The Effect of Molecular Adsorption on Electro-Optical Properties of Graphene-Based Sensors

Extraordinary electrical and optical features of graphene-based materials attract researchers to improve sensing center of different sensors using them. In this research, the effects of sensing molecules on electro-optical features of graphene-based sensors are modeled. The adsorption effect on the Hamiltonian of the system based on tight-binding model is explored, and also the system band structure is investigated analytically. Then, refractive index deviations based on band gap variations are discovered which are used in response modeling of a graphene-based surface plasmon resonance (SPR) sensor.

     

Application of BATMAN and BAYESIL for quantitative <Superscript>1</Superscript>H-NMR based metabolomics of urine: discriminant analysis of lean,obese, and obese-diabetic rats

Introduction

BATMAN and BAYESIL are software tools, which can provide a solution for automated metabolite quantifications based on the proton nuclear magnetic resonance (¹H-NMR) spectral data of bio-fluids. However, their specific application for the quantitative ¹H-NMR based metabolomics of urine has not been investigated.

Objectives

The aim of this study is to evaluate the performance of BATMAN and BAYESIL in the quantitative metabolite analysis of urine based on its ¹H-NMR spectra.

Methods

BATMAN and BAYESIL were used for automated metabolite quantification based on the ¹H-NMR spectra of the urine from the lean, obese and obese-diabetic rat groups. PLS-DA model was used to discriminate the three different groups based on the results from the quantifications.

Results

BATMAN was found to be superior to BAYESIL in identifying and quantifying the metabolites in the urine samples, owing to its flexibility that allows users to define and adjust the relevant signals of the pure standard metabolites in the database in order to fit the signals in the samples, a necessary step since variations and peak shift are natural in most ¹H-NMR spectra. The results of BATMAN also agreed well with that of the manual deconvolution method, which indicated the higher accuracy in metabolite quantification, despite the need of pre-processing and longer processing time than BAYESIL. However, in the case where the problems in baseline correction and peak shift of ¹H-NMR spectra are absent, the use of BAYESIL is more advantageous. Application of quantitative ¹H-NMR based metabolomics of the urine showed that PLS-DA model derived from BATMAN could satisfactorily discriminate the lean, obese, and obese-diabetic rat groups.

Conclusion

Both BATMAN and BAYESIL are useful for the quantitative automation of urine metabolites based on its ¹H-NMR spectra. The results from BATMAN method is superior to BAYESIL but require expertise in spectroscopy and longer computer time. Both methods help in simplifying the interpretation of metabolite status in the VIP analysis.

     

Polystoma macrocnemis n. sp. (Monogenea: Polystomatidae) from the Iranian longlegged wood frog Rana macrocnemis (Ranidae) in Turkey

Polystoma macrocnemis n. sp. (Polystomatidae) is described from the urinary bladder of Rana macrocnemis (Ranidae) in Turkey. Its general morphology is similar to that of other members of the genus, but it is distinguished from closely related species by numerical parameters of the hamuli and also by its host species and geographical range.     

The role of K+ATP channels in the control of pre- and post-ischemic left ventricular developed pressure in septic rat hearts

Myocardial function is impaired 24 h after the induction of sepsis, however, recovery of left ventricular (LV) function after 35 min of global ischemia is complete. The mechanisms by which this protection occurs are unknown. Ischemic preconditioning, another form of myocardial protection from ischemia/reperfusion (I/R) injury, has been shown to be modulated by ATP-sensitive potassium (K+ATP) channels. To investigate the role of K+ATP channels in the regulation of coronary flow (CF) and protection from I/R injury in septic rat hearts, we assessed the effects of the K+ATP channel antagonist glibenclamide (GLIB) and the agonist cromakalim (CROM) on pre- and post-ischemic CF and left ventricular developed pressure (LVDP). Although GLIB decreased pre-ischemic CF in both control and septic rat hearts, LVDP was unaffected. After I/R, CF was decreased in GLIB-treated control and septic rat hearts and LVDP was more severely depressed in control rat hearts than in septic rat hearts. CROM increased pre-ischemic CF in the septic group although LVDP was unaltered in both groups. After I/R, control rat heart CF was depressed but LVDP completely recovered. Post-ischemic CF in septic rat hearts was elevated compared with vehicle-treated septic rat hearts, but the recovery of LVDP was not improved. These results suggest that K+ATP channels modulate CF in septic rat hearts, but do not mediate cardioprotection as observed in control rat hearts.     

Rapid deposition of wheat cell wall structural proteins in response to Fusarium-derived elicitors

Two novel cell wall structural proteins of spring wheat (Triticum aestivum L. em Thell.). undergo rapid deposition in the cell wall matrix in a H(2)O(2)-dependent reaction after the elicitation of cultures with Fusarium graminearum (L.)-derived elicitor. The amino acid compositions of these proteins were remarkably similar and indicated that they were highly acidic (pI 3.8). These proteins contained 13--17% each of Gly, Glx and Ser with lesser amounts (6--8%) of Ala, Asx and Thr, and it has been suggested that they are known as glycine- and serine-rich proteins (GSRPs). SELDI-MS ionization spectra demonstrated that these proteins have low molecular masses of 8590 and 4292 Da. These results are discussed in relation to the possible role of these novel proteins in rapid, cell wall defensive reactions to pathogenic attack.     

Overproduction of TNF-alpha by CD8+ type 1 cells and down-regulation of IFN-gamma production by CD4+ Th1 cells contribute to toxic shock-like syndrome in an animal model of fatal monocytotropic ehrlichiosis

Human monocytotropic ehrlichiosis (HME) is an emerging, life-threatening, infectious disease caused by Ehrlichia chaffeensis, an obligate intracellular bacterium that lacks cell wall LPS. We have previously developed an animal model of severe HME using a strain of Ehrlichia isolated from Ixodes ovatus ticks (IOE). To understand the basis of susceptibility to severe monocytotropic ehrlichiosis, we compared low and high doses of the highly virulent IOE strain and the less virulent Ehrlichia muris strain that are closely related to E. chaffeensis in C57BL/6 mice. Lethal infections caused by high or low doses of IOE were accompanied by extensive liver damage, extremely elevated levels of TNF-alpha in the serum, high frequency of Ehrlichia-specific, TNF-alpha-producing CD8(+) T cells in the spleen, decreased Ehrlicha-specific CD4(+) T cell proliferation, low IL-12 levels in the spleen, and a 40-fold decrease in the number of IFN-gamma-producing CD4(+) Th1 cells. All groups contained negligible numbers of IL-4-producing cells in the spleen. Transfer of Ehrlichia-specific polyclonal Abs and IFN-gamma-producing Ehrlichia-specific CD4(+) and CD8(+) type 1 cells protected naive mice against lethal IOE challenge. Interestingly, infection with high dose E. muris provided protection against rechallenge with a lethal dose of IOE. Cross-protection was associated with substantial expansion of IFN-gamma-producing CD4(+) and CD8(+) cells, but not TNF-alpha-producing CD8(+) T cells, a high titer of IgG2a, and a low serum level of TNF-alpha. In conclusion, uncontrolled TNF-alpha production by CD8(+) T cells together with a weak CD4(+) Th1 cell response are associated with immunopathology and failure to clear IOE in the fatal model of HME.     

Constituents of the stems of Macrococculus pomiferus and their inhibitory activities against cyclooxygenases-1 and -2

As part of our program directed towards the discovery of new cancer chemopreventive agents from plants, the EtOAc-soluble extract of the stems of M. pomiferus was found to inhibit the enzyme cyclooxygenase-2 (COX-2). Bioassay-directed fractionation of this extract led to the isolation of two dibenzylbutyrolactone lignans, (8R,8'R)-3'-O-demethyl-5-hydroxymatairesinol (1) and (8R,8'R)-3'-O-demethyl-5-methoxymatairesinol (2), as well as seven known compounds, (-)-5'-methoxyyatein (3), blumenol A, (-)-deoxypodophyllotoxin (anthricin), (-)-deoxypodorhizone, 2,6-dimethoxyhydroquinone, 4-hydroxybenzaldehyde, and beta-sitosterol glucoside. The structures of compounds 1 and 2 were determined using spectroscopic data (1D and 2D NMR, and HREIMS), and the 8R and 8'R absolute stereochemistry was established for both 1 and 2 on the basis of their CD spectra. All isolates obtained in the present study were evaluated for their inhibitory effects with both COX-1 and -2. Of these, only 5'-methoxyyatein (3) showed weak activity against COX-2, while all other compounds isolated were inactive. The COX-2 inhibitory activity of the EtOAc extract was also traced to the presence of several common fatty acids by LC-MS.     

Microarray results improve significantly as hybridization approaches equilibrium

Dual-channel long oligonucleotide microarrays are in widespread use. Although much attention has been given to proper experimental design and analysis regarding long oligonucleotide microarrays, relatively little information is available concerning the optimization of protocols. We carried out a series of microarray experiments designed to investigate the effects of different levels of target concentration and hybridization times using a long oligonucleotide library. Based on principles developed from nucleic acid renaturation kinetics studies, we show that increasing the time of hybridization from 18 h to 42 h and 66 h, especially when lower than optimal concentrations of target were used, significantly improved the quality of the microarray results. Longer hybridization times significantly increased the number of spots detected, signal-to-noise ratios, and the number of differentially expressed genes and correlations among replicate arrays. We conclude that at 18 h of incubation, target-to-probe hybridization has not reached equilibrium and that a relatively high proportion of nonspecific hybridization occurs. This result is striking, given that most, if not all, published microarray protocols stipulate 8-24 h for hybridization. Using shorter than optimal hybridization times (i.e., not allowing hybridization to reach equilibrium) has the consequence of underestimating the fold change of differentially expressed genes and of missing less represented sequences.     

Single-channel gating and regulation of human L-type calcium channels in cardiomyocytes of transgenic mice

Overexpression of human cardiac L-type Ca(2+) channel pores (hCa(v)1.2) in mice causes heart failure. Earlier studies showed Ca(v)1.2-mRNA increase by 2.8-fold, but whole-cell current density enhancement by 相似文献