Phase-change memory via a phase-changeable self-confined nano-filament.

Phase-change memory (PCM) has been considered a promising candidate for solving von Neumann bottlenecks owing to its low latency, non-volatile memory property and high integration density1,2. However, PCMs usually require a large current for the reset process by melting the phase-change material into an amorphous phase, which deteriorates the energy efficiency2-5. Various studies have been conducted to reduce the operation current by minimizing the device dimensions, but this increases the fabrication cost while the reduction of the reset current is limited6,7. Here we show a device for reducing the reset current of a PCM by forming a phase-changeable SiTex nano-filament. Without sacrificing the fabrication cost, the developed nano-filament PCM achieves an ultra-low reset current (approximately 10 µA), which is about one to two orders of magnitude smaller than that of highly scaled conventional PCMs. The device maintains favourable memory characteristics such as a large on/off ratio, fast speed, small variations and multilevel memory properties. Our finding is an important step towards developing novel computing paradigms for neuromorphic computing systems, edge processors, in-memory computing systems and even for conventional memory applications.

Red cell distribution width as a potential prognostic biomarker in fetal growth restriction.

OBJECTIVE: Red cell distribution width (RDW) is a prognostic marker for adverse outcomes in cardiovascular disease. This association has been attributed to the impaired erythropoiesis and abnormal red blood cell survival originating from chronic hypoxic status or poor nutrition. Considering the pathophysiologic association between fetal growth restriction (FGR) and chronic intrauterine hypoxia, which in turn can result in impaired erythropoiesis, RDW could be a biomarker in FGR. To address this issue, we evaluated the RDW in FGR. STUDY DESIGN: The study population consisted of singleton preterm neonates (24-34 weeks of gestation) and RDW in cord blood was measured at delivery, and was compared between small-for-gestational age (SGA) neonates (birthweight <10 percentile) and non-SGA neonates (birthweight >10 percentile). Among them, RDW was also examined according to the adverse neonatal outcomes. RESULTS: Five hundred eighty-four neonates were included, of these, 117 SGA neonates and 467 non-SGA neonates. RDW in the SGA neonates was significantly higher than that in the non-SGA neonates (18.4 versus 16.4, p < .001). This association between SGA and RDW remained significant after adjustment for gestational age at delivery, histologic chorioamnionitis, and hematologic parameters. Among the SGA neonates, RDW was higher in neonates with adverse neonatal outcomes than those without them. The RDW >90 percentile was an independent parameter for the prediction of neonatal outcomes, even after adjustment. CONCLUSION: The RDW was higher in the SGA neonates and was associated with adverse outcomes. RDW can be a prognostic marker in predicting outcomes among preterm neonates.

The Risk of Spontaneous Preterm Birth according to Maternal Pre-pregnancy Body Mass Index in Twin Gestations.

BACKGROUND: Maternal obesity is a well-known risk factor for both total preterm birth (PTB) and spontaneous PTB in singleton gestation, whereas this association is not well determined in multiple pregnancy. The objective of this study was to determine the risk of spontaneous PTB according to the pre-pregnancy body mass index (BMI) in twin gestations. METHODS: The association between the risk of PTB and pre-pregnancy BMI was determined in women pregnant with twins between 2004 and 2014. Pre-pregnancy BMI values were divided into three groups (underweight/normal/overweight and obese). PTB was classified as spontaneous PTB (following preterm premature rupture of membranes, preterm labor, or cervical insufficiency) or medically indicated PTB (cesarean section or induction of labor because of maternal/fetal indications). RESULTS: A total of 1,959 women were included in the analysis, and the percentages of total PTB and spontaneous PTB were 13.1% and 9.3%. The percentages of total PTB and spontaneous PTB in three groups were 14.1%, 11.9%, 16.3%, respectively, and 11.0%, 8.0%, 12.5% (P < 0.05 between normal and overweight/obese women). The risks of total and spontaneous PTB in overweight/obese women were higher than those in women with normal weight, even after adjustment for prior history of PTB, age, maternal height, parity, in vitro fertilization-embryo transfer (IVF-ET) (odds ratio [OR], 1.43; 95% confidence interval [CI], 1.01-2.03; OR, 1.58; 95% CI, 1.05-2.36). CONCLUSION: The risks of both total and spontaneous PTB were significantly greater in the overweight/obese group than in the normal BMI group.

Tumor resection from retromolar trigone, posterolateral maxilla, and anterior mandibular ramus using lower cheek flap approach: a case report and review of literature.

A surgical approach involving the retromolar trigone, posterolateral maxilla, and pterygoid region is the most challenging in the field of maxillofacial surgery. The upper cheek flap (Weber-Ferguson incision) with subciliary extension and the maxillary swing approach have been considered as alternatives; however, neither approach provides sufficient exposure of the pterygoid region and the anterior portion of the mandibular ramus. In this report, we describe two cases in which a lower cheek flap approach was used for complete tumor resection in the retromolar trigone and the anterior mandibular ramus. This approach allows full exposure of the posterolateral maxilla and the pterygoid region as well as the retromolar trigone without causing major sensory disturbances to the lower lip. A mental nerve anastomosis after tumor resection was performed in one patient and resulted in approximately 90% sensory recovery in the lower lip. The lower cheek flap approach provides adequate exposure of the posterolateral maxilla, including the pterygoid, retromolar trigone, and mandibular ramus areas. If the mental nerve can be anastomosed during flap approximation, postoperative sensory disturbances to the lower lip can be minimized.

Uterine artery pulsatility index in hypertensive pregnancies: When does the index normalize in the puerperium?

OBJECTIVE: To investigate whether the uterine artery pulsatility index (UtA PI) of hypertensive pregnancies is higher than that of normal pregnancies in the puerperium, as well as in the antepartum period. METHODS: The UtA PI was measured in hypertensive (group 1) and normal pregnancies (group 2) during antepartum, immediate postpartum or late postpartum periods. Using the transvaginal approach, the bilateral uterine artery indices were measured. RESULTS: One hundred twenty-two women were enrolled: group 1, hypertensive disease in pregnancy (11 cases in antepartum, 13 cases in immediate postpartum and 10 cases in late postpartum period); group 2, normal pregnancies (32 cases in antepartum, 29 cases in immediate postpartum and 27 cases in late postpartum). In antepartum and immediate postpartum periods, the mean UtA PI and the proportion of cases with an early diastolic notch were higher in group 1 than in group 2 (antepartum mean UtA PI, 1.14 in group 1 vs. 0.68 in group 2, P<0.001; early diastolic notch, 46% vs. 9%, P<0.05; immediate postpartum mean UtA PI, 1.30 vs. 1.08, P<0.05; early diastolic notch, 85% vs. 48%, P<0.05). In late postpartum period, the mean value of UtA PI of group 1 was still higher than that of group 2, although the proportion of cases with an early diastolic notch was not different (mean UtA PI, 1.43 vs. 1.20, P<0.05; early diastolic notch, 60% vs. 52%, P=0.73). CONCLUSION: The UtA PI in hypertensive pregnancies was still higher than normal pregnancies in puerperal periods, suggesting that more than several weeks are required to resolve increased uterine artery vascular impedance.

Cardiomyogenic Differentiation of Human Dental Follicle-derived Stem Cells by Suberoylanilide Hydroxamic Acid and Their In Vivo Homing Property.

The purpose of the present study was to investigate the in vitro cardiomyogenic differentiation potential of human dental follicle-derived stem cells (DFCs) under the influence of suberoylanilide hydroxamic acid (SAHA), a member of the histone deacetylase inhibitor family, and analyze the in vivo homing capacity of induced cardiomyocytes (iCMs) when transplanted systemically. DFCs from extracted wisdom teeth showed mesenchymal stem cell (MSC) characteristics such as plate adherent growing, expression of MSC markers (CD44, CD90, and CD105), and mesenchymal lineage-specific differentiation potential. Adding SAHA to the culture medium induced the successful in vitro differentiation of DFCs into cardiomyocytes. These iCMs expressed cardiomyogenic markers, including alpha-smooth muscle actin (α-SMA), cardiac muscle troponin T (TNNT2), Desmin, and cardiac muscle alpha actin (ACTC1), at both the mRNA and protein level. For the assessment of homing capacity, PKH26 labeled iCMs were intraperitoneally injected (1×106 cells in 100 µL of PBS) into the experimental mice, and the ratios of PKH26 positive cells to the total number of injected cells, in multiple organs were determined. The calculated homing ratios, 14 days after systemic cell transplantation, were 5.6 ± 1.0%, 3.6 ± 1.1%, and 11.6 ± 2.7% in heart, liver, and kidney respectively. There was no difference in the serum levels of interleukin-2 and interleukin-10 at 14 days after transplantation, between the experimental (iCM injected) and control (no injection or PBS injection) groups. These results demonstrate that DFCs can be an excellent source for cardiomyocyte differentiation and regeneration. Moreover, the iCMs can be delivered into heart muscle via systemic administration without eliciting inflammatory or immune response. This can serve as the pilot study for further investigations into the in vitro cardiomyogenic differentiation potential of DFCs under the influence of SAHA and the in vivo homing capacity of the iCMs into the heart muscle, when injected systemically.

Sterilization effect of atmospheric pressure non-thermal air plasma on dental instruments.

PURPOSE: Autoclaves and UV sterilizers have been commonly used to prevent cross-infections between dental patients and dental instruments or materials contaminated by saliva and blood. To develop a dental sterilizer which can sterilize most materials, such as metals, rubbers, and plastics, the sterilization effect of an atmospheric pressure non-thermal air plasma device was evaluated. MATERIALS AND METHODS: After inoculating E. coli and B. subtilis the diamond burs and polyvinyl siloxane materials were sterilized by exposing them to the plasma for different lengths of time (30, 60, 90, 120, 180 and, 240 seconds). The diamond burs and polyvinyl siloxane materials were immersed in PBS solutions, cultured on agar plates and quantified by counting the colony forming units. The data were analyzed using one-way ANOVA and significance was assessed by the LSD post hoc test (α=0.05). RESULTS: The device was effective in killing E. coli contained in the plasma device compared with the UV sterilizer. The atmospheric pressure non-thermal air plasma device contributed greatly to the sterilization of diamond burs and polyvinyl siloxane materials inoculated with E. coli and B. subtilis. Diamond burs and polyvinyl siloxane materials inoculated with E. coli was effective after 60 and 90 seconds. The diamond burs and polyvinyl siloxane materials inoculated with B. subtilis was effective after 120 and 180 seconds. CONCLUSION: The atmospheric pressure non-thermal air plasma device was effective in killing both E. coli and B. subtilis, and was more effective in killing E. coli than the UV sterilizer.