Graphite foils as potential skin and epithelium dosimeters at therapeutic photon energies.

This work builds upon a prior study, examining the dosimetric utility of pencil lead and thin graphitic sheets, focusing upon the measurement of skin doses within the mammographic regime. In recognizing the near soft-tissue equivalence of graphite and the earlier-observed favourable thermoluminescence yield of thin sheets of graphite, this has led to present study of 50 µm thick graphite for parameters typical of external beam fractionated radiotherapy and skin dose evaluations. The graphite layers were annealed and then stacked to form an assembly of 0.5 mm nominal thickness. Using a 6 MV photon beam and delivering doses from 2- to 60 Gy, irradiations were conducted, the assembly first forming a superficial layer to a solid water phantom and subsequently underlying a 1.5 cm bolus, seeking to circumvent the build-up to electronic equilibrium for skin treatments. Investigations were made of several dosimetric properties arising from the thermoluminescence yield of the 50 µm thick graphite slabs, in particular proportionality and sensitivity to dose. The results show excellent sensitivity within the dose range of interest, the thermoluminescence response varying with increasing depth through the stacked graphite layers, obtaining a coefficient of determination of 90%. Acknowledging there to be considerable challenge in accurately matching skin thickness with dose, the graphite sheets have nevertheless shown considerable promise as dosimeters of skin, sensitive in determination of dose from the surface of the graphite through to sub-dermal depth thicknesses.

Radiation shielding assessment for interventional radiology personnel: Geant4 dosimetry of lead-free compositions.

The inherent biological hazards associated with ionizing radiation necessitate the implementation of effective shielding measures, particularly in medical applications. Interventional radiology, in particular, poses a unique challenge as it often exposes medical personnel to prolonged periods of high x-ray doses. Historically, lead and lead-based compounds have been the primary materials employed for shielding against photons. However, the drawbacks of lead, including its substantial weight causing personnel's inflexibility and its toxicity, have raised concerns regarding its long-term impact on both human health and the environment. Barium tantalate has emerged as a promising alternative, due to its unique attenuation properties against low-energy x-rays, specifically targeting the weak absorption area of lead. In the present study, we employ the Geant4 Monte Carlo simulation tool to investigate various formulations of barium tantalate doped with rare earth elements. The aim is to identify the optimal composition for shielding x-rays in the context of interventional radiology. To achieve this, we employ a reference x-ray spectrum typical of interventional radiology procedures, with energies extending up to 90 keV, within a carefully designed simulation setup. Our primary performance indicator is the reduction in air kerma transmission. Furthermore, we assess the absorbed doses to critical organs at risk within a standard human body phantom protected by the shield. Our results demonstrate that specific concentrations of the examined rare earth impurities can enhance the shielding performance of barium tantalate. To mitigate x-ray exposure in interventional radiology, our analysis reveals that the most effective shielding performance is achieved when using barium tantalate compositions containing 15% Erbium or 10% Samarium by weight. These findings suggest the possibility of developing lead-free shielding solutions or apron for interventional radiology personnel, offering a remarkable reduction in weight (exceeding 30%) while maintaining shielding performance at levels comparable to traditional lead-based materials.

Granular vortex spin-torque nano oscillator for reservoir computing.

In this paper, we investigate the granularity in the free layer of the magnetic tunnel junctions (MTJ) and its potential to function as a reservoir for reservoir computing where grains act as oscillatory neurons while the device is in the vortex state. The input of the reservoir is applied in the form of a magnetic field which can pin the vortex core into different grains of the device in the magnetic vortex state. The oscillation frequency and MTJ resistance vary across different grains in a non-linear fashion making them great candidates to be served as the reservoir's outputs for classification objectives. Hence, we propose an experimentally validated area-efficient single granular vortex spin-torque nano oscillator (GV-STNO) device in which pinning sites work as random reservoirs that can emulate neuronal functions. We harness the nonlinear oscillation frequency and resistance exhibited by the vortex core granular pinning of the GV-STNO reservoir computing system to demonstrate waveform classification.

Quorum-quenching activity of some Iranian medicinal plants.

Anti-quorum sensing (QS) or quorum quenching (QQ) is known as a new anti-bacterial strategy to combat bacterial infection. One of the best candidates for this strategy is a natural plant or traditional herbal medicine. This review aimed to summarize and introduce Iranian medicinal plants with anti-QS properties. Biomedical databases (PubMed, Scopus, Google Scholar and Web of sciences) were investigated to retrieve all related manuscripts published in English and Persian. Out of 65 documents, 47 papers were published during 2010-2020. We categorized and summarized 19 papers that particularly presented the anti-QS activity of Iranian medicinal plants. Based on our results, different studies have been completed on the QQ effects of medicinal plants. We identified 106 plant species with different properties in medicine that have been evaluated for anti-QS activities in Iran. The QQ effects of herbal extracts were identified through different in vitro examinations on biosensor and clinical bacterial strains. Only 35 medicinal plants have shown these effects at sub-MICs. Our review summarizes Iranian medicinal plants with anti-QS properties. Some of these herbal extracts showed anti-QS activity against biosensors, standard and clinical bacterial strains. This result is very important because QS systems can be considered as a new target for the development of new remedial strategies and it is a good opportunity to perform QQ studies to effectively combat bacterial infections in the future.

Evaluation of quorum-sensing inhibitory effects of extracts of three traditional medicine plants with known antibacterial properties.

Today an alternative approach to control bacterial infections is the use of natural and traditional plant compounds to interfere with their quorum-sensing (QS) systems. In this study, antibacterial and anti-QS sensing activity of Syzygium aromaticum, Dionysia revoluta Boiss. and Eucalyptus camaldulensis Dehnh. were evaluated. These plants are local to the Middle East region and have since ancient times been used for their antibacterial activity. Plant compounds were extracted with n-hexane, methanol and 96% ethanol mixed solvent. Antibacterial activity of this herbal extracts against five Gram-negative and Gram-positive bacteria were assessed. The effective sub-minimum inhibitory concentration (MIC) of this extract on bacterial QS systems were investigated by a violacein quantification assay in the Chromobacterium violaceum CV026 biosensor strain, inhibition of exogenously QS signal molecules in Aeromonas veronii bv. Sobria strain BC88 and Pseudomonas aeruginosa isolated from a patient with cystic fibrosis in vitro. Results found that Syzygium aromaticum 0.39 to 0.048 mg/mL, Dionysia revoluta Boiss. 3.1 to 0.39 mg/mL and E. camaldulensis 0.78 to 0.097 mg/mL showed anti-QS activities by reducing the violacein formation depletion of QS signals produced in A. veronii and P. aeruginosa at sub-MICs. Regarding the anti-QS effects of these herbal extracts, their effective components may be candidates for use in combating bacterial infections at sub-MICs.

Implementation of an in-patient hip fracture liaison services to improve initiation of osteoporosis medication use within 1-year of hip fracture: a population-based time series analysis using the RE-AIM framework.

A hip fracture liaison service that was implemented in 2 hospitals in Alberta, Canada, co-managed by a nurse and physician, was effective for improving initiation of osteoporosis medication following hip fracture. PURPOSE: To examine implementation of an in-patient hip fracture liaison service (H-FLS) to improve osteoporosis medication use after hip fracture using the RE-AIM framework (reach, effectiveness, adoption, implementation, maintenance). METHODS: Using population-based administrative data from 7 quarters before and up to 7 quarters after H-FLS implementation, we examined new starts, continued use, and overall use (new starts + continued use) of osteoporosis medication after hip fracture. A total of 1427 patients 50 years and older that underwent hip fracture surgery at 1 of 2 tertiary hospitals in a Canadian province and survived to 12 months post-fracture were included. We also compared treatment initiation rates by sex and hospital. RESULTS: Of the 1427 patients, 1002 (70.2%) were female (mean age = 79.3 ± 11.9 years) and 425 (29.8%) were male (mean age = 73.8 ± 13.8 years). Based on pre-fracture residence within the health zone, 1101 (69%) were considered eligible (Reach). New starts of osteoporosis medication increased from 24.7% pre- to 43.9% post-implementation of the H-FLS (p < 0.001) (effectiveness). The proportion of patients prescribed osteoporosis medication prior to a hip fracture remained consistent (15.1% pre-; 14.7% post-implementation; p = 0.88) with a resultant improvement in overall medication use from 39.8% pre- to 58.6% post-implementation (p < 0.001). Both sites significantly improved medication initiation (site 1: 27.9% pre- to 40.3% post-implementation; site 2: 19.6% pre- to 50.0% post-implementation; p < 0.001 for both) (adoption). Medication initiation in females improved from 26.0% pre- to 43.4% post-implementation while initiation in males improved from 21.7% pre- to 45.1% post-implementation (p < 0.001[females]; p = 0.001[males]) (implementation). Post-implementation, elevated initiation rates were retained over the 7 quarters (p = 0.81) (maintenance). CONCLUSIONS: An H-FLS based in two tertiary hospital sites significantly improved use of osteoporosis medications after hip fracture in both males and females.

Effects of regular exercise plus food restriction on left ventricular pathological remodeling in heart failure­induced rats.

BACKGROUND: Cardiac remodeling is the main pathophysiological process leading to heart failure. Exercise and food restriction have been shown to exert some profound physiological benefits. OBJECTIVES: This study investigated the effects of exercise plus food restriction (FR) on rat left ventricular remodeling. METHODS: Fifty male rats were randomly divided into 5 groups. 1) Sham (saline injection), 2) ISO (isoproterenol injection), 3) FR+ ISO (8 weeks with 60 % food restriction and then isoproterenol injection), 4) E+ISO (run-in period of 4 weeks on treadmill and then isoproterenol injection), and 5) FR+E+ISO. Serum levels of creatine kinase, nitric oxide, gene expression of microtubule-associated protein 1 light chain 3-I and II, Beclin-1, Bax and Bcl2 and TUNEL staining were investigated. RESULTS: ISO increased the plasma CK-MB level, gene expression of Bax and TUNEL­positive cells in left ventricle and at the same time, decreased the serum level of NO. Regular exercise plus food restriction enhanced the expression of LC3B-II, Beclin-1, Bcl2 genes and elevated LC3B-II / LC3B-Ι, while decreasing the gene expression of Bax and TUNEL­positive cells in the left ventricle. CONCLUSION: Our results propose that exercise plus food restriction is more effective than either therapy alone for possibly preserving cardiac internal defenses against heart failure consequences and remodeling (Tab. 2, Fig. 3, Ref. 20).

Evaluation of Ge-doped silica fibre TLDs for in vivo dosimetry during intraoperative radiotherapy.

Ge-doped silica fibre (GDSF) thermoluminescence dosimeters (TLD) are non-hygroscopic spatially high-resolution radiation sensors with demonstrated potential for radiotherapy dosimetry applications. The INTRABEAM® system with spherical applicators, one of a number of recent electronic brachytherapy sources designed for intraoperative radiotherapy (IORT), presents a representative challenging dosimetry situation, with a low keV photon beam and a desired rapid dose-rate fall-off close-up to the applicator surface. In this study, using the INTRABEAM® system, investigations were made into the potential application of GDSF TLDs for in vivo IORT dosimetry. The GDSFs were calibrated over the respective dose- and depth-range 1 to 20 Gy and 3 to 45 mm from the x-ray probe. The effect of different sizes of spherical applicator on TL response of the fibres was also investigated. The results show the GDSF TLDs to be applicable for IORT dose assessment, with the important incorporated correction for beam quality effects using different spherical applicator sizes. The total uncertainty in use of this type of GDSF for dosimetry has been found to range between 9.5% to 12.4%. Subsequent in vivo measurement of skin dose for three breast patients undergoing IORT were performed, the measured doses being below the tolerance level for acute radiation toxicity.

Monte Carlo simulations and analysis of transmitted gamma ray spectra through various tissue phantoms.

Studies of radiation interactions with tissue equivalent material find importance in efforts that seek to avoid unjustifiable dose to patients, also in ensuring quality control of for instance nuclear medicine imaging equipment. Use of the Monte Carlo (MC) simulation tool in such characterization processes allows for the avoidance of costly experiments involving transmitted X- and γ-ray spectrometry. Present work investigates MC simulations of γ-ray transmission through tissue equivalent solid phantoms. Use has been made of a range of radionuclide gamma ray sources, 99mTc, 131I, 137Cs, 60Co (offering photons in the energy range from a few keV up to low MeV), popularly applied in medicine and in some cases for gauging in industry, obtaining the transmission spectra following their interaction with various phantom materials and thicknesses. In validation of the model, the simulated values of mass attenuation coefficients (µ/ρ) for different phantom materials and thicknesses were found to be in good agreement with reference values (NIST, 2004) to within 1.1% for all material compositions. For all of the primary photon energies and medium thicknesses of interest herein, results show that multiple scattering peaks are generally located at energies lower than 100 keV, although for the larger phantom thicknesses it is more difficult to distinguish single, double and multiple scattering in the gamma spectra. Transmitted photon spectra investigated for water, soft tissue, breast, brain and lung tissue slab phantoms are demonstrated to be practically independent of the phantom material, while a significant difference is observed for the spectra transmitted through bone that was proved to be due to the density effect and not material composition.

Neutron Skin Effects in Mirror Energy Differences: The Case of

Energy differences between analogue states in the T=1/2 ^{23}Mg-^{23}Na mirror nuclei have been measured along the rotational yrast bands. This allows us to search for effects arising from isospin-symmetry-breaking interactions (ISB) and/or shape changes. Data are interpreted in the shell model framework following the method successfully applied to nuclei in the f_{7/2} shell. It is shown that the introduction of a schematic ISB interaction of the same type of that used in the f_{7/2} shell is needed to reproduce the data. An alternative novel description, applied here for the first time, relies on the use of an effective interaction deduced from a realistic charge-dependent chiral nucleon-nucleon potential. This analysis provides two important results: (i) The mirror energy differences give direct insight into the nuclear skin; (ii) the skin changes along the rotational bands are strongly correlated with the difference between the neutron and proton occupations of the s_{1/2} "halo" orbit.

Monte Carlo skin dose simulation in intraoperative radiotherapy of breast cancer using spherical applicators.

The relatively new treatment modality electronic intraoperative radiotherapy (IORT) is gaining popularity, irradiation being obtained within a surgically produced cavity being delivered via a low-energy x-ray source and spherical applicators, primarily for early stage breast cancer. Due to the spatially dramatic dose-rate fall off with radial distance from the source and effects related to changes in the beam quality of the low keV photon spectra, dosimetric account of the Intrabeam system is rather complex. Skin dose monitoring in IORT is important due to the high dose prescription per treatment fraction. In this study, modeling of the x-ray source and related applicators were performed using the Monte Carlo N-Particle transport code. The dosimetric characteristics of the model were validated against measured data obtained using an ionization chamber and EBT3 film as dosimeters. By using a simulated breast phantom, absorbed doses to the skin for different combinations of applicator size (1.5-5 cm) and treatment depth (0.5-3 cm) were calculated. Simulation results showed overdosing of the skin (>30% of prescribed dose) at a treatment depth of 0.5 cm using applicator sizes larger than 1.5 cm. Skin doses were significantly increased with applicator size, insofar as delivering 12 Gy (60% of the prescribed dose) to skin for the largest sized applicator (5 cm diameter) and treatment depth of 0.5 cm. It is concluded that the recommended 0.5-1 cm distance between the skin and applicator surface does not guarantee skin safety and skin dose is generally more significant in cases with the larger applicators. HIGHLIGHTS: • Intrabeam x-ray source and spherical applicators were simulated and skin dose was calculated. • Skin dose for constant skin to applicator distance strongly depends on applicator size. • Use of larger applicators generally results in higher skin dose. • The recommended 0.5-1 cm skin to applicator distance does not guarantee skin safety.

Measurement of hepatic insulin sensitivity early after the bypass of the proximal small bowel in humans.

OBJECTIVE: Unlike gastric banding or sleeve gastrectomy procedures, intestinal bypass procedures, Roux-en-Y gastric bypass in particular, lead to rapid improvements in glycaemia early after surgery. The bypass of the proximal small bowel may have weight loss and even caloric restriction-independent glucose-lowering properties on hepatic insulin sensitivity. In this first human mechanistic study, we examined this hypothesis by investigating the early effects of the duodeno-jejunal bypass liner (DJBL; GI Dynamics, USA) on the hepatic insulin sensitivity by using the gold standard euglycaemic hyperinsulinaemic clamp methodology. METHOD: Seven patients with obesity underwent measurement of hepatic insulin sensitivity at baseline, 1 week after a low-calorie liquid diet and after a further 1 week following insertion of the DJBL whilst on the same diet. RESULTS: Duodeno-jejunal bypass liner did not improve the insulin sensitivity of hepatic glucose production beyond the improvements achieved with caloric restriction. CONCLUSIONS: Caloric restriction may be the predominant driver of early increases in hepatic insulin sensitivity after the endoscopic bypass of the proximal small bowel. The same mechanism may be at play after Roux-en-Y gastric bypass and explain, at least in part, the rapid improvements in glycaemia.

Tunable phenol remediation from wastewater using SWCNT-based, sub-nanometer porous membranes: reactive molecular dynamics simulations and DFT calculations.

The importance and impact of the application of CNT membranes with sub-nanometer pores for effective water purification are marvelous. Here we demonstrate, by reactive MD simulations, that CNT membranes can efficiently reject phenol due to molecular size exclusion effects and yield high permeability of water. The water flux in armchair CNTs with a pore diameter of about 7 Å is 1.3 orders of magnitude greater than that of the zigzag counterparts, and pore chemistry plays an important role in moderating the water flux. Nanotubes with H-capped atoms on their rims lead to higher fluxes (50 times) than that of the C-passive counterpart. In nanotubes of larger diameters (8 Å), the pore size is large enough to permit phenol molecules to permeate without any restraint. A series of evidence-based investigations on the interaction nature of the systems under consideration was performed to explain the specific molecular factors as well as systematically reliable relationships for water molecules penetrating through various nanotubes. DFT calculations were also performed to evaluate the validity of the reactive potential employed here. We expect these findings to establish a basis for the design of novel energy-efficient nanotube based membranes as an economical means for the removal of organic contaminants from water, and they can be a benchmark for directing experimental efforts, which are presently restricted by the difficulty associated with creating sub-nanometer pores of a specific size for water treatments.

Thermoluminescence Response of Ge-Doped Cylindrical-, Flat- and Photonic Crystal Silica-Fibres to Electron and Photon Radiation.

Study has been made of the thermoluminescence (TL) response of silica-based Ge-doped cylindrical, flat and photonic crystal fibres (referred to herein as PCF-collapsed) to electron (6, 12 and 20 MeV) and photon (6, 10 MV) irradiation and 1.25 MeV γ-rays, for doses from 0.1 Gy to 100 Gy. The electron and photon irradiations were delivered through use of a Varian Model 2100C linear accelerator located at the University of Malaya Medical Centre and γ-rays delivered from a 60Co irradiator located at the Secondary Standard Dosimetry Laboratory (SSDL), Malaysian Nuclear Agency. Tailor-made to be of various dimensions and dopant concentrations (6-10% Ge), the fibres were observed to provide TL yield linear with radiation dose, reproducibility being within 1-5%, with insensitivity to energy and angular variation. The sensitivity dependency of both detectors with respect to field size follows the dependency of the output factors. For flat fibres exposed to 6 MV X-rays, the 6% Ge-doped fibre provided the greatest TL yield while PCF-collapsed showed a response 2.4 times greater than that of the 6% Ge-doped flat fibres. The response of cylindrical fibres increased with core size. The fibres offer uniform response, high spatial resolution and sensitivity, providing the basis of promising TL systems for radiotherapy applications.

Investigation of the relationship between illogical thoughts and dependence on others and marriage compatibility in the Iranian Veterans exposed to chemicals in Iran-Iraq War.

BACKGROUND: Marital satisfaction is one of the main determinants of a family's correct function. A large number of veterans have been reported to suffer from depression, anxiety, mood disorders, post-traumatic stress disorder, and physical disorders. The objective of this study is to examine association between Illogical thoughts and Dependence on Others and Marriage Compatibility in the Iranian Veterans Exposed to Chemicals in Iran-Iraq War. METHODS: The present cross-sectional, analytical study was conducted on 200 veterans exposed to chemicals who were covered by the Foundation of Martyrs and Veterans Affairs, Gilangharb, Kermanshah, Iran. The study sample size was determined according to Krejcie and Morgan formula and the subjects were selected through random sampling. The study data were collected using marriage compatibility questionnaire, illogical thoughts questionnaire, and dependence on others questionnaire. The study data were analyzed using the SPSS statistical software (version18). Pearson correlation coefficient, multiple regression, and t-test were used in order to determine the relationships among the variables and compare the means. RESULTS: The findings of the current study revealed no significant relationship between dependence on others, anxious attention, helplessness, avoiding problems, perfectionism, and autonomy and marriage compatibility. However, a significant relationship was found between failure and marriage compatibility. DISCUSSION: Overall, the findings of the present study showed that the veterans of Gilangharb did not have disorders, but depended on others, particularly their spouses, due to their abnormal physical status. Sometimes, they cannot even do their personal tasks which results in their dependence on others eventually putting the veterans under pressure and stress.

Delay in the diagnosis and treatment of oral cancer.

STATEMENT OF PROBLEM: Oral and pharyngeal cancer is one of the most mortal cancers; however, its quick diagnosis and referral is a crucial factor in enhancing the survival rate of the patients. PURPOSE: The aim of this study was to inspect the referral conditions and the reasons for the delay in curing the patients referred to the educational hospitals in Tehran. MATERIALS AND METHOD: In this retrospective -descriptive study, two hundred and fifty six files related to the oral and pharyngeal cancer were inspected. The documents were obtained from 5 educational hospitals specialized in the field of cancers. Eventually data related to the time difference between the first time of attending to lesion and diagnosing the cancer as patient's delay and until the curing as professional's delay were recorded. RESULTS: The majority of cancers were squamous cell carcinoma (SCC). The patient's delay was recorded in 110 files among the whole files. The mean of the time between the patients' first notice of the problem and the time visiting a primary care clinician was 270 days (range, 0-2520 days). The mean of the time from when the patient visited a primary- care clinician to the starting time of definitive treatment was 90 days (range, 0-270 days). CONCLUSION: In this study, like other studies, SCC was the most common occurring cancer. Delays related to the patients were more than those related to the professionals. And at last, accuracy in recording the files and training the patients were recognized to be the most imperative factors to continue the treatment successfully.

The γ-secretase blocker DAPT impairs recovery from lipopolysaccharide-induced inflammation in rat brain.

γ-Secretase is an important contributing enzyme in Alzheimer's disease and is therefore an important therapeutic target. However, the impact of γ-secretase inhibition is not well studied in acute neuroinflammation induced by systemic infection. In this study the influence of γ-secretase on the expression of some proinflammatory markers was assessed in the acute phase as well as the subsiding phase of neuroinflammation. Cerebral γ-secretase cleavage activity was measured by a fluorometric assay after lipopolysaccharide (LPS) intraperitoneal administration. Time profiles of TNF-α and COX-II expression were then determined to detect the time points relevant to the maximal inflammatory responses and the subsequent recovery phase. γ-Secretase activity coincident with TNF-α protein expression returned to its basal level till 8-12 h after systemic challenge with low dose LPS while COX-II over expression lasted for 48-72 h later. Pharmacological inhibition of γ-secretase with local or systemic administration of DAPT (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester) was performed to indicate the results on the developmental and sinking phases of inflammatory responses in 6 and 72 h post LPS respectively. Our results demonstrate that both local and systemic modulation of γ-secretase hyper-activity with DAPT increase the duration of TNF-α, COX-II, and NFκB induction. We consistently found mild augmented apoptosis in animals treated with DAPT as determined by measuring cleaved caspase-3 expression and by TUNEL assay 72 h following LPS injection. These results suggest that γ-secretase modulation interferes with certain immune regulatory pathways which may restrict some inflammatory transcription factors such as NFκB.

Evidence for a spin-aligned neutron-proton paired phase from the level structure of (92)Pd.

Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing, in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus (92)Pd. Gamma rays emitted following the (58)Ni((36)Ar,2n)(92)Pd fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution γ-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction. We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.

Cellular membranes, the sites for the antifungal activity of the herbicide sethoxydim.

The fungicidal effect of sethoxydim on the canola (Brassica napus var. Olifera) white stem rot pathogen (Sclerotinia sclerotiorum) encouraged us to conduct a series of studies on the mechanism of the antifungal activity of this herbicide commonly applied in Iranian fields under canola cultivation. Present preliminary studies on the changes in the level of Malondialdehyde (MDA) as the main product generated through peroxidation of polyunsaturated fatty acids indicated the disintegration of the fungal bilayer of plasma membrane as the result of the herbicidal treatment. Also, it was demonstrated that the amount of hydrogen peroxide in the treated samples was higher than the control samples with no herbicidal treatment. Therefore, our present results confirm the disintegration of the plasma membrane as one of the mechanism for the antifungal impact of sethoxydim. As with weed plants, the phytotoxic impact of this herbicide has been attributed to the inhibition of the first enzyme in the lipid biosynthesis pathway, acetyl-CoA carboxylase, therefore, it would be very interesting to study on this subject and the relations between the sensitivity of different fungi and their DNA and protein sequences of acetyl-CoA carboxylase.

Consistent and precise localization of brain activity in human primary visual cortex by MEG and fMRI.

The tomographic localization of activity within human primary visual cortex (striate cortex or V1) was examined using whole-head magnetoencephalography (MEG) and 4-T functional magnetic resonance imaging (fMRI) in four subjects. Circular checkerboard pattern stimuli with radii from 1.8 to 5.2 degrees were presented at eccentricity of 8 degrees and angular position of 45 degrees in the lower quadrant of the visual field to excite the dorsal part of V1 which is distant from the V1/V2 border and from the fundus of the calcarine sulcus. Both fMRI and MEG identified spatially well-overlapped activity within the targeted area in each subject. For MEG, in three subjects a very precise activation in V1 was identified at 42 ms for at least one of the two larger stimulus sizes (radii 4.5 and 5.2 degrees ). When this V1 activity was present, it marked the beginning of a weak wave of excitations in striate and extrastriate areas which ended at 50 ms (M50). The beginning of the next wave of activations (M70) was also marked by a brief V1 activation, mainly between 50 and 60 ms. The mean separation between V1 activation centers identified by fMRI and the earliest MEG activation was 3-5 mm.