nuclei ,Up-Regulation ,Biological Sciences ,Agricultural and Veterinary Sciences ,Medical and Health Sciences ,Endocrinology & Metabolism ,Clinical sciences - Abstract
Kisspeptin, encoded by Kiss1, stimulates reproduction. In rodents, one Kiss1 population resides in the hypothalamic anterior ventral periventricular nucleus and neighboring rostral periventricular nucleus (AVPV/PeN). AVPV/PeN Kiss1 neurons are sexually dimorphic (greater in females), yet the mechanisms regulating their development and sexual differentiation remain poorly understood. Neonatal estradiol (E₂) normally defeminizes AVPV/PeN kisspeptin neurons, but emerging evidence suggests that developmental E₂ may also influence feminization of kisspeptin, although exactly when in development this process occurs is unknown. In addition, the obligatory role of GnRH signaling in governing sexual differentiation of Kiss1 or other sexually dimorphic traits remains untested. Here, we assessed whether AVPV/PeN Kiss1 expression is permanently impaired in adult hpg (no GnRH or E₂) or C57BL6 mice under different E₂ removal or replacement paradigms. We determined that 1) despite lacking GnRH signaling in development, marked sexual differentiation of Kiss1 still occurs in hpg mice; 2) adult hpg females, who lack lifetime GnRH and E₂ exposure, have reduced AVPV/PeN Kiss1 expression compared to wild-type females, even after chronic adulthood E₂ treatment; 3) E₂ exposure to hpg females during the pubertal period does not rescue their submaximal adult Kiss1 levels; and 4) in C57BL6 females, removal of ovarian E2 before the pubertal or juvenile periods does not impair feminization and maximal adult AVPV/PeN Kiss1 expression nor the ability to generate LH surges, indicating that puberty is not a critical period for Kiss1 development. Thus, sexual differentiation still occurs without GnRH, but GnRH or downstream E₂ signaling is needed sometime before juvenile development for complete feminization and maximal Kiss1 expression in adult females.
- Published
- 2013
17. Developmental GnRH signaling is not required for sexual differentiation of kisspeptin neurons but is needed for maximal Kiss1 gene expression in adult females.
- Author
-
Kim, Joshua, Tolson, Kristen P, Dhamija, Sangeeta, and Kauffman, Alexander S
- Subjects
Thalamic Nuclei ,Anterior Thalamic Nuclei ,Intralaminar Thalamic Nuclei ,Neurons ,Animals ,Mice ,Inbred C57BL ,Mice ,Mice ,Mutant Strains ,Hypogonadism ,Estradiol ,Nerve Tissue Proteins ,Estrogen Receptor alpha ,Estrogens ,Estrogen Replacement Therapy ,Ovariectomy ,Signal Transduction ,Up-Regulation ,Sex Differentiation ,Sexual Development ,Female ,Gonadotropin-Releasing Hormone ,Kisspeptins ,Endocrinology & Metabolism ,Agricultural and Veterinary Sciences ,Medical and Health Sciences ,Biological Sciences - Abstract
Kisspeptin, encoded by Kiss1, stimulates reproduction. In rodents, one Kiss1 population resides in the hypothalamic anterior ventral periventricular nucleus and neighboring rostral periventricular nucleus (AVPV/PeN). AVPV/PeN Kiss1 neurons are sexually dimorphic (greater in females), yet the mechanisms regulating their development and sexual differentiation remain poorly understood. Neonatal estradiol (E₂) normally defeminizes AVPV/PeN kisspeptin neurons, but emerging evidence suggests that developmental E₂ may also influence feminization of kisspeptin, although exactly when in development this process occurs is unknown. In addition, the obligatory role of GnRH signaling in governing sexual differentiation of Kiss1 or other sexually dimorphic traits remains untested. Here, we assessed whether AVPV/PeN Kiss1 expression is permanently impaired in adult hpg (no GnRH or E₂) or C57BL6 mice under different E₂ removal or replacement paradigms. We determined that 1) despite lacking GnRH signaling in development, marked sexual differentiation of Kiss1 still occurs in hpg mice; 2) adult hpg females, who lack lifetime GnRH and E₂ exposure, have reduced AVPV/PeN Kiss1 expression compared to wild-type females, even after chronic adulthood E₂ treatment; 3) E₂ exposure to hpg females during the pubertal period does not rescue their submaximal adult Kiss1 levels; and 4) in C57BL6 females, removal of ovarian E2 before the pubertal or juvenile periods does not impair feminization and maximal adult AVPV/PeN Kiss1 expression nor the ability to generate LH surges, indicating that puberty is not a critical period for Kiss1 development. Thus, sexual differentiation still occurs without GnRH, but GnRH or downstream E₂ signaling is needed sometime before juvenile development for complete feminization and maximal Kiss1 expression in adult females.
- Published
- 2013
18. Characterization of DNA hybridization kinetics in a microfluidic flow channel
- Author
-
Kim, Joshua Hyong-Seok, Marafie, Alia, Jia, Xi-Yu, Zoval, Jim V, and Madou, Marc J
- Subjects
Fluid Mechanics and Thermal Engineering ,Engineering ,Bioengineering ,Biotechnology ,DNA hybridization kinetics ,microfluidic flow channel ,PDMS ,pressure-driven flow ,Microfluidic flow channel ,Pressure-driven flow ,Optical Physics ,Analytical Chemistry ,Materials Engineering ,Analytical chemistry ,Chemical engineering ,Materials engineering - Abstract
In this investigation we report on the influence of volumetric flow rate, flow velocity, complementary DNA concentration, height of a microfluidic flow channel and time on DNA hybridization kinetics. A syringe pump was used to drive Cy3-labeled target DNA through a polydimethylsiloxane (PDMS) microfluidic flow channel to hybridize with immobilized DNA from the West Nile Virus. We demonstrate that a reduction of channel height, while keeping a fixed volumetric flow rate or a fixed flow velocity, enhances mass transport of target DNA to the capture probes. Compared to a passive hybridization, the DNA hybridization in the microfluidic flow channel generates higher fluorescence intensities for lower concentration of target DNA during the same fixed period of time. Within a fixed 2 min time period the fastest DNA hybridization at a 50 pM concentration of target DNA is achieved with a continuous flow of target DNA at the highest flow rate and the lowest channel height.
- Published
- 2006
19. Characterization of DNA hybridization kinetics in a microfluidic flow channel.
- Author
-
Kim, Joshua Hyong-Seok, Marafie, Alia, Jia, Xi-Yu, Zoval, Jim V, and Madou, Marc J
- Subjects
DNA hybridization kinetics ,Microfluidic flow channel ,PDMS ,Pressure-driven flow ,microfluidic flow channel ,pressure-driven flow ,Analytical Chemistry ,Optical Physics ,Materials Engineering - Abstract
In this investigation we report on the influence of volumetric flow rate, flow velocity, complementary DNA concentration, height of a microfluidic flow channel and time on DNA hybridization kinetics. A syringe pump was used to drive Cy3-labeled target DNA through a polydimethylsiloxane (PDMS) microfluidic flow channel to hybridize with immobilized DNA from the West Nile Virus. We demonstrate that a reduction of channel height, while keeping a fixed volumetric flow rate or a fixed flow velocity, enhances mass transport of target DNA to the capture probes. Compared to a passive hybridization, the DNA hybridization in the microfluidic flow channel generates higher fluorescence intensities for lower concentration of target DNA during the same fixed period of time. Within a fixed 2 min time period the fastest DNA hybridization at a 50 pM concentration of target DNA is achieved with a continuous flow of target DNA at the highest flow rate and the lowest channel height.
- Published
- 2006
20. Wrinkled Micro-Nanostructured Thin Films for Flexible Wearable Electronics and Continuous Health Monitoring Applications
- Author
-
Kim, Joshua
- Subjects
Biomedical engineering ,Materials Science ,Engineering ,Continuous Health Monitoring ,Flexible ,Stretchable ,Wearable - Abstract
The rapid growth of wearable electronics has generated an influx of research in developing highly flexible, stretchable materials and sensors that can conform to the human body. Developing flexible soft sensors that are capable of withstanding large amounts of mechanical stress can enable novel continuous health monitoring devices. However, existing functional materials are rigid and brittle which are not able to flex and stretch with the human body. Therefore, there is a need to engineer materials that are capable of withstanding mechanical stress to develop conformable wearable electronics for continuous health monitoring applications.The work presented here introduces a thermally induced shrinking fabrication platform using pre-stressed thermoplastics to create highly wrinkled structured thin films for stretchable electronic sensing applications. Specifically, mechanically flexible and stretchable wrinkled gold (Au) and carbon nanotube (CNT) thin films were fabricated for stretchable conductive wire, strain, and pressure applications. Electrical-mechanical characterization studies have shown that these wrinkled functional thin film materials, in comparison to its flat counterpart, were able to withstand large amounts of tensile stress and mechanical pressure before electrical failure. When supported by elastomeric substrates, these wrinkled thin film materials may be used as stretchable wires and sensors for wearable applications on the human body. Finally, I will report on potential wearable applications demonstrating continuous health monitoring applications including human motion detection and blood pressure estimation.
- Published
- 2018
21. Low-Power Blocks for UWB Transceivers
- Author
-
Kim, Joshua H.
- Subjects
Electrical engineering ,asymmetry ,low power ,Super regenerative principle ,track and detection ,UWB - Abstract
In this dissertation, low-power blocks in UWB transceiver systems are presented. In particular, the main focus of this study is how low-power blocks in an impulse radio UWB (IR-UWB) system can be employed in sensor networks such as Body Area Networks (BANs). The thesis is divided into three general parts. In the first part, the general history, definitions, regulations, and development of UWB systems are reviewed. In addition, a brief explanation of the fundamental concepts of radio frequency communication in short duration of pulses is given. In the second part, the startup behavior of LC-VCOs used in UWB transmitters is investigated. In order to decrease the power consumption of the circuits without adding any complexity, we deliberately introduce a small asymmetry into the VCO that can greatly reduce the oscillation start-up time. Finally, we study the super-regenerative receiver architecture and the challenges it presents. In this work, we have designed a low-power 4 Mb/s super-regenerative receiver in a 0.18 µm CMOS process that tracks the incoming signal carrier pulse and synchronizes it with a pulse quench signal. The energy consumption for this receiver is 0.17 nJ/bit, which demonstrates the lowest energy consumption reported so far for an IR-UWB receiver system.
- Published
- 2014
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.