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.

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 2.26 mm crack was introduced into cartilage specimens and crack growth was achieved by applying a sinusoidally varying tensile strain at frequencies of 1, 10 and 100 Hz (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 ± 0.4 mm at frequencies of 1, 10 and 100 Hz, respectively following 10,000 cycles. Mean crack growth were 0.3 ± 0.2 and 0.4 ± 0.2 at frequencies of 1 and 10 Hz, respectively. However, this value increased up to 0.6 ± 0.4 mm at a frequency of 100 Hz. 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.

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.

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.

The Adverse Health Effects of Shift Work in Relation to Risk of Illness/Disease: A Review

Biological rhythm of sleeping is a natural disparity in an organism corresponding to and in reply to cyclic environmental changes, such as daylight hours and hours of darkness or elevated and low down flow. There is some evidence, based upon epidemiological studies as well as studies upon smaller groups of subjects, that individuals who work during the night and sleep during the daytime show cognitive impairment at work, have poorer and fragmented daytime sleep, and have increased risks of developing a wide range of social, psychological, physiological and medical impairments and disorders. Circadian rhythms are one of the most important effective factors on the physiological and physical performances of humans and disturbing this normal rhythm leads to different groups of diseases. The majority of investigations in biological rhythm demeanor vary noticeably in regards to the exact type of disease, population and protocols of sampling over the other outcomes or issues. We conducted a systematic review of [Science Direct, Pubmed, Scopus] to identify influence of different kinds of diseases among shift workers in response to abnormal rhythm of sleeping. The results of this review indicate that abnormal patterns of sleeping can lead to immunological issues, hypertension, metabolic syndrome, insomnia, cardiovascular disease, obesity and depression. It is vital for subsequent investigations to find a way to reduce negative effects (such as decreased amount of works’ time and altered diet) without side effects to help them.

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.

Trichinella infection in wildlife of northeast of iran

BACKGROUND

The objective of this investigation was to detect the presence of Trichinella in some carnivores of Mashhad in northeast of Iran and to identify Trichinella species circulating in this area.

METHODS

The present study was carried out using muscle tissue collected from 120 stray dogs, 26 wild boars, 25 rodents, two foxes and two hyenas captured in Mashhad City, province of Khorasan Razavi, Iran.

RESULTS

Trichinella larvae were detected in three stray dogs by artificial digestion and compression. All larvae were identified as T. britovi using multiplex PCR.

CONCLUSION

This is the first report of identification of T. britovi in stray dog in Iran.

Anopheline species composition in borderline of Iran-Azerbaijan

Malaria is still one of the most important health-problems in the world and is endemic in Iran. Since 1994, after collapse of former Soviet Union, a new threat of malaria importation emerged from those countries into the northern Iran. This work was carried out to provide further evidence on the status of anopheline species composition, the malaria parasite species, and natural infectivity of mosquitoes distributed in Pars-Abad district, on the borderline of Azerbaijan in northwestern Iran. Mosquitoes were collected from May to December 2008 in anopheline seasonal activity and were identified at the species level. The genus- and species-specific primers against Plasmodium ssrDNA gene were used for specific amplification on female mosquito head+thorax. Members of the Anoheles maculipennis complex were identified by sequence analysis of the ribosomal internal transcribed spacer II (ITS2-rDNA). Morphological character-based identification showed that out of 1455 anopheline female specimens, 1121 (77%) were of A. maculipennis s.l. and 334 (23%) were of Anoheles hyrcanus. Molecular analysis of the species complex indicated the presence of Anoheles sacharovi 984 (67.6%) and A. maculipennis 137 (9.4%) in the region. None of themosquito's head-thorax was found to be naturally infected by malaria parasite. Results of this study, particularly high dominance of A. sacharovi, suggest a potential risk of malaria epidemic in the region, and the need for a continuous epidemiological surveillance.

Effect of trunk inclination on lower limb joint and lumbar moments in able men during the stance phase of gait

BACKGROUND

Though the effect of imposed trunk posture affects walking patterns little is known about the effect of natural orientation of the trunk on gait. The objectives of this study are to test if the lower limb joint and thoraco-lumbar moments are similar in subjects who maintain an average natural forward or backward trunk inclination during gait and verify if the lower limbs are equally affected.

METHODS

Twenty-five young men were divided according to their natural backward or forward trunk inclination during level walking. Ankle, knee, hip and thoraco-lumbar moments were calculated by an inverse dynamic approach for the two limbs. A two-way ANOVA was performed on peak lower limb moments. A one-way ANOVA was performed on thoraco-lumbar peak moments.

FINDINGS

There was a main effect for both trunk inclinations and lower limb sides but no interaction. For the forward leaners, the duration of hip extension moment was longer (P<0.001) while the hip flexion moment was 1.3 times smaller (P<0.001). Differences between the lower limb sides were noted in all joints but at push-off of the stance phase only. The two thoraco-lumbar extension moments were, respectively, 1.4 times higher for the forward leaners while the two flexion moments were approximately 1.4 times higher for the backward leaners.

INTERPRETATIONS

The backward leaners propel themselves with a strong hip flexor activity at push-off while the forward leaners use their hip muscles throughout stance. These results support the idea that trunk inclinations and moment variations are associated with the type of walking patterns.

A comparative study of antigen and antibody detection in visceral leishmaniasis using serum and urine-based ELISA

An antigen-based ELISA system was evaluated for diagnosis of visceral leishmaniasis (VL). Urine samples from confirmed VL cases were tested by the system in comparison with urine samples from patients with non-VL infectious disease and patients with non-infectious diseases. Antigen was detected in urine of 21 out of 35 (60%) of VL cases. No cross reaction was found with samples from healthy individuals except in 3 samples from non-VL infectious diseases. Two samples from cutaneous leishmaniasis patient and one from patient with toxoplasmosis. The results obtained with the antigen-based ELISA were compared to those obtained with direct agglutination test (DAT), an antibody-based ELISA and indirect immunofluorescent antibody (IFA) revealed that the antigen-based ELISA is comparable in terms of specificity (91.2%; 95% CI=75.2-97.7%) but with a lower sensitivity (60%; 95% CI=42.2-75.6%). These results suggest that the antigen detection in urine by the noninvasive antigen-based ELISA system might offer a useful method for diagnosis of VL.