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New vanadium(IV) and chromium(III) complexes of metformin (MFN) were synthesized upon the chemical interaction between vanadyl(II) sulfate monohydrate or chromium(III) chloride hexahydrate with metformin diabetic drug in the media of a pure grade of methanol solvent. The [(VO) 2 (MFN) 2 (SO 4 ) 2 ]2H 2 O and [Cr(MFN) 3 ]·Cl 3 ·6H 2 O complexes were discussed using microanalytical measurements, molar conductance, spectroscopic (infrared, ESR, XRD, and UV–vis), effective magnetic moment, scanning electron microscopy (SEM), and thermal analyses (TG/DTG). The elemental analysis shows that VO(II) and Cr(III) complexes were associated with 1:1 and 1:3 M ratios, respectively. The infrared spectroscopic results data received from the comparison between free MFN free ligand and their vanadyl(II) and chromium(III) complexes were proven that metformin reacted with respected metal ions as a bidentate ligand through its two imino groups. The kinetic thermodynamic parameters were estimated from the DTG curves. The microstructure changes of the VO(II) and Cr(III) complexes have been probed using positron annihilation lifetime (PAL) and positron annihilation Doppler broadening (PADB) techniques. The PAL and PADB line-shape parameters were found to be dependent on the structure, electronic configuration and molecular weight of metal complexes. Antimicrobial activity of the metformin free ligand and its vanadyl(II) and chromium(III) complexes were evaluated against the gram negative and gram positive bacteria strains and different fungal strains. Moderate antimicrobial activity recorded by disk diffusion inhibition growth zone method in vanadyl(II) and chromium(III) complexes compared to metformin free ligand. [ABSTRACT FROM AUTHOR]

The positron annihilation Doppler broadening (PADB) spectroscopy has been employed to probe the defects and structural changes of various types of materials. In this work, an investigation was carried out for the first time to use PADB spectroscopy in probing the γ irradiated radiochromic films. The GafChromic MD–55 and HD–V2 radiochromic films irradiated with absorbed doses ranges of 0–80 and 0–2000 Gy, respectively, were subjected to Doppler broadening measurements employing a HPGe γ–ray spectrometer. The Doppler broadening line–shape parameters (S and W) of 511 keV annihilation radiations were discussed in terms of the polymerization degree of the active components of these dosimetry films. The S- and W-parameters were found to be dependent on the active component structures of both films. A reasonable correlation was also found between the values of the S–parameter and the optical density of these radiochromic films. In addition, the Doppler broadening line–shape parameters were successfully used to provide explanation of the observed nonlinearity of these films at the end of their dynamic dose ranges. The results demonstrate the applicability of the PADB technique to probe the physical and chemical changes occurred in the active layer of the studied radiochromic films during the solid–state polymerization reaction caused by γ irradiation of different absorbed doses. [ABSTRACT FROM AUTHOR]

Abstract: Metal complexes of Pb(II), Sn(II), Sb(III) and Bi(III) with a barbital sodium were synthesized and characterized by several techniques, including elemental analysis (C, H and N), molar conductance measurements, infrared, Raman, 1H NMR, positron annihilation lifetime and thermogravimetric analysis. Reactions of barbital sodium (NaL) with salts of Pb(NO3)2, SnCl2⋅2H2O, SbCl3 and BiCl3 affords four novel mononuclear complexes [Pb(HL)2], [Sn(L)(H2O)], [Sb(HL)(L)] and [Bi(HL)(L)]. In complexes of Pb(II), Sb(III) and Bi(III), the molar ratio of metal-to-ligand is 1:2. Both of Sb(III) and Bi(III) complexes have six coordination via two molecules of barbital (HL and L), one of them deprotonated NH. The Pb(II) complex has a central metal ion adopts tetradentate fashion which surrounded by two (HL) barbital moieties. The elemental analysis shows that Sn(II) complex is tetradentate 1:1 ratio, chelated through oxygen ), deprotonated (ne coordinated water molecule. The positron annihilation lifetime parameters were found to be dependent on the structure, electronic configuration and molecular weight of metal complexes. [Copyright &y& Elsevier]

Abstract: The environmental pollution caused by the wastewater from a phosphate fertilizer plant in Egypt was investigated. The concentrations of radionuclides and fluoride in phosphate fertilizer (raw materials, end products and by-products) and other types of fertilizer samples were measured. The concentrations of these elements were also measured in environmental samples (water, sediment and plant) collected from the proximity of outlet of wastewater discharge pipes of the phosphate fertilizer company. The fluoride concentration was ranged from 0.03 to 0.25mg/g, 0.002 to 0.006mg/g, 0.42 to 1.88mg/g and 0.44 to 7.3mg/l for phosphate fertilizer, other types of fertilizer, sediment and water samples, respectively. The activity concentrations of 226Ra were ranged from 244 to 1312Bq/kg, 0.6 to 12.1Bq/kg, 15.4 to 33.8Bq/kg, 0.06 to 1.3Bq/l and 8.9 to 17.3Bq/kg for phosphate fertilizer, other types of fertilizer, sediment, water and plant samples, respectively. The 232Th activity concentrations were ranged from 0.7 to 24Bq/kg, 0.7 to 14.5Bq/kg, 10.4 to 19.3Bq/kg, 0.02 to 0.16Bq/l and 2.0 to 29.8Bq/kg for these samples, respectively. Also, the 40K activity concentrations were ranged from 2.1 to 1.4Bq/kg, 2.1 to 5313Bq/kg, 128 to 281Bq/kg, 0.14 to 0.6Bq/l and 686 to 977Bq/kg for these samples, respectively. Low content of 137Cs was determined in only two phosphate fertilizer samples (F2 and F3; mean 1.3Bq/kg) and in most of sediment samples (with range 1.0–2.4Bq/kg). The radium equivalent, as a radiation hazard index, was ranged from 284 to 1316, 9.6 to 432 and 47 to 70Bq/kg for phosphate fertilizer, other types of fertilizer and sediment samples, respectively. The results indicated that the wastewater polluted with fluoride produced from the phosphate fertilizer company may be affecting the environment. The radioactivity content measurements indicated that the environment may be slightly affected with low concentrations of 226Ra and 232Th isotopes due to the discharged wastewater from the phosphate fertilizer industry. On the other hand, the results of comparison studies for radioactivity concentrations are also presented and discussed. [Copyright &y& Elsevier]

Abstract: ICU-acquired neuromyopathy (NMAR) and delirium are the two most frequent and severe neurological complications of intensive care medicine. Their mechanisms still remain to be elucidated. The objective of this review is to address the potential role of sedation in occurrence of these complications. There is no evidence that sedation is involved in NMARs. However, the hypothesis that muscle inactivity induced by sedation fosters NMAR is an argument to discontinue or reduce sedatives infusion whenever possible. It is also recommended not to administer propofol more than 48h at an infusion rate above 5mg/kg per hour in patients with systemic inflammatory response syndrome, because of the risk of propofol infusion syndrome, which includes notably rhabdomyolysis. The relationship between delirium and sedation are controversial because in most studies, patients were considered delirious though being still sedated and multivariate analysis was lacking. One study showed that lorazepam given continuously was an independent risk factor for daily transition to delirium 24h later with a 20% increase risk of every unit dose (expressed as loge mg). The impact of deepness, daily interruption or titration of sedation on the prevalence of delirium has never been assessed but it seems that deep sedation has to be avoided. [Copyright &y& Elsevier]

Abstract: The concentrations and distribution of γ-ray emitting isotopes in Burullus Lake were investigated with the aim of evaluating the environmental radioactivity. Particularly in wetlands, natural properties of the environment can cause the actual inventory to be different from the activity originally deposited. The mean concentrations of 226Ra, 232Th and 40K were 14.3, 15.5 and 224Bq/kg, respectively, in the coastal soils. On the other hand, soil samples from the islands had mean concentrations of 13.5, 17.4 and 341Bq/kg for 226Ra, 232Th and 40K, respectively. Samples from coast and islands show evidence of possible transfer and accumulation of the 137Cs radionuclide. The mean 137Cs activity concentrations in the soil samples were 1.2 and 15.1Bq/kg in the coast and islands, respectively. The vertical migration of 137Cs was studied based on its content in the consequently located three soil layers down to 30cm depth. The radium equivalent, dose rate in air and annual dose equivalent from the terrestrial natural γ-radiation were evaluated. The mean activity concentrations of the γ-ray emitting radionuclides in vegetation were relatively low. [Copyright &y& Elsevier]

The concentrations of 137Cs and 40K in some Egyptian foodstuffs have been measured. The results of this study can be considered as a first step towards calculating the baseline levels of radioactivity in foodstuffs in Egypt. Furthermore, the data presented herein can be used as a reference level for future food radioactivity monitoring after the possible operation of the planned nuclear power plants, as well as to screen imported foodstuffs that are suspected of being contaminated. The overall intake of 137Cs is quite low and no significant radionuclide contamination was found. The highest contents of 137Cs and 40K among the tested foodstuffs were in Jew’s mallow and roquette. Calculations were also made to determine the potential dose to an individual consuming vegetables. [Copyright &y& Elsevier]

Composite materials of Cu 0.6 Zn 0.4 Fe 2 O 4 (CZF) and barium titanate (BT) with different concentrations were prepared by high energy ball milling method. The composite samples of CZF and BT were studied using Infrared, ESR and positron annihilation Doppler broadening (PADB) spectroscopy techniques as well as thermo-electric power measurements. The results confirm formation of the composite, and presence of two ferrimagnetic and ferroelectric phases, simultaneously. In addition, Fe–O bond for both tetrahedral and octahedral sites, population and distribution of cations at A and B sites are varied with BT content. The values of resonance field, line width of ESR spectrum and charge carrier concentration increase by increasing BT content. The value of the g factor for our samples with low BT content is greater than g-factor value of the isolated free electron. On the contrary, the g-factor values for samples with high BT content are smaller than the free isolated electron. PADB line-shape S-parameter suggests that there are increases of the density of the delocalized electrons, defect size and concentration caused by highly adding BT phase. In addition, PADB results confirm the homogeneity of composite phases and same structure of defects in BT-CZF composite samples. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, measurements of naturally occurring radioactive materials and 137Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of 226Ra and 232Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of 137Cs and 40K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of 137Cs and solubilization of 40K in sediment. On the other hand, sediment with high organic matter content traps 137Cs and 40K associated particulates to bottom sediment. [Copyright &y& Elsevier]

PVA/PEG-EY blend structures are synthesized with PEG concentrations of 0, 1, 3, 5, 10, 15 and 20 wt% using casting method. The electrical and dielectric properties of the blend samples were studied with frequency in range (0.1 Hz to 20 MHz), via impedance spectroscopy. The Raman spectroscopy characterized and distinguish the structure of the prepared films. Theoretical results of Raman spectra of PVA, PEG and EY samples were analyzed based on linear response time-dependent density functional theory and then compared with experimental results of the samples. The microstructure and defect distribution of the synthesized samples were inferred using the positron annihilation spectroscopy (PAS). Experimental and theoretical Raman analysis indicates the increase of diffusion of EY and PEG. Broadband dielectric spectroscopy investigation on a broad range of frequencies shows that the enhancement of electrical conductivity of the prepared PVA/PEG-EY film with increasing PEG content. The considerable effect of the PEG content on the film microstructure was approved. The interactions between the PVA and PEG through the formation of hydrogen bonding modify the size and concentration of the free volume holes. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a series of three N2S2-tetradentate ligands and their zinc complexes were investigated by positron annihilation lifetime spectroscopy. The measurements were performed at room temperature. The analysis of lifetime spectra of all samples yielded four lifetime components, except in one sample that yielded three components. The results showed that the formation probability and lifetime of ortho-positronium in this series are dependent on the structure. [Copyright &y& Elsevier]

Abstract: Computational methods were used to reduce the dimensionality and to find clusters of multivariate data. The variables were the natural radioactivity contents and the texture characteristics of sand samples. The application of discriminate analysis revealed that samples with high negative values of the former score have the highest contamination with black sand. Principal component analysis (PCA) revealed that radioactivity concentrations alone are sufficient for the classification. Rough set analysis (RSA) showed that the concentration of 238U, 226Ra or 232Th, combined with the concentration of 40K, can specify the clusters and characteristics of the sand. Both PCA and RSA show that 238U, 226Ra and 232Th behave similarly. RSA revealed that one or two of them can be omitted without degrading predictions. [Copyright &y& Elsevier]

Nano PbZr 0.52 Ti 0.48 O 3 -ordinary Portland cement (PZT-OPC) composites were fabricated by a ball milling technique with different PZT content (30, 50, 70, and 90% by weight). The prepared samples were annealed at 600 °C. The structure, morphology, thermal and electrical properties of these annealed samples were investigated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The effects of PZT on dielectric and piezoelectric properties of the composites were investigated. γ-ray spectroscopy was used to measure the γ-ray attenuation coefficients of the annealed nanocomposite samples using the 661.7 keV γ-ray of 137Cs source. The microstructure changes of the prepared composite samples were investigated using the positron annihilation lifetime (PAL) and Doppler broadening (DB) techniques. The XRD patterns show both PZT and cement peaks. Also, these patterns indicate the presence of PZT retards the hydration process of the Portland cement. The FTIR spectra show the major absorption bands for both PZT and cement. SEM images show the binding between calcium silicate hydrate and PZT which may be a better factor for improving the mechanical properties of the cement. TGA curves show a higher thermal weight loss for 50% PZT-OPC composite sample. The PZT-OPC composite sample with 50% PZT content shows the highest γ-ray mass attenuation coefficient compared with the other composite samples. The positron annihilation spectroscopy (PAS) results show that the size of large voids and the concentration of small defects increase by increasing PZT content. Also, these results reveal that the core electrons slightly reduced by increasing PZT content. The results indicate that the dielectric constant and piezoelectric coefficient values slightly and rapidly increase for composite samples with PZT content <50% and >50%, respectively. Finally, the 50% PZT-OPC composite sample showed novel shielding and acceptable piezoelectric properties to be used as a smart shield. • PZT-OPC composite samples were prepared using a ball milling technique. • The XRD and FTIR results confirm the formation and the mutual interaction between both phases. • SEM images show a homogeneous dispersion for PZT particles in the cement matrices with the highest grain size for 50% PZT. • The shielding performance of the PZT-OPC composite samples is mainly dependent on their grain size properties. • Finally, the 50:50 PZT-OPC composite sample can be used as a multifunctional material for gamma ray shielding. [ABSTRACT FROM AUTHOR]

Abstract: Free volume measurements using positron annihilation lifetime spectroscopy was performed for uncrosslinked and crosslinked starch-grafted polyacrylamide, and their modified amino acid samples including some of their iron(III) complexes. The measurements were performed at room temperature. The analysis of lifetime spectra yielded mostly three lifetime components. It was observed that the values of the short lifetime component τ 1 are slightly higher than the lifetime associated with the self-decay of para-positronium atoms in polymers. The free volume was probed using ortho-positronium pick-off annihilation lifetime parameters. The mean free volume has also been calculated from the lifetime data. The avrage value of this parameter of the crosslinked polymer were found to be higher than those of the uncrosslinked polymer. [Copyright &y& Elsevier]

Abstract: Radionuclide concentrations of beach and dune sand from various sites in Al-Arish city and surrounding area, North Sinai, Egypt, were measured. The sampling sites included locations in the local harbor, Al-Arish valley and Zaranik protected area. The results indicate that the activities of the products of 232Th and 226Ra series in samples from the harbor and along the beach were higher than those from non-coastal sites. The activity concentrations of 232Th for beach sand ranged from 2.3 to 506.5Bq/kg with an average of 83.4Bq/kg, while that for dune sand ranged from 2.2 to 15.1Bq/kg with an average of 6.4Bq/kg. The average activity concentration of 226Ra for beach sand was 56.0Bq/kg (2.9–261.5Bq/kg), while that for dune sand was 6.5Bq/kg (3.0–14.7Bq/kg). The average activity concentrations of 40K for beach and dune sand were 88.1Bq/kg and 178.4Bq/kg, respectively. Six depth profiles in the harbor area were measured up to a depth of 1m within more than two years. These sets of measurements allowed the determination of the migration rate of black sand to be 0.094cm/day. Samples with the smallest grain size (&#60;0.2mm) were found to have the highest level of activities, which were attributed to their high content of black sand. No risk exists for public health based on the calculated effective dose equivalent and the recommended limit of 5mSv/y. On the other hand, local children and adults may receive doses higher than this recommended limit in two locations in the Zaranik protected area according to a model developed in this study. [Copyright &y& Elsevier]

• Quality of life is reduced in myasthenia gravis. • The role of exercise therapy to improve quality of life has not been explored. • This is the first prospective randomized controlled trial of home-based, unsupervised exercise therapy in MG. • Home-based exercise therapy was well-tolerated but did not improve quality of life. The tolerance of exercise and its effects on quality of life in myasthenia gravis are not currently backed up by strong evidence. The aim of this study was to determine whether exercise as an adjunct therapy is well tolerated and can improve health-related quality of life (HRQoL) in stabilized, generalized autoimmune myasthenia gravis (gMG). We conducted a parallel-group, multi-center prospective RCT using computer-generated block randomization. Adults with stabilized, gMG, and no contra-indication to exercise, were eligible. Participants received usual care alone or usual care and exercise. The exercise intervention consisted of 3-weekly 40 min sessions of an unsupervised, moderate-intensity home rowing program over 3 months. The primary endpoint was the change in HRQoL from randomization to post-intervention. Assessor-blinded secondary endpoints were exercise tolerance and effects on clinical, psychological and immunological status. Of 138 patients screened between October 2014 and July 2017, 45 were randomly assigned to exercise (n = 23) or usual care (n = 20). Although exercise was well tolerated, the intention-to-treat analysis revealed no evidence of improved HRQoL compared to usual care (MGQOL-15-F; mean adjusted between-groups difference of -0.8 points, 95%CI -5.4 to 3.7). Two patients hospitalized for MG exacerbation were from the usual care group. [ABSTRACT FROM AUTHOR]

Nanometer-sized PbZr x Ti 1- x O 3 powder was fabricated by the tartrate precursor method with different Zr contents, x = 0, 0.25, 0.52, and 0.75. All samples were annealed at 850 °C. These annealed samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and thermogravimetric analysis (TGA). The γ-ray attenuation coefficients of the annealed PbZr x Ti 1- x O 3 samples were measured as a function of the Zr content for 661.7 keV γ-rays from a137Cs source. Positron annihilation spectroscopy was used to study the microstructural changes of the prepared samples. The XRD patterns indicate the presence of a tetragonal perovskite structure with a main peak corresponding to the (101) plane at 2 θ of nearly 31°. The FTIR spectra show the presence of two absorption bands at around 620 and 390 cm−1, which are due to stretching and bending vibrations of the Ti–O bond, respectively. The nanometer-sized structure of synthesized PbZr x Ti 1- x O 3 particles was confirmed by XRD and TEM. The TGA curves show a high decomposition temperature of more than 800 °C for PbZr 0·52 Ti 0·48 O 3 and more than 650 °C for the other samples. PbZr 0.52 Ti 0.48 O 3 shows the highest γ-ray mass attenuation coefficient among the samples studied. The positron annihilation lifetimes show that the main defect types are Pb monovacancies and Pb–O divacancies, and the samples with x ≥ 0.52 have the lowest average defect density. PbZr 0.52 Ti 0.48 O 3 shows the highest value of the W parameter, which means that the chemical environment of its defects has more core electrons compared with the other samples. Finally, PbZr 0·52 Ti 0·48 O 3 has novel properties for γ-ray shielding. • Nanometer-sized PbZr x Ti 1- x O 3 powders were prepared by the tartrate precursor method for gamma-ray shielding. • The XRD and FTIR results confirm the formation of nanocrystalline PbZr x Ti 1- x O 3 with a single-phase perovskite structure. • TGA revealed high thermal stability for PbZr 0·52 Ti 0·48 O 3 , with the highest decomposition temperature of more than 800 °C. • The PAL spectra indicate the defect type in the samples corresponds to Pb monovacancy and Pb–O divacancy. • Nanometer-sized PbZr 0·52 Ti 0·48 O 3 can be used as a filler for radiation-shielding composite materials. [ABSTRACT FROM AUTHOR]

Background: Mismatch negativity (MMN) is the neurophysiological correlate of cognitive integration of novel stimuli. Although MMN is a well-established predictor of awakening in non-sedated comatose patients, its prognostic value in deeply sedated critically ill patients remains unknown. The aim of this prospective, observational pilot study was to investigate the prognostic value of MMN for subsequent awakening in deeply sedated critically ill patients.Methods: MMN was recorded in 43 deeply sedated critically ill patients on Day 3 of ICU admission using a classical 'odd-ball' paradigm that delivers rare deviant sounds in a train of frequent standard sounds. Individual visual analyses and a group level analysis of recordings were performed. MMN amplitudes were then analysed according to the neurological status (awake vs not awake) at Day 28.Results: Median (inter-quartile range) Richmond Assessment Sedation Scale (RASS) at the time of recording was -5 (range, from -5 to -4.5). Visual detection of MMN revealed a poor inter-rater agreement [kappa=0.17, 95% confidence interval (0.07-0.26)]. On Day 28, 30 (70%) patients had regained consciousness while 13 (30%) had not. Quantitative group level analysis revealed a significantly greater MMN amplitude for patients who awakened compared with those who had not [mean (standard deviation) = -0.65 (1.4) vs 0.08 (0.17) μV, respectively; P=0.003).Conclusions: MMN can be observed in deeply sedated critically ill patients and could help predict subsequent awakening. However, visual analysis alone is unreliable and should be systematically completed with individual level statistics. [ABSTRACT FROM AUTHOR]

Background: Transcranial direct-current stimulation (tDCS) applied over the primary motor cortex induces polarity-dependent changes in excitability: anodal tDCS enhances cortical excitability as assessed using transcranial magnetic stimulation (TMS), whereas cathodal tDCS has the opposite effect. Objective: In this randomized study, we assessed effects of anodal, cathodal, and sham tDCS on the diaphragmatic primary motor cortex. Methods: Twelve healthy right-handed men received anodal, cathodal, and sham tDCS applied to the left diaphragmatic motor cortex. Motor-evoked-potential (MEP) recruitment curves were obtained by recording the surface electromyogram at the right 8th intercostal space during TMS at intensities ranging from the resting motor threshold (MT) to 130% of MT. For each condition, MEPs were recorded before (Pre) tDCS then after 10min (Post1, at tDCS discontinuation in the anodal and cathodal sessions) and 20 (Post2) minutes. Results: Both anodal and cathodal tDCS significantly decreased MEP amplitude at the right hemidiaphragm at both Post1 and Post2, versus Pre. MEP amplitude was unchanged versus Pre during the sham condition. Conclusion: The effects of cathodal and anodal tDCS applied to the diaphragm motor cortex differ from those observed during tDCS of the limb motor cortex. This difference may be related either to the mechanisms involved in the effects of tDCS or to the diaphragm contractions during tDCS. [Copyright &y& Elsevier]