Nuclear Magnetic Resonance Chemical Shift as a Probe for Single-Molecule Charge Transport.

Existing modelling tools, developed to aid the design of efficient molecular wires and to better understand their charge-transport behaviour and mechanism, have limitations in accuracy and computational cost. Further research is required to develop faster and more precise methods that can yield information on how charge transport properties are impacted by changes in the chemical structure of a molecular wire. In this study, we report a clear semilogarithmic correlation between charge transport efficiency and nuclear magnetic resonance chemical shifts in multiple series of molecular wires, also accounting for the presence of chemical substituents. The NMR data was used to inform a simple tight-binding model that accurately captures the experimental single-molecule conductance values, especially useful in this case as more sophisticated density functional theory calculations fail due to inherent limitations. Our study demonstrates the potential of NMR spectroscopy as a valuable tool for characterising, rationalising, and gaining additional insights on the charge transport properties of single-molecule junctions.

Improving postharvest life, quality and bioactive compounds of strawberry fruits using spermine and spermidine.

Small fruits such as strawberries, are a good source of natural antioxidants. In recent decades, many efforts have been made to increase the shelf life of strawberries and maintain its nutritional value in post-harvest conditions. In the present study, the effects of spermine (Spm) and spermidine (Spd) (0, 1.0 and 1.5 mM) on the post-harvest life and quality of strawberry fruits during the 3rd, 6th, and 12th days of storage, were investigated. Applications of Spm and Spd decreased the rate of weight loss, fruit decay, soluble solids content, fruit juice pH and taste index during the storage period in compared to the control. However, titratable acids and vitamin C contents, tissue stiffness, phenolic compounds and antioxidant activity increased in compared to the control. These growth regulators prevented the aging and loss of bioactive compounds of the fruit by increasing the antioxidant activity and preventing the destruction of the fruit tissue. Among the studied treatments, applications of 1.5 mM of Spm and Spd were the most effective treatments to enhance the storage life and quality characters of strawberry fruits.

Potential Role of microRNAs in Response to Aeromonas Infection in Fish.

The genus Aeromonas is a widespread pathogen that includes more than 30 Gram-negative species, many of which are opportunistic bacteria. Aeromonas species are naturally distributed in various aquatic sources. Infectious processes in marine animals such as fish usually develop under stressful conditions, and when their immune systems are weakened. MicroRNAs (miRNAs/miRs) are short, non-coding RNAs that post-transcriptionally regulate gene expression. Their diverse biological functions, such as influencing cell development, proliferation, differentiation, tumorigenesis, metabolism, and apoptosis have been studied in various animals. Fish is the most important source of aquatic nutrients throughout the world, and its market is constantly growing. Overpopulation in aquaculture brings infectious diseases that threaten the development of aquaculture around the world. There is extensive evidence that microRNAs are involved in modulating infectious processes and regulating the inflammatory response to major bacterial fish infections, including Aeromonas. Here, we review the current literature on the fish microRNA repertoire and outline the physiological roles assigned to microRNAs to provide a foundation for future research during Aeromonas infection. Understanding the interaction between microRNAs and Aeromonas may provide clues to a remarkable strategy for preventing Aeromonas infections in fish.

Designing a new bispecific tandem single-chain variable fragment antibody against tumor necrosis factor-α and interleukin-23 using in silico studies for the treatment of rheumatoid arthritis.

Rheumatoid arthritis disease is a chronic auto-immune inflammatory disease that mainly causes synovial joint inflammation and cartilage destruction. The tumor necrosis factor-α (TNF-α) is a pivotal cytokine that plays an important role in rheumatoid arthritis. The treatments focusing on a single cytokine inhibition are clinically able to produce meaningful responses in only about half of the treated patients due to multiple cytokines involved in this disease. In the present study, a bispecific tandem single-chain variable fragment was designed in order to suppress both human tumor necrosis factor-α and interleukin-23 (IL23) as a potential therapeutic drug candidate for this disease. To do so, at first, eight bispecific tandem single-chain variable fragment models were built against tumor necrosis factor-α and interleukin-23 cytokines with different domain orders by the homology modeling, and then 50 ns molecular dynamics simulation was performed for each one and then structural properties were exploited. The MD simulation results indicate the fact that the domains' order strongly affects tandem single-chain variable fragment properties, and in overall, the fragment VLAIL23+Linker+VHAIL23+linker+VLATNF+Linker +VHATNF +His6 (VL and VH are light and heavy chain variable fragments and AIL23 and ATNF are anti-interleukin 23 and anti-tumor necrosis factor-α, respectively, and His6 is the six histidine) not only separated antibody domains accurately but also had better stability and solvation free energy. Therefore, this structure can be considered as an effective potential drug for rheumatoid arthritis. It is expected that the findings of this research could shed a light on the treatment approaches of the rheumatoid arthritis disease.

Effect of frequency on crack growth in articular cartilage.

Cracks can occur in the articular cartilage surface due to the mechanical loading of the synovial joint, trauma or wear and tear. However, the propagation of such cracks under different frequencies of loading is unknown. The objective of this study was to determine the effect of frequency of loading on the growth of a pre-existing crack in cartilage specimens subjected to cyclic tensile strain. A 2.26mm crack was introduced into cartilage specimens and crack growth was achieved by applying a sinusoidally varying tensile strain at frequencies of 1, 10 and 100Hz (i.e. corresponding to normal, above normal and up to rapid heel-strike rise times, respectively). These frequencies were applied with a strain of between 10-20% and the crack length was measured at 0, 20, 50, 100, 500, 1000, 5000 and 10,000 cycles of strain. Crack growth increased with increasing number of cycles. The maximum crack growth was 0.6 ± 0.3 (mean ± standard deviation), 0.8 ± 0.2 and 1.1 ± 0.4mm at frequencies of 1, 10 and 100Hz, respectively following 10,000 cycles. Mean crack growth were 0.3 ± 0.2 and 0.4 ± 0.2 at frequencies of 1 and 10Hz, respectively. However, this value increased up to 0.6 ± 0.4mm at a frequency of 100Hz. This study demonstrates that crack growth was greater at higher frequencies. The findings of this study may have implications in the early onset of osteoarthritis. This is because rapid heel-strike rise times have been implicated in the early onset of osteoarthritis.

Prediction of Post Operative Complication in Patients with Valvular Heart Surgery Based on O2 Challenge Test and A-A Gradient.

Patients with valvular heart diseases may have more physiological lung derangements and therefore at current study we studied correlation of O2 challenge, A-AG tests and spirometry values of patients who underwent valve surgery on post op respiratory complications. METHOD: 180 adult patients undergoing non-emergency cardiac valvular surgery were studied. On operating room all patients had arterial blood gas profile (ABG) at room air, 20 minutes after putting on ventilator with 100% O2, and pump oxygenator. Pulmonary function tests, alveolar Oxygen Pressure, mean Arterial pressure of carbon dioxide and alveolar -arterial gradients measured. RESULTS: FEV1, FVC and FEV1/FVC%, pressure of arterial Blood Gasses (O2 and CO2) with fraction of inspired oxygen of 100% and air (PO2-100 and PO2-air), were significantly different between patients with POPC and patients without POPC (p-value <0.05). Indeed PO2-100 and PO2-air were significantly lower in patients with POPC. A-AG100 (p-value: 0.02) and A -AG21 (p-value: 0.02) were significantly higher in patients with POPC in comparison with patients without POPC. The AUC of A-AG100 for predicting POPC was 0.59 (95% confidence interval (CI) 0.51-0.67). The optimal cut point of A-AG100 was 311 and showed evidence of high relatively sensitivity of 80% and a negative predictive value of 61%. CONCLUSION: Valvular heart surgery still has significant post op complication and mortality. There is significant correlation between A-AG100, A-AG21 percent, PaO2100, and FEV1/FVC with post op complications in these patients. We recommend measurement of these values in pre op evaluation of patient who need cardiac surgery.

Fatigue strength of bovine articular cartilage-on-bone under three-point bending: the effect of loading frequency.

BACKGROUND: The objective of this study was to determine the influence of loading frequency on the failure of articular cartilage-on-bone specimens under three-point bending. METHODS: In this study, cyclic three-point bending was used to introduce failure into cartilage-on-bone specimens at varying loading frequencies. Sinusiodally varying maximum compressive loads in the range 40-130 N were applied to beam-shaped cartilage-on-bone specimens at frequencies of 1, 10, 50 and 100 Hz. RESULTS: The number of cycles to failure decreased when loading frequency increased from normal and above gait (1 and 10 Hz) to impulsive loading frequencies (50 and 100 Hz). It was found that 67 and 27% of the specimens reached run-out at loading of 10,000 cycles at frequencies of 1 and 10 Hz, respectively. However, 0% of the specimens reached run-out at loading frequencies of 50 and 100 Hz. CONCLUSION: The results indicate that increasing the loading frequency reduces the ability of specimens to resist fracture during bending. The findings underline the importance of the loading frequency concerning the failure of articular cartilage-on-bone and it may have implications in the early onset of osteoarthritis.

Quantitative determination of methamphetamine in oral fluid by liquid-liquid extraction and gas chromatography/mass spectrometry.

Methamphetamine abuse is one of the most medical and social problems many countries face. In spite of the ban on the use of methamphetamine, it is widely available in Iran's drug black market. There are many analytical methods for the detection of methamphetamine in biological specimen. Oral fluid has become a popular specimen to test for the presence of methamphetamine. The purpose of the present study was to develop a method for the extraction and detection of methamphetamine in oral fluid samples using liquid-liquid extraction (LLE) and gas chromatography/mass spectrometry (GC/MS) methods. An analytical study was designed in that blank and 50 authentic oral fluid samples were collected to be first extracted by LLE and subsequently analysed by GC/MS. The method was fully validated and showed an excellent intra- and inter-assay precision (reflex sympathetic dystrophy ˂ 10%) for external quality control samples. Recovery with LLE methods was 96%. Limit of detection and limit of quantitation were 5 and 15 ng/mL, respectively. The method showed high selectivity, no additional peak due to interfering substances in samples was observed. The introduced method was sensitive, accurate and precise enough for the extraction of methamphetamine from oral fluid samples in forensic toxicology laboratories.

Effect of mutations in putative hormone binding sites on V2 vasopressin receptor function.

The vasopressin V2 receptor belongs to the large family of the G-protein coupled receptors and is responsible for the antidiuretic effect of the neurohypophyseal hormone arginine vasopressin (AVP). Based on bioinformatic studies it seems that Ala300 and Asp297 of the V2 vasopressin receptor (V2R) are involved in receptor binding. Ala300Glu mutation resulted in lower energy while Asp297Tyr mutation resulted in higher energy in AVP-V2R docked complex rather than the wild type. Therefore we hypothesized that the Ala300Glu mutation results in stronger and Asp297Tyr mutation leads to weaker ligand-receptor binding. Site directed mutagenesis of Asp297Tyr and Ala300Glu was performed using nested polymerase chain reaction. After restriction enzyme digestion, the inserts were ligated into the pcDNA3 vector and Escherichia coli XL1-Blue competent cells were transformed using commercial kit and electroporation methods. The obtained colonies were analyzed for the presence and orientation of the inserts using proper restriction enzymes. After transient transfection of COS-7 cells using ESCORT™ IV transfection reagent, the adenylyl cyclase activity assay was performed for functional studies. The cell surface expression of V2R was analyzed by indirect ELISA method. Based on the obtained results, the Ala300Glu mutation of V2R led to reduced levels of cAMP production without a marked effect on the receptor expression and the receptor binding. Effect of Asp297Tyr mutation on cell surface expression of V2R was the same as the wild type receptor. Pretreatment with 1 nM vasopressin showed an increased level of Asp297Tyr mutant receptor internalization as compared to the wild type receptor, while the effect of 100 nM vasopressin was similar in the mutant and wild type receptors. These data suggest that alterations in Asp297 but not Ala300 would affect the hormone receptor binding.

Optimization of a single-chain antibody fragment overexpression in Escherichia coli using response surface methodology.

Human epidermal growth factor receptor (HER) family plays an important role in various types of cancers. As a result, antibodies against HER and the mechanism of antigen-antibody binding action are under active investigation. We previously constructed a single-chain variable fragment (ScFv) against HER2, i.e. anti-Her2 ScFv, for expressing in the Escherichia coli. In the present study, we report the optimization of anti-Her2 ScFv expression in an E. coli host of BL21 (DE3) pLysS using response surface methodology based on tuning of three cultivation variables, including isopropyl-beta-D-thiogalactopyranoside (IPTG) concentration, temperature and post-induction time. A model for protein expression according to the Box-Behnken design predicted a maximal anti-Her2 ScFv expression at 37 °C, a post-induction time of 10.45 h and 0.75 mM IPTG. In addition, strategies based on inclusion body isolation and affinity chromatography were applied to purify anti-Her2 ScFv. The purity of the final product for inclusion bodies isolation and purification by Ni-NTA resin were 70 % and 95 %, respectively. The solubilization of the inclusion bodies was carried out using two denaturant agents, guanidine hydrochloride and urea. The present study showed that guanidine hydrochloride was more effective than urea in solubilizing the inclusion bodies.

Effect of the variation of loading frequency on surface failure of bovine articular cartilage.

BACKGROUND: Mechanical loading of synovial joints can damage the articular cartilage surface and may lead to osteoarthritis. It is unknown if, independent of load, frequency alone can cause failure in cartilage. This study investigated the variation of articular cartilage surface damage under frequencies associated with normal, above normal and traumatic loading frequencies. METHOD: Cartilage on bone, obtained from bovine shoulder joints, was tested. Damage was created on the cartilage surface through an indenter being sinusoidally loaded against it at loading frequencies of 1, 10 and 100 Hz (i.e., relevant to normal, above normal and up to rapid heel-strike rise times, respectively). The frequencies were applied with a maximum load in the range 60-160 N. Surface cracks were marked with India ink, photographed and their length measured using image analysis software. RESULTS: Surface damage increased significantly (P < 0.0001) with frequency throughout all load ranges investigated. The dependence of crack length, c, on frequency, f, could be represented by, c=A(log10(f))2+B(log10(f))+Dc=A(log10(f))2+B(log10(f))+D where A = 0.006 ± 0.23, B = 0.62 ± 0.23 and D = 0.38 ± 0.51 mm (mean ± standard deviation). CONCLUSION: The increase in crack length with loading frequency indicated that, increased loading frequency can result in cartilage becoming damaged. The results of this study have implications in the early stages of osteoarthritis.

Prevalence of intestinal parasites in a population in Eghbalieh city from Qazvin Province, Iran.

Intestinal parasitic infections are endemic worldwide and have been described as constituting the greatest single worldwide cause of illness and disease. The prevalence of Intestinal parasitic infections was estimated to be 5.92 %. Entamoeba coli was the most common parasite followed by Giardia lamblia and Blastocystis hominis. About 5.15 % of samples contained a single parasite and 0.76 % contained multiple parasites. In this study, the prevalence of intestinal parasites especially helminthic infections was low. The study aimed to estimate prevalence of intestinal parasites in Eghbalieh city from Qazvin Province, Iran.

Long-term and efficient expression of human ß-globin gene in a hematopoietic cell line using a new site-specific integrating non-viral system.

Targeted integration of a therapeutic gene at specific loci in safe genomic regions by a non-viral vector can restore the function of the damaged gene. This approach also minimizes the potential genotoxic effects of transferred DNA. In this study, we have developed a non-viral vector that functions according to site-specific recombination (SSR). The vector contained a bacterial backbone and puromycin resistance gene (pur(r)), a ß-globin expressing cassette and an attB recombination site. We used phiC31 integrase to insert a copy of the vector into specific genomic locations of a human hematopoietic cell line. Site-specific integration of the vector with one or two copies in the transcriptionally active regions of the genome was confirmed. After genomic integration, we used Cre recombinase to remove the bacterial backbone and pur(r). This removal was verified by negative selection and genomic PCR screening. Following deletion of these sequences, the stable ß-chain expression was continued for several months in the absence of selective pressure. Consequently, this vector may potentially be a powerful tool for ex vivo correction of ß-globinopathies such as ß-thalassemia through successful genomic integration of a functional copy of the globin gene into the patient's target cells.

Protecting impact of Jaft against carbendazim induced biochemical changes in male Wistar rats.

Introduction: Pesticides are a critical tool for crop protection and control of different pests and insects. The present research conducted to evaluate the protective role of Jaft extract against oxidative pressure, biochemical variations because of limited time giveaway to carbendazim in Wistar mice males. Fresh fruits of quercus brantii were dried and the internal layer (Jaft) was collected for a hydroalcoholic extract by a maceration method at normal ambient condition. For the experimental study, twenty-four adult male rats (Wistar albino rats weighing 150-200 g) were randomized into 3 teams out of eight. Team I subserved like a vehicle treated group, received corn oil additionally to their food, while the animals in the second team got 0.1 ml carbendazim (50mg/ kg in corn oil) via oral path for nine days. Rats in group III received Jaft (500 mg/ kg orally + in carbendazim for 9 days. Blood samples were obtained by heart puncture to determine alkaline phosphatase (ALP), blood urea nitrogen (BUN), creatinine, alanine (ALT) and aspartate aminotransferases (AST); by using auto-analyzer in serum.Kidneys and liver separated from rats and provided for series of biochemical parameters homogenization like GSH and MDA stages. Result: The serum content of AST, ALT, ALP, BUN and creatinine were significantly elevated by in carbendazim treatment (group II) compared to the negative group (p<0.01).The liver enzymes operations, creatinine and BUN were significantly reduced in rats (p<0.05) when Jaft was received in a short period of time (group III). Hepatic and GSH and renal MDA stages in group (II) were clearly (p<0.05) enhanced and decreased consequently. The GSH and MDA stages content were significantly normalized in mice (p<0.05) when Jaft was received by group III. Conclusions: According to the present data, Jaft can neutralize carbendazim contain pressure of oxidative and recover the abnormal pathological injuries in Wistar mice males.

Mechanical approach to the neutrons spectra collimation and detection.

Neutrons spectra from most of known sources require being collimated for numerous applications; among them one is the Neutron Activation Analysis. High energy neutrons are collimated through a mechanical procedure as one of the most promising methods. The output energy of the neutron beam depends on the velocity of the rotating Polyethylene disks. The collimated neutrons are then measured by an innovative detection technique with high accuracy.

Dissociation and the development of spatial correlation in a molecular ultracold plasma.

Penning ionization initiates the evolution of a dense molecular Rydberg gas to plasma. This process selects for pairs of excited molecules separated by a distance of two Rydberg orbital diameters or less. The deactivated Penning partners predissociate, depleting the leading edge of the distribution of nearest-neighbor distances. For certain density and orbital radii, this sequence of events can form a plasma in which large distances separate a disproportionate fraction of the ions. Experimental results and model calculations suggest that the reduced potential energy of this Penning lattice significantly affects the development of strong coupling in an ultracold plasma.

Quantitative evaluation of DNMT3B promoter methylation in breast cancer patients using differential high resolution melting analysis.

DNA methylation plays an important role in carcinogenesis through epigenetic silencing of tumor suppressor genes. Aberrant methylation usually results from changes in the activity of DNA methyltransferases (DNMTs). Some studies show that the overexpression of the DNMTs may lead to aberrant methylation of tumor suppressor genes. Also the overexpression of DNMTs may be related to methylation status of their genes. Due to limited number of studies on DNMT3B promoter methylation, this study was performed to quantitatively measure the methylation level of DNMT3B gene in archival formalin fixed paraffin embedded (FFPE) tissues from breast cancer patients. Using differential high resolution melting analysis (D-HRMA) technology, the methylation level of DNMT3B gene promoter was quantified in 98 breast cancer FFPE tissues and also 10 fresh frozen normal tissue samples. Statistical analyses used for analyzing the correlation between the methylation and clinical variables. All the normal samples were found to be methylated at the DNMT3B promoter (the average methylation level 3.34%). Patients were identified as hypo-methylated (mean methylation level 0.8%), methylated (mean methylation level 2.48%) and hyper-methylated (mean methylation level 10.5%). Statistical analysis showed a significant correlation between the methylation status and the sample type, cancer type and tumor size. Also the methylation level was significantly associated with histologic grade. It is concluded that quantification of DNMT3B promoter methylation might be used as a reliable and sensitive diagnostic and prognostic tool in breast cancer. Also D-HRMA is demonstrated as a rapid and cost effective method for quantitative evaluation of promoter methylation.

Expression of the recombinant plasminogen activator (reteplase) by a non-lytic insect cell expression system.

Reteplase is a potent thrombolytic agent which is widely used in the management of acute myocardial infarction and stroke. It belongs to the third generation of the thrombolytic drugs and has been derived from native human tissue plasminogen activator by removing three domains of it and keeping the Kringle 2 and Serine protease domains. However, the high cost of this drug, has limited the application of this drug especially in the developing and third world countries. The most laborious steps in the bacterial production of this drug is its purification and refolding steps which keep the process yield low and the cost high. Therefore, in the present study we evaluated the expression of reteplase by a non-lytic insect cell expression system. Following cloning and transfection procedures, recombinant Sf9 insect cell clones expressing the reteplase protein were selected. Primarily, the expression was verified by dot-blot analysis and subsequently it was confirmed by Western Blotting showing a band of about 45 kD on nitrocellulose membrane. The biological activity of the expressed protein was also evaluated and showed to be about 29 IU/ml. This confirmed the possibility of expression and the correct folding of the expressed protein. Hence, optimization of the expression followed by purification of the protein could be the next steps of the study.