检索结果-南通市图书馆

Effect of nitrofurazone on the reproductive organs in adult male mice

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2001年第1期3卷 39-44页

作者： Shio Kumar Singh Sumana Chakravarty department of zoology Banaras Hindu University Varanasi IndiaDepartment of Zoology Banaras Hindu University Varanasi India

Aim: To study the effect of 5-nitro-2-fumldehyde semicarbazone (nitrofurazone), a derivative of nitrofuran, onmale reproductive organs of Parkes (P) swain mice. Methods: Mice were given nitrofurazone orally at a dose of 64mg/kg body weight per day, for 10 and 20 days, and were killed 24 h and/or 56 days after the last treatment. Histo-logical appearance of testis, motility and number of spermatozoa in cauda epididymidis, and biochemical indices in epi-didymis and seminal vesicle were evaluated. Results: Histologically, testis showed marked regressive changes inthe seminiferous tubules in mice treated with nitrofurazone. Ten days after treatment, there was much depletion of germcells in the seminiferous tubules, and the germinal epithelium was lined mainly with Sertoli cells, spermatogonia, sper-matocytes, and a few round spermatids; intraepithelial vacuoles and multinucleated giant cells were also observed intubules. By 20 days, regressive changes in the seminiferous tubules were further pronounced, and pachytene spermato-cytes were the most advanced germ cells noticed in the tubules. In severe cases, the tubules were lined with a thin layerof Sertoli cells and spermatogonia. The treatment also caused marked reductions in the motility and number of sperma-tozoa in the cauda epididymidis, in weight and the level of fructose in the seminal vesicle, and in sialic acid level in theepididymis. Fifty six days after drag withdrawal, the alterations induced in the reproductive organs returned to controllevels. Conclusion: Our results suggest that nitrofurazone treatment in P mice induces marked alterations in themale reproductive organs, and that the alterations are reversible following cessation of treatment.(Asian J Androl 2001 Mar; 3: 39-44)

关键词： nitrofurazone testis epididymis seminal vesicles sperm fructose sialic acids

Robust Half-Metallicity and Magnetic Properties of Cubic Perovskite CaFeO_(3)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2013年第4期30卷 192-196页

作者： Zahid Ali Iftikhar Ahmad Banaras Khan Imad Khan Materials Modeling Center Department of PhysicsUniversity of MalakandChakdaraDir(L)Pakistan department of Physics Hazara UniversityMansehraPakistan

Theoretical studies of the cubic perovskite CaFeO3 are performed using the full potential linearized augmented plane-wave method with GGA+*** calculated structural parameters are consistent with the experimental *** tolerance factor reveals the cubic phase of the *** spin polarized electronic band structures and densities of states as well as the integer value of the magnetic moment of the unit cell(4μB)demonstrate that CaFeO_(3)is half *** in CaFeO_(3)is due to Fe^(+4)–O^(2)–Fe^(+4)superexchange *** robust properties of the compound show that with their compression up to a certain critical lattice constant,known as the robust transition lattice constant,an abrupt change in the electronic and magnetic properties occurs;the compounds lose their integer magnetic moment and become metallic.

关键词： integer cubic magnetic

Diffusion of Six-Atom Cu Islands on Cu(111)and Ag(111)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第5期28卷 99-102页

作者： Sardar Sikandar Hayat I.Ahmad M.Arshad Choudhry department of Physics and Astronomy Hazara UniversityMansehra 23100Pakistan department of Physics The Islamia University of BahawalpurBahawalpur 63120Pakistan

Diffusion of Cu hexamer islands on Cu(111)and Ag(111)is studied using a molecular dynamics simulation technique with many-body potentials obtained from the embedded atom *** are carried out at temperatures 300,500 and 700 K,showing that shape-changing multiple-atom processes are more helpful for the diffusion rather than concerted motion of *** plots of the diffusion coefficients provide effective energy barrier values of 161.29±5 meV for Cu(111)and 179.34±5 meV for Ag(111)*** 700K,one pop-up atom among island atoms is observed with correlative changes in the position and shape of the lower-layer adatoms.

关键词： Cu(111) method Diffusion

Harvesting of forest products and implications for Afrotemperate bird communities in a montane forest of the Eastern Cape, South Africa

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystems 2019年第4期6卷 352-366页

作者： Jessica Leaver Johann C.Carstens Michael I.Cherry department of Botany and zoology Stellenbosch University

Background: Harvesting of forest products is a widespread driver of disturbance in developing nations, where policies are increasingly aimed at managing natural forests for sustainable use. There is thus need for research aimed at understanding the impact of resource use on forest habitats and concomitant effects on *** forests in the Eastern Cape, South Africa are harvested informally for poles and medicinal bark and occur along elevational gradients of 800–1600 m above sea level. Patterns of spatial diversity and human disturbance are expected to be affected by elevation. Furthermore, species’ responses to disturbance are expected to vary depending on their level of habitat specialisation. Understanding harvest impacts on forest biodiversity thus requires disentangling the separate effects of elevation and disturbance, and considering forest-specialist and forest-generalist species separately. This study comprises two components. First, harvest activities, resultant harvestmediated habitat heterogeneity, and avifaunal species richness, composition and beta-diversity were compared across two elevational zones in a harvested forest. Second, the role of harvest-mediated habitat heterogeneity in driving patterns of avifaunal diversity were assessed, while controlling for elevation, and considering forest-specialist and forest-generalist species ***: Harvest rates were higher, and activities more varied in the lower elevation zone, with significant impacts of harvesting on habitat features resulting in higher harvest-mediated habitat heterogeneity at lower ***-mediated increases in habitat heterogeneity positively affected forest-generalist species richness, while forest-specialist richness was negatively affected. While species composition of both groups differed across elevational zones, variation in harvest-mediated habitat heterogeneity did not fully account for this, suggesting that factors other than disturbance

关键词： Human disturbance Habitat heterogeneity Habitat modification Beta-diversity Elevation Generalist species Forest-specialist species

Characterization of ion irradiated silicon surfaces ablated by laser-induced breakdown spectroscopy

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第8期27卷 505-510页

作者： T Iqbal M Abrar M B Tahir M Seemab A Majid S Rafique department of Physics Faculty of Sciences University of Gujrat Hafiz Hayat Campus department of Physics Hazara University Mansehra department of Physics University of Engineering and Technology (UET)Lahore Pakistan

Low energy metallic ions, generated by a Q-switched Nd：YAG laser （1064-nm wavelength, 10-mJ energy, 9-nm 12-ns-pulse width, 1011 W/cm2 intensity） irradiated on a silicon substrate to modify various properties, such as electrical, morphological, and structural modifications. Thomson parabola technique is used to calculate the energy of these metallic ions whereas the electrical conductivity is calculated with the help of Four-point probe. Interestingly circular tracks forming chain like damage trails are produced via these energetic ions which are carefully examined by optical microscopy. It is observed that excitation, ionization, and cascade collisions are responsible for surface modifications of irradiated samples. Four-point probe analysis revealed that the electrical conductivity of substrate has reduced with increasing trend of atomic number of irradiated metallic ions （A1, Ti, Cu, and Au）. The x-ray diffraction analysis elucidated the crystallographic changes leading to reduction of grain size of N-type silicon substrate, which is also associated with the metallic ions used. The decreasing trend of conductivity and grain size is due to thermal stresses, scattering effect, structural imperfections, and non-uniform conduction of energy absorbed by substrate atoms after the ion irradiation.

关键词： ablation Thomson parabola technique four-point probe

V_(2)CT_(x) MXene and its derivatives:synthesis and recent progress in electrochemical energy storage applications

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2022年第3期41卷 775-797页

作者： Zhao-Lin Tan Jing-Xuan Wei Yang Liu Fakhr uz Zaman Wajid Rehman Lin-Rui Hou Chang-Zhou Yuan School of Materials Science and Engineering University of JinanJinan 250022China department of Chemistry Hazara UniversityMansehra 21120Pakistan

With the continuous development of two-dimensional (2D) transition metal carbides and nitrides(collectively referred to as MXene).Nowadays,more than 70 MXene materials have been discovered,and the number is still *** them,the V_(2)CT_(x) MXene has attracted considerable attentions due to its outstanding physical and chemical *** this review,we mainly discussed the emerging V_(2)CT_(x) MXene and its derivative systems in various energy storage ***,an introduction of the V-based MXene and its derivatives along with their synthetic methodologies is provided,then we summarize their applications in specific energy storage devices,such as metal (Li,Na,K,Mg,Zn and Al) ion batteries,lithium-sulfur batteries,supercapacitors and metal-ion ***,the main challenges and future perspectives existing in V-based MXene and its derivatives are reasonably put forward.

关键词： MXene V_(2)CT_(x) Two-dimensional material Derivatives Electrochemical energy storage applications

Tectonic calibrations in molecular dating

在线全文

学校读者我要写书评

暂无评论

Current zoology 2011年第1期57卷 116-124页

作者： Ullasa KODANDARAMAIAH department of zoology Stockholm University Stockholm 10691 Sweden

Molecular dating techniques require the use of calibrations, which are usually fossil or geological vicariance-based. Fossil calibrations have been criticised because they result only in minimum age estimates. Based on a historical biogeographic perspective, I suggest that vicariance-based calibrations are more dangerous. Almost all analytical methods in historical biogeog- raphy are strongly biased towards inferring vicariance, hence vicariance identified through such methods is unreliable. Other studies, especially of groups found on Gondwanan fragments, have simply assumed vicariance. Although it was previously be- lieved that vicariance was the predominant mode of speciation, mounting evidence now indicates that speciation by dispersal is common, dominating vicaziance in several groups. Moreover, the possibility of speciation having occurred before the said geo- logical event cannot be precluded. Thus, geological calibrations can under- or overestimate times, whereas fossil calibrations al- ways result in minimum estimates. Another major drawback of vicariant calibrations is the problem of circular reasoning when the resulting estimates are used to infer ages of biogeographic events. I argue that fossil-based dating is a superior alternative to vicariance, primarily because the strongest assumption in the latter, that speciation was caused by the said geological process, is more often than not the most tenuous. When authors prefer to use a combination of fossil and vicariant calibrations, one suggestion is to report results both with and without inclusion of the geological constraints. Relying solely on vicariant calibrations should be strictly avoided

关键词： Molecular dating Calibrations Fossils Vicariance Paleontological Relaxed clock

Efficacy evaluation of the protein isolated from Peganum harmala seeds as an antioxidant in liver of rats

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2013年第4期6卷 285-295页

作者： Amel M Soliman Helal S Abu-El-Zahab Gamiaa A Alswiai zoology department Faculty of ScienceCairo University zoology department Faculty of Science

Objective:To evaluate the curative effect of the 132 KD protein isolated from the seeds of Peganum harmala（***） L against carbon tetrachloride（CCl4） induced oxidative stress in ***:Animals were post treated intraperitoneally with 132 KO isolated protein at doses of 4 and 8 mg/kg body weight and bovine serum albumin（BSA）（8 mg/kg body weight） as well as vitamin C（250 mg/kg body weight p.o.） for 7 d after they challenged with CCl4 orally（1 ml/Ag body weight） in olive oil（50%） for 2 ***:The purified protein from seeds of *** plant showed in vitro antioxidant activity with DPPH *** of CCl4 induced induction in serum aminotransferases（AST,ALT）,alkaline phosphatase（ALP）,lipid profile parameters and liver malondialdehyde（MDA） and decrease in serum total protein,liver superoxide dismutase （SOD）,catalase（CAT）,and reduced glutathione（GSH） levels.132 KD protein treatment of rats post CCl4 intoxication successfully alleviated the toxic effects of CCl4.Conclusions:The isolated protein possessed strong antioxidant activity comparable to that of BSA（negative control） and vitamin C（positive control）.

关键词： Carbon tetrachloride Peganum harmala Oxidative stress 132 KD isolated protein

The Effects of Spherical Surface and Laser Polarization on the Photodetachment Cross Section of H^-

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2013年第3期59卷 356-360页

作者： Muhammad Haneef Suneela Arif Jehan Akbar Nasrullah Shah Muhammad Zahir Aneela Shamim Hameed Ullah Lab of Atom and Quantum Interference Department of PhysicsHazara UniversityGarden CampusMansehraPakistan department of Chemistry Abdul Wali Khan UniversityMardanPakistan department of Statistics University of PeshawarPakistan department of Chemistry Hazara UniversityGarden CampusMansehraPakistan

We report the combined effects of laser polarization and curvature of the spherical surface on the detached electron spectra from H-. The Theoretical imaging method is used as a tool of investigation. The photodetachment cross sections for various polaxization angles, radii of curvatures and inter ion surface distances axe displayed. The analysis of the spectra reveals that the laser polarization angle θL, curvature of the surface τc and inter ion surface distance d strongly affect oscillations in the spectra. Therefore, a fine control on the laser polaxization and that of curvature in the surface can be used to control oscillations in the photodetachment of negative ions.

关键词： negative ions photodetachment spherical surface