Effects of reservoir mechanical properties on induced seismicity during subsurface hydrogen storage.

The intermittent storage of hydrogen in subsurface porous media such as depleted gas fields could be pivotal to a successful energy transition. Numerical simulations investigate the intermittent storage of hydrogen in a porous, depleted subsurface reservoir. Various parametric studies are performed to assess the effect of mechanical properties of the reservoir (i.e. Young's modulus, Poisson's ratio, Biot coefficient and permeability) on the induced fault slip of a single through-going fault that transverses the entire reservoir. Simulations are run using a three-dimensional, finite element, fully coupled hydromechanical code with explicit representations of layers and faults. The effect of the domain mesh refinement and fault mesh refinement on the fault slip versus operation time solution is investigated. The fault is observed to slip in two distinct events, one during the second injection period and one in the third injection period. The fault is not observed to slip during the storage or withdrawal periods. It is found that in order to minimize seismic risk, a reservoir rock with high Young's modulus (>40 GPa), high Poisson's ratio (>0.30) and high Biot coefficient (>0.65) would be preferable for hydrogen storage. Reservoir rocks of low Young's modulus (10-30 GPa), intermediate Poisson's ratio (0.00-0.30) and low-to-intermediate Biot coefficient (0.25-0.65), at high injection rates, were found to have higher potential of inducing large seismic events.This article is part of the theme issue 'Induced seismicity in coupled subsurface systems'.

The relation of serum prolactin levels and Toxoplasma infection in humans.

BACKGROUND: Toxoplasma gondii is an intracellular protozoan parasite distributed worldwide. Although the infection is benign in immunocompetent individuals, it is life threatening and complicated in immunocompromised patients and fetuses of pregnant women who received their first exposure to T. gondii during the pregnancy. Prolactin (PRL) is a hormone that is secreted by the pituitary gland, and it is confirmed that it plays a role in the immune system. The present study was carried out to assess the possible relation between serum PRL levels and Toxoplasma infection frequency in human. METHODS: In this cross-sectional study, 343 serum samples (240 from women and 103 from men) were collected from individuals who were referred for PRL checking in laboratories of Karaj, Iran. Blood samples were collected, and sera were separated and analyzed for the detection of anti-Toxoplasma IgG antibody by ELISA method. The levels of PRL were measured by Roche Elecsys 2010 analyzer, electrochemiluminescence technology. RESULTS: Of 343 sera, 110 samples (32%) consisting of samples from 42 men and 68 women had anti-T. gondii IgG antibody. The prevalence of T. gondii infection in women with high PRL levels was lower than that in the comparison group with normal levels of PRL and the relationship between these two parameters was statistically significant (P=0.016). In women with hyperprolactinemia, by increasing of PRL levels, the prevalence of T. gondii infection was reduced. CONCLUSION: The results of the current study confirmed the previous studies based on immunoregulatory role of PRL and indicated that high levels of PRL could be related to Toxoplasma seronegativity in women.

100-fold improvement in carrier drift mobilities in alkanephosphonate-passivated monocrystalline TiO2 nanowire arrays.

Single crystal rutile titania nanowires grown by solvothermal synthesis are actively being researched for use as electron transporting scaffolds in perovskite solar cells, in low detection limit ultraviolet photodetectors, in photoelectrochemical water-splitting, and in chemiresistive and electrochemical sensing. The electron drift mobility (µ n ) in solution-grown TiO2 nanowires is very low due to a high density of deep traps, and reduces performance in optoelectronic devices. In this study, the effects of molecular passivation of the nanowire surface by octadecylphosphonic acid (ODPA), on carrier transport in TiO2 nanowire ensembles, were investigated using transient space charge limited current measurements. Infrared spectroscopy indicated the formation of a highly ordered phosphonate monolayer with a high likelihood of bidentate binding of ODPA to the rutile surface. We report the hole drift mobility (µ p ) for the first time in unpassivated solvothermal rutile nanowires to be 8.2 × 10-5 cm2 V-1 s-1 and the use of ODPA passivation resulted in µ p improving by nearly two orders of magnitude to 7.1 × 10-3 cm2 V-1 s-1. Likewise, ODPA passivation produced between a 2 and 3 order of magnitude improvement in µ n from ∼10-5-10-6 cm2 V-1 s-1 to ∼10-3 cm2 V-1 s-1. The bias dependence of the post-transit photocurrent decays in ODPA-passivated nanowires indicated that minority carriers were lost to trapping and/or monomolecular recombination for small values of bias (<5 V). Bimolecular recombination was indicated to be the dominant recombination mechanism at higher bias values.

Optimization of Energy Consumption and Mass Transfer Parameters in a Surface Aeration Vessel.

This paper reports tests on a lab-scale surface aeration vessel was equipped with a Rushton turbine to examine its performance in terms of standard aeration efficiency (SAE), mixing time, and void fraction characteristics. These characteristics were investigated by tests using variations of rotor speed, impeller immersion depth, and water level. Results showed that variation of impeller immersion depth had a greater effect on the SAE compared to variation of water level. Moreover, the SAE increased with rotor speeds up to about 150 to 200 rpm and then decreased. In addition, void fraction improved by impeller immersion depth and rotor speed enhancement; however, mixing time and power number were reduced as rotor speed increased. According to the response surface methodology statistical optimizations, optimum values for rotor speed, impeller immersion depth, and water level were 168.90 rpm, 25 mm, and 30 cm, respectively, to achieve the maximum value of SAE.

Harderian gland in Canadian ostrich (Struthio camelus): a morphological and histochemical study.

Heads of ten healthy adult ostrich obtained from slaughter house were the constituted materials of the study. The Harderian gland (HG) was dissected out, and all of the gross morphometrical parameters including length, width and thickness as well as weight of left and right glands were recorded. Tissue sections were stained, using haematoxylin and eosin, Masson trichrome, periodic acid-Schiff and Alcian blue (pH 2.5) techniques. In ostrich, HG was an orbital organ located ventromedially around the posterior part of the eyeball. It was an oval flatted shape, light pink colour with irregular outline and was pointed in the dorsal end. Its mean length was 35.30 ± 2.84 mm and 35.55 ± 3.58 mm in left and right sides, respectively, and mean width 15.30 ± 1.20 mm and 15.65 ± 1.18 mm in left and right sides, respectively. There was no significant difference between length, thickness, weight and width of left and right glands. Histological results showed that the glandular epithelium was multilobular and compound tubuloalveolar. The gland was surrounded by a connective tissue capsule, and the epithelium was lined by simple columnar epithelial cells of varying height. The secretion of HG was mucous and the secretion type was apocrine. Mucosubstance analysis revealed that secretory units contained acidic and neutral glycoproteins. The granules within the epithelial cells lining the intralobular and inter-lobular excretory ducts of the gland were positive for periodic acid-Schiff and Alcian blue (pH 2.5).

Limited sampling strategy for estimation of amikacin optimal sampling time in critically ill adults.

Aminoglycosides are a class of antibiotics that are commonly used in the treatment of gram-negative pathogens in the critically ill population. Unfortunately, dosing of these aminoglycosides in critically ill patients is difficult due to their altered pharmacokinetics in the critically ill and narrow therapeutic index. In this study, we evaluated whether a limited sampling strategy can be used to predict the area under the concentration (AUC) curve of amikacin concentrations over a 24-hour period after a single dose of intravenous amikacin (25 mg/kg). This open-labelled, non-comparative prospective study recruited 20 adult critically ill trauma patients with a diagnosis of hospital-acquired infection. We assessed the best estimate of plasma amikacin concentrations over a 24-hour period by multiple stepwise regression, using nine blood samples during this study period as the gold standard. Using a jackknife procedure, the AUC of amikacin over a 24-hour period was estimated by choosing a combination of the amikacin concentrations measured at different time-points. Overall, the mean prediction error of all models was not statistically different from zero (P >0.05). Based on bias and imprecision, all models gave good estimate of AUC of amikacin over a 24-hour period, but a two-point sampling strategy at 1.5 and 6 hours post-dose appeared to offer the best compromise between accuracy and cost-effectiveness in optimising the dosing of amikacin in critically ill patients.

Influence of sepsis on higher daily dose of amikacin pharmacokinetics in critically ill patients.

BACKGROUND AND OBJECTIVES: Severe sepsis is a major problem as cause of high rates morbidity and mortality in intensive care units (ICU). Aminoglycosides are an important group of antimicrobials used for severe sepsis. However, aminoglycoside pharmacokinetics in ICU patients may be altered during sepsis, which can affect the drug concentrations. Therefore, this study was undertaken to examine the relationship between amikacin disposition kinetics after a 25 mg/kg loading dose and hemodynamic response to sepsis, as well as clinical parameters, in a population of critically ill patients. METHODS: In this work, 30 patients who were candidate to amikacin therapy following Gram negative sepsis were enrolled. The pharmacokinetic profile of amikacin by a non-compartmental model was calculated for each patient. RESULTS: Mean volume of distribution was 0.36 ± 0.07 L/kg and mean serum amikacin clearance was 3.88 ± 0.97 ml/min/kg. In the case of Vd, APACHE II score correlation was significant. In the case of amikacin clearance, two covariates including creatinine clearance and Sr Cr significant correlation was found. CONCLUSIONS: It appears necessary to use higher amikacin dosage (≥ 25 mg/kg) considering hemodynamic response of patients to sepsis. To achieve therapeutic drug concentration a close drug monitoring and a shift from the population mean toward a value more representative of the critically ill patient subpopulation is crucial.  

Psychiatric nursing as 'different' care: experience of Iranian mental health nurses in inpatient psychiatric wards.

Patients with mental illness require unique and specific care. The purpose of this study was to explore the experiences of nurses, who provide such care for mentally ill people, within the context of Iranian culture. This hermeneutic phenomenological study was carried out in a university-affiliated hospital in an urban area of Iran. We interviewed 10 mental health nurses to capture in detail their experiences in psychiatric units, and the approach developed by Diekelmann et al. was employed to analyse the data. Four themes and five sub-themes were identified: 'being engaged with patients' (sub-themes: 'struggle for monitor/control', 'safety/security concerns', 'supporting physiological and emotional needs'), 'being competent', 'altruistic care' and 'facing difficulties and challenges' (sub-themes: 'socio-cultural' and 'organizational challenges'). The results provide valuable insights and greater understanding of the professional experiences of psychiatric nurses in Iran, and indicate the need for a stable and responsible organizational structure for those nurses who are expected to manage patient care in psychiatric wards.

Frequency and severity of obsessive-compulsive symptoms/disorders, violence and suicidal in schizophrenic patients.

BACKGROUND: This study determined the prevalence and severity of obsessive-compulsive symptoms/disorder (OCS/OCD), aggression and suicidal in schizophrenic patients. Also we compared the prevalence and severity of aggression and suicidal in schizophrenic patients with and without OCS/OCD considering anxiety, depression and substance abuse as confounding factors. METHODS: During 2007 and 2008, 100 schizophrenic patients were evaluated with Yale-Brown Obsessive Compulsive Scale, Positive and Negative Syndrome Scale, Beck Depression Inventory, Spilberger State/Trait Anxiety Inventory, Beck Scale for suicide Ideation, and Overt Aggression Scale. RESULTS: OCS/OCD and suicidal attempts were seen in 33%, 10% and 12% of patients respectively. The most common form of aggression was against others (55%), and aggressive obsessions were seen in 10% of the patients. Comparing patients with and without OCS/OCD, there were no significant differences in the severity of schizophrenia, suicidal and overt aggression. The severity of overt aggression was related to the patients' age and education reversely. Also, there was a relationship between their suicidal thoughts and residence in the cities. CONCLUSIONS: High rate of aggressive obsessions and lack of relationship between severity of aggression and presence of OCD indicated that these patients did not act on these thoughts. The risk of suicide was more serious in patients living in the cities, and risk of violence was more serious in younger and less educated patients.

Evaluation of effect of silymarin on granulosa cell apoptosis and follicular development in patients undergoing in vitro fertilization.

To investigate the effects of silymarin on follicular development, we enrolled 40 healthy women undergoingin vitro fertilization (IVF) due to male factor infertility in this trial. They underwent ovulation induction and on a random and blind basis, patients were assigned to receive silymarin (70 mg x 3/day) or placebo from the beginning of the induction cycle. The number and quality of oocytes retrieved were evaluated and apoptosis of > or = granolusa cells was studied. There was no significant difference between the groups for mean number of follicles 18 mm (P = 0.131), mean number of oocytes retrieved (P = 0.209) or endometrial thickness (P = 0.673). However, the proportion of total apoptosis in the study group was significantly lower than in the placebo group (P = 0.032). These data suggest that administration of silymarin in IVF patients concomitantly with gonadotropin results in reduction of granolusa cell apoptosis but does not have any effect in promotion of follicular development, oocyte retrieval or endometrial thickness.

Evaluation of effect of silymarin on granulosa cell apoptosis and follicular development in patients undergoing in vitro fertilization

To investigate the effects of silymarin on follicular development, we enrolled 40 healthy women undergoing in vitro fertilization [IVF] due to male factor infertility in this trial. They underwent ovulation induction and on a random and blind basis, patients were assigned to receive silymarin [70 mg X 3/day] or placebo from the beginning of the induction cycle. The number and quality of oocytes retrieved were evaluated and apoptosis of granolusa cells was studied. There was no significant difference between the groups for mean number of follicles >/= 18 mm [P = 0.131], mean number of oocytes retrieved [P = 0.209] or endometrial thickness [P = 0.673]. However, the proportion of total apoptosis in the study group was significantly lower than in the placebo group [P = 0.032]. These data suggest that administration of silymarin in IVF patients concomitantly with gonadotropin results in reduction of granolusa cell apoptosis but does not have any effect in promotion of follicular development, oocyte retrieval or endometrial thickness

Estimation of abbreviated mycophenolic acid area under the concentration-time curve during early posttransplant period by limited sampling strategy.

Area under the concentration curve (AUC) of mycophenolic acid (MPA) could help to optimize therapeutic drug monitoring during the early post-renal transplant period. The aim of this study was to develop a limited sampling strategy to estimate an abbreviated MPA AUC within the first month after renal transplantation. In this study we selected 19 patients in the early posttransplant period with normal renal graft function (glomerular filtration rate > 70 mL/min). Plasma MPA concentrations were measured using reverse-phase high-performance liquid chromatography. MPA AUC(0-12h) was calculated using the linear trapezoidal rule. Multiple stepwise regression analysis was used to determine the minimal and convenient time points of MPA levels that could be used to derive model equations best fitted to MPA AUC(0-12h). The regression equation for AUC estimation that gave the best performance was AUC = 14.46 C(10) + 15.547 (r(2) = .882). The validation of the method was performed using the jackknife method. Mean prediction error of this model was not different from zero (P > .05) and had a high root mean square prediction error (8.06). In conclusion, this limited sampling strategy provided an effective approach for therapeutic drug monitoring during the early posttransplant period.

Comparative histomorphological study of ovary and ovarian follicles in Iranian Lori-Bakhtiari sheep and native goat.

In this project, for measuring and comparing dimensions of ovary and ovarian follicles between Lori-Bakthiari sheep and native goat, eighty ovaries of sheep and goat, aged 1-2 years, from Shahrekord abattoir were collected. After weighing the ovaries, some factors such as: length, width and thickness of left and right ovaries by caliper device were measured. For histological studies, after tissue preparation and staining with H and E, diameter of follicles, thickness of follicular layers (granulosa, theca interna and theca externa) by micrometry methods were measured. By analyzing data with t-test and comparing them between sheep and goat we concluded that, there were significant difference between weight and dimensions of ovaries in sheep and goat. These parameters in goats were larger than sheep. Microscopical studies revealed that, the mean thickness of theca externa of graafian follicle in left ovary of sheep was more than right. The mean diameter of oocyte in secondary follicle of goat in left ovary was more than right. Also in goat, the number of layers of cumulus oophorus around corona radiata was more than sheep.

Comparative histomorphological study of uterus between laying hen and duck.

The present investigation was carried out on oviductal duck and laying hen to comparing of histomorphological structures of them. For this purpose, a total of forty adult healthy ducks and hens (each of them twenty), aged 1-1.5 years, were used. After dissecting them, some morphological parameters such as: total weight and length of oviduct were measured and then in each of specimen some morphological parameters such as; length, width and thickness of uterus were measured. For histological studies, after tissue preparation and staining with H and E, histological layers of uterus were recognized and the size of them with micrometry method were determined. By using t-test and analyzing factors between duck and hen we concluded that total weight and length of oviduct in hen was greater than duck and the difference was significant (p < 0.05). By comparing of dimensions and weight of uterus between duck and hen revealed that, in hen the mean of uteral weight (14.98 +/- 2.58 g) and uteral width (5.00 +/- 0.91 cm) were greater than duck. It was observed in duck (9.27 +/- 2.04 g) and (3.19 +/- 0.58 cm), respectively. In histometrical studies, the length of tunica mucosa, primary fold and muscularis mucosa width in duck were greater than hen. There was a significant difference in length of secondary fold and in hen (164.47 +/- 34.16 microm) was greater than duck (119.80 +/- 27.89 microm).

Adverse effects of cadmium on bull spermatozoa.

Cadmium (Cd) is a widespread environmental pollutant. Because of its long biological half-life (10-30 years in humans), Cd accumulates in the biological systems such as gonads. The present study was designed to evaluate the effect of Cd in the concentration range 50-750 micromol/L, in vitro, on the membrane integrity, motility and acrosomal status of bull spermatozoa. The samples were processed for sperm analyses using semen-diluting fluid (phosphate-buffered saline, pH 7.2). A significant elevation in the malondialdehyde level/lipid peroxidation (LPO) rate and a decrease in the spermatocrit values, particularly at a concentration of 750 micromol/L Cd, indicated the deleterious effect of Cd on sperm membrane integrity. There was also a negative correlation between LPO rate and percentage of motile spermatozoa (r = 0.992). The gelatin test indicates that Cd may alter the integrity of acrosomal membranes and shows an abnormal acrosome reaction. In this regard, a strong negative correlation was found between LPO rate and % halos (bright clear zone around sperm heads after gelatin digestion) (r = 0.990). Taking the results together, Cd proved to be a potential toxicant in the category of environmental factors that induce membrane impairment, lower motility, and decrease the rate of acrosome reactions, leading to male infertility. Apparently, the presence of Cd in the environment and seminal plasma exerts a toxic effect on sperm cells.