Multiple-bounce Smith Microfacet BRDFs using the Invariance Principle

Smith microfacet models are widely used in computer graphics to represent materials. Traditional microfacet models do not consider the multiple bounces on microgeometries, leading to visible energy missing, especially on rough surfaces. Later, as the equivalence between the microfacets and volume has been revealed, random walk solutions have been proposed to introduce multiple bounces, but at the cost of high variance. Recently, the position-free property has been introduced into the multiple-bounce model, resulting in much less noise, but also bias or a complex derivation. In this paper, we propose a simple way to derive the multiple-bounce Smith microfacet bidirectional reflectance distribution functions (BRDFs) using the invariance principle. At the core of our model is a shadowing-masking function for a path consisting of direction collections, rather than separated bounces. Our model ensures unbiasedness and can produce less noise compared to the previous work with equal time, thanks to the simple formulation. Furthermore, we also propose a novel probability density function (PDF) for BRDF multiple importance sampling, which has a better match with the multiple-bounce BRDFs, producing less noise than previous naive approximations

Antibiotic Resistomes in Plant Microbiomes

Microorganisms associated with plants may alter the traits of the human microbiome important for human health, but this alteration has largely been overlooked. The plant microbiome is an interface between plants and the environment, and provides many ecosystem functions such as improving nutrient uptake and protecting against biotic and abiotic stress. The plant microbiome also represents a major pathway by which humans are exposed to microbes and genes consumed with food, such as pathogenic bacteria, antibiotic-resistant bacteria, and antibiotic-resistance genes. In this review we highlight the main findings on the composition and function of the plant microbiome, and underline the potential of plant microbiomes in the dissemination of antibiotic resistance via food consumption or direct contact

Testing Heteroscedasticity in Nonparametric Regression Based on Trend Analysis

We first propose in this paper a new test method for detecting heteroscedasticity of the error term in nonparametric regression. Some simulation experiments are then conducted to evaluate the performance of the proposed methodology. A real-world data set is finally analyzed to demonstrate the application of the method

PI3K/Akt/mTOR pathway participates in neuroprotection by dexmedetomidine inhibits neuronic autophagy following traumatic brain injury in rats

Dexmedetomidine (Dex) has been demonstrated to provide neuroprotective effect against brain injury in the central nervous system. However, the underlying mechanism of this neuroprotection remains unclear. In this study, we explored whether Dex has the protective potential in rat models of traumatic brain injury(TBI). More importantly, our study further investigated the role of neuronic autophagy induced by PI3K/Akt/mTOR pathway in this neuroprotective action. Adult male Sprague-Dawley rats were subjected to a diffuse cortical impact injury caused by a modified weight-drop device and Dex (15ug/kg, i.v.) was administered immediately after TBI. Wet-dry weight method was used to evaluate brain edema. Motor function outcome was assessed by Neurologic Severity Score and the spatial learning ability was evaluated in a Morris water maze. The co-localization of microtubule-associated protein 1 light chain 3(LC3) and neuronal nuclei (NeuN), or LC3 and mammalian target of rapamycin (mTOR) were analyzed by immunofluorescence respectively. The expression of LC3, Phosphorylated protein kinase B (p-Akt) and p-mTOR were quantified using Western blot analysis. Our results showed treatment of rats exposed to TBI with Dex caused not only marked reduction in cerebral edema, motor and cognitive functions deficits, but also a decrease in LC3 levels and a increase in p-Akt and p-mTOR levels. Taken together, these findings indicated that treatment with Dex after TBI could inhibited neuronic autophagy in the hippocampus mediated by the activation of the PI3K/Akt/mTOR pathway, finally promoting neurological recovery.Abbreviations: TBI, Traumatic brain injury; Dex, Dexmedetomidine; LC3, Light chain 3; NeuN, Neuronal nuclei; mTOR, Mammalian target of rapamycin; Akt, Protein kinase

Humanin Rescues Cultured Rat Cortical Neurons from NMDA-Induced Toxicity Not by NMDA Receptor

Excitatory neurotoxicity has been implicated in many pathological situations and there is no effective treatment available. Humanin is a 24-aa peptide cloned from the brain of patients with Alzheimer’s disease (AD). In the present study, excitatory toxicity was induced by N-methyl-D-aspartate (NMDA) in primarily cultured rat cortical neurons. MTT assessment, lactate dehydrogenase (LDH) release, and calcein staining were employed to evaluate the protective activity of humanin on NMDA induced toxicity. The results suggested that NMDA (100 μmol/L, 2.5 hr) triggered neuronal morphological changes, lactate dehydrogenase (LDH) release (166% of the control), reduction of cell viability (about 50% of the control), and the decrease of living cell density (about 50% of the control). When pretreated with humanin, the toxicity was suppressed. The living cells’ density of humanin treated group was similar to that of control. The cell viability was attenuated dose-dependently (IC50 = 0.132 nmol/L). The LDH release was also neutralized in a dose-dependent manner. In addition, the intracellular Ca2+ overloading triggered by NMDA reverted quickly and humanin could not inhibit it. These findings indicate that humanin can rescue cortical neurons from NMDA-induced toxicity in rat but not through interfering with NMDA receptor directly

Characterizing the Blood Oxygen Level-Dependent Fluctuations in Musculoskeletal Tumours Using Functional Magnetic Resonance Imaging

This study characterized the blood oxygen level-dependent (BOLD) fluctuations in benign and malignant musculoskeletal tumours via power spectrum analyses in pre-established low-frequency bands. BOLD MRI and T1-weighted imaging (T1WI) were collected for 52 patients with musculoskeletal tumours. Three ROIs were drawn on the T1WI image in the tumours’ central regions, peripheral regions and neighbouring tissue. The power spectrum of the BOLD within each ROI was calculated and divided into the following four frequency bands: 0.01–0.027 Hz, 0.027–0.073 Hz, 0.073–0.198 Hz, and 0.198–0.25 Hz. ANOVA was conducted for each frequency band with the following two factors: the location of the region of interest (LoR, three levels: tumour “centre”, “peripheral” and “healthy tissue”) and tumour characteristic (TC, two levels: “malignant” and “benign”). There was a significant main effect of LoR in the frequencies of 0.073–0.198 Hz and 0.198–0.25 Hz. These data were further processed with post-hoc pair-wise comparisons. BOLD fluctuations at 0.073–0.198 Hz were stronger in the peripheral than central regions of the malignant tumours; however, no such difference was observed for the benign tumours. Our findings provide evidence that the BOLD signal fluctuates with spatial heterogeneity in malignant musculoskeletal tumours at the frequency band of 0.073–0.198 Hz

Functional Analysis of Novel Polymorphisms in the Human SLCO1A2 Gene that Encodes the Transporter OATP1A2

The solute carrier organic anion transporting polypeptide 1A2 (OATP1A2, SLCO1A2) is implicated in the cellular influx of a number of drugs. We identified five novel single nucleotide polymorphisms (SNPs) in coding exons of the SLCO1A2 gene in a cohort of subjects: G550A, G553A, G673A, A775C, and G862A, that encoded the OATP1A2 variants E184K, D185N, V255I, T259P, and D288N, respectively. The function and expression of these variant transporters were assessed in HEK-293 cells. We found that the novel variants, E184K, D185N, T259P, and D288N, were associated with impaired estrone-3-sulfate, imatinib, and methotrexate transport (∼20-50% of wild-type control); function was retained by OATP1A2-V255I. From biotinylation assays, the decreased function of these variants was due, at least in part, to impaired plasma membrane expression. The four loss-of-function variants were studied further using mutagenesis to produce variants that encode residues with different charges or steric properties. From immunoblotting, the replacement of negatively charged residues at amino acid positions 184 and 185 impaired membrane expression, while either a positive or negative charge at residue 288 supported the correct membrane targeting of OATP1A2. Replacement of T259 with bulky residues disrupted transporter stability. From molecular models, E184, D185, and D288 were located near several charged residues such that intramolecular ionic interactions may stabilize the transporter structure. Individuals who carry these novel SNPs in the SLCO1A2 gene may be at risk from impaired efficacy or enhanced toxicity during treatment with drugs that are substrates for OATP1A2.This study was supported by grants from Cancer Council NSW and the Australian National Health and Medical Research Council. The generous gifts of imatinib and 14C-imatinib from Novartis are gratefully acknowledged

Clinical observation on Aralia echinocauIis Hand Mazz Capsula-2 in knee joint of osteoarthritis

目的  观测刺老苞胶囊-2号临床治疗膝关节骨性关节炎的效果。 方法  将2013～2014年门诊收治的膝关节骨性关节炎患者90例(男50例、女40例)分为：治疗-1组35例（男20例，女15例），治疗-2组20例（男10例，女10例），对照组35例（男20例，女15例）。治疗-1组口服刺老苞胶囊-2号，治疗-2组口服刺老苞胶囊-2号+芬必得胶囊，对照组口服芬必得胶囊。连续服药60d后，观察主要症状缓解情况，并按照膝关节功能评分标准比较各组治疗前后效果。 结果  与对照组（总有效率91.43%）相比，治疗-1组（总有效率85.71%）疗效稍逊，治疗-2组（总有效率95.00%）疗效稍好，但组间差异性均不显著（P＞0.05)。 结论  本实验室制备的刺老苞胶囊-2号对膝关节骨性关节炎有一定的治疗效果，如配合芬必得胶囊共同使用，临床疗效更好。Objective: To observe the effect of Aralia echinocauIis Hand. Mazz capsula-2 on the treatment of knee osteoarthritis．Method: 90 cases of knee osteoarthritis (Male 50 cases / Female 40 cases) were collected in 2013 and 2014, and they were divided into three groups. 35 persons (Male 20 cases / Female 15 cases) in treatment group-1 received Aralia echinocauIis Hand. Mazz capsula-2, 20 persons (Male 10 cases / Female 10 cases) in treatment group-2 received Aralia echinocauIis Hand. Mazz capsula-2 +finbid, 35 persons (Male 20 cases / Female 15 cases) in control group received finbid for 60 days in a course of treatment．Result: Compared with control group (91.43%), treatment group-1 ′s effective rate (85.71%) was lower and treatment group-2′s effective rate (95.00%) was higher, but the difference in different groups was no statistically significant (P＞0.05)．Conclusion: Aralia echinocauIis Hand. Mazz capsula-2 in the treatment of knee osteoarthritis showed good efficacy, joint pain could be shortened．If patients were cured by finbid with Aralia echinocauIis Hand. Mazz capsula-2 together, they would get better clinical curative effect

Scaling Behavior of the Quantum Phase Transition from a Quantum Anomalous Hall Insulator to an Axion Insulator

The phase transitions from one plateau to the next plateau or to an insulator in quantum Hall and quantum anomalous Hall (QAH) systems have revealed universal scaling behaviors. A magnetic-field-driven quantum phase transition from a QAH insulator to an axion insulator was recently demonstrated in magnetic topological insulator sandwich samples. Here, we show that the temperature dependence of the derivative of the longitudinal resistance on magnetic field at the transition point follows a characteristic power-law that indicates a universal scaling behavior for the QAH to axion insulator phase transition. Similar to the quantum Hall plateau to plateau transition, the QAH to axion insulator transition can also be understood by the Chalker-Coddington network model. We extract a critical exponent k~ 0.38 in agreement with recent high-precision numerical results on the correlation length exponent of the Chalker-Coddington model at v ~ 2.6, rather than the generally-accepted value of 2.33.Comment: 24 pages, 4 figures, comments are welcom