Abnormal Silicon Etching Behaviors in Nanometer-Sized Channels.

Modern semiconductor fabrication is challenged by difficulties in overcoming physical and chemical constraints. A major challenge is the wet etching of dummy gate silicon, which involves the removal of materials inside confined spaces of a few nanometers. These chemical processes are significantly different in the nanoscale and bulk. Previously, electrical double-layer formation, bubble entrapment, poor wettability, and insoluble intermediate precipitation have been proposed. However, the exact suppression mechanisms remain unclear due to the lack of direct observation methods. Herein, we investigate limiting factors for the etching kinetics of silicon with tetramethylammonium hydroxide at the nanoscale by using liquid-phase transmission electron microscopy, three-dimensional electron tomography, and first-principles calculations. We reveal suppressed chemical reactions, unstripping phenomena, and stochastic etching behaviors that have never been observed on a macroscopic scale. We expect that solutions can be suggested from this comprehensive insight into the scale-dependent limiting factors of fabrication.

Acupuncture inhibits neuroinflammation and gut microbial dysbiosis in a mouse model of Parkinson's disease.

Growing evidences show that gut microbiota is associated with the pathogenesis of Parkinson's disease (PD) and the gut-brain axis can be promising target for the development of the therapeutic strategies for PD. Acupuncture has been used to improve brain functions and inflammation in neurological disorders such as PD, and to recover the gastrointestinal dysfunctions in various gastrointestinal disorders. Thus, we investigated whether acupuncture could improve Parkinsonism and gut microbial dysbiosis induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. First, we observed that acupuncture treatment at acupoints GB34 and ST36 could improve motor functions and comorbid anxiety in PD mice. Next, we found that acupuncture increased the levels of dopaminergic fibers and neurons in the striatum and the substantia nigra, respectively. Acupuncture also restored the overexpression of microglia and astrocyte as well as conversion of Bax and Bcl-2 expression in both the striatum and the substantia nigra, indicating that inflammatory responses and apoptosis were blocked by acupuncture. Additionally, via 16S rRNA sequence analysis, we observed that the relative abundance of 18 genera were changed in acupuncture-treated mice compared to the PD mice. Of them, Butyricimonas, Holdemania, Frisingicoccus, Gracilibacter, Phocea, and Aestuariispira showed significant correlations with anxiety as well as motor functions. Furthermore, the predicted functional analyses showed that acupuncture restored the physiology functions such as glutathione metabolism, methane metabolism, and PD pathway. In conclusion, we suggest that the effects of acupuncture on the enhanced motor function and the protection of the dopaminergic neurons may be associated with the regulation of the gut microbial dysbiosis and thus the inhibition of the neuroinflammation in the PD mice.

Spontaneous Marangoni Mixing of Miscible Liquids at a Liquid-Liquid-Air Contact Line.

We investigate the flow patterns created when a liquid drop contacts a reservoir liquid, which has implications on various physicochemical and biochemical reactions including mixing in microfluidic systems. The localized vortical flow spontaneously triggered by the difference of surface tension between the two liquids is studied, which is thus termed the Marangoni vortex. To quantitatively investigate the strength of vortices, we performed particle image velocimetry (PIV) experiments by varying the surface tension difference, the gap of the flow cell, the density and viscosity of the reservoir liquid, and the size of the drop. A scaling law that balances the interfacial energy of the system with the kinetic energy of the vortical flows allows us to understand the functional dependence of the Marangoni vortex strength on various experimental parameters.

The impact of inappropriate steroid exposure before the diagnosis of Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is a systemic inflammatory disease characterized by vasculitis. In South Korea, some pediatric doctors empirically prescribe steroids to control febrile pediatric patients. This study aimed to evaluate the clinical characteristics of patients with KD after steroid exposure. METHODS: This was a single-center, retrospective, observational study. This study included patients (aged ≤15 years) between January 2020 and July 2022. We compared two groups, one group exposed to steroids and the other group who were not, using the Student's t-test or analysis of variance; otherwise, the Mann-Whitney U test or Kruskal-Wallis test was conducted. Statistical significance was set at p < 0.05. RESULTS: In total, 190 patients with KD were enrolled; of these, 64 (33.7 %) had a history of steroid exposure, and 126 (66.3 %) had no history of steroid exposure. In the steroid exposure group, prolonged fever duration (6.72 ± 1.72 versus 5.61 ± 1.19, p-value = <0.001), a lower proportion of complete KD (29.69 % vs. 88.10 %, p-value = <0.001), and a significantly lower level of C-reactive protein were observed. However, no significant correlations were observed between the Transthoracic Echocardiography (TTE) results (coronary artery aneurysm, existence of pericardial effusion) and prognostic factors (days of hospitalization, the number of intravenous immunoglobulin administrations, and Kobayashi score) between the two groups. CONCLUSIONS: Patients with KD and previous steroid exposure may exhibit an incomplete KD phenotype with prolonged fever. Although previous steroid exposure does not affect the prognosis of KD, including coronary artery aneurysms, it may mask the classic features of KD, resulting in a delayed diagnosis.

The effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on rat testicular function.

Wireless mobile phones and other telecommunication devices are used extensively in daily life. We therefore examined the effects of combined exposure to radiofrequency electromagnetic fields (RF-EMF) on rat testicular function, specifically with respect to sensitive processes such as spermatogenesis. Male rats were exposed to single code division multiple access (CDMA) and wideband code division multiple access (WCDMA) RF signals for 12 weeks. The RF exposure schedule comprised 45 min/day, 5 days/week for a total of 12 weeks. The whole-body average specific absorption rate (SAR) of CDMA and WCDMA was 2.0 W/kg each or 4.0 W/kg in total. We then investigated the correlates of testicular function such as sperm count in the cauda epididymis, testosterone concentration in the blood serum, malondialdehyde concentrations in the testes and epididymis, frequency of spermatogenesis stages, and appearance of apoptotic cells in the testes. We also immunoblotted for p53, bcl2, GADD45, cyclin G, and HSP70 in the testes of sham- and combined RF-exposed animals. Based on the results, we concluded that simultaneous exposure to CDMA and WCDMA RF-EMFs at 4.0 W/kg SAR did not have any observable adverse effects on rat spermatogenesis.

Regional Brain Volume Changes in Catholic Nuns: A Cross-Sectional Study Using Deep Learning-Based Brain MRI Segmentation.

OBJECTIVE: Religious behaviors are considered as complex brain-based phenomena that may be associated with structural brain change. To identify the pattern of regional brain volume change in nuns, we investigated structural alterations in the brains of nuns using a fast processing automated segmentation method based on deep learning algorithms. METHODS: We retrospectively reviewed the medical records of the catholic sisters between the ages of 31 and 80 who are members of the charity of St. Vincent de Paul of Korea. A total of 193 asymptomatic subjects (86 nuns and 107 control subjects) received comprehensive health screening and underwent brain MRI scans. We compared cortical and sub-cortical volume between groups across multiple locations using our in-house U-Net++ deep learning-based automatic segmentation tool. RESULTS: Compared to the control group, the nun group displayed increased gray matter volume in the right lingual cortex, left isthmus-cingulate, posterior-cingulate, rostral-middle-frontal, superior-frontal, supramarginal, temporal-pole cortices, and bilateral pars-triangularis cortices after correction for multiple comparisons. On the other hand, the nun group showed reduced gray matter volume in the temporal and parietal regions relative to healthy controls. CONCLUSION: Our study suggests that spiritual practice may affect brain structure, especially in several frontal regions involved in a higher level of insight function.

Growth time-dependent density and surface evolution of silicon nanowires in a vapor-liquid-solid process.

Single crystalline silicon nanowires (SiNWs) were grown on Si(100) substrate using a gold (Au)-catalyzed vapor-liquid-solid (VLS) approach. The dependence of the growth time (i.e., the time of exposure to the Si source) on the density and surface evolution of the grown SiNWs is considered. It was observed that the density of grown SiNWs on Si substrate increased with increasing growth time. The highest density (approximately 1.1 x 10(6) mm(-2)) was reached at 4 hr. Upon further exposure to the Si source, we observed that the density was maintained for up to 9 hr. We suggest that the increased Si chemical potential in Au-Si droplets with increased growth time enhanced the SiNW growth rate at the interfaces between Au-Si droplets and SiNWs, and enhanced the transition of the NWs from the existing Au-Si droplets onto Si substrate. This allows the SiNW density to increase with increased growth time of up to 4 hr. Moreover, we examined the influence of the growth time on surface evolution including Au diffusion, facet and taper formation, and vapor-solid (VS) growth of the SiNWs. To explain the behavior of the grown SiNWs in the VLS process, we propose a combined model using the VLS and VS growth mechanisms.

Lymphoma development of simultaneously combined exposure to two radiofrequency signals in AKR/J mice.

There are public concerns regarding possible carcinogenic or cancer-promoting effects of radiofrequency electromagnetic fields (RF-EMFs) because of the extensive use of wireless mobile phones and other telecommunication devices in daily life. However, so far it is unclear if non-thermal exposure of single EMF exposure in animal studies has a direct influence on carcinogenesis. Here, carcinogenic effects of combined signal RF-EMFs on AKR/J mice, which were used for the lymphoma animal model, were investigated. Six-week-old AKR/J mice were simultaneously exposed to two types of RF signals: single code division multiple access (CDMA) and wideband code division multiple access (WCDMA). AKR/J mice were exposed to combined RF-EMFs for 45 min/day, 5 days/week, for a total of 42 weeks. The whole-body average specific absorption rate (SAR) of CDMA and WCDMA fields was 2.0 W/kg each, 4.0 W/kg in total. When we examined final survival, lymphoma incidence, and splenomegaly incidence, no differences were found between sham- and RF-exposed mice. However, occurrence of metastasis infiltration to the brain in lymphoma-bearing mice was significantly different in RF-exposed mice when compared to sham-exposed mice, even though no consistent correlation (increase or decrease) was observed between male and female mice. However, infiltration occurrence to liver, lung, and spleen was not different between the groups. From the results, we suggested that simultaneous exposure to CDMA and WCDMA RF-EMFs did not affect lymphoma development in AKR/J mice.

Novel streptavidin-functionalized silicon nanowire arrays for CD4+ T lymphocyte separation.

Silicon nanowires (SiNWs) offer promising inorganic nanostructures for biomedical application. Here, we report the development of a novel SiNW array designed for isolating primary CD4(+) T lymphocytes from the heterogeneous mixture of cell populations. Our system employed the specific high-affinity binding features of streptavidin (STR)-functionalized SiNW with biotin-labeled CD4(+) T lymphocytes. Fabricated SiNW arrays easily separated the CD4(+) T lymphocytes from the mouse whole splenocytes with over approximately 88% purity and demonstrated tight attachment to CD4(+) T lymphocytes by scanning electron microscopy. Thus, our STR-SiNW arrays provide a potential tool for specific cell separation and further present a possibility to be applied to the other area of biomedical applications.

The lack of histological changes of CDMA cellular phone-based radio frequency on rat testis.

We examined the histological changes by radiofrequency (RF) fields on rat testis, specifically with respect to sensitive processes such as spermatogenesis. Male rats were exposed to 848.5 MHz RF for 12 weeks. The RF exposure schedule consisted of two 45-min RF exposure periods, separated by a 15-min interval. The whole-body average specific absorption rate (SAR) of RF was 2.0 W/kg. We then investigated correlates of testicular function such as sperm counts in the cauda epididymis, malondialdehyde concentrations in the testes and epididymis, frequency of spermatogenesis stages, germ cell counts, and appearance of apoptotic cells in the testes. We also performed p53, bcl-2, caspase 3, p21, and PARP immunoblotting of the testes in sham- and RF-exposed animals. Based on these results, we concluded that subchronic exposure to 848.5 MHz with 2.0 W/kg SAR RF did not have any observable adverse effects on rat spermatogenesis.

Expressions of Semenogelin Gene in Male Syrian Hamsters according to Photoperiod.

The morphogenetically matured spermatozoa (sperm) are generated in the testes by the spermatogenesis. They travel male reproductive tract with many substances secreted from the accessory reproductive organs. One of the substances is the semenogelin (SEMG) released from the seminal vesicles that is involved in the post-testicular maturation. The expression of SEMG gene was investigated in seminal vesicle tissues of sexually matured and regressed male Syrian hamsters by reverse transcription polymerase chain reaction (RT-PCR). The SEMG gene was uniquely identified in the seminal vesicles of the matured Syrian hamsters and compared to the genes reported previously. But the expression of SEMG gene was not observed in reproductively and completely regressed testes of Syrian hamsters. These results indicate that the expressions of the SEMG gene are related to the reproductive capability in the male Syrian hamsters.

The effects of repetitive transcranial magnetic stimulation on body weight and food consumption in obese adults: A randomized controlled study.

BACKGROUND: Although some studies have reported significant reductions in food cravings following the single-session of repetitive transcranial magnetic stimulation (rTMS), there is little research on the effects of multi-session of rTMS on food consumption and body weight in obese subjects. OBJECTIVE: We conducted 4-week randomized, sham-controlled, single-blind, parallel-group trial to examine the effect of rTMS on body weight in obese adults. METHODS: Forty-three obese patients (body mass index [BMI] ≥25 kg/m2) aged between 18 and 70 years were randomized to the sham or real treatment group (21 in the TMS group and 22 in the sham treatment group). A total of 8 sessions of rTMS targeting the left dorsolateral prefrontal cortex (DLPFC) was provided over a period of 4 weeks. The primary outcome measure was weight change in kilograms from baseline to 4 weeks. Secondary endpoints included changes in anthropometric measures, cardiovascular risk factors, food intake, and appetite. RESULTS: Participants in the rTMS group showed significantly greater weight loss from baseline following the 8 session of rTMS (-2.75 ±â€¯2.37 kg vs. 0.38 ±â€¯1.0 kg, p < 0.01). Consistent with weight loss, there was a significant reduction in fat mass and visceral adipose tissue at week 4 in the rTMS group compared with the control group (p < 0.01). After the 8 sessions of rTMS, the TMS group consumed fewer total kilocalories and carbohydrates per day than the control group (p < 0.05). CONCLUSIONS: 8 sessions of HF rTMS delivered to the left DLPFC were effective in inducing weight loss and decreasing food intake in obese patients. TRIAL REGISTRATION: Clinical trial registered with the Clinical Trials Registry at http://cris.cdc.go.kr (KCT0002548).

The determination of modified barrier heights in Ti/GaN nano-Schottky diodes at high temperature.

We have investigated the size-effect of the nano-Schottky diodes on the electrical transport properties and the temperature-dependent current transport mechanism in a metal-semiconductor nanowire junction (a Ti/GaN nano-Schottky diode) using current-voltage characterization in the range of 300-423 K. We found that the modified mean Schottky barrier height (SBH) was approximately 0.7 eV with a standard deviation of approximately 0.14 V using a Gaussian distribution model of the barrier heights. The slightly high value of the modified mean SBH (approximately 0.11 eV) compared to the results from the thin-film based Ti/GaN Schottky diodes could be due to an additional oxide layer at the interface between the Ti and GaN nanowires. Moreover, we found that the abnormal behavior of the barrier heights and the ideality factors in a Ti/GaN nano-Schottky diode at a temperature below 423 K could be explained by a combination of the enhancement of the tunneling current and a model with a Gaussian distribution of the barrier heights.

Characteristics of dielectrophoretically aligned UV-blue GaN nanowire LEDs.

This is a report on the characteristics of UV-blue light emitting diodes (LEDs) containing homojunction gallium nitride (GaN) nanowires (NWs). These LEDs were prepared by the dielectrophoresis assisted assembly deposition (DAAD) method. The incorporation of an additional silicon dioxide (SiO2) and a Au capping metal layer was found to improve the electrical and optical properties of the DAAD-prepared GaN NW LEDs. These LEDs exhibited a parasitic series resistance of 120-180 komega with a sharp turn-on forward voltage of 3.4-4.0 V and had as low as approximately approximately 7 x 10(-7) A of leakage current for a reverse bias of -10 V. Typical electroluminescence (EL) spectra, observed from these LEDs under a forward bias, had a broad ultraviolet (UV)-blue emission with a wavelength of 388-422 nm. These LEDs could be seen with the naked eye. We concluded that the high-brightness EL spectra resulted from the enhancement of the carrier injection due to the size effect of the n-GaN nanowires on the p-GaN substrate.

The Expressional Pattern of Epididymal Protease Inhibitor (EPPIN) in the Male Syrian Hamsters.

The spermatogenesis is the process by which spermatozoa are generated in the testes. The spermatozoa travel male reproductive tract during which they meet many substances secreted from reproductive organs. One of the substances is epididymal protease inhibitor (EPPIN) that is involved in the post-testicular maturation including capability of fertilizing the eggs. The expression of EPPIN gene was investigated in various tissues of sexually mature and regressed male Syrian hamsters by reverse transcription polymerase chain reaction (RT-PCR). The EPPIN gene was identified in the testis and epididymis of the male Syrian hamsters and compared to the genes reported previously. There was no expression of EPPIN gene in reproductively and completely regressed testes of Syrian hamster. These results suggest that the expressions of the EPPIN gene are associated with the reproductive capability in the Syrian hamsters.

The effects of repetitive transcranial magnetic stimulation on eating behaviors and body weight in obesity: A randomized controlled study.

BACKGROUND: Although some studies have reported significant reductions in food cravings following repetitive transcranial magnetic stimulation (rTMS), none have examined changes in body weight. OBJECTIVE: We conducted 2-week randomized, sham-controlled, single-blind, parallel-group trial to examine the effect of rTMS on body weight in obese patients. METHODS: Sixty obese patients (body mass index [BMI] ≥25 kg/m2) aged between 18 and 65 years were recruited. A total of 4 sessions of rTMS targeting the left dorsolateral prefrontal cortex (DLPFC) was provided over a period of 2 weeks, with a follow-up assessment conducted two weeks after treatment had finished. The primary outcome measure was weight change in kilograms from baseline to 4 weeks. Secondary endpoints included changes in anthropometric measures, cardiovascular risk factors, food intake, and appetite. RESULTS: Of the 60 volunteers, 57 completed the 4-week follow-up (29 in the TMS group and 28 in the sham treatment group). Participants in the rTMS group showed significantly greater weight loss from baseline following the 4 session of rTMS (p = 0.002). Consistent with weight loss, there was a significant reduction in BMI, fat mass and VAT at week 4 in the rTMS group compared with the control group (p < 0.05). After the 4 sessions of rTMS, the TMS group consumed fewer total kilocalories per day than the control group (p < 0.01). CONCLUSIONS: rTMS delivered to the left DLPFC was effective in decreasing food intake and facilitating weight loss in obese patients. The results of this study suggest that rTMS could be an effective treatment option for obesity. TRIAL REGISTRATION: Clinical trial registered with the Clinical Trials Tegistry at https://cris.nih.go.kr (KCT0001455).

Formation of a new solo-LTR of the human endogenous retrovirus H family in human chromosome 21.

Human endogenous retroviruses (HERVs) contribute to various kinds of genomic instability via rearrangement and retrotransposition events. In the present study the formation of a new human-specific solo-LTR belonging to the HERV-H family (AP001667; chromosome 21q21) was detected by a comparative analysis of human chromosome 21 and chimpanzee chromosome 22. The solo-LTR was formed as a result of an equal homologous recombination excision event. Several evolutionary processes have occurred at this locus during primate evolution, indicating that mammalian-wide interspersed repeat (MIR) and full-length HERV-H elements integrated into hominoid genomes after the divergence of Old World monkeys and hominoids, and that the solo-LTR element was created by recombination excision of the HERV-H only in the human genome.

Endogenous retrovirus-related sequences provide an alternative transcript of MCJ genes in human tissues and cancer cells.

The MCJ gene is a member of the DNAJ family, and its transcriptional event is controlled by methylation of the CpG island. In our study, we found LTR33 and LTR7 elements provided an alternative transcript within the MCJ gene. To detect different expression patterns between the originally reported MCJ transcript and the LTR-related transcript, we performed a RT-PCR approach using various human tissues and cancer cells. The original MCJ transcript was detected in human tissues and cancer cells, whereas the LTR-related transcript was only revealed in some cancer cells (HCT106, MCF-3, TE-1, Hela, and CCHM). We also performed a PCR analysis to compare the insertion lineage of the LTR elements with the genomic DNAs of primates, indicating that those LTR33 and LTR7 elements of HERV-H have been integrated into the primate genome at different times. Taken together, we suggest that HERV-related elements trigger transcriptome diversification during primate evolution.

Comparative radiologic evaluation of percutaneous endoscopic lumbar discectomy and open microdiscectomy: a matched cohort analysis.

BACKGROUND: Only a few studies comparing percutaneous endoscopic discectomy and open discectomy have been reported in the literature. The purpose of this study was to compare the radiographic changes in patients treated with percutaneous endoscopic lumbar discectomy (PELD) with those of patients treated with open lumbar microdiscectomy (OLM). METHODS: A total of 30 patients who underwent PELD with a minimum three years of follow-up were randomly selected. To compare with the PELD group, 30 patients who underwent OLM during the same period were also randomly selected according to sex, age, and disc level. The clinical outcomes were evaluated by the Macnab criteria. Statistical analysis was performed using independent sample t-test, paired sample t-test, chi-square test, Fisher's exact test, and analysis of variance (ANOVA). RESULTS: The successful clinical outcomes were 96.7% in the PELD group and 93.3% in the OLM group. Among the various radiological parameters, changes of disc height (1.41 +/- 1.19 mm in the PELD group and 2.29 +/- 2.12 mm in the OLM group, p=0.024) and foraminal height (1.26 +/- 0.91 mm in the PELD group and 1.85 +/- 0.92 mm in the OLM group, p=0.017) were significantly different between the two groups. CONCLUSIONS: Although the clinical outcomes were similarly satisfactory in both groups, PELD is a less invasive procedure than open microdiscectomy in s elected cases.