Cryoprotectant with a mitochondrial derived peptide, humanin, improves post-thaw quality of buffalo spermatozoa.

BACKGROUND: Semen cryopreservation results in deleterious effects on spermatozoa, including lipid peroxidation and a reduction in the total antioxidant components of seminal plasma. The ultimate outcome of these changes is a reduction in post-thaw semen quality. A mitochondrial derived peptide, humanin, a potent cytoprotective and antioxidant agent was used in the present study. OBJECTIVE: To evaluate the efficacy of a mitochondrial-derived peptide, humanin to improve the post-thaw quality of buffalo spermatozoa. MATERIALS AND METHODS: A total of 18 ejaculates from three Murrah buffalo bulls (n=6 each) were collected. Each ejaculate was divided into four aliquots. The first aliquot was diluted with standard EYTG dilutor (Group I, control), whereas the other three aliquots were diluted with EYTG supplemented with 2 µM (Group II), 5 µM (Group III) and 10 µM humanin (Group IV), respectively. Semen was evaluated for physico-morphological and functional attributes such as progressive motility, viability, abnormality, acrosome integrity, plasmamembrane integrity of fresh samples, pre-freeze and post-thaw stages. Oxidative stress parameters [lipid peroxidation (LPO) and total antioxidant capacity (TAC)] were also measured at the pre-freeze and post-thaw stages. RESULTS: Humanin supplementation resulted in significantly higher (p < 0.05) post-thaw motility in all treatment groups and, higher (p < 0.05) viability in Groups III and IV in comparison to the control at the post-thaw stage. Spermatozoa with intact acrosome and plasma membrane were higher (p < 0.05) in Groups III and IV as compared to Groups I and II. The LPO levels at the post-thaw stage were found to be lower (p < 0.05) in all treatment groups versus the control group, whereas, higher (p≤0.05) TAC values were recorded in Groups III and IV in comparison to the control and Group II. CONCLUSION: Humanin supplementation in the extender improved the freezabilty of buffalo spermatozoa.

Cryoprotection of humanin-like peptides in seminal plasma for ejaculated spermatozoa of crossbred bulls.

BACKGROUND: Cryopreservation process negatively affects spermatozoa functions. Humanin, a small polypeptide encoded in the mitochondrial genome, is well known for its role in cell survival. OBJECTIVE: To quantify the endogenous levels of humanin in seminal plasma of crossbred Frieswal bulls and to study its role in cryoprotection. The presence of humanin in bull spermatozoa was also investigated. MATERIALS AND METHODS: A total of 40 semen samples were separated into two groups based on the initial progressive motility (IPM): Good (IPM >70%) and Poor (IPM <50%) groups; and/or based on the post-thaw motility (PTM): Freezable (PTM>50%) and Non-freezable (PTM < 50%) groups. Humanin concentration in seminal plasma (SP-HN) was quantified using ELISA. RESULTS: SP-HN concentration ranged from undetectable to 67.6 pg/mL with a median level of 35.2 pg/mL. SP-HN level was significantly higher in the good quality semen group than in the poor quality semen group (p<0.001), and also significantly higher in the freezable group than in the non-freezable group (p<0.001). SP-HN level was positively correlated with initial progressive motility, post-thaw semen motility, viability, acrosome intactness and plasma membrane integrity, but negatively correlated the level of reactive oxygen species and malondialdehyde content. Immunochemical localization showed the presence of humanin in the proximal region of the middle piece of spermatozoa. CONCLUSION: Endogenous humanin level had significant correlation with semen quality and might protect sperm cells against freeze-induced oxidative stress. doi.org/10.54680/fr22510110712.

Fluorescent spectroscopic assessment before and after radiation treatment in oral cavity cancer and its clinical correlation.

BACKGROUND: Biochemical changes in irradiated malignant tissue lead to altered autofluorophores status which should be different for cancerous tissue (residual/recurrence) and irradiated normal tissue. If this irradiated tissue is examined through fluorescent spectroscopy, we can find the spectroscopic changes occurring after the completion of treatment which can be helpful in evaluating treatment response. METHODS: Punch biopsy sample was examined through fluorescent spectroscopy in oral cavity cancer patients before and after definitive radiation treatment. The change in spectroscopic pattern before and after radiation treatment was recorded and assessed. RESULTS: Final analysis was done in 36 samples. In irradiated tissue, it has been observed that there was increase in the intensity of collagen fluorescence. It was found that the Half width half maximum (HWHM) is more in case of preirradiated sample. The decrease in the HWHM in case of irradiated sample shows the decrease in the number of cells (cell density as compared to that in preirradiated sample). These spectral findings are well-explained pathophysiologically and clinically as amount of collagen are increased in irradiated tissues due to loss of cancerous cells and regeneration of collagen cross-links (fibrosis) and reproduction of normal tissue as a response to radiation treatment. CONCLUSION: After thorough study in a large number of samples, we may be able in the future to grade the alteration in fluorescence of collagen obtained after radiation treatment in terms of complete, partial, or no response.

Effect of Mito-TEMPO Incorporated Semen Extender on Physico-morphological Attributes and Functional Membrane Integrity of Frozen Thawed Buffalo Spermatozoa.

BACKGROUND: Sperm mitochondria are the major site of reactive oxygen species (ROS) production and excess production during freezing-thawing process inflicts oxidative damages to spermatozoa. Buffalo spermatozoa are more prone to oxidative damage due to inherently more polyunsaturated fatty acids and low cholesterol to phospholipids ratio in the plasma membrane. A mitochondrial targeted antioxidant, Mito-TEMPO was used in this study. OBJECTIVE: To study the effect of Mito-TEMPO incorporated semen extender on the post-thaw semen quality in buffalo. MATERIALS AND METHODS: A total of 18 ejaculates from three murrah buffalo bulls with ≥70% individual progressive motility were utilized for the study. Each semen sample was equally divided and extended with five groups: Group I (Control, without Mito-TEMPO addition); Group II (10 µM Mito-TEMPO); Group III (50 µM Mito-TEMPO); Group IV (100 µM Mito-TEMPO); Group V (500 µM Mito-TEMPO) to have 80×106 progressive motile sperm/mL of extender, filled and sealed in French mini straws (0.25 mL) and frozen following equilibration. The effect of Mito-TEMPO was assessed at fresh/post-dilution and post-thaw stages by evaluating physico-morphological attributes and functional membrane integrity such as hypo-osmotic swelling test (HOST). RESULTS: Initial progressive motility, viability, acrosomal integrity and HOS response was significantly (p<0.05) improved and sperm abnormality was significantly (p<0.05) reduced in extended semen with Mito-TEMPO (50 µM) compared to control at post-thaw stage, although improvement was also observed at 10 and 100 µM in post-thaw samples. CONCLUSION: Mito-TEMPO incorporated semen extender at 50 µM concentration, could be part of a rationale for improving post-thaw semen quality in buffalo.

Phonon and magnetoelastic coupling in Al0.5Ga0.5FeO3: Raman, magnetization and neutron diffraction studies.

The intriguing coupling phenomena among spin, phonon, and charge degrees of freedom in materials having magnetic, ferroelectric and/or ferroelastic order have been of research interest for the fundamental understanding and technological relevance. We report a detailed study on structure and phonons of Al0.5Ga0.5FeO3 (ALGF), a lead-free magnetoelectric material, carried out using variable temperature dependent powder neutron diffraction and Raman spectroscopy. Neutron diffraction studies suggest that Al3+ ions are distributed in one tetrahedrally (BO4) and three octahedrally (BO6) coordinated sites of the orthorhombic (Pc21n) structure and there is no structural transition in the temperature range of 7-800 K. Temperature dependent field-cooled and zero-field-cooled magnetization studies indicate ferrimagnetic ordering below 225 K (TN), and that is reflected in the low temperature powder neutron diffraction data. An antiferromagnetic type arrangement of Fe3+ ions with net magnetic moment of 0.13 µB/Fe3+ was observed from powder neutron diffraction analysis and it corroborates the findings from magnetization studies. At the magnetic transition temperature, no drastic change in lattice strain was observed, while significant changes in phonons were observed in the Raman spectra. The deviation of several mode frequencies from the standard anharmonicity model in the ferrimagnetic phase (below 240 K) is attributed to coupling effect between spin and phonon. Spin-phonon coupling effect is discernable from Raman bands located at 270, 425, 582, 695, 738, and 841 cm-1. Their coupling strengths (λ) have been estimated using our phonon spectra and magnetization results. BOn (n = 4, 6) libration (restricted rotation) mode at 270 cm-1 has the largest coupling constant (λ∼ 2.3), while the stretching vibrations located at 695 and 738 cm-1 have the lowest coupling constant (λ∼ 0.5). In addition to the libration mode, several internal stretching and bending modes of polyhedral units are strongly affected by spin ordering.

Incubation with Cholesterol-loaded Cyclodextrin and Subsequent Dilution in Partially Deoxygenated Extender Improves the Freezability of Cross-bred Bull Sperm.

BACKGROUND: The cryopreservation process induces osmotic stress, membrane changes and production of reactive oxygen species resulting in damage to the spermatozoa. Together, the presence of oxygen in the extender aggravates the oxidative stress that further reduces the cryosurvival rate of sperm cells. OBJECTIVE: To study the combined effect of cholesterol loaded cyclodextrin (CLC) and partial deoxygenation on post-thaw semen quality in crossbred bulls. MATERIALS AND METHODS: A total of 18 ejaculates from three crossbred bulls with >3+ mass motility and >70% individual progressive motility were utilized for the study. Each semen sample was divided into four groups: Group I (containing extender without partial deoxygenation or CLC addition); Group II (extender containing 3 mg CLC/120X106 spermatozoa); Group III (extender containing 3 mg CLC/120X106 spermatozoa and 4 ppm dissolved oxygen (DO) level); Group IV (extender containing 3 mg CLC/120X106 spermatozoa and 6 ppm DO level). The samples in each group were finally extended to have 80×106 progressive motile sperm/mL of extender, filled and sealed in French mini straws (0.25 mL) and frozen following equilibration. The effect of CLC addition and partial deoxygenation was assessed at fresh (post-dilution), pre-freeze and post-thaw stages by evaluating various variables [sperm motility, viability, hypo-osmotic swelling (HOS) response, acrosomal integrity, capacitation status and mitochondrial membrane potential (MMP)]. RESULTS: The sperm population was significantly more positive for motility, viability, HOS response, acrosome intactness, high MMP and had less capacitation-like changes in groups supplemented with CLC and partially deoxygenation. However, the positive effect was most pronounced in the group that had extender with CLC+4 ppm DO. CONCLUSION: Partial deoxygenation of extender, and CLC addition in combination, could be part of a rationale for improving post-thaw semen quality in cross-bred bulls.

Reduction of dissolved oxygen in semen extender with nitrogen gassing reduces oxidative stress and improves post-thaw semen quality of bulls.

The objective of the present study was to investigate the effects of two different concentrations of dissolved oxygen (DO, 4 and 8) ppm in the extender on oxidative stress affecting plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), and deoxyribonucleic acid (DNA) damage of bull spermatozoa following cryopreservation. For the experiment, nitrogen (N2) gassing of the extender for varied time intervals yielded extender with DO concentration of 4 ppm and 8 ppm (Groups II and III, respectively). For the Control (Group I) without N2 gassing, a DO concentration of 11.7 ppm was recorded. Following sample selection, ejaculates were divided into three aliquots and were extended to have 80 × 106 spermatozoa/mL of extender in the three groups. Semen samples were evaluated for reactive oxygen species (ROS), lipid peroxidation (LPO), total antioxidant capacity (TAC) and superoxide dismutase (SOD) at the fresh, pre-freeze, and post-thaw stages. Evaluation of PMI, MMP, and DNA damage were conducted on frozen-thawed samples. There were greater (P < 0.05) increase in ROS and LPO and decrease in TAC concentrations in Group I than Groups II and III. Mean values of SOD at the post-thaw stage was greater (P < 0.05) in Group II than Group I. There was a similar trend in the PMI in Groups II and III; MMP and DNA integrity in Group II was greater compared with Group I. In conclusion, results indicate there was a beneficial effect of maintaining DO concentrations at 4 rather than of 8 or 11.7 ppm in extender for sustaining post-thaw semen quality.

Effect of Liquid Nitrogen Flushing of Extender on Seminal Antioxidant Profile of Murrah Buffalo during Cryopreservation.

BACKGROUND: The dissolved oxygen in the extender may act as a source for the production of reactive oxygen species that may lead to reduced seminal antioxidant profile which in turn may be responsible for impaired frozen thawed sperm quality and fertility. OBJECTIVE: To study the effect of adding liquid nitrogen into the extender on semen freezability and seminal antioxidant profile in buffalo. MATERIALS AND METHODS: Semen extender was prepared freshly and divided into two sub extenders namely, Extender I: control (non deoxygenated) and Extender II: partially deoxygenated by using LN2 flushing). The estimation of dissolved oxygen (DO) level was done in both extenders. Semen samples with mass motility of ≥ 3+ and individual progressive motility of 70% and above, collected from murrah buffalo bulls were utilized for the present study. Each semen sample was split into two group's viz., group I: diluted with extender I and group II: diluted with extender II up to 60×106 sperm/mL. The diluted semen samples were packed into French mini straws (0.25 mL), sealed with polyvinyl alcohol powder, kept for 3 h at 5°C for equilibration and then kept in automatic programmable freezer until temperature of straws reached -145°C followed by plunging into liquid nitrogen (-196°C). The evaluation of semen samples was carried out for various seminal attributes (sperm motility, live sperm count, acrosomal integrity, and hypo-osmotic swelling (HOS) response) and antioxidant profile (superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant capacity (TAC)) at pre freeze and post thaw stage. RESULTS: Sperm motility, live sperm count, acrosomal integrity, HOS response were significantly (P<0.05) higher in group II as compared to group I. The average seminal SOD, GPx and TAC levels were significantly (P<0.05) higher in group II as compared to group I at pre freeze and post thaw stage. CONCLUSION: It is concluded that partial deoxygenation of the extender prior to its addition to semen enhances sperm quality in terms of sperm motility, live sperm count, acrosomal integrity, and hypo-osmotic swelling (HOS) response and also improves seminal antioxidant profile (superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant capacity (TAC).

Partial deoxygenation of extender improves sperm quality, reduces lipid peroxidation and reactive oxygen species during cryopreservation of buffalo (Bubalus bubalis) semen.

The present study was designed to investigate the effect of partial deoxygenation of extender on sperm quality, lipid peroxidation (LPO) and reactive oxygen species (ROS) in buffalo (Bubalus bubalis) during cryopreservation of semen. Semen extender was prepared freshly and split into three sub-extenders [Extender I: control (non-deoxygenated), Extender II (partially deoxygenated by using LN2 flushing) and Extender III (partially deoxygenated mechanically by vacuum pump)]. Amounts of dissolved oxygen (DO) were determined in all the three extenders and also in post-thaw semen. Ejaculates with mass motility of ≥3+ and individual progressive motility of 70% or greater were collected from Murrah buffalo bulls and utilized in the study. Each semen sample was divided into Groups I (diluted with Extender I), II (diluted with Extender II) and III (diluted Extender III) with a maximum of 60 × 106 sperm/mL. French mini straws (0.25 mL) were filled with the extended semen samples, sealed with polyvinyl alcohol powder, kept for 3 h at 5 °C for equilibration and then stored in an automatic programmable freezer until the temperature of straws reached -145 °C followed by plunging the straws into liquid nitrogen (-196 °C). Semen samples were evaluated at pre-freeze and post-thaw stages for various variables [sperm motility, live sperm count, acrosomal integrity, hypo-osmotic swelling (HOS) response, LPO and ROS concentrations]. The mean DO was less (P < 0.05) in Extender II as compared to I and III. The DO was less (P < 0.05) in Group II (semen extended with Extender II) as compared with III (semen extended with Extender III) and I (semen extended with Extender I). The percentages for sperm motility, viability and intact acrosomes (PIA) were greater (P < 0.05) in Groups II and III as compared to the control group at the pre-freeze stage, while at the post-thaw stage, percentages of sperm motility, viability, PIA and HOS response were greater (P < 0.05) in Group II as compared with the control group and Group III. Pre-freeze HOS response (%) was greater (P < 0.05) in Group II as compared with the control and Group III. At the pre-freeze stage, sperm LPO and ROS were less (P < 0.05) in Groups II and III as compared with the control and at post-thaw stage, spermatic LPO and ROS concentrations were less (P < 0.05) in Group II than in the control group and Group III. In conclusion, partial deoxygenation of extender improves sperm quality, reduces sperm LPO and ROS concentrations in buffalo during cryopreservation. Partial deoxygenation of the extender with LN2 flushing may be one of the ways for improving quality and fertility of frozen-thawed buffalo sperm.

Elastic and anelastic relaxation behaviour of perovskite multiferroics II: PbZr0.53Ti0.47O3 (PZT)-PbFe0.5Ta0.5O3 (PFT).

Elastic and anelastic properties of ceramic samples of multiferroic perovskites with nominal compositions across the binary join PbZr0.53Ti0.47O3-PbFe0.5Ta0.5O3 (PZT-PFT) have been assembled to create a binary phase diagram and to address the role of strain relaxation associated with their phase transitions. Structural relationships are similar to those observed previously for PbZr0.53Ti0.47O3-PbFe0.5Nb0.5O3 (PZT-PFN), but the magnitude of the tetragonal shear strain associated with the ferroelectric order parameter appears to be much smaller. This leads to relaxor character for the development of ferroelectric properties in the end member PbFe0.5Ta0.5O3. As for PZT-PFN, there appear to be two discrete instabilities rather than simply a reorientation of the electric dipole in the transition sequence cubic-tetragonal-monoclinic, and the second transition has characteristics typical of an improper ferroelastic. At intermediate compositions, the ferroelastic microstructure has strain heterogeneities on a mesoscopic length scale and, probably, also on a microscopic scale. This results in a wide anelastic freezing interval for strain-related defects rather than the freezing of discrete twin walls that would occur in a conventional ferroelastic material. In PFT, however, the acoustic loss behaviour more nearly resembles that due to freezing of conventional ferroelastic twin walls. Precursor softening of the shear modulus in both PFT and PFN does not fit with a Vogel-Fulcher description, but in PFT there is a temperature interval where the softening conforms to a power law suggestive of the role of fluctuations of the order parameter with dispersion along one branch of the Brillouin zone. Magnetic ordering appears to be coupled only weakly with a volume strain and not with shear strain but, as with multiferroic PZT-PFN perovskites, takes place within crystals which have significant strain heterogeneities on different length scales.

Effect of incubation on freezability of cholesterol-loaded cyclodextrin treated buffalo (Bubalus bubalis) spermatozoa.

AIM: The aim of this study was to investigate the effect of incubation on freezability of cholesterol loaded cyclodextrin (CLC) treated buffalo spermatozoa. MATERIALS AND METHODS: Semen samples with mass motility of 3+ and greater, collected from Murrah buffalo bulls were utilized. Immediately after collection, four equal groups of semen sample were made. Group I was kept as control and diluted with Tris upto concentration of 60×10(6) sperm/ml, where as Groups II, III, and IV were treated with CLC at 3 mg/120× 10(6) spermatozoa, incubated at 37°C for action of CLC for 10, 15 and 20 min, respectively, and diluted with tris upto concentration of 60×10(6) sperm/ml. All groups were subjected to equilibration and freezing. The evaluation of semen samples from all groups was carried out at fresh, pre-freeze and post-thaw stage for progressive motility, viability and hypo-osmotic swelling response (HOS response). RESULTS: At the pre-freeze stage, significantly (p<0.05) higher percentage of progressive motility and viability was observed in treatment groups as compared to control with no significant difference among treatment groups. HOS response was significantly (p<0.05) higher in treatment groups as compared to control at pre-freeze stage. At post-thaw stage, significantly (p<0.05) higher percentage of progressive motility, viability and HOS response was recorded in Group II as compared to control and other treatment groups (III and IV). Group II retained significant post-thaw motility and viability at various post-thaw incubation periods. CONCLUSION: Incubation period of 10 min for CLC treated buffalo spermatozoa yielded significantly higher results in terms of freezability as compared to incubation for 15 and 20 min.

Elastic and magnetoelastic relaxation behaviour of multiferroic (ferromagnetic + ferroelectric + ferroelastic) Pb(Fe0.5Nb0.5)O3 perovskite.

Resonant Ultrasound Spectroscopy has been used to characterize elastic and anelastic anomalies in a polycrystalline sample of multiferroic Pb(Fe(0.5)Nb(0.5))O(3) (PFN). Elastic softening begins at ~550 K, which is close to the Burns temperature marking the development of dynamical polar nanoregions. A small increase in acoustic loss at ~425 K coincides with the value of T(*) reported for polar nanoregions starting to acquire a static or quasi-static component. Softening of the shear modulus by ~30-35% through ~395-320 K, together with a peak in acoustic loss, is due to classical strain/order parameter coupling through the cubic → tetragonal → monoclinic transition sequence of ferroelectric/ferroelastic transitions. A plateau of high acoustic loss below ~320 K is due to the mobility under stress of a ferroelastic microstructure but, instead of the typical effects of freezing of twin wall motion at some low temperature, there is a steady decrease in loss and increase in elastic stiffness below ~85 K. This is attributed to freezing of a succession of strain-coupled defects with a range of relaxation times and is consistent with a report in the literature that PFN develops a tweed microstructure over a wide temperature interval. No overt anomaly was observed near the expected Néel point, ~145 K, consistent with weak/absent spin/lattice coupling but heat capacity measurements showed that the antiferromagnetic transition is actually smeared out or suppressed. Instead, the sample is weakly ferromagnetic up to ~560 K, though it has not been possible to exclude definitively the possibility that this could be due to some magnetic impurity. Overall, evidence from the RUS data is of a permeating influence of static and dynamic strain relaxation effects which are attributed to local strain heterogeneity on a mesoscopic length scale. These, in turn, must have a role in determining the magnetic properties and multiferroic character of PFN.

Postnatal developmental anatomy of testes and epididymis of Gaddi goats / Desarrollo anatómico postnatal de los testículos y epidídimo de cabras Gaddi

The study revealed that the testes of one-day-old Gaddi goats have descended in the scrotum along with adnexa. They were elongated compressed latero-medially and became ovoid during their postnatal growth and morphogenesis. The two testes were not different significantly in their weight and measurement. The average weight which was about 2.9 gm at birth grew to 107 gm (40X) in pubertal animals and nearly maintained it during the post-puberty (113 g). The mean length (1.46 cm), width (0.85 cm) and thickness (0.62 cm) also grew by 47, 60, and 83 times, respectively. In post-pubertal animals it measured 7.06 x 5.20 x 5.10 cm. The study indicated a very fast growth of the testes from birth to puberty, which did not alter significantly after that. A relatively much faster growth in thickness and width over the length was the reason behind the change of the morphology from more elongated shape at birth to ovoid shape on maturity. The mediastinum testis was grossly discernible in the testis even at birth. Epididymis was identifiable into caput, corpus and cauda. The gross linear mensuration of these components did not differ in the caput and cauda regions on either side, whereas the length of corpus was more on the left side in all age group of animals. The growth curve revealed a continuous growth of all segments, but the fastest growth occurred in the early postnatal life (at 12­18 month age).

El estudio reveló que los testículos de las cabras Gaddi, de un día de edad, descienden al escroto junto con sus anexos. Se elongaron en dirección latero-medial y convirtieron en ovoides durante su crecimiento postnatal y en la morfogénesis. Los dos testículos no fueron significativamente diferentes en su peso y medidas. El peso promedio fue aproximadamente de 2,9 g al nacer, y aumentó a 107 g (40X) en animales púberes y casi mantuvo su peso durante la post-pubertad (113 g). La longitud (1,46 cm), ancho (0,85 cm) y espesor (0,62 cm) también crecieron unas 47, 60 y 83 veces, respectivamente. En los animales post-puberales las medidas fueron de 7,06 x 5,20 x 5.10 cm. Se observó un crecimiento muy rápido de los testículos desde el nacimiento hasta la pubertad, sin alterarse de manera significativa posteriormente. Un crecimiento relativamente mucho más rápido en espesor y anchura, sobre la longitud, fue la razón detrás del cambio de la morfología desde la forma más alargada, presente en el nacimiento, a la forma ovoide de la madurez. El mediastino testicular fue claramente identificado en el testículo, inclusive en el nacimiento. En el epidídimo se identificaron las porciones de la cabeza, cuerpo y cola. La medición lineal de estos componentes no difirió en las regiones de la cabeza y cola de cada lado, mientras que la longitud del cuerpo fue mayor en el lado izquierdo en todos los grupos. La curva de crecimiento reveló un crecimiento continuo de todos los segmentos, pero el mayor crecimiento se produjo en la vida postnatal temprana (entre los 12 y 18 meses).

Tunneling electroresistance in multiferroic heterostructures.

We demonstrate the room temperature polar switching and tunneling in PbZr0.52Ti0.48O3 (PZT) ultra-thin films of thickness 3-7 nm, sandwiched between platinum metal and ferromagnetic La0.67Sr0.33MnO3 (LSMO) layers, which also shows magnetic field dependent tunnel current switching in Pt/PbZr0.52Ti0.48O3/La0.67Sr0.33MnO3 heterostructures. The epitaxial nature, surface quality and ferroelectric switching of heterostructured films were examined with the help of x-ray diffraction patterns, atomic force microscopy, and piezo force microscopy, respectively. The capacitance versus voltage graphs show butterfly loops above the coercive field (> ±3 V) of PZT for small probe area (∼16 µm(2)). The effect of ferroelectric switching was observed in current density versus voltage curves with a large variation in high-resistance/low-resistance (HRS/LRS) ratio (2:1 to 100:1), however, these effects were more prominent in the presence of in-plane external magnetic field. The conductance is fitted with Brinkman's model, and the parabolic conductance upon bias voltage implies electron tunneling governs the transport.

Postnatal development of testis in gaddi goat (capra hircus) / Desarrollo postnatal del testículo en la cabra gaddi (capra hircus)

A study was conducted on the testicles of 30 male Gaddi goats, divided into 3 groups viz; prepubertal (0 day to 18 months), pubertal (<18 months to >5 yrs) and post- pubertal (>5 yrs) ages. The study revealed that the testis was covered by fibroserous tunica albuginia having outer fibrous layer and inner vascular layer with smooth muscle fibers at birth. The tunica albuginia continuously grew in thickness from prepubertal to postpubertal animals. The septula testis arising from the tunica albuginia, divided the parenchyma in lobules and converged at mediastinum testis. Few differentiated and undifferentiated Leydig cells were present in the intertubular spaces of neonates, which enormously increased in pubertal animals and replaced by fibroblasts in the postpubertal animals. The parenchyma comprised of solid sex cords in new born kids. These were converted into luminated tubules after 6 months of age and had clear cut tubuli contorti and tubuli recti leading to the mediastinum testis. In "0" day old kids, sex cords were filled with undifferentiated small cells located peripherally along the basement membrane and large primordial germ cells located centrally. By six months of age, latter started showing sign of degeneration and thus luminization of tubules started. Spermatogenesis startedin the seminiferous tubules of 12-18 months goat. In pubertal animals all the stages of spermatogenic cells and Sertoli cells were identified in the seminiferous tubules. The population of gonia cells and primary + secondary spermatocytes were 35% and 30% respectively. In postpubertal animals gonia cells were reduced to <30% and Primary + secondary spermatocytes were <20%. Many degenerating seminiferous tubules showed hyalinization, fibrosis and giant cells. The stroma and parenchyma ratio which was 35:65 at birth became 30:60 at 6 months, 25:75 at 12 months and 15:85 in pubertal and 20:80 in postpubertal animals. Increased stroma in last phase was associated with replacement of seminiuferous tubules by fibrous elements.

Se realizó un estudio en 30 testículos de cabras Gaddi machos divididos en 3 grupos: prepúberes (0 días a 18 meses), púberes (<18 meses y >5 años) y post-púberes (>5 años). El estudio reveló que los testículos al nacimiento estaban cubiertos por una túnica albugínea fibroserosa con una capa fibrosa externa y otra capa vascular interna con fibras musculares lisas. En los animales prepúberes hasta los pospúberes, la túnica albugínea mostró un crecimiento continuo de espesor. El septo testicular derivado de la túnica albugínea, divide el parénquima en lóbulos convergentes en el mediastino testicular. En los espacios intertubulares de los testículos de los recién nacidos, se observaron escasas células interticiales diferenciadas e indiferenciadas, sin embargo, se registró un aumento importante en los animales púberes las cuales fueron reemplazadas por fibroblastos después de la pubertad. El parénquima en los testículos de los animales recién nacidos estaba compuesto por cordones sexuales continuos. Estos se convierten en túbulos luminados después de los 6 meses de edad, evidenciando túbulos contorneados y rectos que conducen al mediastino testicular. En animales de 0 días de edad, los cordones sexuales presentaban pequeñas células no diferenciadas y situadas periféricamente a lo largo de la membrana basal y grandes células germinales primordiales céntricas. A los seis meses de edad, este último comenzó a mostrar signos de degeneración. La espermatogénesis se inició en los túbulos seminíferos desde los 12 a 18 meses de edad. En los animales púberes se identificaron en los túbulos seminíferos todas las etapas de las células de espermatogénesis y células sustentaculares. La población de células gonia fue del 35% y de espermatocitos primarios más secundarios 30%. En los animales pospúberes las células gonia se redujeron a <30% y espermatocitos primarios más secundarios a < 20%. Muchos túbulos seminíferos presentaron degeneración. La relación parénquima/estroma fue 35:65 al nacer, luego de 30:60 a los 6 meses, de 25:75 a los 12 meses, de 15:85 en animales prepúberes y 20:80 en la pubertad. El aumento del estroma en la última fase fue asociado con el reemplazo de los túbulos seminíferos por elementos fibrosos.

Switching ferroelectric domain configurations using both electric and magnetic fields in Pb(Zr,Ti)O3-Pb(Fe,Ta)O3 single-crystal lamellae.

Thin single-crystal lamellae cut from Pb(Zr,Ti)O3-Pb(Fe,Ta)O3 ceramic samples have been integrated into simple coplanar capacitor devices. The influence of applied electric and magnetic fields on ferroelectric domain configurations has been mapped, using piezoresponse force microscopy. The extent to which magnetic fields alter the ferroelectric domains was found to be strongly history dependent: after switching had been induced by applying electric fields, the susceptibility of the domains to change under a magnetic field (the effective magnetoelectric coupling parameter) was large. Such large, magnetic field-induced changes resulted in a remanent domain state very similar to the remanent state induced by an electric field. Subsequent magnetic field reversal induced more modest ferroelectric switching.

Complete sequence of RNA3 of Cucumber mosaic virus isolates infecting Gerbera jamesonii suggests its grouping under IB subgroup.

The complete RNA3 genome of Cucumber mosaic virus (CMV) was amplified by RT-PCR from three infected gerbera (Gerbera jamesonii) leaf samples exhibiting severe chlorotic mosaic and flower deformation symptoms. The amplicons obtained were cloned sequenced and deposited in GenBank under the accessions JN692495, JX913531 (from cv. Zingaro) and JX888093 (from cv. Silvester). These sequences shared 98-99 % identities to each other and with a strain of CMV-Banana reported from India, and 90-95 % identities with various strains of CMV reported worldwide. Phylogenetic analysis revealed their closest affinity with CMV-Banana strain, and close relationships with several other strains of CMV of subgroup IB. This study provides evidence of subgroup IB CMV causing severe chlorosis and flower deformation in two cultivars (Zingaro and Silvester) of G. jamesonii in India.

Studies of the Room-Temperature Multiferroic Pb(Fe0.5Ta0.5)0.4(Zr0.53Ti0.47)0.6O3: Resonant Ultrasound Spectroscopy, Dielectric, and Magnetic Phenomena.

Recently, lead iron tantalate/lead zirconium titanate (PZTFT) was demonstrated to possess large, but unreliable, magnetoelectric coupling at room temperature. Such large coupling would be desirable for device applications but reproducibility would also be critical. To better understand the coupling, the properties of all 3 ferroic order parameters, elastic, electric, and magnetic, believed to be present in the material across a range of temperatures, are investigated. In high temperature elastic data, an anomaly is observed at the orthorhombic mm2 to tetragonal 4mm transition, Tot = 475 K, and a softening trend is observed as the temperature is increased toward 1300 K, where the material is known to become cubic. Thermal degradation makes it impossible to measure elastic behavior up to this temperature, however. In the low temperature region, there are elastic anomalies near ≈40 K and in the range 160-245 K. The former is interpreted as being due to a magnetic ordering transition and the latter is interpreted as a hysteretic regime of mixed rhombohedral and orthorhombic structures. Electrical and magnetic data collected below room temperature show anomalies at remarkably similar temperature ranges to the elastic data. These observations are used to suggest that the three order parameters in PZTFT are strongly coupled.

Dynamic nanocrystal response and high temperature growth of carbon nanotube-ferroelectric hybrid nanostructure.

A long standing problem related to the capping of carbon nanotubes (CNT) by inorganic materials at high temperature has been solved. In situ dynamic response of Pb(Zr0.52Ti0.48)O3 (PZT) nanocrystals attached to the wings of the outer surface of PZT/CNT hybrid-nanostructure has been demonstrated under a constant-energy high-resolution transmission electron microscopy (HRTEM) e-beam. PZT nanocrystals revealed that the crystal orientations, positions, faces, and hopping states change with time. HRTEM study has been performed to investigate the microstructure of hybrid nanostructures and nanosize polycrystal trapped across the wings. Raman spectroscopy was utilized to investigate the local structures, defects, crystal qualities and temperature dependent growth and degradation of hybrid nanostructures. Raman spectra indicate that MWCNT and PZT/MWCNT/n-Si possess good quality of CNT before and after PZT deposition until 650 °C. The monoclinic Cc/Cm phase of PZT which is optimum in piezoelectric properties was prominent in the hybrid structure and should be useful for device applications. An unusual hexagonal faceting oscillation of the nano-crystal perimeter on a 10-30 s period is also observed.

N-doped ZnO thin film for development of magnetic field sensor based on surface plasmon resonance.

Magnetic-field-dependent optical properties of nitrogen-doped ZnO (ZnO:N) thin films were investigated using surface plasmon resonance (SPR) and a highly sensitive (4.65/Tesla) magnetic field sensor has been realized. The refractive index (RI) of ZnO:N film increases from 1.949 to 2.025 with increase in N doping from 0% to 10% demonstrating tunable RI. In contrast to pure ZnO, SPR curves for ZnO:N films exhibit a shift toward lower angles with increasing applied magnetic field from 0 to 35 mT due to change in reflectance of light upon reflection from ferromagnetic surface. Results indicate promising application of ferromagnetic ZnO:N film as a magnetic field sensor.