PIEZO1 activation may serve as an early tissue biomarker for the prediction of irradiation-induced salivary gland dysfunction.

Irradiation (IR)-induced xerostomia is the most common side effect of radiation therapy in patients with head and neck cancer (HNC). Xerostomia diagnosis is mainly based on the patient's medical history and symptoms. Currently, no direct biomarkers are available for the early prediction of IR-induced xerostomia. Here, we identified PIEZO1 as a novel predictive tissue biomarker for xerostomia. Our data demonstrate that PIEZO1 is significantly upregulated at the gene and protein levels during IR-induced salivary gland (SG) hypofunction. Notably, PIEZO1 upregulation coincided with that of inflammatory (F4/80) and fibrotic markers (fibronectin and collagen fibers accumulation). These findings suggest that PIEZO1 upregulation in SG tissue may serve as a novel predictive marker for IR-induced xerostomia.

High-Performance Self-Powered Quantum Dot Infrared Photodetector with Azide Ion Solution Treated Electron Transport Layer.

The demand for self-powered photodetectors (PDs) capable of NIR detection without external power is growing with the advancement of NIR technologies such as LIDAR and object recognition. Lead sulfide quantum dot-based photodetectors (PbS QPDs) excel in NIR detection; however, their self-powered operation is hindered by carrier traps induced by surface defects and unfavorable band alignment in the zinc oxide nanoparticle (ZnO NP) electron-transport layer (ETL). In this study, an effective azide-ion (N3 - ) treatment is introduced on a ZnO NP ETL to reduce the number of traps and improve the band alignment in a PbS QPD. The ZnO NP ETL treated with azide ions exhibited notable improvements in carrier lifetime and mobility as well as an enhanced internal electric field within the thin-film heterojunction of the ZnO NPs and PbS QDs. The azide-ion-treated PbS QPD demonstrated a increase in short-circuit current density upon NIR illumination, marking a responsivity of 0.45 A W-1 , specific detectivity of 4 × 1011 Jones at 950 nm, response time of 8.2 µs, and linear dynamic range of 112 dB.

Major Congenital Anomalies in Korean Livebirths in 2013-2014: Based on the National Health Insurance Database.

BACKGROUND: In Korea, there have been no reports comparing the prevalence of major congenital anomalies with other countries and no reports on surgical treatment and long-term mortality. We investigated the prevalence of 67 major congenital anomalies in Korea and compared the prevalence with that of the European network of population-based registries for the epidemiological surveillance of congenital anomalies (EUROCAT). We also investigated the mortality and age at death, the proportion of preterm births, and the surgical rate for the 67 major congenital anomalies. METHODS: Korean National Health Insurance claim data were obtained for neonates born in 2013-2014 and admitted within one-year-old. Sixty-seven major congenital anomalies were defined by medical diagnoses classified by International Classification of Diseases-10 codes according to the EUROCAT definition version 2014. Mortality and surgery were defined if any death or surgery claim code was confirmed until 2020. Poisson distribution was used to calculate the 95% confidence interval of the congenital anomaly prevalence. RESULTS: The total prevalence of the 67 major anomalies was 433.5/10,000 livebirths. When compared with the prevalence of each major anomaly in EUROCAT, the prevalence of spina bifida, atrial septal defect (ASD), congenital megacolon, hip dislocation and/or dysplasia and skeletal dysplasia were more than five times higher in Korea. In contrast, the prevalence of aortic atresia/interrupted aortic arch and gastroschisis was less than one-fifth in Korea. The proportion of preterm births was 15.7%; however, more than 40% of infants with anencephaly, annular pancreas and gastroschisis were preterm infants. Additionally, 29.2% of the major anomalies were admitted to the neonatal intensive care units at birth, and 25.6% received surgical operation. The mortality rate was 1.7%, and 78.2% of the deaths occurred within the first year of life. However, in neonates with tricuspid valve atresia and stenosis, duodenal atresia or stenosis, and diaphragmatic hernia, more than half died within their first month of life. ASD and ventricular septal defect were the most common anomalies, and trisomy 18 and hypoplastic left heart syndrome were the most fatal anomalies. All infants with aortic atresia/interrupted aortic arch and conjoined twins received surgery. CONCLUSION: The proportion of surgeries, preterm births and mortality was high in infants with major congenital anomalies. The establishment of a national registry of congenital anomalies and systematic support by national medical policies are needed for infants with major congenital anomalies in Korea.

Nationwide Long-Term Growth and Developmental Outcomes of Infants for Congenital Anomalies in the Digestive System and Abdominal Wall Defects With Surgery in Korea.

BACKGROUND: Infants with congenital anomalies of the digestive system and abdominal wall defects requiring surgery are at risk of growth and developmental delays. The aim of this study was to analyze long-term growth and developmental outcomes for infants with congenital anomalies of the digestive system and abdominal wall defects who underwent surgery in Korea. METHODS: We extracted data from the Korean National Health Insurance Service database for the years 2013-2019. Major congenital anomalies were defined according to the International Classification of Diseases-10 and surgery insurance claim codes. The χ² test and the Cochran-Armitage trend test were performed for data analysis. RESULTS: A total of 4,574 infants with major congenital anomalies in the digestive system and abodminal wall defects, who had undergone surgey, were reviewed. Anorectal obstruction/stenosis was the most prevalent anomaly (4.9 per 10,000 live births). The prevalence of congenital anomalies of the digestive system was 15.5 per 10,000 live births, and that of abdominal wall defects was 1.5 per 10,000 live births. Seven percent of infants with congenital anomalies in the digestive system died, of which those with diaphragmatic hernia had the highest mortality rate (18.8%). Among 12,336 examinations at 6, 12, 24, 36, 48, 60, and 72 months of age, 16.7% showed a weight below the 10th percentile, 15.8% had a height below the 10th percentile, and 13.2% had a head circumference below the 10th percentile. Abnormal developmental screening results were observed in 23.0% of infants. Infants with esophageal atresia with/without tracheoesophageal fistula most often had poor growth and development. Delayed development and cerebral palsy were observed in 490 (10.7%) and 130 (2.8%) infants respectively. Comparing the results of infants born in 2013 between their 24- and 72-month health examinations, the proportions of infants with poor height and head circumference growth increased by 6.5% and 5.3%, respectively, whereas those with poor weight growth and abnormal developmental results did not markedly change between the two examinations. CONCLUSION: Infants with congenital anomalies of the digestive system and abdominal wall defects exhibit poor growth and developmental outcomes until 72 months of age. Close monitoring and careful consideration of their growth and development after discharge are required.

Revisiting the Classical Wide-Bandgap HOMO and Random Copolymers for Indoor Artificial Light Photovoltaics.

Organic indoor photovoltaics (IPVs) are attractive energy harvesting devices for low-power consumption electronic devices and the Internet of Things (IoTs) owing to their properties such as being lightweight, semitransparent, having multicoloring capability, and flexibility. It is important to match the absorption range of photoactive materials with the emission spectra of indoor light sources that have a visible range of 400-700 nm for IPVs to provide sustainable, high-power density. To this end, benzo[1,2-b:4,5-b']dithiophene-based homopolymer (PBDTT) is synthesized as a polymer donor, which is a classical material that has a wide bandgap with a deep highest occupied molecular orbitals (HOMO) level, and a series of random copolymers by incorporating thieno[3,4-c]pyrrole-4,6,-dione (TPD) as a weak electron acceptor unit in PBDTT. The composition of the TPD unit is varied to fine tune the absorption range of the polymers; the polymer containing 70% TPD (B30T70) perfectly covers the entire range of indoor lamps such as light-emitting diodes (LEDs) and fluorescent lamp (FL). Consequently, B30T70 shows a dramatic enhancement of the power conversion efficiency (PCE) from 1-sun (PCE: 6.0%) to the indoor environment (PCE: 18.3%) when fabricating organic IPVs by blending with PC71 BM. The simple, easy molecular design guidelines are suggested to develop photoactive materials for efficient organic IPVs.

Energy recycling under ambient illumination for internet-of-things using metal/oxide/metal-based colorful organic photovoltaics.

Colorful indoor organic photovoltaics (OPVs) have attracted considerable attention in recent years for their autonomous function in internet-of-things (IoT) devices. In this study, a solution-processed TiO2layer in a metal-oxide-metal (MOM) color filter electrode is used for light energy recycling in P3HT:ICBA-based indoor OPVs. The MOM electrode allows for tuning of the optical cavity mode to maximize photocurrent production by modulating the thickness of the TiO2layer in the sandwich structure. This approach preserves the OPVs' optoelectronic properties without damaging the photoactive layer and enables them to display a suitable range of vivid colors. The optimized MOM-OPVs demonstrated an excellent power conversion efficiency (PCE) of 8.8% ± 0.2%, which is approximately 20% higher than that of reference opaque OPVs under 1000 lx light emitting diode illumination. This can be attributed to the high photocurrent density due to the nonresonant light reflected from metals into the photoactive layer. Additionally, the proposed MOM-OPVs exhibited high external quantum efficiency and large parasitic shunt resistances, leading to improved fill factor and PCE values. Thus, the study's MOM electrode provides excellent feasibility for realizing colorful and efficient indoor OPVs for IoT applications.

Influence of flexible substrate in low temperature polycrystalline silicon thin-film transistors: temperature dependent characteristics and low frequency noise analysis.

The carrier transport of p-type low temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) on flexible substrate has been intensively studied and compared to that on glass substrate in order to improve device performance. To investigate the origin of carrier transport on different substrates, temperature dependent characterizations are carried out for electrical device parameters such as threshold voltage (V TH ), subthreshold swing (SS), on-current (I on ) and effective carrier mobility (µeff ). The poly-Si grain size L grain and the barrier height E B between grain boundaries are well known to be the main parameters to determine transport in polycrystalline silicon and can be extracted based on the polycrystalline mobility model. However, our systemic studies show that it is not grain size but E B that has more influence on the degradation of LTPS TFT on flexible substrates. The E B of flexible substrate is roughly 18 times higher than glass substrate whereas grain size is similar for both devices on different substrates. Compared to the LTPS TFT on glass substrate, higher E B degrades approximately 24 % of Ion , 30 % of SS and 21 % of µ eff on the flexible substrate at room temperature. From low frequency noise (LFN) analysis, it is observed that the total trap density (N t) for flexible substrate is up to four times higher than that of glass substrate, which also supports the high value of EB in the device fabricated on the flexible substrate.

Efficient Neural Differentiation of hPSCs by Extrinsic Signals Derived from Co-cultured Neural Stem or Precursor Cells.

In this study, we found that undifferentiated human pluripotent stem cells (hPSCs; up to 30% of total cells) present in the cultures of neural stem or precursor cells (NPCs) completely disappeared within several days when cultured under neural differentiation culture conditions. Intriguingly, the disappearance of undifferentiated cells was not due to cell death but was instead mediated by neural conversion of hPSCs. Based on these findings, we propose pre-conditioning of donor NPC cultures under terminal differentiation culture conditions as a simple but efficient method of eliminating undifferentiated cells to treat neurologic disorders. In addition, we could establish a new neural differentiation protocol, in which undifferentiated hPSCs co-cultured with NPCs become differentiated neurons or NPCs in an extremely efficient, fast, and reproducible manner across the hESC and human-induced pluripotent stem cell (hiPSC) lines.

Relationship between Breastfeeding, Birth History, and Acute Pyelonephritis in Infants.

BACKGROUND: Although the clinical importance of the immunological benefits of breastfeeding has been emphasized for decades, their direct relationship with acute pyelonephritis (APN) is still not clear. Our goal was to determine whether breastfeeding truly provides protection against APNs, while investigating the effects of other factors such as sex, age, mode of delivery, and birth weight on APN. METHODS: A total of 62 infants under 6 months of age who had both microbiologically and radiologically-confirmed APN were enrolled in the case group. Healthy infants (n = 178) who visited the hospital for scheduled vaccinations were enrolled in the control group. The following participant characteristics were compared between the case and control groups: age, sex, birth order among siblings, feeding methods, weight percentile by month, birth weight percentile by gestational age, gestational age at birth, and mode of delivery. RESULTS: Babies exclusively fed with manufactured infant formulae before 6 months of age had significantly higher risk for APN than breastfed or mixed-fed infants (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.687-7.031; P = 0.001). Firstborn babies had lower risk for APN than 2nd- or 3rd-born babies (OR, 0.43; 95% CI, 0.210-0.919). Other factors that increased the risk for APN were low birth weight percentiles (OR, 8.33; 95% CI, 2.300-30.166) and birth via caesarean section (OR, 2.32; 95% CI, 1.097-4.887). There were more preterm births in the case group (10.9% vs. 1.7%; P = 0.002), but this did not increase the risk for APN (OR, 4.47; P = 0.063). CONCLUSION: Feeding exclusively with formula before 6 months of age was related to higher risk for APN, which demonstrates that breastfeeding has a protective effect against APN. The other risk factors for APN were birth order (≥ 2nd-born), low birth weight, and birth via caesarean section.

Multisystem Inflammatory Syndrome in Children Related to COVID-19: the First Case in Korea.

Since mid-April 2020, cases of multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease 2019 that mimics Kawasaki disease (KD) have been reported in Europe and North America. However, no cases have been reported in Korea. We describe an 11-year old boy with fever, abdominal pain, and diarrhea who developed hypotension requiring inotropes in intensive care unit. His blood test revealed elevated inflammatory markers, thrombocytopenia, hypoalbuminemia, and coagulopathy. Afterward, he developed signs of KD such as conjunctival injection, strawberry tongue, cracked lip, and coronary artery dilatation, and parenchymal consolidation without respiratory symptoms. Microbiological tests were all negative including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcription polymerase chain reaction. However, serum immunoglobulin G against SARS-CoV-2 was positive in repeated tests using enzyme-linked immunosorbent assay and fluorescent immunoassay. He was recovered well after intravenous immunoglobulin administration and discharged without complication on hospital day 13. We report the first Korean child who met all the criteria of MIS-C with features of incomplete KD or KD shock syndrome.

Ternary Blend Strategy for Achieving High-Efficiency Organic Photovoltaic Devices for Indoor Applications.

Monomeric perylene diimide (PDI) small molecules display a high absorption coefficient and crystallinity in solid-state thin films due to strong π-π interactions between the molecules. To take advantage of these exciting properties of PDIs, N,N'-bis(1-ethylpropyl)perylene-3,4,9,10-tetracarboxylic diimide (EP-PDI) was mixed with a binary blend of PTB7 and PC71 BM to fabricate an efficient ternary blend, which were in turn used to produce organic photovoltaic (OPV) devices well suited to indoor applications (PTB7=poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}), PC71 BM=[6,6]-phenyl-C71 -butyric acid methyl ester). We varied the PC71 BM/EP-PDI weight ratio to investigate the influence of EP-PDI on the optical, electrical, and morphological properties of the PTB7:PC71 BM:EP-PDI ternary blend. Compared with the reference PTB7:PC71 BM binary blend, the ternary blends showed strong optical absorption in the wavelength range in which the spectra of indoor LED lamps show their strongest peaks. The addition of EP-PDI to the binary blend was found to play an important role in altering the morphology of the blend in such a way as to facilitate charge transport in the resulting ternary blend. Apparently, as a result, the optimal PTB7:PC71 BM:EP-PDI-based inverted OPV device exhibited a power conversion efficiency (PCE) of 15.68 %, a fill factor (FF) of 68.5 %, and short-circuit current density (JSC ) of 56.7 µA cm-2 under 500 lx (ca. 0.17 mW cm-2 ) indoor LED light conditions.

Precise control of nanoscale spacing between electrodes using different natured self-assembled monolayers.

Herein, we introduce an interdigitated horizontal electrode (IHE) structure with a metal-based electron-collecting (or -injecting) electrode and a hole-collecting (or -injecting) electrode composed of a conductive polymeric material that has a nanoscale distance and is horizontally separated. In the IHE, a metal electrode is fabricated on a silicon-oxide substrate, and a self-assembled monolayer (SAM) is selectively bonded to the metal and the oxide to form a conductive polymer electrode by dip coating. Each of the SAM materials is composed of a head part bonded to the substrate surface and a tail part that is hydrophilic or hydrophobic. This inherent property makes the metal electrode hydrophobic and the oxide substrate hydrophilic. Ag is used as a metal electrode material and is combined with alkanethiol SAMs. The alkylsilane SAMs are combined with the silicon oxide substrate to make them hydrophilic, using poly (3, 4-ethylenedioxythiophene)-poly (PEDOT: PSS) as the conductive polymer material. In this study, we have found that there is a difference in the spacing between the two electrodes that depends on the combination of SAM materials. Each interval was spaced from a minimum of 140 nm to a maximum of 385 nm.

Erratum: Correction of Error in Result: Comparison of Follow-up Courses after Discharge from Neonatal Intensive Care Unit between Very Low Birth Weight Infants with and without Home Oxygen.

[This corrects the article on p. 1295 in vol. 32, PMID: 28665066.].

Influence of Local Myocardial Infarction on Endothelial Function, Neointimal Progression, and Inflammation in Target and Non-Target Vascular Territories in a Porcine Model of Acute Myocardial Infarction.

BACKGROUND: Patients with acute myocardial infarction (AMI) have worse clinical outcomes than those with stable coronary artery disease despite revascularization. Non-culprit lesions of AMI also involve more adverse cardiovascular events. This study aimed to investigate the influence of AMI on endothelial function, neointimal progression, and inflammation in target and non-target vessels. METHODS: In castrated male pigs, AMI was induced by balloon occlusion and reperfusion into the left anterior descending artery (LAD). Everolimus-eluting stents (EES) were implanted in the LAD and left circumflex (LCX) artery 2 days after AMI induction. In the control group, EES were implanted in the LAD and LCX in a similar fashion without AMI induction. Endothelial function was assessed using acetylcholine infusion before enrollment, after the AMI or sham operation, and at 1 month follow-up. A histological examination was conducted 1 month after stenting. RESULTS: A total of 10 pigs implanted with 20 EES in the LAD and LCX were included. Significant paradoxical vasoconstriction was assessed after acetylcholine challenge in the AMI group compared with the control group. In the histologic analysis, the AMI group showed a larger neointimal area and larger area of stenosis than the control group after EES implantation. Peri-strut inflammation and fibrin formation were significant in the AMI group without differences in injury score. The non-target vessel of the AMI also showed similar findings to the target vessel compared with the control group. CONCLUSION: In the pig model, AMI events induced endothelial dysfunction, inflammation, and neointimal progression in the target and non-target vessels.

Microbial Metabolites Determine Host Health and the Status of Some Diseases.

The gastrointestinal (GI) tract is a highly complex organ composed of the intestinal epithelium layer, intestinal microbiota, and local immune system. Intestinal microbiota residing in the GI tract engages in a mutualistic relationship with the host. Different sections of the GI tract contain distinct proportions of the intestinal microbiota, resulting in the presence of unique bacterial products in each GI section. The intestinal microbiota converts ingested nutrients into metabolites that target either the intestinal microbiota population or host cells. Metabolites act as messengers of information between the intestinal microbiota and host cells. The intestinal microbiota composition and resulting metabolites thus impact host development, health, and pathogenesis. Many recent studies have focused on modulation of the gut microbiota and their metabolites to improve host health and prevent or treat diseases. In this review, we focus on the production of microbial metabolites, their biological impact on the intestinal microbiota composition and host cells, and the effect of microbial metabolites that contribute to improvements in inflammatory bowel diseases and metabolic diseases. Understanding the role of microbial metabolites in protection against disease might offer an intriguing approach to regulate disease.

Dopamine neurons derived from human ES cells efficiently engraft in animal models of Parkinson's disease.

Human pluripotent stem cells (PSCs) are a promising source of cells for applications in regenerative medicine. Directed differentiation of PSCs into specialized cells such as spinal motoneurons or midbrain dopamine (DA) neurons has been achieved. However, the effective use of PSCs for cell therapy has lagged behind. Whereas mouse PSC-derived DA neurons have shown efficacy in models of Parkinson's disease, DA neurons from human PSCs generally show poor in vivo performance. There are also considerable safety concerns for PSCs related to their potential for teratoma formation or neural overgrowth. Here we present a novel floor-plate-based strategy for the derivation of human DA neurons that efficiently engraft in vivo, suggesting that past failures were due to incomplete specification rather than a specific vulnerability of the cells. Midbrain floor-plate precursors are derived from PSCs 11 days after exposure to small molecule activators of sonic hedgehog (SHH) and canonical WNT signalling. Engraftable midbrain DA neurons are obtained by day 25 and can be maintained in vitro for several months. Extensive molecular profiling, biochemical and electrophysiological data define developmental progression and confirm identity of PSC-derived midbrain DA neurons. In vivo survival and function is demonstrated in Parkinson's disease models using three host species. Long-term engraftment in 6-hydroxy-dopamine-lesioned mice and rats demonstrates robust survival of midbrain DA neurons derived from human embryonic stem (ES) cells, complete restoration of amphetamine-induced rotation behaviour and improvements in tests of forelimb use and akinesia. Finally, scalability is demonstrated by transplantation into parkinsonian monkeys. Excellent DA neuron survival, function and lack of neural overgrowth in the three animal models indicate promise for the development of cell-based therapies in Parkinson's disease.

Comparison of Follow-up Courses after Discharge from Neonatal Intensive Care Unit between Very Low Birth Weight Infants with and without Home Oxygen.

In order to investigate the clinical impact of home oxygen use for care of premature infants, we compared the follow-up courses after neonatal intensive care unit (NICU) discharge between very low birth weight infants (VLBWIs) with and without home oxygen. We retrospectively identified 1,232 VLBWIs born at 22 to 32 weeks of gestation, discharged from the NICU of 43 hospitals in Korea between April 2009 and March 2010, and followed them up until April 2011. Clinical outcomes, medical service uses, and readmission and death rates during follow-up after the NICU discharge were compared between VLBWIs with (HO, n = 167) and those without (CON, n = 1,056) home oxygen at discharge. The HO infants comprised 13.7% of the total VLBWIs with significant institutional variations and showed a lower gestational age (GA) and birth weight than the CON infants. The HO infants had more frequent regular pediatric outpatient clinic visits (12.7 ± 7.5 vs. 9.5 ± 6.6; P < 0.010) and emergency center visits related to respiratory problems (2.5 ± 2.2 vs. 1.8 ± 1.4; P < 0.010) than the CON infants. The HO infants also had significantly increased readmission (adjusted hazard ratio [HR], 1.60; 95% confidence interval [CI], 1.25-2.04) and death risks (adjusted HR, 7.40; 95% CI, 2.06-26.50) during up to 2 years following the NICU discharge. These increased readmission and death risks in the HO infants were not related to their prematurity degree. In conclusion, home oxygen use after discharge increases the risks for healthcare utilization, readmission, and death after NICU discharge in VLBWIs, regardless of GA, requiring more careful health care monitoring during their follow-up.

Transparent resistive switching memory using aluminum oxide on a flexible substrate.

Resistive switching memory (ReRAM) has attracted much attention in recent times owing to its fast switching, simple structure, and non-volatility. Flexible and transparent electronic devices have also attracted considerable attention. We therefore fabricated an Al2O3-based ReRAM with transparent indium-zinc-oxide (IZO) electrodes on a flexible substrate. The device transmittance was found to be higher than 80% in the visible region (400-800 nm). Bended states (radius = 10 mm) of the device also did not affect the memory performance because of the flexibility of the two transparent IZO electrodes and the thin Al2O3 layer. The conduction mechanism of the resistive switching of our device was explained by ohmic conduction and a Poole-Frenkel emission model. The conduction mechanism was proved by oxygen vacancies in the Al2O3 layer, as analyzed by x-ray photoelectron spectroscopy analysis. These results encourage the application of ReRAM in flexible and transparent electronic devices.

Negative Capacitance in Organic/Ferroelectric Capacitor to Implement Steep Switching MOS Devices.

Because of the "Boltzmann tyranny" (i.e., the nonscalability of thermal voltage), a certain minimum gate voltage in metal-oxide-semiconductor (MOS) devices is required for a 10-fold increase in drain-to-source current. The subthreshold slope (SS) in MOS devices is, at best, 60 mV/decade at 300 K. Negative capacitance in organic/ferroelectric materials is proposed in order to address this physical limitation in MOS technology. Here, we experimentally demonstrate the steep switching behavior of a MOS device-that is, SS ∼ 18 mV/decade (much less than 60 mV/decade) at 300 K-by taking advantage of negative capacitance in a MOS gate stack. This negative capacitance, originating from the dynamics of the stored energy in a phase transition of a ferroelectric material, can achieve the step-up conversion of internal voltage (i.e., internal voltage amplification in a MOS device). With the aid of a series-connected negative capacitor as an assistive device, the surface potential in the MOS device becomes higher than the applied gate voltage, so that a SS of 18 mV/decade at 300 K is reliably observed.

In vitro generation of mature dopamine neurons by decreasing and delaying the expression of exogenous Nurr1.

Neural stem/progenitor cell (NSC/NPC) cultures can be a source of dopamine (DA) neurons for experimental and transplantation purposes. Nurr1, a steroid receptor transcription factor, can overcome the limitations associated with differentiation of cultured NPCs into DA neurons. However, forced Nurr1 expression in NPC cultures generates non-neuronal and/or immature DA cells. We show here that the Nurr1 level and period of expression crucially affect the differentiation and maturation of Nurr1-induced DA neurons. Mature DA neurons were generated by manipulating Nurr1 expression patterns to resemble those in the developing midbrain.