Strong intramolecular charge-transfer effect strengthening naphthoquinone-based chemosensor: Experimental and theoretical evaluation

An aminophenol-linked naphthoquinone-based fluorometric and colorimetric chemosensor 2-chloro-3-((3-hydroxyphenyl) amino) naphthalene-1,4-dione (2CAN-Dione) was synthesized for selective detection of Sn2+ ion in aqueous solution. The amine and conversion of carbonyl into carboxyl groups play a vital role in the sensing mechanism when Sn2+ is added to 2CAN-Dione. Comprehensive characterization of the sensor was carried out using standard spectral and analytical approaches. Because of the intramolecular charge transfer (ICT) effect and the turn-on sensing mode, the strong fluorometric emission towards Sn2+ was observed at about 435 nm. The chemosensor exhibited good selectivity for Sn2+ in the presence of coexisting metal ions. An improved linear connection was established with a low limit of detection (0.167 μM). FT-IR, 1H NMR, 13C NMR, and quantum chemistry methods were performed to verify the binding coordination mechanism. The chemosensing probe 2CAN-Dione was successfully employed in bioimaging investigations, demonstrating that it is a reliable fluorescent marker for Sn2+ in human cancer cells.

Tri-component hydrocolloid as egg white replacement in meringues: gellan gum with soy protein isolate and maltodextrin

BACKGROUND

In the quest for sustainable food ingredients, the present study delves into the potential of a tri-component hydrocolloid blend, comprising gellan gum (GG), soy protein isolate (SPI) and maltodextrin (MD), as a replacement for egg white in meringue production. The research aims to elucidate the intricate physical properties of meringue containing this tri-component structure, focusing on foaming dynamics, rheological behavior and the textural properties of the resulting meringue cookies.

RESULTS

Experiments were conducted with various hydrocolloids (k-carrageenan, GG, and locust bean gum) and GG was identified as optimal for improving foaming capacity and foaming stability. Rheological evaluations showed a positive correlation between increased GG concentration within the tri-component matrix and an increase in both storage modulus (G') and loss modulus (G"), indicating improved structural integrity. Furthermore, a comparative analysis of the texture profiles of cookies prepared with this blend highlighted the ability of higher GG concentrations to satisfactorily replicate the tactile and visual qualities of traditional egg white-based meringues. This result was particularly evident compared to formulations utilizing solely SPI or the combined SPI-MD configuration.

CONCLUSION

Conclusively, the results of the present study highlight the significant potential of the GG-SPI-MD tri-component structure to closely mimic the critical properties of egg white, thus offering a promising plant-based alternative for meringue production. © 2024 Society of Chemical Industry.

The technical potential of a sous-vide processing method for developing high-moisture textured soy protein

This study explored the potential of sous-vide processing as a novel technique for transforming low-moisture textured soy protein (TSP) into a product with high moisture content and texture comparable to meat. We hypothesized that the sous-vide treatment would enable precise control of the TSP microstructure. In the ensuing process, the TSP maintained the moisture content at approximately 70% and changed color towards darker tones. Additionally, the porous microstructure changed, transitioning from a large to a smaller air layer. As the treatment continued, both the hardness and texturization index of the TSP were reduced. Furthermore, the secondary structure of the protein exhibited an increase in β-sheet and α-helix structures, indicating enhanced hydrogen bonds, hydrophobic interactions, and disulfide bonds. Optimally, a sample with 24 h at 90℃ displayed textural characteristics similar to chicken breast. The investigation underlines the sous-vide method as a revolutionary technique yielding high-moisture content and improved texture for TSP.

Particulate matter 10 induces oxidative stress and apoptosis in rhesus macaques skin fibroblast

Background

Particulate matter (PM) is a major air pollutant that affects human health worldwide. PM can pass through the skin barrier, thus causing skin diseases such as heat rash, allergic reaction, infection, or inflammation. However, only a few studies have been conducted on the cytotoxic effects of PM exposure on large-scale animals. Therefore, herein, we investigated whether and how PM affects rhesus macaque skin fibroblasts.

Methods

Rhesus macaque skin fibroblasts were treated with various concentrations of PM10 (1, 5, 10, 50, and 100 μg/mL) and incubated for 24, 48, and 72 h. Then, cell viability assay, TUNEL assay, and qRT-PCR were performed on the treated cells. Further, the reactive oxygen species, glutathione, and cathepsin B levels were determined. The MTT assay revealed that PM10 (>50 μg/mL) proportionately reduced the cell proliferation rate.

Results

PM10 treatment increased TUNEL-positive cell numbers, following the pro-apoptosis-associated genes (CASP3 and BAX) and tumor suppressor gene TP53 were significantly upregulated. PM10 treatment induced reactive oxidative stress. Cathepsin B intensity was increased, whereas GSH intensity was decreased. The mRNA expression levels of antioxidant enzyme-related genes (CAT, GPX1 and GPX3) were significantly upregulated. Furthermore, PM10 reduced the mitochondrial membrane potential. The mRNA expression of mitochondrial complex genes, such as NDUFA1, NDUFA2, NDUFAC2, NDUFS4, and ATP5H were also significantly upregulated. In conclusion, these results showed that PM10 triggers apoptosis and mitochondrial damage, thus inducing ROS accumulation. These findings provide potential information on the cytotoxic effects of PM10 treatment and help to understand the mechanism of air pollution-induced skin diseases.

The fibronectin concentration that optimally maintains porcine satellite cells

OBJECTIVE

'Cultured meat' has been suggested as means of solving the problems associated with overpopulation and gas emissions. Satellite cells are a major component in the production of cultured meat; however, these cells cannot be maintained in vitro over long periods. Fibronectin is a glycoprotein that affects biological processes such as cell adhesion, differentiation, and migration. Unfortunately, the characteristics of porcine satellite cells grown in a long-term culture when exposed to fibronectin-coated dishes are unknown. The objective of this study was to investigate the appropriate concentration of fibronectin coated dishes for proliferation and maintenance of porcine satellite cells at long-term culture.

METHODS

In this study, we isolated the satellite cells and fibroblast cells with pre-plating method. We next analyzed the cell doubling time, cell cycle, and rate of expressed paired box 7 (Pax7) and myogenic differentiation 1 (MyoD1) in porcine satellite cells cultured with 20 μg/mL of fibronectin-, gelatin-, and non-coated dishes at early and late passage. We then analyzed the proliferation of porcine satellite cells with various concentrations of mixed gelatin/fibronectin. We next determined the optimal concentration of fibronectin that would encourage proliferation and maintenance of porcine satellite cells in a long-term culture.

RESULTS

Doubling time was lowest when 20 μg/mL of fibronectin was used (as tested during an early and late passage). Levels of expressed Pax7 and MyoD1, assessed using immunocytochemistry, were highest in cells grown using fibronectin-coated dishes. The proliferation of gelatin/fibronectin mixed coatings had no significant effect on porcine satellite cells. The concentration of 5 μg/mL fibronectin coated dishes showed the lowest doubling time and maintained expression of Pax7.

CONCLUSION

Fibronectin with 5μg/mL effectively maintains porcine satellite cells, a discovery that will be of interest to those developing the next generation of artificial meats.

Heterogeneous integration of a GaN-based photonic integrated circuit with an Si-based transimpedance amplifier

The heterogeneous integration of a GaN-based photonic integrated circuit (PIC) and an Si-based transimpedance amplifier (TIA) is demonstrated in this work. The monolithic GaN PIC, fabricated from a GaN-on-Si light-emitting diode (LED) wafer, comprises LEDs whose optical outputs are coupled to photodetectors (PD) through suspended waveguides. The PIC chip is mounted onto a printed circuit board together with a TIA chip and two filter chip capacitors, occupying a compact footprint. The components are interconnected directly using wire-bonds to minimize signal delays and attenuation. The integrated system achieves rise and fall times of 2.21 and 2.10 ns, respectively, a transmission delay of 3.54 ns, and a bandwidth exceeding 390 MHz. Transmission of a pseudorandom binary sequence-3 (PRBS-3) signal across the integrated system is also demonstrated at the data transmission rate of 280 Mbit/s with a clearly resolved open eye diagram.

Acceleration of Mesenchymal-to-Epithelial Transition (MET) during Direct Reprogramming Using Natural Compounds

Induced pluripotent stem cells (iPSCs) can be generated from somatic cells using Oct4, Sox2, Klf4, and c-Myc (OSKM). Small molecules can enhance reprogramming. Licochalcone D (LCD), a flavonoid compound present mainly in the roots of Glycyrrhiza inflata, acts on known signaling pathways involved in transcriptional activity and signal transduction, including the PGC1-α and MAPK families. In this study, we demonstrated that LCD improved reprogramming efficiency. LCD-treated iPSCs (LCD-iPSCs) expressed pluripotency-related genes Oct4, Sox2, Nanog, and Prdm14. Moreover, LCD-iPSCs differentiated into all three germ layers in vitro and formed chimeras. The mesenchymal-to-epithelial transition (MET) is critical for somatic cell reprogramming. We found that the expression levels of mesenchymal genes (Snail2 and Twist) decreased and those of epithelial genes (DSP, Cldn3, Crb3, and Ocln) dramatically increased in OR-MEF (OG2^+/+/ROSA26^+/+) cells treated with LCD for 3 days, indicating that MET effectively occurred in LCD-treated OR-MEF cells. Thus, LCD enhanced the generation of iPSCs from somatic cells by promoting MET at the early stages of reprogramming.

Meta-Analysis and Systematic Review of the Thermal Stress Response: Gallus gallus domesticus Show Low Immune Responses During Heat Stress

Heat stress, which affects broiler growth performance and immunity, is a major concern in the poultry industry. This meta-analysis aimed to demonstrate the significant effect of heat stress on broiler mass gain and immunoglobulin levels, which regulates the mortality rate of broilers. A total of 2,585 studies were downloaded from PubMed, Web of Science, and Google Scholar from January 1, 2015, to September 1, 2021. Eventually, 28 studies were selected based on specific criteria. The results for body mass gain, total mass of immune organs (thymus, spleen, and bursa of Fabricius), immunoglobulin (IgA, IgG, and IgM) levels, and mortality rate were analyzed using odds ratio or the random-effects model (REM) at a confidence interval (CI) of 95%. Compared to the control, heat stress significantly decreased body mass gain (10 trials: REM = 1.35, 95% CI: 1.21, 1.50). Compared to that in the control, heat stress significantly increased immunoglobulin levels: IgA (7 trials: REM = 1.69, 95% CI: 0.90, 3.16), IgG (6 trials: REM = 1.24, 95% CI: 0.85, 1.81), IgM (8 trials: REM = 0.69, 95% CI: 0.44, 1.08), and heat stress also increased the broiler mortality rate (6 trials: REM = 0.06, 95% CI: 0.01, 0.27). However, there were no significant changes in the immune organs between the control and heat-stressed groups. In conclusion, heat stress remarkably alters the mass gain and immunoglobulin levels of broilers, which may be a cause of the high mortality rate.

Generation of Miniaturized Ovaries by In Vitro Culture from Mouse Gonads

The incidence of infertility among individuals of reproductive age has been growing due to genetic and environmental factors, and considerable research efforts are focused on solving this issue. Ovarian development is an overly complex process in the body, involving the interaction between primordial germ cells and gonad somatic cells. However, follicles located in the center of the in vitro ovary are poorly formed owing to ovarian complexity, nutrient deficiency, and signaling deficiency. In the present study, we optimized methods for dissociating gonads and culture conditions for the in vitro generation of miniaturized ovaries. The gonads from embryos were dissociated into cell masses and cultured on a Transwell-COL membrane for 3–5 weeks. Approximately 12 follicles were present per in vitro ovary. We observed that miniaturized ovaries successfully matured to MII oocytes in vitro from 150 to 100 µm gonad masses. This method will be useful for investigating follicle development and oocyte production.

Performance Evaluation of VITEK MS for the Identification of a Wide Spectrum of Clinically Relevant Filamentous Fungi Using a Korean Collection

The correct identification of filamentous fungi is challenging. We evaluated the performance of the VITEK MS v3.0 system (bioMérieux, Marcy-l’Étoile, France) for the identification of a wide spectrum of clinically relevant filamentous fungi using a Korean collection. Strains that were added to the upgraded v3.2 database were additionally identified by the VITEK MS v3.2 system. Of the 105 tested isolates, including 37 Aspergillus (nine species), 41 dermatophytes (seven species), and 27 other molds (17 species), 43 (41.0%) showed “no identification” or “multiple species identification” results at the initial VITEK MS testing; these isolates were retested using the same method. Compared with sequence-based identification, the correct identification rate using VITEK MS for Aspergillus, dermatophytes, other molds, and total mold isolates was 67.6%, 56.1%, 48.1%, and 58.1% at the initial testing and 94.6%, 78.0%, 55.6%, and 78.1% with retesting, respectively. Following retesting, 19 (18.1%) and two (1.9%) isolates showed “no identification” and “misidentification” results, respectively. VITEK MS reliably identified various filamentous fungi recovered in Korea, with a very low rate of misidentification.

Whispering-gallery mode InGaN microdisks on GaN substrates

Microdisks fabricated with III-nitride materials grown on GaN substrates are demonstrated, taking advantage of the high material quality of homoepitaxial films and advanced micro-fabrication processes. The epitaxial structure consists of InGaN/GaN multi-quantum wells (MQWs) sandwiched between AlGaN/GaN and InAlN/GaN superlattices as cladding layers for optical confinement. Due to lattice-matched growth with low dislocations, an internal quantum efficiency of ∼40% is attained, while the sidewalls of the etched 8 µm-diameter microdisks patterned by microsphere lithography are optically smooth to promote the formation of whispering-gallery modes (WGMs) within the circular optical cavities. Optically pumped lasing with low threshold of ∼5.2 mJ/cm² and quality (Q) factor of ∼3000 at the dominant lasing wavelength of 436.8 nm has been observed. The microdisks also support electroluminescent operation, demonstrating WGMs consistent with the photoluminescence spectra and with finite-difference time-domain (FDTD) simulations.

Growth factors improve the proliferation of Jeju black pig muscle cells by regulating myogenic differentiation 1 and growth-related genes

OBJECTIVE

The growth rate of pigs is related to differentiation and proliferation of muscle cells, which are regulated by growth factors and expression of growth-related genes. Thus, the objective of this study was to establish optimal culture conditions for Jeju black pig (JBP) muscle cells and determine the relationship of various factors involved in muscle growth with the proliferation of JBP muscle cells.

METHODS

Muscles were taken from the femur skeletal muscle of JBP embryos. After isolation of the muscle cells, cells were cultured in a 6-well plate under four different culture conditions to optimize culture conditions for JBP muscle cells. To analyze proliferation rate of JBP muscle cells, these muscle cells were seeded into 6-well plates at a density of 1.5×105 cells per well and cultured for 3 days. Western blot and quantitative real-time polymerase chain reaction were applied to verify the myogenic differentiation 1 (MyoD) expression and growth-related gene expression in JBP muscle cells, respectively.

RESULTS

We established a muscle cell line from JBP embryos and optimized its culture conditions. These muscle cells were positive for MyoD, but not for paired box 7. The proliferation rate of these muscle cells was significantly higher in a culture medium containing bFGF and epidermal growth factor + basic fibroblast growth factor (EGF+bFGF) than that without a growth factor or containing EGF alone. Treatment with EGF and bFGF significantly induced the expression of MyoD protein, an important transcription factor in muscle cells. Moreover, we checked the changes of expression of growth-related genes in JBP muscle cells by presence or absence of growth factors. Expression level of collagen type XXI alpha 1 gene was changed only when EGF and bFGF were added together to culture media for JBP muscle cells.

CONCLUSION

Concurrent use of EGF and bFGF increased the expression of MyoD protein, thus regulating the proliferation of JBP muscle cells and the expression of growth-related genes.

Direct exposure to mild heat stress stimulates cell viability and heat shock protein expression in primary cultured broiler fibroblasts

Fibroblasts produce collagen which is mainly essential for repairing tissue damage and maintaining the structural integrity of tissues. However, studies have given scientific evidence about harmful effect of thermal manipulation in fibroblast. Therefore, the aim of this study was to determine the mild heat stress temperature which increased broiler fibroblast viability. The experiment was divided into two groups (37 °C and 41 °C), and each group was divided into five subgroups based on different incubation times (6 h, 12 h, 24 h, 48 h, and 72 h) with three replications. In experimental group (41 °C), fibroblast viability increased significantly in 12 h but decreased in 72 h compared with control (37 °C). At 41 °C, live cell increased significantly in 24 h and then declined in 48 h as well as 72 h than control. Moreover, the S phase lengthened in shorter incubation time of experimental group compared with control. Protein and mRNA (HSP70, HSP60, and HSP47) expressions were significantly higher at 41 °C compared with 37 °C, but at the end of the experiment, HSP expression level was higher in both groups. Finally, this study recommended 41 °C as a mild heat stress temperature for increasing broiler fibroblast viability.

Acute Heat Stress Induces the Differential Expression of Heat Shock Proteins in Different Sections of the Small Intestine of Chickens Based on Exposure Duration

In this study, we examined the protein and gene expression of heat shock proteins (HSPs) in different sections of the small intestine of chickens. In total, 300 one-day-old Ross 308 broiler chicks were randomly allocated to the control and treatment groups. The treatment group was divided into four subgroups, according to the duration of acute heat exposure (3, 6, 12, and 24 h). The influence of heat stress on the protein and gene expression of HSP70, HSP60, and HSP47 in different sections of the small intestine of chickens was determined. The protein expression of HSP70 and HSP60 was significantly higher at 6 h in the duodenum and jejunum and 12 h in the ileum. The HSP47 protein expression was significantly higher at 3 h in the duodenum and ileum and at 6 h in the jejunum. The gene expression levels of HSP70, HSP60, and HSP47 were significantly higher at the 3 h treatment group than the control group in the duodenum, jejunum, and ileum. The glutamate pyruvate transaminase and glutamate oxaloacetate transaminase levels were significantly higher at 12 and 24 h in the serum of the blood. Acute heat stress affected the expression of intestinal proteins and genes in chickens, until the induction of heat tolerance.

Rapid recovery of coastal environment and ecosystem to the Hebei Spirit oil spill's impact

The 2007 Hebei Spirit oil spill (HSOS), the largest in the national history, has negatively impacted the entire environment and ecosystem along the west coast of South Korea. Although many studies have reported the damages and impacts from the HSOS, quantitative assessment evaluating the recovery time and status have not been documented. Here, we first address the recovery timeline of the HSOS, by comprehensive analyses of 10-years accumulated data in quantitative manner. Concentrations of residual oils in seawater, sediments, and oysters rapidly dropped to backgrounds in 16, 75, and 33 months, respectively. Also, damaged benthic communities of intertidal and subtidal areas were fully recovered only after ~6 years. The present results collectively indicated unexpectedly fast recovery of the damaged environment and ecosystem from such a huge oil spill. The high tidal mixing (~9 m tidal height) and intensive human cleanup (~1.2 million volunteers) at the initial cleanup period might have contributed to rapid recovery; cf. 4-5 times faster than the Exxon Valdez oil spill. However, potential risk to human health remains unclear. Thus, it is warranted to conduct more in depth epidemiological studies to address chronic health effects associated with the cleanup volunteers as well as the local residents who have been living nearby the oil spill impacted sites.

Development of Poly(methyl methacrylate)-Based Copolymers with Improved Heat Resistance and Reduced Moisture Absorption

Poly(methyl methacrylate) (PMMA) is widely used as a transparent material for optical applications, owing to its high light transmittance. However, it exhibits poor heat resistance and high moisture absorption, leading to distortion and deformation upon exposure to elevated temperatures and/or moisture. These structural changes decrease the transparency of PMMA, critically limiting its applicability. In this study, we synthesized poly(methyl methacrylate-co-styrene-co-acrylamide) (PMSAm) as a reference polymer and introduced one of four different comonomers [N-phenylmaleimide (PMI), N-cyclohexylmaleimide (CHMI), allyltrimethylsilane (ATMS), or 2,2,2-trifluoroethyl methacrylate (TF)] as a means to improve heat resistance and reduce moisture absorption. Four series of PMMA-based random copolymers (PMSAm-PMI, PMSAm-CHMI, PMSAm-ATMS, and PMSAm-TF) were synthesized by conventional thermal radical polymerization. All of the polymers synthesized exhibited improved heat resistance, with PMSAm-CHMI exhibiting the highest glass transition temperature (T_g = 122.54 °C) and 5% weight loss thermal decomposition temperature (T_5d = 343.40 °C) as well as the lowest thermal expansion coefficient (90.3 μm m^-1 °C^-1). The highest hydrophobicity was exhibited by PMSAm-TF, with a water contact angle of 78.9°, indicating higher hydrophobicity compared to that of pure PMMA (69.4°). More importantly, high transparency (∼90%) was exhibited by all of the synthesized polymers. Thus, our copolymerization strategy successfully addresses the limitations, i.e., low heat resistance and high moisture absorption, of conventional PMMA-based materials.

P5719Plasma proteomics identify plaque-related proteins that predict long-term recurrent coronary events in patients with acute coronary syndrome

Background

Coronary plaque burden and composition drive recurrent ischaemic events in coronary artery disease.

Purpose

We first investigated the association between plasma proteins and coronary plaque characteristics in a cohort of asymptomatic individuals with low-intermediate Framingham Risk Score. Plaque-related proteins were further evaluated in a second cohort of patients with acute coronary syndrome (ACS) to determine their prognostic value for predicting future myocardial infarction (MI).

Methods

We profiled 1305 plasma proteins using an aptamer-based array (SOMAscan) in asymptomatic individuals who had undergone 384-slice coronary computed tomography angiography. Plaques were categorized by composition as calcified or non-calcified. First, we identified proteins that were different (based on multiple testing adjusted p-values: q-value <0.05) between 250 ACS patients who suffered a recurrent MI event on follow-up compared with another 250 ACS patients who remained event-free using Mann-Whitney U test. Next, protein candidates that also correlated (Pearson's p<0.05) with specific categories of plaque composition were evaluated using a cox proportional hazards model to determine the risk of recurrent MI, adjusting for potential confounders in the second cohort.

Results

A total of 65 and 120 plasma proteins were significantly associated with calcified and non-calcified plaques respectively in the asymptomatic cohort (N=79). Of these 185 proteins, 23 proteins were differentially expressed (DE) between ACS patients with and without recurrent MI events (median follow-up 1811 days). The top three up-and down-regulated proteins in the recurrent MI group were macrophage-capping protein, trefoil factor 3 and cystatin-SN (median FC 1.22, 1.17 and 1.17; q-value 4.34x10–6, 2.18x10–4, 3.17x10–3 respectively) and fibroblast growth factor 20, lymphotoxin a2/b1 and vascular endothelial growth factor receptor 2 (median FC 0.92, 0.94 and −0.090; q-value 1.31x10–3, 9.45x10–3 and 3.90x10–3) respectively. The quartiles of these protein concentrations were also associated with risk of recurrent MI, (log-rank test p-value range from 2.71x10–7 to 0.04). Of the DE proteins, the adjusted hazards ratio (HR) of cystatin-SN in the highest quartile (Q4) was 1.44 times that of the first quartile (Q1) (adjusted HR: 1.44, 95% CI: 0.93–2.2) and higher plasma concentration of cystatin-SN was associated with increasing risk of recurrent MI events (Trend test p=0.004). On the other hand, the highest quartile of fibroblast growth factor 20 was associated with 44% reduction in risks of recurrent MI adjusted HR: 0.56, 95% CI of HR: 0.35–0.87), with significant trend test (p=0.0096).

Conclusions

Large-scale plasma proteomics identified novel plaque-related proteins predictive of recurrent coronary events in patients with ACS. Further studies may help unravel the biological underpinnings of these circulating proteins and their potential as novel prognostic biomarkers.

Acknowledgement/Funding

This work was supported by grant NMRC/CSA-INV/0001/2016 from the National Medical Research Council, Singapore.

Derivation of primitive neural stem cells from human-induced pluripotent stem cells

Human-induced pluripotent stem cells (hiPSCs) have facilitated studies on organ development and differentiation into specific lineages in in vitro systems. Although numerous studies have focused on cellular differentiation into neural lineage using hPSCs, most studies have initially evaluated embryoid body (EB) formation, eventually yielding terminally differentiated neurons with limited proliferation potential. This study aimed to establish human primitive neural stem cells (pNSCs) from exogene-free hiPSCs without EB formation. To derive pNSCs, we optimized N2B27 neural differentiation medium through supplementation of two inhibitors, CHIR99021 (GSK-3 inhibitor) and PD0325901 (MEK inhibitor), and growth factors including basic fibroblast growth factor (bFGF) and human leukemia inhibitory factor (hLIF). Consequently, pNSCs were efficiently derived and cultured over a long term. pNSCs displayed differentiation potential into neurons, astrocytes, and oligodendrocytes. These early NSC types potentially promote the clinical application of hiPSCs to cure human neurological disorders.

Attention-Deficit/Hyperactivity Disorder Symptom Characteristics in Korean Elementary School Children: Comparison with US Population

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in elementary school children. The present study investigated the characteristics of ADHD in Korean elementary school children using the Korean version of the ADHD Rating Scale (K-ARS). The data was compared with those obtained from a comparable American population.

METHODS

Participants included 29,914 elementary school children, aged 6-12 years, from a medium-sized city. The parents completed the home version of the K-ARS. The total and subscale-specific normative data and sex- and age-related mean score differences were analyzed. These data were compared with those obtained from the American population using independent t-tests.

RESULTS

Mean total and subscale K-ARS scores were significantly higher among boys (vs. girls) and younger children aged equal to or less than 8 years old (vs. older children). Mean scores on the hyperactivity-impulsivity subscale were lower than those of American children, but similar to another Korean sample.

CONCLUSION

Our data characterized ADHD symptoms in Korean children. However, further studies are needed to identify the cultural differences underlying ratings of ADHD symptom severity.

JAK2 regulation by licochalcone H inhibits the cell growth and induces apoptosis in oral squamous cell carcinoma

BACKGROUND

Licochalconce (LC) H is an artificial compound in the course of synthesizing LCC in 2013. So far, few studies on the effects of LCH have been found in the literature. Despite progress in treatment modalities for oral cancer, the cure from cancer has still limitations.

PURPOSE

The effects of LCH were investigated on human oral squamous cell carcinoma (OSCC) cells to elucidate its mechanisms.

STUDY DESIGN

We explored the mechanism of action of LCH by which it could have effects on JAK2/STAT3 signaling pathway.

METHODS

To confirm LCH anti-cancer effect, analyzed were MTT assay, DAPI staining, soft agar, kinase assay, molecular docking simulation, flow cytometry and Western blotting analysis.

RESULTS

According to docking and molecular dynamics simulations, the predicted pose of the complex LCH and JAK2 seems reasonable and LCH is strongly bound to active JAK2 with opened activation loop. The LCH inhibitor is surrounded by specific ATP-binding pocket in which it is stabilized by forming hydrogen bonds and hydrophobic interactions. It is shown that LCH plays as a competitive inhibitor in an active state of JAK2. LCH caused a dose-dependent decrease in phosphorylation of JAK2 and STAT3. More interestingly, LCH suppressed JAK2 kinase activity in vitro by its direct binding to the JAK2. LCH significantly inhibited the JAK2/STAT3 signaling pathway, causing the down-regulation of target genes such as Bcl-2, survivin, cyclin D1, p21 and p27. In addition, LCH inhibited cell proliferation and colony formation of OSCC cells in a dose- and time-dependent manner, as well as induction of cell apoptosis through extrinsic and intrinsic pathway. The induction of apoptosis in OSCC cells by LCH was evident in the increased production of ROS, loss of mitochondrial membrane potential, release of cyto c, variation of apoptotic proteins and activation of caspase cascade.

CONCLUSION

LCH not only induces apoptosis in OSCC cells through the JAK/STAT3 signaling pathway but also inhibits cell growth. It is proposed that LCH has a promising use for the chemotherapeutic agent of oral cancer.

Licochalcone H induces the apoptosis of human oral squamous cell carcinoma cells via regulation of matrin 3

Licochalcone H (LCH) is a chemical compound that is a positional isomer of licochalcone C (LCC), a chalconoid isolated from the root of Glycyrrhiza inflata, which has various pharmacological properties including anti-inflammatory, antioxidant, antitumor, and anticancer effects. However, the efficacy of LCH on cancer cells has not been investigated. The present study examined the effects of LCH on cell proliferation, induction of apoptosis, and the regulation of matrin 3 (Matr3) protein in oral squamous cell carcinoma (OSCC) cells by Annexin V/propidium iodide (PI) staining and western blot analysis. LCH reduced cell viability and colony forming ability, and induced cell cycle arrest and apoptosis in HSC2 and HSC3 cells through the suppression of Matr3. It was also found that LCH directly bound to Matr3 in a Sepharose 4B pull-down assay. Consequently, the results of the present study suggest that LCH may be used as an anticancer drug in combination with conventional chemotherapy for the treatment of OSCC, and that Matr3 may be a potential effective therapeutic target.

Reprogramming of Extraembryonic Trophoblast Stem Cells into Embryonic Pluripotent State by Fusion with Embryonic Stem Cells

Pluripotential reprogramming has been examined using various technologies, including nuclear transfer, cell fusion, and direct reprogramming. Many studies have used differentiated cells for reprogramming experiments, and nearly all type of somatic cells can acquire pluripotency. However, within the embryo, other cells types are present in addition to somatic cells. The blastocyst stage embryo consists of two main types of cells, inner cell mass and trophectoderm (TE). TE cells are the first differentiated form of the totipotent zygote and differ from epiblast cells. Thus, we examined whether extraembryonic cells can be reprogrammed using a cell-cell fusion method. Trophoblast stem cells (TSCs), which can be obtained from the TE, are known to acquire pluripotency by transcription factor Oct4 overexpression or somatic cell nuclear transfer. In this study, we demonstrated that TSCs can acquire pluripotent properties by cell fusion with embryonic stem cells (ESCs). TSC-ESC hybrids reactivated Oct4-GFP and displayed self-renewal properties. They expressed the pluripotency markers Oct4 and Nanog, whereas the expression of Cdx2 and Tead4, trophoblast lineage markers, was diminished. Moreover, these cells developed into three germ layers similarly to other pluripotent stem cells. RNA-seq analysis showed that global gene expression patterns of TSC-ESC hybrids are more similar to ESCs than TSCs. Thus, we demonstrated that TSCs successfully complete reprogramming and acquire pluripotency by cell fusion-induced reprogramming.

Licochalcone C induced apoptosis in human oral squamous cell carcinoma cells by regulation of the JAK2/STAT3 signaling pathway

Oral cancer is of an aggressive malignancy that arises on oral cavity and lip, 90% of cancers histologically originated in the squamous cells. Licochalcone (LC)C has been known as natural phenolic chalconoid substances, and its origin is the root of Glycyrrhiza glabra or Glycyrrhiza inflata. LCC inhibited oral squamous cell carcinoma (OSCC) cell viability, mitochondrial function, and anchorage-independent growth in a dose-dependent manner. To investigate the ability of LCC to target Janus kinase 2 (JAK2), we performed pull-down binding assay, kinase assay, and docking simulation. The molecular docking studies were performed between JAK2 and the potent inhibitor LCC. It was shown that LCC tightly interacted with ATP-binding site of JAK2. In addition, LCC inhibited the JAK2/signal transducer and activator of transcription 3 pathway, upregulated p21, and downregulated Bcl-2, Mcl-1, and Survivin, while it disrupted mitochondrial membrane potential and subsequently caused cytochrome c release with activation of multi-caspase, eventually leading to apoptosis in HN22 and HSC4 cells. LCC elevated the protein levels of Bax, cleaved Bid and PARP, and increased Apaf-1, and this effect was reversed by LCC treatment. Our results demonstrated that treatment of OSCC cells with LCC induced the death receptor (DR)4 and DR5 expression level with the generation of reactive oxygen species and the upregulation of CHOP protein expression. Taken together, these results could provide the basis for clinical application as a new therapeutic strategy in the treatment of oral cancer.

Licochalcone D directly targets JAK2 to induced apoptosis in human oral squamous cell carcinoma

Licochalcone (LC) families have been reported to have a wide range of biological function such as antioxidant, antibacterial, antiviral, and anticancer effects. Although various beneficial effects of LCD were revealed, its anticancer effect in human oral squamous cancer has not been identified. To examine the signaling pathway of LCD's anticancer effect, we determined whether LCD has physical interaction with Janus kinase (JAK2)/signal transducer and activator of transcription-3 (STAT3) signaling, which is critical in promoting cancer cell survival and proliferation. Our results demonstrated that LCD inhibited the kinase activity of JAK2, soft agar colony formation, and the proliferation of HN22 and HSC4 cells. LCD also induced mitochondrial apoptotic events such as altered mitochondrial membrane potential and reactive oxygen species production. LCD increased the expression of apoptosis-associated proteins in oral squamous cell carcinoma (OSCC) cells. Finally, the xenograft study showed that LCD significantly inhibited HN22 tumor growth. Immunohistochemical data supported that LCD suppressed p-JAK2 and p-STAT3 expression and induced cleaved-caspase-3 expression. These results indicate that the anticancer effect of LCD is due to the direct targeting of JAK2 kinase. Therefore, LCD can be used for therapeutic application against OSCC.

Packaging of InGaN stripe-shaped light-emitting diodes

We demonstrate the fabrication of InGaN/GaN stripe-shaped light-emitting diodes (LEDs) in flip-chip packaging (FC-LED) and vertically mounted packaging (VM-LED). Compared to conventionally packaged LEDs, these packaging schemes enhance light output and emission divergence in ways favorable for general lighting applications. The FC-LED can sustain efficiency at high current operations due to effective heat sinking, while the VM-LED excels at light extraction efficiency due to the exposure of two large emission surfaces. Together with the properties of low luminous exitance and emission uniformity, the stripe-shaped LEDs are ideal for the assembly of luminaires. An LED light tube comprising a continuous linear array of 10 stripe-shaped LED chips has been assembled. The optical performance of the light tube is compared to another light tube assembled with conventional square-shaped LED chips (with and without external diffuser) by confocal microscopy. It is found that emission uniformity of the stripe-shaped LED tube is significantly improved, with a threefold increase in illumination area, without efficiency loss associated with diffusers.

Correlation of Fe-Based Superconductivity and Electron-Phonon Coupling in an FeAs/Oxide Heterostructure

Interfacial phonons between iron-based superconductors (FeSCs) and perovskite substrates have received considerable attention due to the possibility of enhancing preexisting superconductivity. Using scanning tunneling spectroscopy, we studied the correlation between superconductivity and e-ph interaction with interfacial phonons in an iron-based superconductor Sr_{2}VO_{3}FeAs (T_{c}≈33  K) made of alternating FeSC and oxide layers. The quasiparticle interference measurement over regions with systematically different average superconducting gaps due to the e-ph coupling locally modulated by O vacancies in the VO_{2} layer, and supporting self-consistent momentum-dependent Eliashberg calculations provide a unique real-space evidence of the forward-scattering interfacial phonon contribution to the total superconducting pairing.

Generation of in vivo neural stem cells using partially reprogrammed cells defective in in vitro differentiation potential

Pluripotent stem cells can be easily differentiated in vitro into a certain lineage through embryoid body formation. Recently, however, we reported partially reprogrammed cells showing some pluripotent characteristics, which failed to differentiate in vitro. Here, we attempted to generate neural stem cells (NSCs) from partially reprogrammed cells using an in vivo differentiation system involving teratoma formation. Partially reprogrammed cells formed teratomas after injection into immunocompromised mice, and NSCs could be isolated from these teratomas. These in vivo NSCs expressed NSC markers and terminally differentiated into neurons and glial cells. Moreover, these NSCs exhibited molecular profiles very similar to those of brain-derived NSCs. These results suggest that partially reprogrammed cells defective in in vitro differentiation ability can differentiate into pure populations of NSCs through an in vivo system.

Paternal age as an independent factor does not affect embryo quality and pregnancy outcomes of testicular sperm extraction-intracytoplasmic sperm injection in azoospermia

This study was performed to evaluate the independent influence of paternal age affecting embryo development and pregnancy using testicular sperm extraction (TESE)-intracytoplasmic sperm injection (ICSI) in obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). Paternal patients were divided into the following groups: ≤30 years, 31-35 years, 36-40 years, 41-45 years and ≥46 years. There were no differences in the rates of fertilisation or embryo quality according to paternal and maternal age. However, clinical pregnancy and implantation rates were significantly lower between those ≥46 years of paternal age compared with other age groups. Fertilisation rate was higher in the OA than the NOA, while embryo quality, pregnancy and delivery results were similar. Clinical pregnancy and implantation rates were significantly lower for patients ≥46 years of paternal age compared with younger age groups. In conclusion, fertilisation using TESE in azoospermia was not affected by the independent influence of paternal age; however, as maternal age increased concomitantly with paternal age, rates of pregnancy and delivery differed between those with paternal age <41 years and ≥46 years. Therefore, paternal age ≥46 years old should be considered when applying TESE-ICSI in cases of azoospermia, and patients should be advised of the associated low pregnancy rates.

Fabrication of Patterned Superhydrophobic/Hydrophilic Substrates by Laser Micromachining for Small Volume Deposition and Droplet-Based Fluorescence

The deposition of nanoliter and subnanoliter volumes is important in chemical and biochemical droplet-based microfluidic systems. There are several techniques that have been established for the deposition/generation of small volumes including the use of surfaces with patterned differences in wettability. Many such methods require complex and time-consuming lithographic techniques. Here, we present a facile method for the fabrication of superhydrophobic surfaces with patterned hydrophilic regions by laser micromachining. A comprehensive study of fabrication parameters (laser machining speed, laser power, and patch size) on the material, patch wettability, and droplet volume is presented. Patch sizes as small as 100 μm diameter and as large as 1500 μm diameter were investigated, and volumes as low as 400 pL were observed. As an example application of such patterned materials and the deposition of small volumes, halide salts were preconcentrated on the hydrophilic patches, and their fluorescence quenching constants were rapidly calculated using a 3D-printed device coupled to a fluorescence spectrometer.

In vivo differentiation of induced pluripotent stem cells into neural stem cells by chimera formation

Like embryonic stem cells, induced pluripotent stem cells (iPSCs) can differentiate into all three germ layers in an in vitro system. Here, we developed a new technology for obtaining neural stem cells (NSCs) from iPSCs through chimera formation, in an in vivo environment. iPSCs contributed to the neural lineage in the chimera, which could be efficiently purified and directly cultured as NSCs in vitro. The iPSC-derived, in vivo-differentiated NSCs expressed NSC markers, and their gene-expression pattern more closely resembled that of fetal brain-derived NSCs than in vitro-differentiated NSCs. This system could be applied for differentiating pluripotent stem cells into specialized cell types whose differentiation protocols are not well established.

Distinct Enhancer Activity of Oct4 in Naive and Primed Mouse Pluripotency

Naive and primed pluripotent stem cells (PSCs) and germ cells express the Oct4 gene. The Oct4 gene contains two cis-regulatory elements, the distal enhancer (DE) and proximal enhancer (PE), which differentially control Oct4 expression in a cell-type-specific and stage-specific manner. Here, we generated double transgenic mice carrying both Oct4-ΔPE-GFP and Oct4-ΔDE-tdTomato (RFP), enabling us to simultaneously monitor the activity of DE and PE. Oct4 expression is stage-specifically regulated by DE and PE during embryonic and germ cell development. Using this dual reporter system, we successfully cultured pure populations of naive (GFP⁺RFP⁻) and primed (GFP⁻RFP⁺) PSCs. We found that GFP⁺RFP⁻ cells were metastable (not naive) in serum-containing medium; stable naive pluripotent cells were observed in medium containing two inhibitors (Meki and GSKi) but lacked serum. Finally, we suggest that the activity of Oct4 DE and PE is regulated by the repressive histone marks and DNA methylation in a cell-type-specific manner.

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A defined model for Oct4 enhancer activity in the totipotent cycle

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Culturing pure populations of naive and primed PSCs by a double reporter system

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Altering Oct4 enhancer activity in PSCs by changing culture conditions

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Histone modification and DNA methylation regulate Oct4 enhancer activity

Flexible Free-Standing III-Nitride Thin Films for Emitters and Displays

The majority of a GaN light-emitting diode (LED) is released from its sapphire substrate through selective-area laser lift-off to form a freely suspended light emitter. By virtue of being suspended in air without supporting substrates, the ultrathin crystalline and crack-free film possesses flexibility and bendability. The free-standing LEDs benefit from significant relaxation of strain, evident from red-shifting of the E2(high) phonon frequencies as measured by Raman spectroscopy toward those of strain-free free-standing GaN substrates. The phonon frequencies remain invariant upon bending of the film; this indicates that the properties of the flexible device will not be dependent on the bending curvatures. The observation of pronounced spectral blue-shifts from the photoluminescence (PL) spectrum from the flexible regions further confirms the occurrence of strain relaxation in the quantum wells. Being free-standing and thus lacking a direct heat-sinking pathway, emissions from the different regions of the suspended film can be affected by thermal effects to different extents, which are investigated by long-wave infrared thermometry. Heat accumulation is determined to be most severe at the far end of the flexible stripe at higher currents, leading to reduced efficiencies and electroluminescence (EL) spectral red-shifts. Based on this architecture, a monolithic 3 × 4 dot-matrix microdisplay prototype is demonstrated, comprising three adjacent flexible stripe emitters with four individually addressable pixels on each stripe. This proof-of-concept demonstration opens up new opportunities for GaN optoelectronics for a wide range of flexible display and visual applications.

In Vivo Generation of Neural Stem Cells Through Teratoma Formation

Pluripotent stem cells have the potential to differentiate into all cell types of the body in vitro through embryoid body formation or in vivo through teratoma formation. In this study, we attempted to generate in vivo neural stem cells (NSCs) differentiated through teratoma formation using Olig2-GFP transgenic embryonic stem cells (ESCs). After 4 to 6 weeks of injection with Olig2-GFP transgenic ESCs, Olig2-GFP(+) NSCs were identified in teratomas formed in immunodeficient mice. Interestingly, 4-week-old teratomas contained higher percentage of Olig2-GFP(+) cells (∼11%) than 6-week-old teratomas (∼3%). These in vivo-derived NSCs expressed common NSC markers (Nestin and Sox2) and differentiated into terminal neuronal and glial lineages. These results suggest that pure NSC populations exhibiting properties similar to those of brain-derived NSCs can be established through teratoma formation.

A Pair of Oviduct-Born Pickpocket Neurons Important for Egg-Laying in Drosophila melanogaster

During copulation, male Drosophila transfers Sex Peptide (SP) to females where it acts on internal sensory neurons expressing pickpocket (ppk). These neurons induce a post-mating response (PMR) that includes elevated egg-laying and refractoriness to re-mating. Exactly how ppk neurons regulate the different aspects of the PMR, however, remains unclear. Here, we identify a small subset of the ppk neurons which requires expression of a pre-mRNA splicing factor CG3542 for egg-laying, but not refractoriness to mating. We identify two CG3542-ppk expressing neurons that innervate the upper oviduct and appear to be responsible for normal egg-laying. Our results suggest specific subsets of the ppk neurons are responsible for each PMR component.

Changes in Parthenogenetic Imprinting Patterns during Reprogramming by Cell Fusion

Differentiated somatic cells can be reprogrammed into the pluripotent state by cell-cell fusion. In the pluripotent state, reprogrammed cells may then self-renew and differentiate into all three germ layers. Fusion-induced reprogramming also epigenetically modifies the somatic cell genome through DNA demethylation, X chromosome reactivation, and histone modification. In this study, we investigated whether fusion with embryonic stem cells (ESCs) also reprograms genomic imprinting patterns in somatic cells. In particular, we examined imprinting changes in parthenogenetic neural stem cells fused with biparental ESCs, as well as in biparental neural stem cells fused with parthenogenetic ESCs. The resulting hybrid cells expressed the pluripotency markers Oct4 and Nanog. In addition, methylation of several imprinted genes except Peg3 was comparable between hybrid cells and ESCs. This finding indicates that reprogramming by cell fusion does not necessarily reverse the status of all imprinted genes to the state of pluripotent fusion partner.

Mitochondrial Remodeling in Chicken Induced Pluripotent Stem-Like Cells

Chicken pluripotent stem cells (PSCs), such as embryonic stem cells and blastoderm cells, have been used to study development and differentiation in chicken. However, chicken PSCs are not widely used because they are hard to maintain in long-term culture. Recent reports suggest that chicken somatic cells can be reprogrammed to pluripotent state by defined factors to form induced pluripotent stem cells (iPSCs). These chicken iPSCs showed pluripotent differentiation potential and could be maintained in long-term culture. However, intracytoplasmic remodeling during reprogramming of chicken cells remains largely unknown. In this study, we generated chicken iPS-like cells (ciPSLCs) from chicken embryonic fibroblasts using a retroviral expression system encoding human reprogramming factors. These ciPSLCs could be maintained for more than 10 passages and expressed the endogenous chicken pluripotency markers, cNonog and cSox2. Moreover, the ciPSLCs showed higher nucleus to cytoplasm ratio and contained globular mitochondria with immature cristae. This morphology was similar to that of mammalian PSCs, but different from that of avian somatic cells, which showed lower nucleus to cytoplasm ratio and mature mitochondria. These results suggest that intracytoplasmic organelles in differentiated somatic cells could be successfully remodeled into the pluripotent state during reprogramming in chicken.

Protein Kinase A Signaling Is Inhibitory for Reprogramming into Pluripotent Stem Cells

Somatic cells may be reprogrammed into pluripotent cells by the ectopic expression of defined transcription factors. However, some of the hurdles that affect the generation of induced pluripotent stem cells include extremely low efficiency and slow reprogramming. In the present study, we examined the effects of small molecules on cellular reprogramming and found that 8-Bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP), an analog of cyclic adenosine monophosphate (cAMP), improves the reprogramming efficiency of reprogrammable mouse fibroblasts induced with dox in serum replacement (SR) medium. Interestingly, treatment with 8-Br-cAMP in mouse embryonic stem cell culture conditions does not affect reprogramming into the pluripotent state; however, reprogramming efficiency is significantly enhanced by inhibition of protein kinase A (PKA) in SR medium. Therefore, our results suggest that PKA signaling is unnecessary and may in fact act as a barrier to reprogramming into pluripotent stem cells.

Generation of Partially Reprogrammed Cells and Fully Reprogrammed iPS Cells by Plasmid Transfection

Induced pluripotent stem (iPS) cells can be directly generated from somatic cells by overexpression of defined transcription factors. iPS cells can perpetually self-renew and differentiate into all cell types of an organism. iPS cells were first generated through infection with retroviruses that contain reprogramming factors. However, development of an exogene-free iPS cell generation method is crucial for future therapeutic applications, because integrated exogenes result in the formation of tumors in chimeras and regain pluripotency after differentiation in vitro. Here, we describe a method to generate iPS cells by transfection of plasmid vectors and to convert partially reprogrammed cells into fully reprogrammed iPS cells by switching from mouse ESC culture conditions to KOSR-based media with bFGF. We also describe basic methods used to characterize fully reprogrammed iPS cells.

Ageing-related changes in GABAergic inhibition in mouse auditory cortex, measured using in vitro flavoprotein autofluorescence imaging

KEY POINTS

Ageing is associated with hearing loss and changes in GABAergic signalling in the auditory system. We tested whether GABAergic signalling in an isolated forebrain preparation also showed ageing-related changes. A novel approach was used, whereby population imaging was coupled to quantitative pharmacological sensitivity. Sensitivity to GABAA blockade was inversely associated with age and cortical thickness, but hearing loss did not independently contribute to the change in GABAA ergic sensitivity. Redox states in the auditory cortex of young and aged animals were similar, suggesting that the differences in GABAA ergic sensitivity are unlikely to be due to differences in slice health. To examine ageing-related changes in the earliest stages of auditory cortical processing, population auditory cortical responses to thalamic afferent stimulation were studied in brain slices obtained from young and aged CBA/CAj mice (up to 28 months of age). Cortical responses were measured using flavoprotein autofluorescence imaging, and ageing-related changes in inhibition were assessed by measuring the sensitivity of these responses to blockade of GABAA receptors using bath-applied SR95531. The maximum auditory cortical response to afferent stimulation was not different between young and aged animals under control conditions, but responses to afferent stimulation in aged animals showed a significantly lower sensitivity to GABA blockade with SR95531. Cortical thickness, but not hearing loss, improved the prediction of all imaging variables when combined with age, particularly sensitivity to GABA blockade for the maximum response. To determine if the observed differences between slices from young and aged animals were due to differences in slice health, the redox state in the auditory cortex was assessed by measuring the FAD+/NADH ratio using fluorescence imaging. We found that this ratio is highly sensitive to known redox stressors such as H2 O2 and NaCN; however, no difference was found between young and aged animals. By using a new approach to quantitatively assess pharmacological sensitivity of population-level cortical responses to afferent stimulation, these data demonstrate that auditory cortical inhibition diminishes with ageing. Furthermore, these data establish a significant relationship between cortical thickness and GABAergic sensitivity, which had not previously been observed in an animal model of ageing.

Geographic predictors of primary multidrug-resistant tuberculosis cases in an endemic area of Lima, Peru

SETTING

Peru reports among the highest multidrug-resistant tuberculosis (MDR-TB) rates in the Americas, with a growing proportion in previously untreated tuberculosis (TB) cases. The identification of clusters of primary MDR-TB compared with drug-susceptible TB (DS-TB) could help prioritize interventions.

OBJECTIVE

To examine the clustering of primary MDR-TB case residences and their proximity to high-risk locations in San Juan de Lurigancho District, Lima, Peru.

DESIGN

Enrolled primary MDR-TB and primary DS-TB cases were interviewed and their primary residence was recorded using handheld Global Positioning System devices. Kuldorff's spatial scan statistic was used for cluster detection (SaTScan(TM), v. 9.1.1). Identified clusters were visualized in Quantum Geographic Information Systems software (v1.8.0). The following cluster centers were tested: a health centre with the highest TB and MDR-TB rates (Clinic X), a hospital and two prisons. Using regression analyses, we examined predictors of primary MDR-TB cases.

RESULTS

A statistically significant cluster of primary MDR-TB cases was identified within a 2.29 km radius around Clinic X. Proximity to Clinic X remained a significant predictor of primary MDR-TB in adjusted regression analyses.

CONCLUSION

We identified a hotspot of primary MDR-TB cases around Clinic X in a TB-endemic area. Causes of this clustering require investigation; targeted interventions for this high-risk area should be considered.

Whispering gallery mode lasing in optically isolated III-nitride nanorings

III-nitride nanorings fabricated from a combination of hybrid-nanosphere-lithography and laser lift-off processes is demonstrated. Being formed on an interfacial metallic layer optically coupling between the optical ring and its substrate is eliminated, maximizing optical confinement of whispering gallery resonant mode within the ring cavity. The tapered cross-sectional profile also promotes coupling of emitted light into resonant modes. Optically pumped lasing with a dominant peak at 421.5 nm is observed at room temperature, with threshold energy density of ∼6.5  mJ/cm2. Etch-induced sidewall roughness causes scattering of light at the interface to diminish confinement, and is also responsible for the mode-splitting effect according to finite-difference time-domain simulations.

InGaN light-emitting diode stripes with reduced luminous exitance

InGaN light-emitting diodes of stripe geometries have been demonstrated. The elongated geometry facilitates light spreading in the longitudinal direction. The chips are further shaped by laser-micromachining to have partially-inclined sidewalls. The light extraction efficiencies of such 3D chip geometries are enhanced by ~12% (~8% according to ray-trace simulations), leading to a reduction of junction temperatures. The effective emission area is also increased four times compared to a cubic chip. The stripe LEDs are thus more efficient emitters with reduced luminous exitance, making them more suitable for a wide range of lighting applications.

Mitochondrial and metabolic remodeling during reprogramming and differentiation of the reprogrammed cells

Reprogramming is one of the most essential areas of research in stem cell biology. Despite this importance, the mechanism and correlates of reprogramming remain largely unknown. In this study, we investigated the cytoplasmic remodeling and changes in metabolism that occur during reprogramming and differentiation of pluripotent stem cells. Specifically, we examined the cellular organelles of three pluripotent stem cells, embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and epiblast stem cells (EpiSCs), by electron microscopy. We found that the cellular organelles of primed pluripotent EpiSCs were more similar to those of naive pluripotent ESCs and iPSCs than somatic cells. EpiSCs, as well as ESCs and iPSCs, contain large nuclei, poorly developed endoplasmic reticula, and underdeveloped cristae; however, their mitochondria were still mature relative to the mitochondria of ESCs and iPSCs. Next, we differentiated these pluripotent stem cells into neural stem cells (NSCs) in vitro and compared the morphology of organelles. We found that the morphology of organelles of NSCs differentiated from ESCs, iPSCs, and EpiSCs was indistinguishable from brain-derived NSCs. Finally, we examined the changes in energy metabolism that accompanied mitochondrial remodeling during reprogramming and differentiation. We found that the glycolytic activity of ESCs and iPSCs was greater compared with EpiSCs, and that the glycolytic activity of EpiSCs was greater compared with NSCs differentiated from ESCs, iPSCs, and EpiSCs. These results suggest that a change in the cellular state is accompanied by dynamic changes in the morphology of cytoplasmic organelles and corresponding changes in energy metabolism.

Establishment of a primed pluripotent epiblast stem cell in FGF4-based conditions

Several mouse pluripotent stem cell types have been established either from mouse blastocysts and epiblasts. Among these, embryonic stem cells (ESCs) are considered to represent a “naïve”, epiblast stem cells (EpiSCs) a “primed” pluripotent state. Although EpiSCs form derivatives of all three germ layers during invitro differentiation, they rarely incorporate into the inner cell mass of blastocysts and rarely contribute to chimera formation following blastocyst injection. Here we successfully established homogeneous population of EpiSC lines with efficient chimera-forming capability using a medium containing fibroblast growth factor (FGF)-4. The expression levels of Rex1 and Nanog was very low although Oct4 level is comparable to ESCs. EpiSCs also expressed higher levels of epiblast markers, such as Cer1, Eomes, Fgf5, Sox17, and T, and further showed complete DNA methylation of Stella and Dppa5 promoters. However, the EpiSCs were clustered separately from E3 and T9 EpiSC lines and showed a completely different global gene expression pattern to ESCs. Furthermore, the EpiSCs were able to differentiate into all three germ layers in vitro and efficiently formed teratomas and chimeric embryos (21.4%) without germ-line contribution.