18,723 research outputs found

    The essence of fertilization: oocyte meets sperm

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    The problem of reduced fertility in high yielding dairy cattle is a very complicated one, and the relationship between various measures of fertility and level of milk production remains controversial. In this brief review the essence of the problem is considered: what is the oocyte's and the sperm's contribution, and what is the importance of the resulting embryo in the declining fertility of the Holstein Friesian cow

    Chemopreventive and renal protective effects for docosahexaenoic acid (DHA): implications of CRP and lipid peroxides

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    <p>Abstract</p> <p>Background</p> <p>The fish oil-derived ω-3 fatty acids, like docosahexanoic (DHA), claim a plethora of health benefits. We currently evaluated the antitumor effects of DHA, alone or in combination with cisplatin (CP) in the EAC solid tumor mice model, and monitored concomitant changes in serum levels of C-reactive protein (CRP), lipid peroxidation (measured as malondialdehyde; MDA) and leukocytic count (LC). Further, we verified the capacity of DHA to ameliorate the lethal, CP-induced nephrotoxicity in rats and the molecular mechanisms involved therein.</p> <p>Results</p> <p>EAC-bearing mice exhibited markedly elevated LC (2-fold), CRP (11-fold) and MDA levels (2.7-fold). DHA (125, 250 mg/kg) elicited significant, dose-dependent reductions in tumor size (38%, 79%; respectively), as well as in LC, CRP and MDA levels. These effects for CP were appreciably lower than those of DHA (250 mg/kg). Interestingly, DHA (125 mg/kg) markedly enhanced the chemopreventive effects of CP and boosted its ability to reduce serum CRP and MDA levels. Correlation studies revealed a high degree of positive association between tumor growth and each of CRP (r = 0.85) and leukocytosis (r = 0.89), thus attesting to a diagnostic/prognostic role for CRP.</p> <p>On the other hand, a single CP dose (10 mg/kg) induced nephrotoxicity in rats that was evidenced by proteinuria, deterioration of glomerular filtration rate (GFR, -4-fold), a rise in serum creatinine/urea levels (2–5-fold) after 4 days, and globally-induced animal fatalities after 7 days. Kidney-homogenates from CP-treated rats displayed significantly elevated MDA- and TNF-α-, but reduced GSH-, levels. Rats treated with DHA (250 mg/kg, but not 125 mg/kg) survived the lethal effects of CP, and showed a significant recovery of GFR; while their homogenates had markedly-reduced MDA- and TNF-α-, but -increased GSH-levels. Significant association was detected between creatinine level and those of MDA (r = 0.81), TNF-α ) r = 0.92) and GSH (r = -0.82); implying causal relationships.</p> <p>Conclusion</p> <p>DHA elicited prominent chemopreventive effects on its own, and appreciably augmented those of CP as well. The extent of tumor progression in various mouse groups was highly reflected by CRP levels (thus implying a diagnostic/prognostic role for CRP). Further, this study is the first to reveal that DHA can obliterate the lethal CP-induced nephrotoxicity and renal tissue injury. At the molecular level, DHA appears to act by reducing leukocytosis, systemic inflammation, and oxidative stress.</p

    Perceived barriers to organizational creativity

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    PurposeThe overall purpose of this research is to further the understanding of how future marketing managers in Egypt and the UK perceive creativity barriers. The paper also examines the construct validity of the barriers to creativity scale in an Arab non‐Western context.Design/methodology/approachA sample of 125 respondents was used to achieve the research purpose. Respondents completed a 17‐item instrument designed to assess barriers to creativity in business organizations.FindingsDiscriminant analysis results showed that Egyptians differ from British with respect to their attitudes towards organizational creativity barriers. t‐test procedure confirmed also that gender and age have significant effects on the attitudes towards creativity barriers.Originality/valueThis study has provided some insights into the factors associated with organizational creativity barriers in Egypt and the UK. The more is known of how future managers perceive creativity barriers, the more quickly and efficiently creativity can be stimulated.</jats:sec

    A study of retrograde degeneration of median nerve forearm segment in carpal tunnel syndrome of variable severities

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    Introduction: Carpal tunnel syndrome (CTS) is a disorder of the hand which results from compression of the median nerve within its fibro-osseous tunnel at the wrist. The slowing in the forearm motor conduction velocity suggests the presence of retrograde degeneration. Existing studies conflict regarding a correlation between the severities of the entrapment neuropathy in CTS and slowing of median motor nerve conduction velocity in the forearm.Aims: The objective of this work was to study retrograde degeneration (RGD) of the median nerve forearm segment in patients with CTS and its relation to variable severity of CTS in Egyptian patients.Patients and methods: Twenty-four patients with CTS were included in this study. The Forearm mixed nerve conduction is presumed to be indicative of the conduction of the median nerve over the forearm and is used widely to assess the causes of slowing forearm conduction velocity in CTS. In addition to conventional nerve conduction studies of the upper limb, forearm median mixed conduction studies were performed. Median motor forearm amplitudes and nerve conduction velocities (NCVs) as well as forearm median mixed amplitudes and NCVs were considered as parameters of RGD. Results: There were statistically significant differences as regards forearm mixed nerve action potential (MNAP) amplitude and median motor amplitude in the forearm segment but there were no statistically significant differences as regards forearm median mixed peak latency and NCV. There was no statistically significant relation between grades of severities of CTS in the studied hands and both forearm median motor NCV and forearm MNAP amplitude using Monte Carlo test (MCp = 0.323 and 0.464).Conclusions: Retrograde degeneration exists in patients with CTS. Forearm median motor NCV and median mixed conduction study are valid electrophysiologic tools for the assessment of RGD in patients with CTS. Retrograde degeneration is not related to grade of severity of CTS.KEYWORDS Carpal tunnel syndrome; Electrodiagnosis; Forearm median mixed study; Retrograde degeneratio

    High scrotal approach for secondary orchidopexy in cases of recurrent and iatrogenic undescended testes

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    Background/purpose Secondary orchidopexy is often difficult due to altered anatomy and dense scarring following previous operation. The aim of this study was to assess the feasibility and results of secondary transcrotal orchidopexy for the palpable recurrent and iatrogenic undescended testes.Patients and methods The case records of all children who underwent secondary orchidopexy through high scrotal incision during the study period May 2004 to April 2009 were retrospectively reviewed.Results Redo orchiopexy using the high scrotal approach was used to treat 41 testes during a 4-year period. Eight of these cases occurred after an inguinal hernia repair and 33 cases occurred after a previous orchiopexy. At follow-up, 39 of the 41 orchidopexies (95.2%) testes were found viable. Two testes (4.8%) were recorded to have atrophied.Conclusion This study shows that secondary orchidopexy through a high scrotal incision is a safe, effective, and applicable technique for recurrent and iatrogenic undescended testes.Keywords: high scrotal approach, redo orchidopexy, undescended testi

    Temperature effects on the electrical performance of large area multicrystalline silicon solar cells using the current shunt measuring technique

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    The temperature effects on the electrical performance of a large area multicrystalline silicon solar cell with back-contact technology have been studied in a desert area under ambient conditions using the current shunt measuring technique. Therefore, most of the problems encountered with traditional measuring techniques are avoided. The temperature dependency of the current shunt from 5ÂșC up to 50ÂșC has been investigated. Its temperature coefficient proves to be negligible which means that the temperature dependency of the solar cell is completely independent of the current shunt. The solar module installed in a tilted position at the optimum angle of the location, has been tested in two different seasons (winter and summer). The obtained solar cell short circuit current, open circuit voltage and output power are correlated with the measured incident radiation in both seasons and all results are discussed

    An improved design of a fully automated multiple output micropotentiometer

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    This paper describes in details a new design of a fully automated multiple output micropotentiometer (?pot). A prototype has been built at the National Institute for Standards (NIS), Egypt to establish this highly improved AC voltage source in the millivolt range. The new device offers three different outputs covering a wide frequency range from only one outlet. This valuably supports the precise sourcing ranges of low AC voltage at NIS. The design and the operation theory of this prototype have been discussed in details. An automatic calibration technique has been introduced through specially designed software using the LabVIEW program to enhance the calibration technique and to reduce the uncertainty contributions. Relative small AC-DC differences of our prototype in the three output ranges are fairly verified. The expanded uncertainties of the calibration results for the three output ranges have been faithfully estimated. However, further work is needed to achieve the optimum performance of this new device

    Synthesis and Cytotoxicity Screening of Some Novel Benzofuranoyl-pyrazole Derivatives against Liver and Cervix Carcinoma Cell Lines

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    A series of new pyrazole, thiazole and thiazolinone derivatives incorporated into benzofuran were synthesized by using 3-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-4-carboxaldehyde as starting material. A total of 41 novel compounds were synthesized. Some of these synthesized compounds were evaluated for cytotoxicity activity against HEPG2 (liver carcinoma cell line) and HELA (cervix carcinoma cell line). The tested compounds (1, 2c, 7c, 8b, 9b, 13b and 14b) showed better activities at low concentration against the commonly used human carcinoma cell lines. A detailed synthesis, spectroscopic data and cytotoxicity screening for the new compounds are described.Keywords: Pyrazole, thiazolinone, benzofuran, benzofuranoyl-pyrazoles, cytotoxic screening, HEPG2, HELAPDF and Supplementry file attache
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