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1.
Discov Nano ; 19(1): 111, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38970699

RESUMEN

Experimental and simulation studies demonstrated that the initial voltage setting significantly influences the open-circuit voltage (VOC) in triboelectric nanogenerators (TENGs). Utilizing diode configurations, we consistently observed two distinct VOCs independent of the initial settings. A lower VOC corresponded to the surface voltage (VSurface), while a higher VOC was amplified by the product of the VSurface and the TENG's characteristic impedance ratio. Notably, a lower measurement system capacitance provided a more precise representation of the inherent characteristics of the TENG. Conversely, an increase in system impedance led to a convergence of the two VOCs and a reduction in their magnitudes relative to VSurface. These findings suggest that optimizing the initial/repeated charge balancing and minimizing capacitive loads are crucial for maximizing TENG output power in practical applications.

2.
Ophthalmic Epidemiol ; : 1-7, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38865601

RESUMEN

PURPOSE: This study investigated the relationship between near work hours and myopia in Korean adults. METHODS: We used data from the 2021 Korean National Health and Nutrition Examination Survey. Associations between near work time, physical activity, and myopia were assessed using chi-square tests and multiple logistic regression analyses. RESULTS: The overall prevalence of myopia was 60.2% in adults aged 19-59 years. The prevalence of myopia was 46.2% for individuals who used smart devices for less than one hour per day, while it was 68.0% for those who used smart devices for more than four hours. In the multiple logistic regression analysis, the odds ratio (OR) for myopia was significantly higher among individuals using smart devices for 3 hours (OR = 1.55, 95% CI = 1.08-2.23) or more than 4 hours (OR = 1.75, 95% CI = 1.27-2.42), compared to users with less than 1 hour of usage. Regarding sitting time, the OR for myopia was significantly higher in individuals who sat for more than 12 hours (OR = 1.66, 95% CI = 1.05-2.61) compared to those who sat less than 4 hours. CONCLUSION: This study found that near work and sitting times were positively associated with myopia. Given the high prevalence of myopia and its implications for serious eye diseases, it is essential to implement measures to manage myopia. Considering the increased near work hours resulting from the COVID-19 pandemic, it is necessary to adopt supplementary measures, such as ensuring sufficient rest time for the eyes and adjusting the brightness of lights, to improve eye health.

3.
Arch Craniofac Surg ; 25(2): 99-103, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38742338

RESUMEN

Because facial nerve injuries affect the quality of life, leaving them untreated can have devastating effects. The number of patients with traumatic and iatrogenic facial nerve paralysis is considerably high. Early detection and prompt treatment during the acute injury phase are crucial, and immediate surgical treatment should be considered when complete facial nerve injury is suspected. Symptom underestimation by patients and clinical misdiagnosis may delay surgical intervention, which may negatively affect outcomes and in some cases, impair the recovery of the injured facial nerve. Here, we report two cases of facial nerve injury that were treated with nerve grafts during the subacute phase. In both cases, subacute facial nerve grafting achieved significant improvements. These cases highlight surgical intervention in the subacute phase using nerve grafts as an appropriate treatment for facial nerve injuries.

4.
Nutr Res Pract ; 18(2): 282-293, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38584812

RESUMEN

BACKGROUND/OBJECTIVES: The prevalence of hypertension is increasing, and noodles have a high sodium content, so noodle consumption might be associated with a higher prevalence of hypertension. This study aimed to analyze the association between total and types of noodle intake and the risk of hypertension among Korean adults. Subjects aged 40-69 years were selected for this study. SUBJECTS/METHODS: This study included 56,580 participants (18,246 men and 38,334 women) aged 40-69 years old from the Health Examinees study. Noodle and nutrient intakes were assessed using the food frequency questionnaire. Hypertension was diagnosed as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg or antihypertensive medication use. Cox proportional hazard models were used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for hypertension. RESULTS: Higher noodle consumption was associated with increased hypertension among men (HR, 1.273; 95% CI, 1.166-1.390) and women (HR, 1.116; 95% CI, 1.038-1.199). CONCLUSION: We recommended reducing noodle intake and consuming vegetables and fruits to increase potassium intake, which can prevent vascular diseases.

5.
Alcohol ; 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38432421

RESUMEN

BACKGROUND: Alcohol consumption is a significant public health concern in Korea, with many individuals engaging in risky drinking behaviors. This study aims to analyze the association between facial flushing responses and the progression of hypertension in Korean adults, stratified by gender, using a large-scale prospective cohort study. METHODS: This study included 39,868 participants (males 10,868 and females 29,000) from the health examinees cohort. Participants were divided into two groups according to their weekly drinking patterns (moderate and heavy) and facial flushing responses (non-flusher and flusher) for statistical analysis. A multivariate Cox proportional hazards regression model was used to calculate hazard ratios and 95% confidence intervals between flushing response after alcohol consumption and hypertension risk. RESULTS: In males, the flusher group with a moderate alcohol intake pattern had a decreased risk of incident hypertension compared with non-flushers. In females, the flusher group had relatively higher risk of pre-hypertension and hypertension compared to the non-flusher group. CONCLUSION: The association between facial flushing and hypertension varies depending on the level of alcohol consumption and should be considered in relation to gender differences. Further research is needed to understand the relationship between facial flushing response and the risk of hypertension based on alcohol consumption levels.

6.
Discov Nano ; 19(1): 52, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38503898

RESUMEN

We investigated the polarity dependence of a capacitive energy management circuit in a triboelectric nanogenerator (TENG) power system. In a half-wave rectifying circuit, the Simulation Program with Integrated Circuit Emphasis and analytical models show that the charge dump to the load varied depending on the polarity of the rectifying circuit even with the same charge output from TENG. Depending on the polarity of the rectifying circuit, a fast saturation of the direct current (DC) output voltage or a high DC output voltage was obtained. Experiments with a half-wave rectifier and Bennet doubler confirmed our simulation and theoretical results. The charge dump from the minimum capacitance of the separated TENG to the load capacitance and the charge dump from the maximum capacitance of the contacted TENG to the load resulted in asymmetric charging behavior. We concluded that it is necessary to analyze the TENG and the capacitive energy management circuit as a single system rather than considering them as independent units in the rectifying circuit of the TENG. This work can provide insights for the design of triboelectric energy harvesting systems.

7.
Polymers (Basel) ; 16(5)2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38475280

RESUMEN

We report chemically tunable n-type titanium oxides using ethanolamine as a nitrogen dopant source. As the amount of ethanolamine added to the titanium oxide precursor during synthesis increases, the Fermi level of the resulting titanium oxides (ethanolamine-incorporated titanium oxides) significantly changes from -4.9 eV to -4.3 eV, and their free charge carrier densities are enhanced by two orders of magnitudes, reaching up to 5 × 1018 cm-3. Unexpectedly, a basic ethanolamine reinforces not only the n-type properties of titanium oxides, but also their basicity, which facilitates acid-base ionic junctions in contact with acidic materials. The enhanced charge carrier density and basicity of the chemically tuned titanium oxides enable multi-junction solar cells to have interconnecting junctions consisting of basic n-type titanium oxides and acidic p-type PEDOT:PSS to gain high open-circuit voltages of 1.44 V and 2.25 V from tandem and triple architectures, respectively.

8.
Mol Cells ; 47(3): 100007, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38238205

RESUMEN

Recent evidence establishes a pivotal role for obesity-induced inflammation in precipitating insulin resistance and type-2 diabetes. Central to this process is the proinflammatory M1 adipose-tissue macrophages (ATMs) in epididymal white adipose tissue (eWAT). Notably, natural killer (NK) cells are a crucial regulator of ATMs since their cytokines induce ATM recruitment and M1 polarization. The importance of NK cells is shown by the strong increase in NK-cell numbers in eWAT, and by studies showing that removing and expanding NK cells respectively improve and worsen obesity-induced insulin resistance. It has been suggested that NK cells are activated by unknown ligands on obesity-stressed adipocytes that bind to NKp46 (encoded by Ncr1), which is an activating NK-cell receptor. This was supported by a study showing that NKp46-knockout mice have improved obesity-induced inflammation/insulin resistance. We therefore planned to use the NKp46-knockout mice to further elucidate the molecular mechanism by which NKp46 mediates eWAT NK-cell activation in obesity. We confirmed that obesity increased eWAT NKp46+ NK-cell numbers and NKp46 expression in wild-type mice and that NKp46-knockout ablated these responses. Unexpectedly, however, NKp46-knockout mice demonstrated insulin resistance similar to wild-type mice, as shown by fasting blood glucose/insulin levels and glucose/insulin tolerance tests. Obesity-induced increases in eWAT ATM numbers and proinflammatory gene expression were also similar. Thus, contrary to previously published results, NKp46 does not regulate obesity-induced insulin resistance. It is therefore unclear whether NKp46 participates in the development of obesity-induced inflammation and insulin resistance. This should be considered when elucidating the obesity-mediated molecular mechanisms that activate NK cells.


Asunto(s)
Resistencia a la Insulina , Animales , Ratones , Inflamación/metabolismo , Insulina , Células Asesinas Naturales , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/metabolismo , Receptores de Células Asesinas Naturales
9.
Physiol Rep ; 11(21)2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37962017

RESUMEN

Menopause is associated with vascular dysfunction attributed to reduced estrogen levels. Exercise has been proposed to promote angiogenesis and vascular dysfunction. However, studies of brain angiogenesis during menopause are limited. We analyzed the effects of exercise on angiogenesis-related factors in menopausal rat model. Twenty-week-old female Sprague-Dawley rats (N = 18) were randomly divided into a normal control group (N, n = 6), an ovariectomized control group (OVX, n = 6), and an ovariectomy + exercise group (OVX-EX, n = 6). Treadmill exercises were conducted in the OVX-EX group for 8 weeks (15-60 m/min, 1 h/day, and 5 days/week). The current study showed that the expression of angiogenesis-related factors (platelet-derived growth factor subunit A, B, vascular endothelial growth factor, angiopoietin 1, and angiopoietin 2) significantly decreased in the cortex of the OVX group. However, these factors were significantly restored in the cortex of the OVX-EX group after 8 weeks of treadmill exercise. In summary, estrogen deficiency causes vascular dysfunction by inhibiting the expression of angiogenesis-related factors. However, exercise can restore angiogenesis-related factors in OVX rats. Exercise eventually prevents vascular dysfunction in the brain and may help prevent cognitive dysfunction in menopausal women.


Asunto(s)
Condicionamiento Físico Animal , Humanos , Ratas , Femenino , Animales , Ratas Sprague-Dawley , Factor A de Crecimiento Endotelial Vascular , Encéfalo , Estrógenos , Ovariectomía
10.
Nutrients ; 15(15)2023 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-37571326

RESUMEN

This study investigated the potential therapeutic properties of fermented ginseng berry extract (GBE) for Alzheimer's disease (AD). Fermented GBE was examined for its ginsenoside content and physiological properties, which have been suggested to have neuroprotective effects and improve cognitive function. The results showed that fermented GBE contains high levels of major active ginsenosides and exhibits antioxidant and acetylcholinesterase inhibitory activities. Post-fermented GBE demonstrated therapeutic potential in AF64A-induced damaged neural stem cells and an animal model of AD. These findings suggest that fermented GBE may hold promise as a candidate for developing new therapeutic interventions for memory deficits and cognitive disorders associated with AD and other neurodegenerative conditions. However, further studies are needed to evaluate the safety, tolerability, and efficacy of fermented GBE in human subjects and to determine its clinical applications. In conclusion, our study provides evidence that fermented GBE has potential as a natural product for the prevention and treatment of AD. The high levels of active ginsenosides and antioxidant and acetylcholinesterase inhibitory activities of fermented GBE suggest that it may be a promising therapeutic agent for improving cognitive function and reducing neurodegeneration.


Asunto(s)
Ginsenósidos , Panax , Animales , Humanos , Ginsenósidos/farmacología , Ginsenósidos/uso terapéutico , Extractos Vegetales/efectos adversos , Antioxidantes/efectos adversos , Frutas , Acetilcolinesterasa , Trastornos de la Memoria/tratamiento farmacológico , Trastornos de la Memoria/prevención & control , Trastornos de la Memoria/inducido químicamente , Cognición
11.
J Med Internet Res ; 25: e43439, 2023 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-37195757

RESUMEN

BACKGROUND: With the widespread use of social media, people share their real-time thoughts and feelings via interactions on these platforms, including those revolving around mental health problems. This can provide a new opportunity for researchers to collect health-related data to study and analyze mental disorders. However, as one of the most common mental disorders, there are few studies regarding the manifestations of attention-deficit/hyperactivity disorder (ADHD) on social media. OBJECTIVE: This study aims to examine and identify the different behavioral patterns and interactions of users with ADHD on Twitter through the text content and metadata of their posted tweets. METHODS: First, we built 2 data sets: an ADHD user data set containing 3135 users who explicitly reported having ADHD on Twitter and a control data set made up of 3223 randomly selected Twitter users without ADHD. All historical tweets of users in both data sets were collected. We applied mixed methods in this study. We performed Top2Vec topic modeling to extract topics frequently mentioned by users with ADHD and those without ADHD and used thematic analysis to further compare the differences in contents that were discussed by the 2 groups under these topics. We used a distillBERT sentiment analysis model to calculate the sentiment scores for the emotion categories and compared the sentiment intensity and frequency. Finally, we extracted users' posting time, tweet categories, and the number of followers and followings from the metadata of tweets and compared the statistical distribution of these features between ADHD and non-ADHD groups. RESULTS: In contrast to the control group of the non-ADHD data set, users with ADHD tweeted about the inability to concentrate and manage time, sleep disturbance, and drug abuse. Users with ADHD felt confusion and annoyance more frequently, while they felt less excitement, caring, and curiosity (all P<.001). Users with ADHD were more sensitive to emotions and felt more intense feelings of nervousness, sadness, confusion, anger, and amusement (all P<.001). As for the posting characteristics, compared with controls, users with ADHD were more active in posting tweets (P=.04), especially at night between midnight and 6 AM (P<.001); posting more tweets with original content (P<.001); and following fewer people on Twitter (P<.001). CONCLUSIONS: This study revealed how users with ADHD behave and interact differently on Twitter compared with those without ADHD. On the basis of these differences, researchers, psychiatrists, and clinicians can use Twitter as a potentially powerful platform to monitor and study people with ADHD, provide additional health care support to them, improve the diagnostic criteria of ADHD, and design complementary tools for automatic ADHD detection.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Medios de Comunicación Sociales , Humanos , Emociones
12.
Nutr Metab Cardiovasc Dis ; 33(6): 1158-1166, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36849318

RESUMEN

BACKGROUND AND AIMS: Research suggests that meat intake may increase the risk of coronary heart disease (CHD), but most studies take place in Western countries, where the types and amount of meat products consumed differ from those in Asian countries. We aimed to identify the association between meat intake and CHD risk in Korean male adults, using the Framingham risk score. METHODS AND RESULTS: We used data from the Korean Genome and Epidemiology Study (KoGES) Health Examinees (HEXA) study, including 13,293 Korean male adults. We estimated the association of meat intake with ≥20% 10-year CHD risk using Cox proportional hazards regression models to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs). Subjects with the highest total meat intake had a 53% (model 4: HR 1.53, 95% CI 1.05-2.21) increased 10-year CHD risk compared to those with the lowest intake. Those with the highest red meat intake had a 55% (model 3: HR 1.55, 95% CI 1.16-2.06) increased 10-year CHD risk compared to those with the lowest intake. No association was observed between poultry or processed meat intake and 10-year CHD risk. CONCLUSIONS: Consumption of total meat and red meat was associated with a higher risk of CHD in Korean male adults. Further studies are needed to provide criteria for the appropriate meat intake by meat type to reduce CHD risk.


Asunto(s)
Enfermedad Coronaria , Carne Roja , Adulto , Humanos , Masculino , Dieta/efectos adversos , Estudios Prospectivos , Factores de Riesgo , Carne/efectos adversos , Carne Roja/efectos adversos , Enfermedad Coronaria/diagnóstico , Enfermedad Coronaria/epidemiología , Enfermedad Coronaria/prevención & control , República de Corea/epidemiología , Modelos de Riesgos Proporcionales
13.
Sci Adv ; 8(48): eadd4644, 2022 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-36459556

RESUMEN

Materials displaying negative Poisson's ratio, referred to as auxeticity, have been found in nature and created in engineering through various structural mechanisms. However, uniting auxeticity with high strength and high stiffness has been challenging. Here, combining in situ nanomechanical testing with microstructure-based modeling, we show that the leading part of limpet teeth successfully achieves this combination of properties through a unique microstructure consisting of an amorphous hydrated silica matrix embedded with bundles of single-crystal iron oxide hydroxide nanorods arranged in a pseudo-cholesteric pattern. During deformation, this microstructure allows local coordinated displacement and rotation of the nanorods, enabling auxetic behavior while maintaining one of the highest strengths among natural materials. These findings lay a foundation for designing biomimetic auxetic materials with extreme strength and high stiffness.

14.
J Breast Cancer ; 25(3): 233-243, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35775702

RESUMEN

PURPOSE: This study investigated changes in attitudes toward marriage and childbearing assuming a BRCA1/2 mutation carrier status among healthy, unmarried individuals in Korea. METHODS: A nationally representative sample of healthy, unmarried individuals aged 20-39 years was surveyed. A questionnaire on marriage and childbearing intentions was administered to the participants before and after providing them with information on BRCA1/2 mutation carriers' breast and ovarian cancer risks and their autosomal dominant inheritance pattern. The participants were asked about their attitudes toward childbearing through preimplantation genetic diagnosis (PGD). RESULTS: Of the participants who initially wanted to marry, the assumption that they or their partners had BRCA1/2 mutation caused 25.3% to no longer want to get married and 36.2% to change their attitude from wanting to bear children to no longer wanting them. Females were more likely than males to change their attitudes toward marriage and childbearing. The participants who had negative attitudes toward genetic testing were more likely to change their attitudes regarding marriage and childbearing than those who were favorable toward both disclosure and testing. More than 50% of the participants who did not want children were willing to bear children through PGD when it was assumed that they were BRCA mutation carriers. CONCLUSION: On the assumption of being carriers, general, young, and healthy females were more likely than males to negatively change their attitudes toward marriage and childbearing. Public education on the implications of living with mutation carriers and reproductive options may be required.

15.
Adv Mater ; 34(28): e2203030, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35514107

RESUMEN

Fuel cells recombine water from H2 and O2 thereby can power, for example, cars or houses with no direct carbon emission. In anion-exchange membrane fuel cells (AEMFCs), to reach high power densities, operating at high pH is an alternative to using large volumes of noble metals catalysts at the cathode, where the oxygen-reduction reaction occurs. However, the sluggish kinetics of the hydrogen-oxidation reaction (HOR) hinders upscaling despite promising catalysts. Here, the authors observe an unexpected ingress of B into Pd nanocatalysts synthesized by wet-chemistry, gaining control over this B-doping, and report on its influence on the HOR activity in alkaline conditions. They rationalize their findings using ab initio calculations of both H- and OH-adsorption on B-doped Pd. Using this "impurity engineering" approach, they thus design Pt-free catalysts as required in electrochemical energy conversion devices, for example, next generations of AEMFCs, that satisfy the economic and environmental constraints, that is, reasonable operating costs and long-term stability, to enable the "hydrogen economy."

16.
Nanoscale Res Lett ; 17(1): 42, 2022 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-35366682

RESUMEN

Triboelectric nanogenerator (TENG) uses charge transfer between two asymmetric charge affinity materials such as metal and dielectrics. Metal electrode acts as charge collector from dielectrics and acts as charge transfer path to an external load, which model deals with only a net charge of metal electrode concerning electrical output. In this work, we found that metal electrode in triboelectric generator has non-negligible surface charge polarization causing open-circuit voltage difference in the model TENG system. The output voltage depends on the initial preparation conditions of the TENG for I-V measurements, even for the same measured charge densities. The measured output voltage difference with the same charge density implies that electric charges of TENG are composed of movable charges that affect current and voltage output and the bounded fixed charges that only affect open-circuit voltage.

17.
Ultramicroscopy ; 237: 113517, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35427885

RESUMEN

This work presents the new template matching capabilities implemented in Pyxem, an open source Python library for analyzing four-dimensional scanning transmission electron microscopy (4D-STEM) data. Template matching is a brute force approach for deriving local crystal orientations. It works by comparing a library of simulated diffraction patterns to experimental patterns collected with nano-beam and precession electron diffraction (NBED and PED). This is a computationally demanding task, therefore the implementation combines efficiency and scalability by utilizing multiple CPU cores or a graphical processing unit (GPU). The code is built on top of the scientific Python ecosystem, and is designed to support custom and reproducible workflows that combine the image processing, template library generation, indexation and visualization all in one environment. The tools are agnostic to file size and format, which is significant in light of the increased adoption of pixelated detectors from different manufacturers. This paper details the implementation and validation of the method. The method is illustrated by calculating orientation maps of nanocrystalline materials and precipitates embedded in a crystalline matrix. The combination of speed and flexibility opens the door for automated parameter studies and real-time on-line orientation mapping inside the TEM.

18.
Inorg Chem ; 61(10): 4459-4467, 2022 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-35238559

RESUMEN

Three Li- and Mg-cosubstituted compounds in the Gd5-x(Li/Mg)xGe4 (x = 1.04(2), 1.17(2), 1.53(2)) system have been successfully prepared by conventional high-temperature reactions. According to powder and single-crystal X-ray diffraction analyses, all three compounds adopt a Gd5Si4-type phase with the orthorhombic Pnma space group (Pearson code oP16, Z = 4) and six crystallographically independent atomic sites. The crystal structure can be described as a combination of two-dimensional Mo2FeB2-type ∞2[Gd2(Li/Mg)Ge2] layers and [Ge2] dimers. Interestingly, as 64% of Li and 26% of Gd at the RE3 and RE2 sites, respectively, were exclusively substituted by Mg in Gd3.47(1)Li0.36(2)Mg1.17(3)Ge4, the lattice parameter b was selectively shortened as a result of the RE3-Ge1 bond shrinkage in comparison to that in Gd4LiGe4, while lattice parameters a and c remained nearly intact. A series of theoretical calculations using the tight-binding linear muffin-tin orbital (TB-LMTO) method indicated that the reduction of the particular RE3-Ge1 bond distance in the title compounds could also be explained by an optimization of bonding based on the corresponding RE3-Ge1 crystal orbital Hamilton population (COHP) curve. Moreover, the specific site preference of Mg for the RE3 site was supported by both size-factor as well as electronic-factor criteria on the basis of the smallest atomic size and the highest electronegativity of Mg among the three cations. Therefore, the overall electronic structure was further interrogated by a density of states (DOS) analysis. The influence of nonmagnetic Li/Mg cosubstitution for the magnetic Gd atoms in the title Gd5-x(Li/Mg)xGe4 system on the magnetic characteristics was also thoroughly studied by isofield magnetization at 100 Oe and 10 kOe and isothermal magnetization measurements at 4 K using two of the title compounds: Gd3.83(1)Li0.48Mg0.69(3)Ge4 and Gd3.47(1)Li0.36(2)Mg1.17(3)Ge4.

19.
J Am Chem Soc ; 144(2): 987-994, 2022 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-34982554

RESUMEN

Metal nanogels combine a large surface area, a high structural stability, and a high catalytic activity toward a variety of chemical reactions. Their performance is underpinned by the atomic-level distribution of their constituents, yet analyzing their subnanoscale structure and composition to guide property optimization remains extremely challenging. Here, we synthesized Pd nanogels using a conventional wet chemistry route, and a near-atomic-scale analysis reveals that impurities from the reactants (Na and K) are integrated into the grain boundaries of the poly crystalline gel, typically loci of high catalytic activity. We demonstrate that the level of impurities is controlled by the reaction condition. Based on ab initio calculations, we provide a detailed mechanism to explain how surface-bound impurities become trapped at grain boundaries that form as the particles coalesce during synthesis, possibly facilitating their decohesion. If controlled, impurity integration into grain boundaries may offer opportunities for designing new nanogels.

20.
PLoS Genet ; 17(10): e1009871, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34714823

RESUMEN

Kohlschütter-Tönz syndrome (KTS) manifests as neurological dysfunctions, including early-onset seizures. Mutations in the citrate transporter SLC13A5 are associated with KTS, yet their underlying mechanisms remain elusive. Here, we report that a Drosophila SLC13A5 homolog, I'm not dead yet (Indy), constitutes a neurometabolic pathway that suppresses seizure. Loss of Indy function in glutamatergic neurons caused "bang-induced" seizure-like behaviors. In fact, glutamate biosynthesis from the citric acid cycle was limiting in Indy mutants for seizure-suppressing glutamate transmission. Oral administration of the rate-limiting α-ketoglutarate in the metabolic pathway rescued low glutamate levels in Indy mutants and ameliorated their seizure-like behaviors. This metabolic control of the seizure susceptibility was mapped to a pair of glutamatergic neurons, reversible by optogenetic controls of their activity, and further relayed onto fan-shaped body neurons via the ionotropic glutamate receptors. Accordingly, our findings reveal a micro-circuit that links neural metabolism to seizure, providing important clues to KTS-associated neurodevelopmental deficits.


Asunto(s)
Ciclo del Ácido Cítrico/fisiología , Ácido Glutámico/metabolismo , Convulsiones/metabolismo , Animales , Ácido Cítrico/metabolismo , Ciclo del Ácido Cítrico/genética , Transportadores de Ácidos Dicarboxílicos/genética , Transportadores de Ácidos Dicarboxílicos/metabolismo , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Ácido Glutámico/genética , Masculino , Redes y Vías Metabólicas/genética , Redes y Vías Metabólicas/fisiología , Mutación/genética , Neuronas/metabolismo , Convulsiones/genética , Simportadores/genética , Simportadores/metabolismo
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