Effect of Co and Mg doping at Cu site on structural, magnetic and dielectric properties of α-Cu2V2O7

We have studied the effect of doping of both magnetic (Co) and nonmagnetic (Mg) ions at the Cu site on phase transition in polycrystalline α-Cu₂V₂O₇through structural, magnetic, and electrical measurements. X-ray diffraction reveals that Mg doping triggers an onset ofα- toβ-phase structural transition in Cu_2-xMg_xV₂O₇above a critical Mg concentrationx_c= 0.15, and both the phases coexist up tox= 0.25. Cu₂V₂O₇possesses a non-centrosymmetric crystal structure and antiferromagnetic ordering along with a non-collinear spin structure in theαphase, originated from the microscopic Dzyaloshinskii-Moriya interaction between the neighboring Cu spins. Accordingly, a weak ferromagnetic (FM) behavior has been observed up tox= 0.25. However, beyond this concentration, Cu_2-xMg_xV₂O₇exhibits complex magnetic properties. A clear dielectric anomaly is observed in α-Cu_2-xMg_xV₂O₇around the magnetic transition temperature, which loses its prominence with the increase in Mg doping. The analysis of experimental data shows that the magnetoelectric coupling is nonlinear, which is in agreement with the Landau theory of continuous phase transitions. Co doping, on the other hand, initiates a sharpαtoβphase transition around the same critical concentrationx_c= 0.15 in Cu_2-xCo_xV₂O₇but the FM behavior is very weak and can be detected only up tox= 0.10. We have drawn the magnetic phase diagram which indicates that the rate of suppression in transition temperature is the same for both types of doping, magnetic (Co) and nonmagnetic (Zn/Mg).

The simultaneous emergence of free exciton emission and d0 ferromagnetism for undoped ZnO nanoparticles

Free excitonic emission is observed for the ferromagnetic undoped ZnO nanoparticles prepared by mechanical milling.

Defect driven ferromagnetism in SnO2: a combined study using density functional theory and positron annihilation spectroscopy

Room temperature ferromagnetic ordering has been observed in polycrystalline SnO₂. Defect characterization by positron annihilation technique and ab initio calculation indicates that tin vacancies are mainly responsible for inducing magnetic moment in oxygen irradiate SnO₂.

Role of Zn-interstitial defect states on d0 ferromagnetism of mechanically milled ZnO nanoparticles

An impurity defect level formed by interstitial zinc at the surfaces of undoped ZnO nanoparticles plays a crucial role for d0 ferromagnetism.

Dielectric spectroscopy of T-shaped blue-phase-III liquid crystal

Dielectric relaxation spectra of a liquid crystalline (LC) material showing blue-phase-III (BPIII) for a considerably large temperature regime consisting of T-shaped molecules are investigated. A low frequency relaxation mode is observed in the isotropic phase (I) as well as in BPIII of the investigating material which is attributed to the short axis rotation of the T-shaped molecules. The outcome of the temperature and dc bias field variation of dielectric strength (Δε) and relaxation frequency (ν(c)) in the vicinity of the I-BPIII transition is also discussed. The temperature dependence of ν(c) in BPIII with a minor deviation from Arrhenius activities in the fluctuation-dominated nonlinear region (FDNLR) is found to follow the unusual thermal behavior of the activation energy (E(A)). The growth of pretransitional fluctuations is found to be nonlinear in the vicinity of the I-BPIII transition. A moderate growth of transition fluctuation commences from the value of the exponent α(eff)=0.38/°C, which is obtained by an exponential variation of ν(c) with respect to temperature in BPIII. Observed dynamic phenomenon in the vicinity of the I-BPIII transition regions is explained on the basis of the Landau-de Gennes and Maier-Saupe Theories.

Antidiabetic effect of aqueous extract of seed of Tamarindus indica in streptozotocin-induced diabetic rats

In Indian traditional system of medicine, herbal remedies are prescribed for the treatment of diseases including diabetes mellitus. In recent years, plants are being effectively tried in a variety of pathophysiological states. Tamarindus indica Linn. is one of them. In the present study, aqueous extract of seed of Tamarindus indica Linn. was found to have potent antidiabetogenic activity that reduces blood sugar level in streptozotocin (STZ)-induced diabetic male rat. Supplementation of this aqueous extract by gavage at the dose of 80 mg/0.5 ml distilled water/100 g body weight per day in STZ-induced diabetic rat resulted a significant diminution of fasting blood sugar level after 7 days. Continuous supplementation of this extract for 14 days resulted no significant difference in this parameter from control level. Moreover, this supplementation produced a significant elevation in liver and skeletal muscle glycogen content, activity of liver glucose-6-phosphate dehydrogenase in respect to diabetic group. Activities of liver glucose-6-phosphatase, liver and kidney glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities were decreased significantly in the aqueous extract supplemented group in respect to diabetic group. All these parameters were not resettled to the controlled level after 7 days of this extract supplementation but after 14 days of this supplementation, all the above mentioned parameters were restored to the control level.

Effect of Stephania hernandifolia leaf extract on testicular activity in rats

AIM

The testicular inhibitory effect of the aqueous fraction of methanol extract of Stephania hernandifolia leaf was studied in male Wistar rats.

METHODS

The supernatent and the precipitate part of aqueous fractions of the methanol extract of the leaf were gavaged separately to rat at a similar dose of 200 mg/mL per 100 g body weight per day for 28 days. After cessation of treatment, various observations were conducted.

RESULTS

In both treated groups, there were significant decreases in the relative weights of the sex organs, the testicular key androgenic enzymes activities, the plasma level of testosterone, the number of different germ cells at stage VII of seminiferous epithelial cell cycle and the seminiferous tubular diameter in comparison to the controls. Neither of the parts had somatic, renal and hepatic toxicity. This study suggested that the active molecules present in the aqueous fraction of methanol extract of Stephania hernandifolia leaves might be steroids as indicated by thin layer chromatography using specific staining substance for steroid molecules.

CONCLUSION

In rats, the aqueous fraction of methanol extract of the S. hernandifolia leaves possesses certain testis-inhibitory substances, which may be steroid-like agents.

Testicular toxicity in sodium fluoride treated rats: association with oxidative stress

This study examined the effect of sodium fluoride, a water pollutant important through the world, including India, on testicular steroidogenic and gametogenic activities in relation to testicular oxidative stress in rats. Sodium fluoride treatment at 20mg/kg/day for 29 days by oral gavage resulted in significant diminution in the relative wet weight of the testis, prostate, and seminal vesicle without alteration in the body weight gain. Testicular delta(5),3beta-hydroxysteroid dehydrogenase (HSD) and 17beta-HSD activities were decreased significantly along with significant diminution in plasma levels of testosterone in the fluoride-exposed group compared to the control. Epididymal sperm count was decreased significantly in the fluoride-treated group and qualitative examination of testicular sections revealed fewer mature luminal spermatozoa in comparison to the control. The seminiferous tubules were dilated in treated animals. Fluoride treatment was associated with oxidative stress as indicated by an increased level of conjugated dienes in the testis, epididymis, and epididymal sperm pellet with respect to control. Peroxidase and catalase activities in the sperm pellet were decreased significantly in comparison to the control. The results of this experiment indicate that fluoride at a dose encountered in drinking water in contaminated areas exerts an adverse effect on the male reproductive system and this effect is associated with indicators of oxidative stress.

Effects of leaf extract of Stephania hernandifolia on testicular gametogenesis and androgenesis in albino rats: a dose-dependent response study

The present study was undertaken to evaluate the dose-dependent effects of a leaf extract of Stephania hernandifolia on testicular activities in albino rats. Whether this leaf extract has any toxic effect on metabolic organs or on the liver or kidney was studied. Adult male Wistar rats, maintained under standard laboratory conditions, were forcefully fed with the aqueous extract of these leaves at the dose of 2 g or 4 g of leaves/mL distilled water/100 g body weight/day for 28 days. All the animals, along with vehicle-treated controls, were killed on the Day 29 of the experiment. Treatment with this leaf extract at both doses resulted in significant reduction in relative weight in the testis, the seminal vesicles, the prostate, and the epididymis without any significant change in the liver and kidney weight in comparison to control. Activities of testicular steroidogenic key enzymes and plasma testosterone level were decreased significantly, along with a significant reduction in the number of germ cells at stage VII of the spermatogenic cycle and in the seminiferous tubular diameter in both treated groups in comparison to control. Activities of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, acid phosphatase, and alkaline phosphatase were not altered significantly in the liver and kidney in both treated groups compared with controls. We concluded that treatment with an aqueous extract of leaves resulted in diminution in the activities of testicular androgenic key enzymes and plasma level of testosterone along with inhibition of spermatogenesis without any induction of hepatic and renal toxicity.

Effect of human chorionic gonadotrophin coadministration on the activities of ovarian Delta5-3beta-hydroxysteroid dehydrogenase, and 17beta-hydroxysteroid dehydrogenase, and ovarian and uterine histology in lithium chloride-treated albino rats

Lithium chloride, a compound with clinical use in bipolar disorder, produces adverse effects on ovarian function in amphibian and rodent models. This study examined the effect of human chorionic gonadotrophin coadministration on ovarian steroidogenic and gametogenic activities in lithium chloride-treated rats. Relative ovarian and uterine weights, ovarian Delta(5)-3beta-hydroxysteroid dehydrogenase and 17beta-hydroxysteroid dehydrogenase activities, folliculogenesis, uterine diameter, endometrial and myometrial thickness, and uterine luminal epithelial height were decreased significantly after lithium chloride treatment for 28 days at 1.6 mg/kg/day, the human therapeutic dose. These parameters were unchanged from the control level when subcutaneous (s.c.) human chorionic gonadotrophin (hCG) at 25 microg/kg/day was coadministered with the lithium chloride. The duration of the oestrous cycle was increased in lithium chloride-treated rat with longer metestrous and diestrous phases. Administration of hCG with lithium chloride prevented these estrous cycle alterations. We conclude that hCG can protect ovarian steroidogenic and gametogenic function after lithium chloride treatment.

Bilateral frontal lobe ct scan abnormality following ect in an adolescent

A case is described of bilateral frontal lobe CT Scan abnormality associated with ECT in an adolescent. Possible causes and risk factors are discussed.