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PurposeTo develop and validate a quantitative model based on gross tumor volume (GTV) of gastric adenocarcinoma (GA) corresponding to N-stage measured at multidetector computed tomography (CT) for preoperative determination of resectabilityMaterials and methods493 consecutive patients with confirmed GA undergoing contrast-enhanced CT two weeks before treatments were randomly enrolled into the training cohort (TC, n = 271), internal validation cohort (IVC, n = 107) and external validation cohort (EVC, n = 115). GTV was measured on CT by multiplying sums of all tumor areas by section thickness. In TC, univariate and multivariate analyses were performed to select factors associated with resectability. Receiver operating characteristic (ROC) analysis was to determine if N-stage based GTV could identify resectability. In IVC and EVC, unweighted Cohen’s Kappa tests were to evaluate performances of the ROC models.ResultsAccording to univariate analysis, age, cT stage, cN stage and GTV were related to resectability in TC (all P-values < 0.05), and multivariate analysis suggested that cN stage and GTV were independent risk factors with odds ratios of 1.594 (95% confidence interval [CI]: 1.105–2.301) and 1.055 (95%CI: 1.035–1.076), respectively. ROC analysis in TC revealed the cutoffs of 21.81, 21.70 and 36.93 cm3 to differentiate between resectable and unresectable cancers in stages cN0-3, cN2 and cN3 with areas under the curves of more than 0.8, respectively, which was validated in IVC and EVC with average Cohen k-values of more than 0.72.ConclusionsGTV and cN stage can be independent risk factors of unresectable GA, and N-stage based GTV can help determine resectability.

Different from conventional ferromagnetic methods, producing a spin-polarized current through electrical ways in spintronic devices can greatly increase operating speed, reduce power consumption, and improve device integration. Inspired by recent experimental progress on the synthesis of a heptauthrene molecule, we investigate its spin-dependent transport contacted with Au electrodes through first-principles calculations. By applying a gate voltage, the transmission can be switched between completely spin-up and spin-down polarized states, achieving an electrically controlled dual-spin filter. Furthermore, a fine tuning on the spin polarization, between 100% and − 100%, can also be realized, where the transport with any ratio of spin-up to spin-down electron quantities can be realized beyond the traditional devices. The peculiar transmission spectra and their shift are found to play crucial roles, where transmission peaks distribute on both sides of the Fermi level with opposite spin components. Such a spin-polarization modulating effect is found to be robust to the molecule-electrode contacting site, indicating it is an intrinsic feature of such systems. Moreover, the dimension of the device is at the single-molecule level, suggesting great application potential. [ABSTRACT FROM AUTHOR]

Ferroelectricity in two-dimensional (2D) systems generally arises from phonons and has been widely investigated. On the contrary, electronic ferroelectricity in 2D systems has been rarely studied. Using first-principles calculations, the ferroelectric behavior of the buckled blue SiSe monolayer under strain are explored. It is found that the direction of the out-of-plane ferroelectric polarization can be reversed by applying an in-plane strain. And such polarization switching is realized without undergoing geometric inversion. Besides, the strain-triggered polarization reversal emerges in both biaxial and uniaxial strain cases, indicating it is an intrinsic feature of such a system. Further analysis shows that the polarization switching is the result of the reversal of the magnitudes of the positive and negative charge center vectors. And the variation of buckling is found to play an important role, which results in the switch. Moreover, a non-monotonic variation of band gap with strain is revealed. Our findings throws light on the investigation of novel electronic ferroelectric systems. [ABSTRACT FROM AUTHOR]

Different from the honeycomb monolayer (like graphene), the single-layer boron chalcogenide B2X3 (X = S, Se, Te) exhibits a kagome lattice. Using the first-principles calculations, the existence of sliding ferroelectricity in van der Waals kagome-B2X3 bilayers is demonstrated. The sliding ferroelectricity results from the breaking of the inversion symmetry by interlayer sliding. In addition, there are multiple stable states in a unit cell for kagome-lattice bilayers. The bandgap is found to vary with sliding distance. By choosing specific pathways, not only the out-of-plane polarization but also the in-plane polarization can be reversed by interlayer sliding. Such a simultaneous reversal for both in-plane and out-of-plane polarizations by sliding would be useful for applications in various devices. These behaviors are found in all the three configurations (X = S, Se, Te), suggesting they are the intrinsic features of such systems and may throw light on the development of future devices. [ABSTRACT FROM AUTHOR]

Different from conventional materials, structures with a negative Poisson's ratio (NPR) contract/expand laterally under a longitudinal compressive/tensile strain, usually exhibiting peculiar features. Through first-principles calculations, we investigate the electronic and transport properties of Pd9B16 molecules. Its Poisson's ratio is found to be negative under uniaxial strain along a specific direction. By contacting with Au nanowires, atomic Au chains and atomic C chain electrodes, two kinds of transitions for transmission states could be realized by the modulation of the strain and the contacting site, i.e., metallic–semiconducting transition and spin polarized–unpolarized transition. Further analysis shows that it is the suppression and shifting of density of states, caused by the strain or contacting electrodes, that trigger the transitions. Those findings combine NPR and spintronics at the single-molecule level, which may throw light on the development of nanoelectronic devices. [ABSTRACT FROM AUTHOR]

Natural products have long been a crucial source of, or provided inspiration for new agrochemical discovery. Naturally occurring 18β-glycyrrhetinic acid shows broad-spectrum bioactivities and is a potential skeleton for novel drug discovery. To extend the utility of 18β-glycyrrhetinic acid for agricultural uses, a series of novel 18β-glycyrrhetinic acid amide derivatives were prepared and evaluated for their antibacterial potency. Notably, compound 5k showed good antibacterial activity in vitro against Xanthomonas oryzae pv. oryzae (Xoo, EC50=3.64 mg L–1), and excellent protective activity (54.68%) against Xoo in vivo. Compound 5k induced excessive production and accumulation of reactive oxygen species in the tested pathogens, resulting in damaging the bacterial cell envelope. More interestingly, compound 5k could increase the activities of plant defense enzymes including catalase, superoxide dismutase, peroxidase, and phenylalanine ammonia lyase. Taken together, these enjoyable results suggested that designed compounds derived from 18β-glycyrrhetinic acid showed potential for controlling intractable plant bacterial diseases by disturbing the balance of the phytopathogen’s redox system and activating the plant defense system.

Studies in the past few years have shown that simple salts, such as pyridinium salts and imidazole salts, have excellent antibacterial activity. However, their application in drugs and agrichemicals development has been limited due to their high toxicity. In this study, we found that synthesized target compounds with pyridinium salt unit A1 and B6 displayed excellent anti-Xac (Xanthomonas. axonopodis pv. citri) and Xoo (Xanthomonas oryzae pv. oryzae) activity, with EC50 values of 7.67 μg/mL and 1.37 μg/mL, respectively. On searching for a toxicity reduction strategy, an ion exchange method was adopted to obtain a new type of various organic acid-decorated pyridinium salt derivatives containing with glycyrrhetinic acid framework, and their structure was characterized by FTIR and 1H NMR. Furthermore, bioassays and toxicity tests were used to show that these organic acid-exchanged compounds not only exhibited lower toxicity to plants but also had excellent antibacterial activity towards virulent phytopathogenic bacteria, especially compound D3, which provided an EC50 of 1.60 μg/mL toward Xoo. Subsequently, the pot experiments determined that compound D3 exhibited suitable protective and curative activities for the management of rice bacterial leaf blight at 200 μg/mL, with control efficacies of 54.09% and 38.50%, respectively. In addition, studies evaluating potential antibacterial mechanisms suggested that apoptosis was responsible for the antibacterial behavior of the target compounds. Overall, this study proved that the ion exchange method was a feasible strategy to reduce the toxicity of pyridinium salts and was promising for use in the development of novel antimicrobial agents.

Mammalian centromeres are generally composed of dispersed repeats and the satellites such as α-satellites in human and major/minor satellites in mouse. Transcription of centromeres by RNA polymerase II is evolutionary conserved and critical for kinetochore assembly. In addition, it has been found that the transcribed satellite RNAs can bind DNA repair proteins such as MRE11 and PRKDC, and excessively expressed satellite RNAs could induce genome instability and facilitate tumorigenesis. During the maturation of female oocyte, centromeres are critical for accurate segregation of homologous chromosomes and sister chromatids. However, the dynamics of oocyte centromere transcription and whether it associated with DNA repair proteins are unknown. In this study, we found the transcription of centromeres is active in growing oocytes but it is silenced when oocytes are fully grown. DNA repair proteins like Mlh1, Mre11 and Prkdc are found associated with the minor satellites and this association can be interfered by RNA polymerase II inhibitor α-amanitin. When the growing oocyte is in vitro matured, Mlh1/Mre11/Prkdc foci would release from centromeres to the ooplasm. If the oocytes are treated with Mre11 inhibitor Mirin, the meiosis resumption of growing oocytes with Mre11 foci can be suppressed. These data revealed the dynamic of centromeric transcription in oocytes and its potential association with DNA repair proteins, which provide clues about how oocytes maintain centromere stability and assemble kinetochores.

Kawasaki disease (KD) is characterized by systemic vasculitis of unknown etiology. A study from Japan reported that G to A substitution of a single-nucleotide polymorphism (SNP) located in the 5′-untranslated region of caspase 3 (CASP3) (rs72689236), which was associated with nuclear factor of activated T cell-mediated T-cell activation, is responsible for susceptibility to KD. This study was conducted to investigate whether the polymorphism of CASP3 is responsible for susceptibility and coronary artery lesion (CAL) formation in KD in the Taiwanese population. A total of 1092 subjects (341 KD patients and 751 controls) were investigated to identify an SNP of rs72689236 using Invader assays (Third Wave Technologies). Our data provided a borderline significant association between the genotypes and allele frequency of rs72689236 in control subjects and KD patients (P=0.0535 under the dominant model; P=0.0575 under the allelic model). The A allele of rs72689236 in KD patients and in patients with CAL and intravenous immunoglobulin resistance was seen in a higher frequency. Importantly, a significant association was obtained between rs72689236 and KD patients with aneurysm formation (P=0.009, under the recessive model). The A allele of rs72689236 is very likely to be a risk allele in the development of aneurysm in patients with KD. [ABSTRACT FROM AUTHOR]

We investigated the power density spectrum (PDS) and time lag of ultraluminous X-ray sources (ULXs) observed by XMM-Newton. We determined the PDSs for each ULX and found that five of them show intrinsic variability due to obvious quasi-periodic oscillations (QPOs) of mHz–1 Hz, consistent with previous reports. We further investigated these five ULXs to determine their possible time lag. The ULX QPOs exhibit a soft time lag that is linearly related to the QPO frequency. We discuss the likelihood of the ULX QPOs being type-C QPO analogs, and the time lag models. The ULXs might harbor intermediate-mass black holes if their QPOs are type-C QPO analogs. We suggest that the soft lag and the linearity may be due to reverberation. [ABSTRACT FROM AUTHOR]

Objectives: To compare the levels of plasma glutamate and glutamine in drug-resistant or drug-responsive symptomatic focal epilepsy. Dysfunctional glutamate neurotransmission plays an essential role in epilepsy pathophysiology., Methods: This cross-sectional study included 80 drug-resistant and 42 drug-responsive symptomatic focal epileptic patients and 132 healthy controls from June 2017 to February 2018. Plasma glutamate and glutamine levels were assessed via high-performance liquid chromatography., Results: Patients with drug-resistant symptomatic focal epilepsy had significantly higher plasma glutamate levels than healthy controls, whereas those with the drug-responsive disease had higher plasma glutamine levels than healthy controls. These results indicate that plasma glutamate and glutamine levels can discriminate patients with drug-resistant and drug-responsive symptomatic focal epilepsy from control individuals with the areas under the curve values of 0.931 and 0.72, respectively., Conclusion: Elevated plasma glutamate levels are associated with drug-resistant symptomatic focal epilepsy and may aid the diagnosis of drug-resistant symptomatic focal epilepsy., (Copyright: © Neurosciences.)

A novel HPLC method with the quantitative analysis of multi-components by single marker( QAMS) combined with the dual-wavelength method was developed for simultaneous determination of six flavonoids in Dendrobium officinale stems from different producing areas,cultivation and processing methods to clarify the main factors contributing to the different composition of flavonoids.The separation of six flavonoids was performed on a Shiseido Capcell PAK MGⅡ C18 column( 4. 6 mm×250 mm,5 μm) using a linear gradient elution system of acetonitrile-0. 1% formic acid aqueous solution. Schaftoside,isoschaftoside,vicenin-2,and glucosylvitexin were simultaneously analyzed using rutin as a reference standard at detection wavelength of 340 nm,and naringenin was determined at290 nm. The credibility and feasibility of QAMS method were validated and the results demonstrated that no significant differences were observed as compared with the external standard method. Finally,a total of 82 batches of D. officinale samples were analyzed and principal component analysis( PCA) and discriminant analysis were applied to distinguish and compare D. officinale samples from different producing areas,cultivation and processing methods. The results showed that the total flavonoid content of D. officinale stems cultivated in the simulated wild( attached tree cultivation or attached stone cultivation) was significantly higher than that in greenhouse bed cultivation. The content of flavonoids in simulated-wild D. officinale stems was higher in Jiangxi,Guizhou,Zhejiang,and Fujian provinces,while that in greenhouse bed cultivation was higher in Fujian and Zhejiang provinces. The content of naringenin was positively correlated with processing temperature,and that of the other five flavonoids was negatively correlated with processing temperature. PCA showed that wild-simulated D. officinale and greenhouse bed-cultivated D. officinale could be roughly divided into two clusters. The samples cultivated in the greenhouse bed were divided into four categories according to the geographical habitats. Wild-simulated D. officinale samples from Guizhou gathered together,and there was no obvious rule in samples from other producing areas. The established method simplified the determination method of flavonoids in D. officinale,and could provide the basis for effective quality control,cultivation and processing of D. officinale.

Polymorphonuclear leukocytes (PMNs) are the major leukocytes in the circulation and play an important role in host defense. Intact PMN functions include adhesion, migration, phagocytosis, and reactive oxygen species (ROS) release. It has been known for a long time that adenosine can function as a modulator of adult PMN functions. Neonatal plasma has a higher adenosine level than that of adults; however, little is known about the modulating effects of adenosine on neonatal PMNs. The aim of this study was to investigate the effects of adenosine on neonatal PMN functions. We found that neonatal PMNs had impaired adhesion, chemotaxis, and ROS production abilities, but not phagocytosis compared to adult PMNs. As with adult PMNs, adenosine could suppress the CD11b expressions of neonatal PMNs, but had no significant suppressive effect on phagocytosis. In contrast to adult PMNs, adenosine did not significantly suppress chemotaxis and ROS production of neonatal PMNs. This may be due to impaired phagocyte reactions and a poor neonatal PMN response to adenosine. Adenosine may not be a good strategy for the treatment of neonatal sepsis because of impaired phagocyte reactions and poor response.

Objective: Kawasaki disease (KD) is an acute systematic vasculitis in children which causes coronary arterial lesions and hydrops of gallbladder. Our objective is to correlate the clinical significance and influence on disease outcome of patients with gallbladder abnormalities in Kawasaki dissease., Methods: Children who met KD diagnosis criteria and were admitted for IVIG treatment were retrospectively enrolled for analysis. Patients with abdominal sonography were divided into 2 groups based on the absence (Group A, N = 61) or presence (Group B, N = 16) of gallbladder abnormalities (GBA), defined as hydrops or acalculous cholecystitis. Between the two groups, clinical features, demographic data (including admission days, coronary artery lesions, IVIG resistance), and laboratory data before/after IVIG treatment were collected for analysis., Results: The presence of sonographic gallbladder abnormalities is correlated with higher levels of serum CRP, GPT, and neutrophils. It also points to an increased number of IVIG resistance rates in group B. There was no significant statistical difference among clinical features, age, gender, admission days, or coronary artery lesions between the two groups., Conclusion: Sonographic gallbladder abnormalities are associated with higher CRP, GPT, neutrophil and IVIG resistance in KD. It can be used as a predictor of IVIG resistance in patients with KD.