Observation of degenerate one-dimensional sub-bands in cylindrical InAs nanowires

One-dimensional (1D) sub-bands in cylindrical InAs nanowires (NWs) are electrically mapped as a function of NW diameter in the range of 15-35 nm. At low temperatures, stepwise current increases with the gate voltage are clearly observed and attributed to the electron transport through individual 1D sub-bands. The two-fold degeneracy in certain sub-band energies predicted by simulation due to structural symmetry is experimentally observed for the first time. The experimentally obtained sub-band energies match the simulated results, shedding light on both the energies of the sub-bands as well as the number of sub-bands populated per given gate voltage and diameter. This work serves to provide better insight into the electrical transport behavior of 1D semiconductors.Comment: 20 pages, 5 figures, supporting information include

Ciprofloxacin-resistant Salmonella enterica Typhimurium and Choleraesuis from Pigs to Humans, Taiwan

We evaluated the disk susceptibility data of 671 nontyphoid Salmonella isolates collected from different parts of Taiwan from March 2001 to August 2001 and 1,261 nontyphoid Salmonella isolates from the National Taiwan University Hospital from 1996 to 2001. Overall, ciprofloxacn resistance was found in 2.7% (18/671) of all nontyphoid Salmonella isolates, in 1.4% (5/347) of Salmonella enterica serotype Typhimurium and in 7.5% (8/107) in S. enterica serotype Choleraesuis nationwide. MICs of six newer fluoroquinolones were determined for the following isolates: 37 isolates of ciprofloxacin-resistant (human) S. enterica Typhimurium (N = 26) and Choleraesuis (N = 11), 10 isolates of ciprofloxacin-susceptible (MIC <1 μg/mL) (human) isolates of these two serotypes, and 15 swine isolates from S. enterica Choleraesuis (N = 13) and Typhmurium (N = 2) with reduced susceptibility to ciprofloxacin (MIC >0.12 μg/mL). Sequence analysis of the gryA, gyrB, parC, parE, and acrR genes, ciprofloxacin accumulation; and genotypes generated by pulsed-field gel electrophoresis with three restriction enzymes (SpeI, XbaI, and BlnI) were performed. All 26 S. enterica Typhimurium isolates from humans and pigs belonged to genotype I. For S. enterica Choleraesuis isolates, 91% (10/11) of human isolates and 54% (7/13) of swine isolates belonged to genotype B. These two genotypes isolates from humans all exhibited a high-level of resistance to ciprofloxacin (MIC 16–64 μg/mL). They had two-base substitutions in the gyrA gene at codons 83 (Ser83Phe) and 87 (Asp87Gly or Asp87Asn) and in the parC gene at codon 80 (Ser80Arg, Ser80Ile, or Ser84Lys). Our investigation documented that not only did these two S. enterica isolates have a high prevalence of ciprofloxacin resistance nationwide but also that some closely related ciprofloxacin-resistant strains are disseminated from pigs to humans

The role of glucocorticoids in ovarian development of sleep deprived rats

Objective: Sleep deprivation (SD) adversely affects female reproductive function. In this study, we investigated the role of glucocorticoids in ovarian development in sleep deprived rats. Materials and methods: Female rats were subjected to SD for 1–4 days. Concentrations of serum estradiol and corticosterone were assessed. Betamethasone (BET) and/or recombinant human follicle-stimulating hormone (FSH) were administered to 21-day-old female rats for 2 days to evaluate ovarian status for follicular development. Intact preantral follicles were mechanically dissected from the rat's ovaries and cultured for 72 h with or without FSH in the presence or absence of BET to evaluate follicular development. Results: SD led to a significant difference in serum estradiol concentrations between the sham and SD groups, and corticosterone concentrations were significantly elevated in groups with more than 2 days of SD (P < 0.05). FSH stimulated ovarian growth in immature rats, whereas BET inhibited ovarian development caused by the FSH treatment. Treatment of the preantral follicles with FSH induced an increase in both follicle size and follicular cell number, while follicular cell differentiation was accompanied by enhanced inhibin-α and connexin 43 expression. Inhibition of FSH-stimulated follicular growth through BET treatment exhibited a dose-dependent reciprocal trend; as the BET dose increased (0.001–1 μg/mL), preantral follicular growth decreased. This decrease was associated with a decrease in follicular cell numbers and suppression of a proliferating cell nuclear antigen, inhibin-α, and connexin 43 expression. Conclusion: The findings suggest that the adverse effects of SD may inhibit follicular development during ovarian hyperstimulation by corticosterone elevation in rat. Keywords: Betamethasone, Connexin 43, Inhibin-α, Ovarian follicle, Sleep deprivatio

Anticancer Effects and Molecular Mechanisms of Apigenin in Cervical Cancer Cells

Cervical cancer is the fourth most frequent malignancy in women. Apigenin is a natural plant-derived flavonoid present in common fruit, vegetables, and herbs, and has been found to possess antioxidant and anti-inflammatory properties as a health-promoting agent. It also exhibits important anticancer effects in various cancers, but its effects are not widely accepted by clinical practitioners. The present study investigated the anticancer effects and molecular mechanisms of apigenin in cervical cancer in vitro and in vivo. HeLa and C33A cells were treated with different concentrations of apigenin. The effects of apigenin on cell viability, cell cycle distribution, migration potential, phosphorylation of PI3K/AKT, the integrin β1-FAK signaling pathway, and epithelial-to-mesenchymal transition (EMT)-related protein levels were investigated. Mechanisms identified from the in vitro study were further validated in a cervical tumor xenograft mouse model. Apigenin effectively inhibited the growth of cervical cancer cells and cervical tumors in xenograft mice. Furthermore, the apigenin down-regulated FAK signaling (FAK, paxillin, and integrin β1) and PI3K/AKT signaling (PI3K, AKT, and mTOR), inactivated or activated various signaling targets, such as Bcl-2, Bax, p21cip1, CDK1, CDC25c, cyclin B1, fibronectin, N-cadherin, vimentin, laminin, and E-cadherin, promoted mitochondrial-mediated apoptosis, induced G2/M-phase cell cycle arrest, and reduced EMT to inhibit HeLa and C33A cancer cell migration, producing anticancer effects in cervical cancer. Thus, apigenin may act as a chemotherapeutic agent for cervical cancer treatment

Effect of morphokinetics and morphological dynamics of cleavage stage on embryo developmental potential: A time-lapse study

Objective: Using a non-invasive method to select the most competent embryo is essential in in vitro fertilization (IVF). Since the beginning of clinical application of time-lapse technology, several studies have proposed models using the time-lapse imaging system for predicting the IVF outcome. This study used both morphokinetic and morphological dynamic parameters to select embryos with the highest developmental potential. Materials and Methods: A total of 23 intracytoplasmic sperm injection treatment cycles with 138 fertilized oocytes were included in this study. All embryos were cultured to the blastocyst stage, and embryo development was recorded every 10 min by using a time-lapse imaging system. Morphokinetic parameters and eight major abnormal division behaviors were studied to determine their effects on blastocyst formation. The most influential variables were used in hierarchical classification for blastocyst formation prediction. Results: Several parameters were significantly related to the developmental potential. Embryos with the timing of pronuclear fading (tPNF) of >26.4 h post insemination (hpi), the timing of division to two cells (t2) of >29.1 hpi, and the timing of division to four cells (t4) of >41.3 hpi showed the lowest blastocyst formation rate. The abnormal division behaviors of fragmentation >50%, direct cleavage, reverse cleavage, and delayed division or developmental arrest were found to be detrimental to blastocyst formation. On the basis of these results, we propose a hierarchical model classification, in which embryos are classified into groups A-D according to their developmental potential. The blastocyst formation rates of groups A, B, C, and D were 80.0%, 77.8%, 53.7%, and 22.2% (p < 0.001). The good blastocyst rates of groups A, B, C, and D were 60.0%, 44.4%, 14.6%, and 11.1% (p = 0.007). Conclusion: We propose a hierarchical classification system for blastocyst formation prediction, which provides information for embryo selection by using a time-lapse imaging system

Gate-Tunable and Programmable n-InGaAs/Black Phosphorus Heterojunction Diodes

Semiconductor heterostructures have enabled numerous applications in diodes, photodetectors, junction field-effect transistors, and memory devices. Two-dimensional (2D) materials and III-V compound semiconductors are two representative materials providing excellent heterojunction platforms for the fabrication of heterostructure devices. The marriage between these semiconductors with completely different crystal structures may enable a new heterojunction with unprecedented physical properties. In this study, we demonstrate a multifunctional heterostructure device based on 2D black phosphorus and n-InGaAs nanomembrane semiconductors that exhibit gate-tunable, photoresponsive, and programmable diode characteristics. The device exhibits clear rectification with a large gate-tunable forward current, which displays rectification and switching with a maximum rectification ratio of 4600 and an on/off ratio exceeding 10(5), respectively. The device also offers nonvolatile memory properties, including large hysteresis and stable retention of storage charges. By combining the memory and gate-tunable rectifying properties, the rectification ratio of the device can be controlled and memorized from 0.06 to 400. Moreover, the device generate three different electrical signals by combining a photoresponsivity of 0.704 A/W with the gate-tunable property, offering potential applications, for example, multiple logic operator. This work presents a heterostructure design based on 2D and III-V compound semiconductors, showing unique physical properties for the development of multifunctional heterostructure devices