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.

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.

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.

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.

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.

Effect of Diabetes Mellitus on the Spectrum of Uropathogens and the Antimicrobial Resistance in Patients with Urinary Tract Infection.

Patients with diabetes mellitus frequently experience urinary tract infections (UTIs). In the present study, we looked at how glycemic control affects diabetic patients' rates of UTI, the causing pathogens, the presence of multi-drug-resistant (MDR) and extensively drug-resistant organisms, and the infections' relation to diabetes. Diabetes patients' midstream urine samples were included, after collecting and identifying the organisms, disc diffusion antibiotic sensitivity tests were conducted. The HbA1c was measured for all patients. A total of 500 diabetic patients provided urine samples for this study, and 189 (37.2%) of them had UTIs. Compared to 59 patients with managed glycemia, 130 individuals in the uncontrolled glycemic group experienced the most UTI cases. In both diabetic groups, females had a significantly higher prevalence of UTI than males (88.4% and 11.6%, respectively). The most common bacterial isolate, E. coli, displayed 58.4% MDR. Regardless of age or gender, glycemic control in diabetes patients is essential for decreasing UTI rates.

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.

Central and peripheral anti-inflammatory effects of maprotiline on carrageenan-induced paw edema in rats.

OBJECTIVE: To explore the site of action of maprotiline, as an atypical antidepressant, on carrageenan-induced paw edema. SUBJECTS: Male Wistar rats were used. METHODS: Firstly, the anti-inflammatory effect of systemic maprotiline (12.5, 25 and 50 mg kg(-1)) was assessed using a paw edema model. Secondly, different doses of maprotiline were administrated intracerebroventricularly, intrathecally and locally before carrageenan challenge. Finally, we tried to reverse the anti-inflammatory effect of maprotiline by propranolol (10 mg kg(-1)), prazosin (4 mg kg(-1)), yohimbine (10 mg kg(-1)), naloxone (4 mg kg(-1)) and mifepristone (5 mg kg(-1)). RESULTS: Systemic, intracerebroventricular and subplantar application of maprotiline significantly inhibited peripheral edema, but intrathecal maprotiline did not alter the degree of paw swelling. The applied antagonists failed to change the anti-inflammatory activity of maprotiline. CONCLUSION: These results demonstrate that maprotiline has a potent anti-inflammatory effect and this effect is linked to the peripheral and supraspinal actions of the drug.

Quality of life in stoma patients: appropriate and inappropriate stoma sites.

BACKGROUND: The objective of the cross-sectional study reported here was to compare the quality of life of patients with an appropriate stoma site and with that of patients with an inappropriate stoma site. MATERIALS AND METHODS: Two groups of patients with permanent intestinal stomas were assessed, 174 patients with appropriate stoma sites and 174 patients with inappropriate stoma sites. We used the EORTC QLQ-C30 and the EORTC QLQ-CR38, which evaluate 26 quality of life (QoL) scales. Data analysis was performed with SPSS software. RESULTS: From a total of 9 functional scales, 3 scales in patients with an appropriate stoma site were significantly higher than in patients with an inappropriate stoma site: sexual enjoyment (71.2% vs. 63.2%; p = 0.02), physical functioning (74.3% vs. 68.2%; p = 0.005), and role functioning (74.3% vs. 64.4%; p < 0.0001). From the total of 16 symptom scales, patients with an inappropriate stoma site had significantly more problems than patients with an appropriate stoma site in 8 scales: micturation (27% vs. 22.5%; p = 0.04), gastrointestinal problems (32.6% vs. 27%; p = 0.01), weight loss (36.5% vs. 29.2%; p = 0.03), dyspnea (25.95% vs. 12.5%; p = 0.0001), pain (39.3% vs. 29.6%; p = 0.001), fatigue (43.5% vs. 34.5%; p < 0.0001), nausea and vomiting (18.15% vs. 12.8%; p = 0.03), and insomnia (39.8% vs. 31.1%; p = 0.01). Patients with an appropriate stoma site scored global QoL significantly higher than those with an inappropriate stoma site (56.2% vs. 49.7%; p = 0.007) CONCLUSIONS: A perfectly placed intestinal stoma is strongly related to good QoL for affected patients. From the total of 26 QoL scales assessed in the study, patients with appropriate stoma sites achieved better results in at least 50% of the scales.

Effect of strontium ions substitution on gene delivery related properties of calcium phosphate nanoparticles.

Gene therapy has been considered a strategy for delivery of therapeutic nucleic acids to a specific site. Calcium phosphates are one gene delivery vector group of interest. However, low transfection efficiency has limited the use of calcium phosphate in gene delivery applications. Present work aims at studying the fabrication of strontium substituted calcium phosphate nanoparticles with improved gene delivery related properties. Strontium substituted calcium phosphate was prepared using a simple sol gel method. X-ray diffraction analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, specific surface area analysis, zeta potential measurement and ion release evaluation were used to characterize the samples. This characterization showed strontium and carbonate co-substituted calcium phosphate which resulted in nano size particles with low crystallinity, high specific surface area, positive surface charge, and a high dissolution rate. These improved properties could increase the DNA concentration on the vector as well as the endosomal escape of the complex that leads to higher transfection efficiency of this novel gene delivery vector.

Mg2+ substituted calcium phosphate nano particles synthesis for non viral gene delivery application.

Gene therapy provides a unique approach to medicine as it can be adapted towards the treatment of both inherited and acquired diseases. Recently, calcium phosphate vectors as a new generation of the non viral gene delivery nano carriers have been studied because of their biocompatibility and DNA condensation and gene transfer ability. Substituting cations, like magnesium, affects physical and chemical properties of calcium phosphate nano particles. In this study, Mg(2+) substituted calcium phosphate nano particles have been prepared using the simple sol gel method. X-ray diffraction analysis, Fourier transform infra red spectroscopy, transmission electron microscopy, specific surface area analysis, zeta potential measurement and ion release evaluation were used for characterization of the samples. It was concluded that presence of Mg ions decrease particle size and crystallinity of the samples and increase positive surface charge as well as beta tricalcium phosphate fraction in chemical composition of calcium phosphate. These properties result in increasing the DNA condensation ability, specific surface area and dissolution rate of the samples which make them suitable particles for gene delivery application.

Mutation of the histidin residue of the DRH motif in vasopressin V2 receptor expression and function.

BACKGROUND AND THE PURPOSE OF THE STUDY: Vasopressin type 2 receptor (V2R), a G protein coupled receptor (GPCR), plays an important role in the regulation of renal antidiuretic function. The highly conserved DRH motif is essential for G protein signaling of V2R; however its role especially regarding the histidin residue is not fully understood.. METHODS: Site directed mutagenesis was performed with replacements of the histidin to isoleucine by using nested polymerase chain reaction. ELISA was performed for receptor expression assay and the adenylyl cyclase activity assay was performed for functional characterization of DRI mutation on V2R signaling. RESULTS AND MAJOR CONCLUSION: The adenylyl cyclase activity assay in COS-7 cells showed no difference in the amount of cAMP production between the wild type and the mutant V2 receptors. The V2 receptor expression was not changed in the presence of this mutation using ELISA assay. These results suggest that the role of histidin residue is not critical in the V2 receptor function, however further mutagenesis studies are required to define the role of this motif in V2R function.

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.

Antioxidant supplementation of culture medium during embryo development and/or after vitrification-warming; which is the most important?

PURPOSE: To determine the most optimal stage for antioxidant supplementation of culture medium to improve developmental competence, cryotolerance and DNA-fragmentation of bovine embryos. METHODS: Presumptive zygotes were first cultured in presence or absence of beta-mercaptoethanol (beta-ME), for 8 days. Subsequently, half of the expanded blastocysts developed in both groups were vitrified, warmed within 30 min and post-warming embryos along with their corresponding non-vitrified embryos were cultured for two further days in presence or absence of (100 microM) betaME. RESULTS: For vitrified and non-vitrified embryos, the best effect was found when betaME was added from day 1 of in vitro culture in continuation with post-warming culture period. Day 1-8 supplementation significantly increased the rates of cleavage, day 7 and day 8 blastocyst production. For non-vitrified embryos, betaME addition during day 1-8 and/or 9-10 of embryo culture improved both hatching rate and quality of hatched embryos. For vitrified embryos, however, the percentage of DNA-fragmentation (18.5%) was significantly higher (p < or = 0.05) than that of embryos developed in absence of betaME but supplemented with betaME during post-warming period (13.5%). CONCLUSIONS: Exogenous antioxidant increases the chance of embryos, even those of fair-quality, to develop to blastocyst. However, antioxidant inclusion during in vitro embryo development is not sufficient to maintain the redox state of these embryos during the critical period of post-warming embryo culture, and therefore, there should be a surplus source of exogenous antioxidant during post-warming embryo culture.

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.

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.

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.

Protective effects of calcium-magnesium soft gels in morphine tolerant and dependent mice.

The present study was aimed at evaluating the acute effects of Calcium-Magnesium soft gels (CalMag) in morphine tolerant and dependent mice. Mice were rendered tolerant and dependent on morphine by subcutaneous injection of morphine over a fixed time period. Withdrawal signs were precipitated by injecting naloxone 2 h after the final injection of morphine. The tail-pinch assay was used to investigate the effects of various compounds on the development and reversal of morphine tolerance. Acute injection of CalMag (containing 50 mg/kg calcium and 25 mg/kg magnesium) significantly reduced the number of jumps, stands and fast breathing in morphine dependent mice. Co-administration of calcium (50 mg/kg) and magnesium (25 mg/kg) was also effective in preventing the development of morphine tolerance and dependence. Administration of calcium (up to 50 mg/kg) alone did not significantly block the development of tolerance and dependence. The mean latency to pain was significantly increased in animals pretreated with CalMag (containing 50 mg/kg calcium and 25 mg/kg magnesium). The mixture of calcium and magnesium at specific concentrations seem to be critical for preventing the development of morphine tolerance and dependence.