Systematic {\em ab initio} study of the phase diagram of epitaxially strained SrTiO3_3

We use density-functional theory with the local-density approximation to study the structural and ferroelectric properties of SrTiO$_3$ under misfit strains. Both the antiferrodistortive (AFD) and ferroelectric (FE) instabilities are considered. The rotation of the oxygen octahedra and the movement of the atoms are fully relaxed within the constraint of a fixed in-plane lattice constant. We find a rich misfit strain-induced phase transition sequence and is obtained only when the AFD distortion is taken into account. We also find that compressive misfit strains induce ferroelectricity in the tetragonal low temperature phase only whilst tensile strains induce ferroelectricity in the orthorhombic phases only. The calculated FE polarization for both the tetragonal and orthorhombic phases increases monotonically with the magnitude of the strains. The AFD rotation angle of the oxygen octahedra in the tetragonal phase increases dramatically as the misfit strain goes from the tensile to compressive strain region whilst it decreases slightly in the orthorhombic (FO4) phase. This reveals why the polarization in the epitaxially strained SrTiO$_3$ would be larger when the tensile strain is applied, since the AFD distortion is found to reduce the FE instability and even to completely suppress it in the small strain region. Finally, our analysis of the average polar distortion and the charge density distribution suggests that both the Ti-O and Sr-O layers contribute significantly to the FE polarization

Effects of Light Quality on the Chlorophyll Degradation Pathway in Rice Seedling Leaves

The objective of this study was to investigate the dynamics of chlorophyll (Chl), biosynthetic intermediates (protoporphyrin IX, magnesium protoporphyrin IX, and protochlorophyllide), degradation intermediates [chlorophyllide (Chlide), pheophytin (Phe), and pheophorbide (Pho)], and carotenoids (Car) in leaves of rice seedlings. Two rice varieties, 'Taichung Shen 10' ('TCS10') and 'IR1552', were grown under different light quality conditions controlled by light emitting diodes (LED). Lighting treatments for rice seedlings were included by red (R), blue (B), green (G), and red + blue (RB), with fluorescent lighting (FL) as the control and photosynthetic photon flux density being set at 105 µmol m-2 s-1. The results show that lower levels of Chl and Car in leaves were detected under G lighting, and light quality did not mediate porphyrins in biosynthetic pathways. Rice seedling leaves took Chl→Phe→Pho and Chl→Chlide→Pho as the major and minor degradation routes, respectively. Furthermore, higher Phe/Chlide ratios were observed under G and FL lighting conditions, indicating that green-enriched environments can up-regulate the minor degradation route in leaves

Comparison between the recovery time of alfentanil and fentanyl in balanced propofol sedation for gastrointestinal and colonoscopy: a prospective, randomized study

BACKGROUND: There is increasing interest in balanced propofol sedation (BPS) titrated to moderate sedation (conscious sedation) for endoscopic procedures. However, few controlled studies on BPS targeted to deep sedation for diagnostic endoscopy were found. Alfentanil, a rapid and short-acting synthetic analog of fentanyl, appears to offer clinically significant advantages over fentanyl during outpatient anesthesia. It is reasonable to hypothesize that low dose of alfentanil used in BPS might also result in more rapid recovery as compared with fentanyl. METHODS: A prospective, randomized and double-blinded clinical trial of alfentanil, midazolam and propofol versus fentanyl, midazolam and propofol in 272 outpatients undergoing diagnostic esophagogastroduodenal endoscopy (EGD) and colonoscopy for health examination were enrolled. Randomization was achieved by using the computer-generated random sequence. Each combination regimen was titrated to deep sedation. The recovery time, patient satisfaction, safety and the efficacy and cost benefit between groups were compared. RESULTS: 260 participants were analyzed, 129 in alfentanil group and 131 in fentanyl group. There is no significant difference in sex, age, body weight, BMI and ASA distribution between two groups. Also, there is no significant difference in recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between two groups. Though deep sedation was targeted, all cardiopulmonary complications were minor and transient (10.8%, 28/260). No serious adverse events including the use of flumazenil, assisted ventilation, permanent injury or death, and temporary or permanent interruption of procedure were found in both groups. However, fentanyl is New Taiwan Dollar (NT$) 103 (approximate US$ 4) cheaper than alfentanil, leading to a significant difference in total cost between two groups. CONCLUSIONS: This randomized, double-blinded clinical trial showed that there is no significant difference in the recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between the two most common sedation regimens for EGD and colonoscopy in our hospital. However, fentanyl is NT$103 (US$ 4) cheaper than alfentanil in each case. TRIAL REGISTRATION: Institutional Review Board of Buddhist Tzu Chi General Hospital (IRB097-18) and Chinese Clinical Trial Registry (ChiCTR-TRC-12002575

Potassium {4-[(3S,6S,9S)-3,6-dibenzyl-9-isopropyl-4,7,10-trioxo-11–oxa-2,5,8-triazadodecyl]phenyl}trifluoroborate

[[abstract]]The reported compound 4 was synthesized and fully characterized by 1H NMR, 13C NMR, 11B NMR, 19F NMR, and high resolution mass spectrometry.[[booktype]]電子版[[countrycodes]]CH

The antagonism between MCT-1 and p53 affects the tumorigenic outcomes

<p>Abstract</p> <p>Background</p> <p>MCT-1 oncoprotein accelerates p53 protein degradation via a proteosome pathway. Synergistic promotion of the xenograft tumorigenicity has been demonstrated in circumstance of p53 loss alongside MCT-1 overexpression. However, the molecular regulation between MCT-1 and p53 in tumor development remains ambiguous. We speculate that MCT-1 may counteract p53 through the diverse mechanisms that determine the tumorigenic outcomes.</p> <p>Results</p> <p>MCT-1 has now identified as a novel target gene of p53 transcriptional regulation. MCT-1 promoter region contains the response elements reactive with wild-type p53 but not mutant p53. Functional p53 suppresses MCT-1 promoter activity and MCT-1 mRNA stability. In a negative feedback regulation, constitutively expressed MCT-1 decreases p53 promoter function and p53 mRNA stability. The apoptotic events are also significantly prevented by oncogenic MCT-1 in a p53-dependent or a p53-independent fashion, according to the genotoxic mechanism. Moreover, oncogenic MCT-1 promotes the tumorigenicity in mice xenografts of p53-null and p53-positive lung cancer cells. In support of the tumor growth are irrepressible by p53 reactivation <it>in vivo</it>, the inhibitors of p53 (MDM2, Pirh2, and Cop1) are constantly stimulated by MCT-1 oncoprotein.</p> <p>Conclusions</p> <p>The oppositions between MCT-1 and p53 are firstly confirmed at multistage processes that include transcription control, mRNA metabolism, and protein expression. MCT-1 oncogenicity can overcome p53 function that persistently advances the tumor development.</p

miRNA arm selection and isomiR distribution in gastric cancer

BACKGROUND: MicroRNAs (miRNAs) are small non-protein-coding RNAs. miRNA genes need several biogenesis steps to form function miRNAs. However, the precise mechanism and biology involved in the mature miRNA molecules are not clearly investigated. In this study, we conducted in-depth analyses to examine the arm selection and isomiRs using NGS platform. METHODS: We sequenced small RNAs from one pair of normal and gastric tumor tissues with Solexa platform. By analyzing the NGS data, we quantified the expression profiles of miRNAs and isomiRs in gastric tissues. Then, we measured the expression ratios of 5p arm to 3p arm of the same pre-miRNAs. And, we used Kolmogorov-Smirnov (KS) test to examine isomiR pattern difference between tissues. RESULTS: Our result showed the 5p arm and 3p arm miRNA derived from the same pre-miRNAs have different tissue expression preference, one preferred normal tissue and the other preferred tumor tissue, which strongly implied that there could be other mechanism controlling mature miRNA selection in addition to the known hydrogen-bonding selection rule. Furthermore, by using the KS test, we demonstrated that some isomiR types preferentially occur in normal gastric tissue but other types prefer tumor gastric tissue. CONCLUSIONS: Arm selections and isomiR patterns are significantly varied in human cancers by using deep sequencing NGS data. Our results provided a novel research topic in miRNA regulation study. With advanced bioinformatics and molecular biology studies, more robust conclusions and insight into miRNA regulation can be achieved in the near future

Antioxidant Activities of the Methanol Extracts of Various Parts of Phalaenopsis Orchids with White, Yellow, and Purple Flowers

Phalaenopsis (Phal.) orchids including white, yellow, and purple flowers are some of the most important commercial orchids worldwide. These flowering plants can be considered to be promising sources of antioxidants since several medicinal orchids were shown to have potential antioxidant activities. The antioxidant activities and several secondary metabolite compounds of the methanolic extracts of four parts (the root, pedicel, leaf, and flower) of three hybrids of white (Phal. ‘City More’), yellow (Phal. ‘Sogo Meili’), and purple (Phal. ‘Queen Beer’) flowering orchids were investigated. Results showed that the highest levels of chlorophyll a and chlorophyll b were respectively obtained in leaf extracts of white and purple orchids, whereas carotenoid showed the highest content in the flower extract of the yellow orchid. Among all tested extracts, flavonoids and anthocyanin demonstrated the highest levels in the flower extract of the purple orchid, whereas the highest level of polyphenols was observed in the flower extract of the yellow orchid. The leaf extract of the white orchid was the most effective extract with a 50% inhibitory concentration in the DPPH-scavenging activity assay, while the highest ferrous iron-chelating effect was observed in flower extracts of the yellow orchid and purple orchid, and the pedicel extract of the purple orchid. In the reducing power assay, the flower extract of the white orchid showed the most potent extract, followed by the leaf extract of the yellow orchid and the flower extract of the purple orchid. Relationships between flower colors and antioxidant activities of these orchids showed them to be potential sources of antioxidants for both medicinal use and stress-tolerance in these orchids