191 research outputs found

    An Analysis of Internal Gravity Wave Tunnelling in a Stratified Region Along with Rotation

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    The internal gravity wave tunnelling in presence of earths rotation is studied for different density barriers. An exponential approximation used reveals the existence of evanescence in the barrier region which signifies the trapping of wave energy in the tunnelling region. The Transmission coefficients are computed for different density barriers and the comparative study shows that across the locally mixed region the transmission is enhanced. The asymptotic analysis of the transmission co-efficient using the rotational parameter reveals the convergence and the graphs shows that the transmission decreases continuously and leads to the non-rotating case. The results are compared with the non-rotations case and we observe that the evanescence caused by the rotation makes the waves travel more along the horizontal direction than in the vertical direction

    Developing an Online/Onsite Community of Practice to Support K-8 Teachers’ Improvement in Nature of Science Conceptions

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    Publisher's, offprint versionResearch shows that teachers do not have adequate conceptions of science as inquiry and must be exposed to both content and pedagogical demands of inquiry to effectively teach using inquiry (Anderson, 2002). These results are especially unfortunate for the teacher and the learner because understanding of science as inquiry is reciprocally related to understanding important aspects of the nature of science (NOS) (Akerson, et al., 2008). This problem is coupled with the need to teach NOS and inquiry throughout all elementary grades (NSTA, 2000). Most elementary teacher preparation programs do not include specific courses on NOS or inquiry, and what teachers learn is usually embedded in a science methods course (Backus & Thompson, 2006). Certainly teachers can conceptualize and teach NOS once they understand it, are convinced of its importance, and have strategies to teach it to their own students. Professional development programs can help teachers attain these goals. We have found communities of practice (CoP) (Wenger, 1998) especially useful when working with inservice teachers in terms of helping them conceptualize and to teach NOS when used in an on-site professional development program (Akerson et al, 2009; Wenger, 2002). The CoP enabled the teachers to be committed to a vision of reform in their teaching, and to share ideas and provide peer feedback. To develop a COP there must be mutual engagement around a shared theme in which participants are engaged with colleagues, and share and respond to ideas in the context of the theme (in our case, NOS). In addition, a CoP should have a shared mission (joint enterprise) in which the community works toward a common purpose (for us, improving science teaching). Also, a CoP must include a shared repertoire of ideas, techniques, practices, terminology, as a needed outcome for the CoP and its participants (for us, shared strategies for NOS instruction) (Kerwald, 2008; Wenger, 1998; Wenger, 2006)

    Numerical Solution of Fredholm Integral Equations of Second Kind using Haar Wavelets

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    Integral equations have been one of the most important tools in several areas of science and engineering. In this paper, we use Haar wavelet method for the numerical solution of one-dimensional and two-dimensional Fredholm integral equations of second kind. The basic idea of Haar wavelet collocation method is to convert the integral equation into a system of algebraic equations that involves a finite number of variables. The numerical results are compared with the exact solution to prove the accuracy of the Haar wavelet method

    Similarity Solutions of the MHD Boundary Layer Flow Past a Constant Wedge within Porous Media

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    The two-dimensional magnetohydrodynamic flow of a viscous fluid over a constant wedge immersed in a porous medium is studied. The flow is induced by suction/injection and also by the mainstream flow that is assumed to vary in a power-law manner with coordinate distance along the boundary. The governing nonlinear boundary layer equations have been transformed into a third-order nonlinear Falkner-Skan equation through similarity transformations. This equation has been solved analytically for a wide range of parameters involved in the study. Various results for the dimensionless velocity profiles and skin frictions are discussed for the pressure gradient parameter, Hartmann number, permeability parameter, and suction/injection. A far-field asymptotic solution is also obtained which has revealed oscillatory velocity profiles when the flow has an adverse pressure gradient. The results show that, for the positive pressure gradient and mass transfer parameters, the thickness of the boundary layer becomes thin and the flow is directed entirely towards the wedge surface whereas for negative values the solutions have very different characters. Also it is found that MHD effects on the boundary layer are exactly the same as the porous medium in which both reduce the boundary layer thickness

    Inguinal lymph node metastases from a testicular seminoma: a case report and a review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>We report the case of a true hermaphrodite with testicular seminoma with resulting metastases to the inguinal lymph nodes eight months after radical orchidectomy. This is an unusual presentation of testicular cancer and, to the best of our knowledge, the first report of this kind in the literature.</p> <p>Case presentation</p> <p>A 45-year-old Caucasian true hermaphrodite, raised as a male, developed a testicular seminoma. He had undergone a left orchidopexy at the age of 10 for undescended testes. Metastases from testicular tumors to inguinal lymph nodes are a rare occurrence. It has been suggested that previous inguinal or scrotal surgery may alter the pattern of nodal metastasis of testicular cancer. We review the literature to evaluate the incidence of inguinal lymph node involvement in early stage testicular cancer and discuss possible routes of metastases to this unusual site. We also discuss the management of the inguinal lymph nodes in patients with testicular tumors and a previous history of inguinal or scrotal surgery, as this remains controversial.</p> <p>Conclusion</p> <p>Inguinal lymph node metastases from testicular cancer are rare. A history of inguinal or scrotal surgery may predispose involvement of the inguinal nodes. During radical inguinal orchidectomy, the surgeon should be careful to minimize the handling of the testis and ensure high ligation of the spermatic cord up to the internal inguinal ring to reduce the risk of inguinal lymph node metastasis.</p

    Sinteza i biološko djelovanje novih supstituiranih derivata tiazolin-kinolina

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    5-Acyl-8-hydroxyquinoline-2-(3\u27-substituted-4\u27-aryl-2,3-dihydrothiazol-2\u27-ylide- ne)hydrazones, 5a-e to 10a-c, were prepared by the reaction of the appropriate 5-acyl-8-hydroxyquinoline-4-substituted thiosemicarbazones 3a-e and phenacyl bromides 4a-e. Structures of the new compounds were verified on the basis of spectral and elemental analyses. Twenty-eight new compounds were tested for their possible antimicrobial activities. Most of the tested compounds showed weak to moderate antibacterial activity against most of the bacterial strains used in comparison with gatifloxacin as a reference drug. The test compounds showed weak to moderate antifungal activity against tested fungi in comparison with ketoconazole as a reference drug. On the other hand, the newly synthesized compounds were tested for their anti-inflammatory effects and most of them showed good to excellent anti-inflammatory activity compared to indomethacin. Moreover, ulcerogenicity and the median lethal dose (LD50) of the most active anti-inflammatory compounds 6b and 9e were determined in mice; they were non-toxic at doses up to 400 mg kg-1 after i.p. administration.5-Acil-8-hidroksikinolin-2-(3\u27-supstituirani-4\u27-aril-2,3-dihidrotiazol-2\u27-ilid- ne)hidrazoni 5a-e do 10a-c pripravljeni su reakcijom odgovarajućih 5-acil-8-hidroksikinolin-4-supstituiranih tiosemikarbazona 3a-e i fenacil bromida 4a-e. Strukture novih spojeva potvrđene su na temelju spektralnih i elementarnih analiza. Dvadeset osam novih spojeva testirano je na potencijalno antimikrobno djelovanje. Većina spojeva pokazuje slabo do umjereno antibakterijsko djelovanje protiv većine testiranih bakterijskih sojeva u usporedbi s gatifloksacinom kao referentim lijekom, te slabo do umjereno antifungalno djelovanje protiv gljivica u usporedbi s ketokonazolom kao referentnim lijekom. Testovi na protuupalno djelovanje pokazuju da većina spojeva posjeduje dobro ili snažno protuupalno djelovanje u usporedbi s indometacinom. Ulcerogeno djelovanje i srednje letalne doze (LD50) najaktivnijih spojeva 6b i 9e određeni su na miševima. Rezultati pokazuju da su netoksični u dozama do 400 mg kg-1 nakon i.p. primjene

    Growth hormone secretagogue increases muscle strength during immobilization after canine hindlimb immobilization

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    Summary: Twenty-two beagles were divided into two equal groups, and the right hindlimb of each animal was immobilized at 105&quot; of knee flexion by external fixation. After 10 weeks of fixation, the device was removed, allowing free mobility for the following 5 weeks. Each day throughout the 1. 5 weeks, one group received a growth hormone secretagogue (treatment) at a dose of 5 mg/kg, and the other received a lactose placebo (control). A t weeks 0, 10, and 15, strength as indicated by maximum isometric extension torque was measured in the right hindlimb, biopsies of the vastus lateralis muscle were taken, and the dogs were weighed. Weekly blood samples were analyzed for insulin-like growth factor-1, blood urea nitrogen, and creatine phosphokinase. Between weeks 0 and 10, tetanic torque declined by about 60% (p &lt; 0.001) in both groups, with no significant difference between the groups (p &gt; 0.7). Between weeks 10 and 15, tetanic torque in the treated group increased by 0.81 Nm; this was significantly greater than the increase of 0.25 Nm in the placebo group (p &lt; 0.05). The diameters of slow (type-1) and fast (type-2) fibers measured from the vastus lateralis muscle followed the same trend. At all time points, fiber diameter correlated strongly with torque; this argues against nonmuscular causes such as nerve injury for strength loss. The mean levels of insulin-like growth factor-1 increased 100% by week 4 in the treated group and remained elevated by about 60% throughout the experiment. Levels of insulin-like growth factor-1 in the placebo group decreased 30% within week 1 and remained depressed throughout the experiment. Our interpretation of these data suggests that the growth hormone secretagogue elevated levels of serum insulin-like growth factor-1, which in turn increased the size and strength of the quadriceps muscle during remobilization. These data may ultimately have therapeutic application to humans during rehabilitation after prolonged inactivity. - The strengthening of skeletal muscle after surgery or prolonged disuse remains a primary goal of rehabilitation. Many approaches -including electrical stimulation (lo), voluntary exercise (15), continuous passive motion (7), and hormone therapy (32) -have been used to strengthen atrophied muscles. In some cases, treatment modalities are limited by a patient&apos;s access to rehabilitation professionals or rehabilitation devices. Medical treatment of muscle atrophy with hormone therapy offers the advantage of requiring relatively little effort on the part of the patient to achieve the desired therapeutic result. There is ample evidence of hypertrophy of skeletal muscle in response to anabolic steroids. strong correlations were demonstrated between muscle strength and serum testosterone concentration in elderly men in whom a marked loss of muscle function was correlated with low testosterone levels relative to stronger age-matched controls (1). In related studies, the administration of testosterone to elderly men (to increase serum testosterone to a range observed in younger men) increased lean body mass (32) and grip strength (25). The effect of this hormone may be mediated, at least in part, by serum insulin-like growth factor-1 (IGF-1) (4). The anabolic effects on humans of I G F -1 administration have been well documented. For example, recombinant IGF-1 attenuated the catabolic effects of glucocorticoids (23) and increased muscle protein synthesis in young men (9). Similar results were obtained in vitro with other muscle growth factors such as fibroblast growth factor (FGF). At the cellular level, skeletal muscle myotubes grown in culture in the presence of FGF demonstrated a marked increase in protein synthesis. This effect was enhanced 51

    Prediction of progression in pTa and pT1 bladder carcinomas with p53, p16 and pRb

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    Currently available prognostic tools appear unable to adequately predict recurrence and progression in non muscle-invasive bladder carcinomas. We aimed to assess the prognostic value of immunohistochemical evaluation of the cell cycle markers p53, p16 and pRb. Paraffin blocks were obtained from 78 cases of pTa and pT1 transitional cell carcinomas, for which long-term follow-up was available. Representative sections were stained using antibodies against p53, p16 and pRb. Altered marker expression was found in 45, 17 and 30% of cases, respectively. Concurrent alteration of two or three markers occurred in 19% of cases, and was significantly associated with grade and stage. In univariate survival analysis, the concurrent alteration of any two markers was significantly associated with progression. The greatest risk was produced by alteration of both p53 and p16, which increased the risk of progression by 14.45 times (95% confidence interval (CI) 3.10-67.35). After adjusting for grade and stage, this risk was 7.73 (CI 1.13-52.70). The markers did not generally predict tumour recurrence, except in the 25 pT1 tumours. In these, p16 alteration was associated with a univariate risk of 2.83 (CI 1.01-7.91), and concurrent p53 and p16 alteration with a risk of 9.29 (CI 1.24-69.50). Overall, we conclude that the immunohistochemical evaluation of p53 and p16 may have independent prognostic value for disease progression, and may help guide management decisions in these tumours

    QSAR studies on a number of pyrrolidin-2-one antiarrhythmic arylpiperazinyls

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    The activity of a number of 1-[3-(4-arylpiperazin-1-yl)propyl]pyrrolidin-2-one antiarrhythmic (AA) agents was described using the quantitative structure–activity relationship model by applying it to 33 compounds. The molecular descriptors of the AA activity were obtained by quantum chemical calculations combined with molecular modeling calculations. The resulting model explains up to 91% of the variance and it was successfully validated by four tests (LOO, LMO, external test, and Y-scrambling test). Statistical analysis shows that the AA activity of the studied compounds depends mainly on the PCR and JGI4 descriptors

    A nuclear role for the respiratory enzyme CLK-1 in regulating mitochondrial stress responses and longevity

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    The coordinated regulation of mitochondrial and nuclear activities is essential for cellular respiration and its disruption leads to mitochondrial dysfunction, a hallmark of ageing. Mitochondria communicate with nuclei through retrograde signalling pathways that modulate nuclear gene expression to maintain mitochondrial homeostasis. The monooxygenase CLK-1 (human homologue COQ7) was previously reported to be mitochondrial, with a role in respiration and longevity. We have uncovered a distinct nuclear form of CLK-1 that independently regulates lifespan. Nuclear CLK-1 mediates a retrograde signalling pathway that is conserved from Caenorhabditis elegans to humans and is responsive to mitochondrial reactive oxygen species, thus acting as a barometer of oxidative metabolism. We show that, through modulation of gene expression, the pathway regulates both mitochondrial reactive oxygen species metabolism and the mitochondrial unfolded protein response. Our results demonstrate that a respiratory enzyme acts in the nucleus to control mitochondrial stress responses and longevity
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