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Introduction: One of the secondary consequences of burnout is a significant reduction in cognitive functions, the most obvious and important of which is the cognitive function of attention and control, which can play a vital role in efficiency and prevention of errors at work in many occupations. On the other hand, a neurological examination is needed to understand better the relationship between burnout and its consequent depressive disorder regarding the cognitive function of the attention network of these individuals. Depressed people usually have neuropsychological disorders. Therefore, the present study aimed to investigate the cognitive performance of executive control of healthcare workers with shift jobs on the verge of burnout using the Attention Network Test (ANT) Event-Related Potential (ERP). Materials and Methods: The sample included 26 health care providers on the verge of burnout in Rasoul Akram Hospital in Tehran (15 without depression and 11 with mild to moderate depression) selected by purposive sampling. The rate of burnout was assessed by the Maslach Scales (1981); depression was evaluated by the Depression, Anxiety and Stress Scale-21 (DASS-21); attention was assessed by the Network Attention Test (ANT) and simultaneously with the behavioral test. We investigated the event-related potential (ERP) indicators of attention processing. Independent t-test and paired t-test were used for data analysis. Results: The results of behavioral performance revealed no significant difference between the two groups in the three attention networks; however, Significant differences can be seen in ERP brain waves related to the executive function of attention, especially by increasing the SP wave and N2 wave component compared to normal individuals without depression Conclusion: : Significant differences can be seen in ERP brain waves related to the executive function of attention, especially by increasing the SP wave and N2 wave component compared to normal individuals without depression. According to the study results, it can be stated that to improve cognitive performance in people's work environments, measures should be taken to reduce burnout and depression, and employees should perform their activities with better performance and help the quality growth of the work environment.

The paper shows the combined effects of couple stress fluids and lubricant viscosity variation with pressure in squeeze film performance of parallel triangular plates. By solving Reynolds equation and using perturbation method, the pressure distribution is obtained with consideration of viscosity variation with pressure. Also, with integrating pressure in the film region, load-carrying capacity is derived. A fourth-order Rang–Kutta is used to solve the nonlinear differential equation between lubricant film thickness and time. Various cases of couple stress, iso-viscous and piezo-viscous contributions are analyzed. According to the results, it is found that using couple stress fluid as a lubricant and considering viscosity–pressure dependency will increase characteristics of the squeeze film such as load-carrying capacity, pressure distribution, and triangular plates moving time, significantly as compared to the classical Newtonian iso-viscous lubricant.

Purpose The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by ferro-fluid couple stress lubricant. Design/methodology/approach Based upon the Stokes couple stress theory, ferro-hydrodynamic model of Shliomis and Christensen rough surfaces model, squeeze-film characteristics between two rough parallel circular discs considering rotational inertia effects are obtained. Findings According to the results, it is found that the combined effects of couple stresses and ferro-fluid lubricants increases squeeze film performance with respect to the classical Newtonian lubricant. However, increasing the rotational inertia parameter reduces squeeze film characteristics. On the other hand, depending on the structure of surface roughness, the squeeze film characteristics can be increased or decreased. Furthermore, results show that the surface roughness with circular pattern increases squeeze film characteristics, while the surface roughness with radial pattern will decrease it. Originality/value This paper is relatively original and describes the squeeze film characteristics between two parallel circular discs with ferro- fluid, rotational inertia, couple stresses and surface roughness effects.

Purpose The purpose of this paper is to investigate squeezing motion between conical plates lubricated by ferro-fluid couple stress lubricants considering convective fluid inertia effects. Design/methodology/approach Based upon the Stokes couple stress theory, Ferro-hydrodynamic model of Shliomis and averaged inertia principle, squeeze film characteristics between conical plates are obtained. Findings According to the results, it is found that couple stress ferro-fluid lubricants increase squeeze film characteristics. Moreover, with increasing convective fluid inertia parameter, the squeeze film characteristics are increased. In contrast, the dimensionless load-carrying capacity diminishes when half cone angle of conical plate increases. Originality/value This paper is relatively original and it describes the squeeze film characteristics between conical plates with ferro-fluid, convective inertia, couple stresses and half cone angle of conical plate effects.

Electromechanical nanothermometers are instruments that work on the basis of the van der Waals (vdW) potential energy and interaction force of their constituent carbon nanotubes (CNTs). The CNT-based nanothermometers have two di fferent con gurations: telescope and shuttle con gurations. In this article, based on the Lennard-Jones potential function together with the continuum approximation, fi rst, the vdW potential energy and interaction force for a telescope con guration with nite CNTs are derived, which have not been obtained in the previous research studies. Thereafter, by employing the interaction force, the equation of motion between constituent CNTs is solved. Subsequently, a new semi-analytical expression is obtained which enables one to precisely evaluate the oscillation frequency. By employing the given formulae, e ffects ofdi erent system parameters on the vdW interactions and oscillation frequency are shown.

The present study aims at investigating a couple stress ferrofluid lubricant effects on the performance of the squeezed film when a uniform external magnetic field is applied. For this purpose, Shliomis ferrohydrodynamic and couple stress fluid models are employed. The considered geometry is parallel triangular plates. The effects of couple stress, volume concentration, and Langevin parameters on squeeze film characteristics including time vs. height relationship and load-carrying capacity are investigated. According to the results, employing couple stress ferrofluid lubricant in the presence of the magnetic field leads to an increased performance of the squeeze film.

Random walk algorithms: Definitions, weaknesses, and learning automata based approach -- Intelligent Models of Random Walk -- Applications -- Conclusions.

Purpose – The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by piezo – viscous couple stress lubricant with pressure-dependent viscosity variation. Design/methodology/approach – Based upon the Stokes couple stress theory, Barus viscosity-pressure dependency relation and Christensen rough surfaces model, squeeze film characteristics between two rough parallel circular discs are obtained. Findings – According to the results, it is found that, the combined effects of couple stresses and viscosity-pressure dependency increases squeeze film performance with respect to the classical Newtonian iso-viscous (constant viscosity) lubricant. However, increasing the rotational inertia parameter reduces squeeze film characteristics. On the other hand, depending on the structure of surface roughness, the squeeze film characteristics can be increased or decreased. Furthermore, results show that the surface roughness with circular pattern increases squeeze film characteristics, while the surface roughness with radial pattern will decrease it. Originality/value – This paper is relatively original and describes the squeeze film characteristics between two parallel circular discs with viscosity-pressure dependency, rotational inertia, couple stresses and surface roughness effects.

CTCF is a highly conserved protein among eukaryotes and it is involved in many of regulatory functions including, transcriptional repression and activation, chromatin insulation, imprinting, X chromosome inactivation, higher-order chromatin organization, and alternative splicing. Studies performed on mouse embryos indicate that CTCF can be a maternal-effect gene, and is essential for normal development of embryos. CTCF can be used as a molecular effector for the proper epigenetic establishment of embryonic development. The aim of this study was to determine changes in transcript levels of the CTCF gene in bovine preimplantation embryos. RNA was extracted from immature and mature oocytes and embryos at various developmental stages (two-cell, four-cell, eight-cell, and blastocysts). Results showed that the amounts of CTCF transcripts decreased in mature oocyte in comparison with immature oocytes, but this change was not significant. In addition, the amount of CTCF transcript in embryos at two-cell, four-cell, eight-cell, and blastocyst stages significantly increased in comparison with immature oocytes. These data show that CTCF expression in bovine embryo begins at minor embryonic genome activation.

Contents Ecat1 is a maternal effect gene that is exclusively expressed in oocytes and embryonic stem cells, and has an important role in pre-implantation development. This study was designed to investigate the expression of bovine Ecat1 gene in immature and in vitro matured oocytes as well as during early embryonic development, and also Ecat1 protein localization. Samples were obtained from slaughtered animals. RNA extractions were carried out from ovary, immature and in vitro matured oocytes and also different stages of embryonic development (2-, 4-, 8- to 16-cell stages and blastocysts). RT-PCR analysis revealed the expression of Ecat1 in ovary, oocytes and embryos. Analysis in FGENESH online tool predicted three exons and one transcription start site (TSS) in Ecat1 gene, and the 3′ RACE-PCR result showed that just one splice variant was amplified. By quantitative real-time PCR technique, we showed that Ecat1 transcript increased at 8- to 16-cell-stage embryos and decreased in blastocyst stage (p

This article presents predictive analysis of load-carrying capacity, tractive efficiency and response time of parallel annular discs intervened with a film of lubricant under combined shear and squeeze film motions. This configuration represents operational characteristics of viscous coupling systems. In particular, the case of viscous dampers for tractive torque generation and distribution in all-wheel-drive off road vehicles is studied. Various forms of lubricant behaviour, from idealised Newtonian to that of non-Newtonian silicone-based fluids and incompressible isothermal electrically conducting couple stress fluids, subjected to a magneto-hydrodynamic field are studied. The solution for the magneto-hydrodynamics includes combined solution of modified Reynolds equation and Stoke’s micro-continuum for couple stress fluids in squeeze and shear with rotational fluid inertia, an approach not hitherto reported in the literature. It is shown that in general magneto-hydrodynamic couple stress fluids enhance the load-carrying capacity of the contact and inhibit the incidence of thin films, which can result in direct contact of surfaces. Rotational inertia decreases the load-carrying capacity, although in general the magneto-hydrodynamic fluids show better load-carrying capacity and tractive efficiency than the other alternatives. However, they exhibit a lower response time under the assumed isothermal condition. Nevertheless, the magneto-hydrodynamic fluids are best suited to applications in viscous coupling systems because of their controllability.

The paper presents analytical solution of squeeze film characteristics in wide parallel rectangular conjunctions with incompressible electrically conducting couple stress fluids subjected to a magnetic field. Analytical expressions are obtained by combined solution of modified Reynolds equation and Stokes micro-continuum for couple stress fluids with averaged inertia. Various cases of magneto-hydrodynamic, conducting and non-conducting fluid characteristics with and without convective inertial contributions are investigated. It is shown that, in general, couple stress fluids enhance the load carrying capacity of the contact and inhibit the incidence of thin films which can result in direct contact of surfaces. Convective inertia also significantly improves the load carrying capacity. However, with impulsive loading the response time of couple stress fluids deteriorates relative to Newtonian lubricants on account of their increased viscosity. An important conclusion of the study is that magneto-hydrodynamic couple stress fluids are best suited to applications with high relatively steady load applications. © IMechE 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions. nav.

Electromechanical carbon nanothermometers are devices that work based on the interactions and relative motions of double-walled carbon nanotubes (DWCNTs). In this paper, the mechanics of carbon nanotubes (CNTs) constituting two well-known configurations for nanothermometer, namely shuttle configuration and telescope configuration are fully investigated. Lennard-Jones (LJ) potential function along with the continuum approximation is employed to investigate van derWaals (vdW) interactions between the interacting entities. Accordingly, semi-analytical expressions in terms of single integrals are obtained for vdW interactions. Acceptance condition and suction energy are studied for the shuttle configuration. In addition, a universal potential energy is presented for the shuttle configuration consisting of two finite CNTs. Also, for the telescope configuration, extensive studies are performed on the distributions of potential energy and interaction force for various radii and lengths of CNTs. It is found that these geometrical parameters have a considerable effect on the potential energy.

Objective: Chitosan has been widely used in wound healing, including burn wounds. ChitoHeal gel, a novel chitosan-based gel, is studied to assess the effectiveness and rate of wound healing in second degree burns compared with traditional wound dressings. Method: New Zealand rabbits were divided into two groups, control and treatment. Second degree burn wounds were created using a hot round aluminium stamp. It was heated up to 80°C and applied 14 seconds without additional pressure. Morphological, histological, and molecular parameters were used to evaluate the effects of the chitosan-based gel on burn healing. Results: The study exhibited that in the control group with an increase in the number of keratinocytes due to the papillary growth of the epidermis, melanocyte pigmentation increased, and some melanin was observed in the dermis. In the treatment group, however, there was no hyper pigmentation nor overgrowth of the epidermis. Transmission electron microscopy micrographs of healed epidermis in treatment group showed melanocyte with normal morphology. Conclusion: The result of the present study is likely to be important for the development of novel strategies for wound healing using chitosan gel.

The aim of this study was to evaluate the effectiveness of different cryodevices (Open Pulled Straw (OPS), Electron Microscopy Grid (EMG) and cryotop for vitrification of immature bovine oocytes. Polar body, MII stage, survivability and subsequent developmental rates were compared. Only oocytes with 4-5 layers of cumulus cells were used. Oocytes were equilibrated in the first vitrification solution (VS1; HS+10% DMSO+10% Ethylene Glycol (EG)) for 30-45 sec and then in the second vitrification solution (VS2; 20% DMSO+20% EG+0.5 M Sucrose) for 25 sec. Within 30 sec they were mounted on one of the cryodevices and directly plunged into Liquid Nitrogen (LN2) for 10 days. Immature oocytes vitrified using cryotop represented higher rate of polar body extrusion and nuclear maturity (p

The solution of a Volterra type screw dislocation problem in an orthotropic rectangular plane with finite length and width and various boundary conditions is obtained by means of a separation of variables technique. A distributed dislocation method is employed to obtain integral equations of the plane with cracks and cavities under an anti-plane traction. The ensuing equations are of the Cauchy singular type and have been solved numerically. Several examples are presented to demonstrate the applicability of the proposed solution.

The effectiveness of different cryodevices (open-pulled straw (OPS), electron microscopy grid (EMG), and Cryotop was evaluated for vitrification of immature bovine oocytes. Polar body, metaphase II stage (MII), survivability, and subsequent developmental rates were determined. Only oocytes with four or five layers of cumulus cells were used. Oocytes were equilibrated in two vitrification solutions - 1: 10% DMSO + 10% ethylene glycol (EG) for 30-45sec and 2: 20% DMSO + 20% EG +0.5M sucrose for 25sec -, mounted on one of the cryodevices and directly plunged into liquid nitrogen for 10 days. Immature vitrified oocytes using Cryotop showed the highest rates of polar body extrusion (PB) and nuclear maturity (MII); 41 and 58% respectively. Vitrified oocytes using OPS and EMG showed 26 and 32%; and 35 and 46% of PB and MII rates, respectively. The highest survivability resulted from Cryotop and EMG groups and no significant difference was found between them. Vitrified oocytes using Cryotop had the highest cleavage and blastocyst rates. All of the mean rates for vitrified immature oocytes were significantly lower than that of control group (P

Beside cooling/warming rates and composition of vitrification solution, developmental stage of immature oocytes may also affect their vitrification outcome. The aim of the present study was to evaluate the selection effect of developmentally competent immature bovine oocytes by Brilliant Cresyl Blue (BCB) on maturity of oocytes after vitrification. Oocytes were obtained from slaughterhouse ovaries. Only oocytes with 4-5 layers of cumulus cells and homogenous cytoplasm were used. After exposure to BCB stain, immature oocytes were divided into colored (BCB+) and colorless (BCB-) cytoplasm groups. Immature oocytes were equilibrated in VS1 (7.5 Ethylene Glycol (EG)+7.5% DMSO) for 10-12 min and then exposed to VS2 (15% EG+ 15% DMSO+0.5M sucrose) for 1 min. Thereafter, oocytes were loaded on Cryotop and directly plunged into liquid nitrogen. After warming, oocytes were examined for presence of polar body and nuclear maturity. Higher number of oocytes in BCB+group extruded first polar body in comparison with other vitrified groups but not significantly (p>0.05). Compared to the BCB- oocytes, there was significantly lower percentage of degeneration for BCB+oocytes (p

Problem statement: Development of efficient culture system to support embryonic development would be valuable when quality of produced embryos was important. However, the rate of bovine embryo production in vitro was still lower than expected. Present study, incl uding of three experiments, was carried out to investigate the eff ect of insulin on nuclear maturation and subsequent development of immature bovine oocytes and in vitro fertilized embryos. Approach: Grade one cumulus-oocyte-complexes harvested from slaughterhouse ovaries were selected and randomly allocated in each treatment groups. In experiment 1 , in vitro maturation medium (Hepes-buffered medium 199 + fetal calf serum + gonadotrophins + antibiotics) supplemented with 0 (control), 1, 10, 20 and 100 µg mL -1 of insulin. In experiment 2, to eliminate the effe ct of serum and hormones, Hepes- buffered medium 199 was supplemented with 1 mg mL -1 polyvinyl alcohols (PVA) and same levels of insulin. In experiment 3, the effect of insulin on bovine in vitro embryo development was assessed. Presumptive zygotes were randomly cultured in synthetic oviductal fluid added with 0 (control), 1, 10, 20 and 100 µg mL -1 of insulin. Results: In experiment 1, nuclear maturation and embryo development rates were significantly higher in 1 and 10 µg mL -1 compared with other groups (P

Problem statement: Vitrification is replacing conventional slow freezing to cryopreserve gametes and embryos especially for in vitro production of embryo in domestic animal species. However, the results are still not satisfactory. The aim of this experiment was to study the effect of different equilibration temperatures on in vitro viability of immature bovine oocytes after vitrification. Approach: Oocytes were obtained from slaughterhouse ovaries. Only grade one oocytes were used. Oocytes were equilibrated in three different temperatures: 32, 37, or 41°C. Immature oocytes were equilibrated in VS1 (7.5 Ethylene Glycol (EG) + 7.5% DMSO) for 10-12 min and then exposed to VS2 (15% EG + 15%DMSO + 0.5M sucrose) for one min. Thereafter oocytes were loaded on hand-made Cryotop and directly plunged into liquid nitrogen. After warming, oocytes were examined for viability, maturation, cleavage and blastocyst production. Results: Oocytes that were equilibrated at 37°C had significantly higher (p

Background Psoriasis is a chronic inflammatory skin disease characterized by pathological skin lesions because of various exogenous and endogenous factors and associated with a number of biochemical and immunological disturbances. Objective The aim of the present study was to determine the level of adenosine deaminase activity, serum trypsin inhibitory capacity and total antioxidant capacity of plasma in psoriatic patients. Subjects and methods The study was performed in controls (n = 46) and in psoriatic patients (n = 40). The patients were scored with PASI (psoriasis area and severity index). The serum ADA activity was determined using Aguisti and Galanti method and serum trypsin inhibitory capacity (sTIC) were measured by enzymatic assay. Besides, serum total antioxidant capacity was measured using ferric reducing ability of plasma. Results The serum ADA activity of the psoriatic patients was found to be significantly higher (P

The present study analyzed the dose-dependent cyto- and genotoxicity of graphene oxide and reduced graphene oxide on spermatogonial stem cells (SSCs) for the first time. The results showed that graphene oxide significantly increased oxidative stress at concentrations of 100 and 400μg/ml, while low concentrations did not have a significant effect. In addition, according to the MTT assay, the cell number decreased in high-concentration (100 and 400μg/ml) graphene oxide-treated samples compared to untreated cells. However, a reduced graphene-treated sample demonstrated a significant increase in cell number. Moreover, microscopic analysis found high concentrations of graphene nanosheets in cell culture medium that reduced the number of colonies and colony forming cells. We conclude that a high concentration of graphene can be toxic to SSCs. However, such toxicity can be reduced by the surface modification of graphene nanomaterials.

This study presents combined effects of couple stress fluids and rotational inertia together with considering lubricant viscosity variation with pressure in squeeze film characteristics of parallel annular plates. Squeeze film characteristics are obtained by combined solution of modified Reynolds equation and Stoke's microcontinuum for couple stress fluids with consideration of viscosity variation with pressure. Various cases of couple stress, inertial, and noninertial characteristics with isoviscous and piezoviscous contributions are investigated. The pressure distribution and load-carrying capacity for lubricant film are obtained in a closed form, using a small perturbation method. Furthermore, numerical solution of the film height versus response time is calculated employing the fourth-order Runge–Kutta method. The result shows that the combined effects of couple stresses and viscosity–pressure dependency improve the load-carrying capacity and lengthen the response time, as compared to the classical Newtonian lubricant with constant viscosity. However, increasing rotational inertia parameter decreases squeeze film characteristics.

The porous calcium phosphate scaffolds with defined pore-channel interconnectivity were successfully prepared via negative replica method. The internal channel architecture was achieved using a water-insoluble polyurethane sponge. The PU sponge was first filled with aqueous slurry of biphasic calcium phosphate material containing pore forming agent. After drying at room temperature, a heat treatment was employed to remove all organic material. The bodies were finally sintered at the temperature of 1200°C. The phase composition and chemical structure of bodies were determined by X-ray diffraction (XRD) and FT-IR methods. Scanning electron microscopy (SEM) was used to study the pore size and distribution and pore-pore and pore-channel interconnectivity. The scaffold bodies were principally composed of HA and β-TCP with some traces of a-TCP. No residue of polymer replica or pore agent was remained. The scaffolds contained an interconnected pore-pore and pore-channel structure with a pore size less than 500 μm. The company of desired phase composition and pore-channel structure here increases the hope for the production of more effective biodegradable scaffolds for hard tissue engineering.

Summary The study describes the length–weight and length–length relationships for three cyprinid species, namely Barbus lacerta, Squalius lepidus and Pseudorasbora parva, and a balitorid species, Oxynoemacheilus angorae from the Sirwan River (located in Kurdistan and Kermanshah provinces, Iran. This study presents the first reference on LWR for most of the species in their distribution range.

Summary Length–weight and length–length relationships (LWR and LLR) and the gonadosomatic index (GSI) were estimated for smallhead hairtail (Eupleurogrammus muticus). A total of 441 fish were collected on a monthly basis from October 2011 to August 2012 using a bottom trawl net at depths of 5–30 m. The length-weight relationship did not differ significantly between males and females (P > 0.05). Data on the gonadosomatic index (GSI) revealed that spawning is principally from January to June.

Fourteen-year-old male patient was admitted to the emerency due to falling from the height and blunt abdominal trauma n December 2010. The patient had abdominal tenderness and istension. Abdominal sonography showed free fluid in the abdomnal cavity. The patient also had decreased hemoglobulin level Hg = 11 mg/dL). Abdominal exploration was done and a traumaized spleen (stage V) was identified. Splenectomy was done and ue to patient’s young age auto-transplantation of the splenic issue (3 cm × 3 cm × 1 cm pieces) in the omentum was perormed. The patient was discharged from the hospital 3 days ost operation. One year post operation, the patient was referred o the nuclear medicine department for evaluation of splenic uto-transplantation function. 99mTc-denatured (heat damaged)

This work has been undertaken to study the cell behavior of L929 fibroblasts on the laser irradiated polyethylene terephthalate (PET) surface. To modify the surface properties of the PET, CO2 pulsed laser at the wavelength of 9.25 microm and KrF excimer laser at 248 nm with various number of pulses were used. Laser irradiation caused some changes in the chemical and physical properties of the laser-treated film surfaces, which were evaluated using different techniques. These changes may affect the cell adhesion and growth on the laser-treated PET. Therefore, cell attachment and spreading were investigated on the laser-treated PET in vitro. The data from in vitro assays showed the fibroblast cells were attached and proliferated extensively on the CO2 and KrF laser-treated films in comparison with the unmodified PET. The results obtained from the cell behavior studies revealed that surface morphology and wettability affected cell adhesion and spreading on the laser-treated PET.

Based on previous studies for vitrification of oocytes, it has been shown that short term exposure to DMSO during vitrification could improve the maturation rate and cause not spontaneous parthenogenesis (Isachenko et al., 2006). In addition, it was reported that DMSO in freezing media caused disassembly of microfilaments and chromosomal abnormalities in mouse oocytes (Vincent et al., 1990). On the other hand, DMSO is categorized as a potent glass former and its existence in vitrification solution seems necessary. The aim of this study was to determine the in vitro viability of immature bovine oocytes vitrified by short or long time exposure to DMSO. Materials and Methods: Cumulus oocytes complexes (COCs) with homogenous ooplasm were recovered from slaughterhouse ovaries and used in this study. The vitrification protocol was adapted from Kuwayama et al (2005) with minor modifications. Briefly, oocytes were washed twice in holding solution (HS, Hepes-buffered TCM medium supplemented with 20% fetal calf serum, FCS) and kept there for about 15 min. Group of four COCs were incubated in the first vitrification solution (VS1; 7.5% DMSO and 7.5% EG in HS) for 12 min. Equilibration in VS1 was performed in three steps of increasing concentration. First (F) and second (S) steps contained 1/3 and 2/3 of VS1 diluted in HS, and the third (T) step contained only pure VS1. Based on removal of DMSO from each step, five treatment groups were designed: (G1) control, (G2) VS1, (G3) F w/o DMSO, (G4) F+S w/o DMSO, and (G5) F+S+T w/o DMSO. For G3, G4 and G5, similar concentration of EG was added to replace DMSO in VS1. All treatment groups were equilibrated into the second vitrification solution (VS2; 15% DMSO, 15% EG and 0.5M sucrose in HS) for a further 60 sec. Two experiments were performed: (a) cytotoxicity after only exposure, and (b) in vitro viability after vitrification processes. In cytotoxicity test, immature oocytes were directly transferred to the warming solution (WS). In vitrification experiment, oocytes were instantly loaded on a Cryotop device and submerged into liquid nitrogen (LN2) for storage. The time of exposure from VS2 to LN2 was not longer than 90 s. Vitrified samples were maintained in LN2 for at least 10 days. Immediately after removing the Cryotop from LN2, thin strip of Cryotop was submerged in 3 ml HS plus 1M sucrose (WS; 39°C) and smoothly tried to detach oocytes from Cryotop device. Immature oocytes were left in WS for one minute and then transferred to HS plus 0.5M and 0.15M sucrose solution for 3 and 5 min, respectively. Finally, the immature oocytes were washed twice in HS for 5 min each and processed for in vitro maturation. Significant differences among treatments used in the experiment were revealed by one-way analysis of variance and followed by Duncan's multiple range test for mean comparisons (P < 0.05) using SAS software (ver. 9.1).

The temporal pattern of expression of genes for several growth factor ligands and receptors was examined in preimplantation water buffalo embryos and oviduct epithelial cells using RT-PCR. The identity of the resulting PCR products was confirmed by their expected size, restriction analysis, Southern blot hybridization and nucleotide sequence analysis. Preimplantation stage embryos from the one-cell to the blastocyst stage were derived after maturation, fertilization and culture of oocytes in vitro. Expression of members of the insulin-like growth factor (IGF) family was observed predominantly in preimplantation stage embryos and oviduct epithelial cells. Similarly, transcripts encoding insulin and IGF-I receptors were detected at each stage of embryonic development. The mRNA transcript of the IGF-I receptor was not detected in oviduct epithelial cells, but a prominent band corresponding to the insulin receptor was observed. Insulin and IGF-II mRNA were expressed as maternal transcripts that were not detected at the two- to four-cell stage but were present as zygotic transcripts at the eight-cell stage. Transcripts encoding IGF-I were detected in oviduct epithelial cells, but were not observed in any of the preimplantation stage embryos. Transforming growth factor (TGF) alpha and beta and epidermal growth factor mRNA transcripts were not detected in any of the preimplantation stage embryos. These results indicate that IGF-I acts via a paracrine mechanism to promote growth and development of preimplantation water buffalo embryos. Similarly, IGF-II appears to act through a heterologous autocrine mechanism via the IGF-I or the insulin receptor. Furthermore, the presence of TGF-alpha in oviduct epithelial cells indicates that it may have a critical role during development.