Nonlinear Transport due to Magnetic-Field-Induced Flat Bands in the Nodal-Line Semimetal ZrTe_{5}.

The Dirac material ZrTe_{5} at very low carrier density was recently found to be a nodal-line semimetal, where ultraflat bands are expected to emerge in magnetic fields parallel to the nodal-line plane. Here, we report that in very low carrier-density samples of ZrTe_{5}, when the current and the magnetic field are both along the crystallographic a axis, the current-voltage characteristics presents a pronounced nonlinearity which tends to saturate in the ultra quantum limit. The magnetic-field dependence of the nonlinear coefficient is well explained by the Boltzmann theory for flat-band transport, and we argue that this nonlinear transport is likely due to the combined effect of flat bands and charge puddles; the latter appear due to very low carrier densities.

Gigantic Magnetochiral Anisotropy in the Topological Semimetal ZrTe_{5}.

Topological materials with broken inversion symmetry can give rise to nonreciprocal responses, such as the current rectification controlled by magnetic fields via magnetochiral anisotropy. Bulk nonreciprocal responses usually stem from relativistic corrections and are always very small. Here we report our discovery that ZrTe_{5} crystals in proximity to a topological quantum phase transition present gigantic magnetochiral anisotropy, which is the largest ever observed to date. We argue that a very low carrier density, inhomogeneities, and a torus-shaped Fermi surface induced by breaking of inversion symmetry in a Dirac material are central to explain this extraordinary property.

Relationship between toxicity of cryoprotectants, osmotic and oxidative stresses in awassi ram sperm.

BACKGROUND: The relationship between the toxicity of cryoprotectants and their osmotic and/or oxidative stresses remains to be further investigated. OBJECTIVE: To investigate the toxic effects of different cryoprotectants and osmotic stress on Awassi ram sperm and to determine the relationship between oxidative and antioxidative status of the sperm. MATERIALS AND METHODS: Pooled sperm samples were exposed to sucrose solutions of different concentrations (75 to 900 mOsm) and isosmotic condition (290-325 mOsm) was re-established by adding HEPES buffered Tyrode's lactate. Sperm samples were mixed with 0.5, 1.0 and 1.5 M of glycerol, methanol, 2-methoxyethanol, dimethylacetamide or 1,2-propanediol for 5 min and returned to isosmotic condition. Sperm samples were exposed to cryoprotectants at 4 degree C for 2 hours and isosmotic conditions were re-established. Motility, viability, acrosome integrity and oxidative or antioxidative parameters were determined. RESULTS: Treatment with hypo- or hyperosmotic sucrose solution reduced motility and viability without affecting acrosome integrity. The addition and removal of glycerol and dimethylacetamide (1.0 or 1.5 M) decreased sperm motility, while cryoprotectants had no effect on viability except for 1.5 M glycerol. Chilling significantly reduced the motility and viability of the sperm, but not the acrosome integrity. Rapid addition or removal of cryoprotectants also did not affect the acrosome integrity. Cryoprotectants changed only the ceruloplasmin level, while there were significant post-chilling differences in lipid hydroperoxide, paraoxonase and ceruloplasmin levels. CONCLUSION: Cryoprotectants without other additives have limited protection and glycerol can be toxic to spermatozoa. The oxidative stress plays a role in cryoprotectant toxicity and chilling stress. doi.org/10.54680/fr22210110612.

Impacts of Specific Cryoprotectants on Sperm Freezing and Relationships Between Cryodamage and Oxidation Stress Parameters in Awassi Ram Sperm.

BACKGROUND: The role of oxidative stress during cryoprotectant treatment has received little attention. OBJECTIVE: To assess the effects of different cryoprotectants and discover relationships between cryodamage and oxidative stress parameters on Awassi ram sperm. MATERIALS AND METHODS: The sperm samples diluted with Salamon's tris-citrate (TRIS) containing 20% centrifuged egg yolk and 0.5, 1.0 or 1.5 M Glycerol (Gly), methanol (M), 2-methoxyethanol (2-ME), dimethylacetamide (DMA) and 1.2 propanediol (PR). After 2 h of equilibration at +4 ºC, the sperm samples were frozen in liquid nitrogen vapour and stored. RESULTS: The best post-thaw motility (43.3%, 41.7%) of sperm was achieved when protected with 0.5 and 1.0 M glycerol. Arylesterase and ceruloplasmin parameters were significantly different after equilibration, whereas sulfhydryl groups were significantly different after freezing in their respective groups (P < 0.05). CONCLUSION: The increased use of glycerol caused greater loss of motility. The role of oxidative stress in freezing was also found to be limited.

Treatment with Melatonin Enhances the Embryo Quality and the Development of Vitrified/warmed Eight Cell Mouse Embryos by Solid Surface Vitrification (SSV).

BACKGROUND: Melatonin is an endocrine hormone secreted from the pineal gland located outside the blood-brain barrier. OBJECTIVE: In this study, in vitro propagated eight-cell mouse embryos were vitrified by the Solid Surface Vitrification (SSV) method and after thawing, their in vitro development and embryo qualities in melatonin added media were investigated. METHODS: Pronuclear stage embryos obtained from super ovulated B6CBAF1/J strain mice, were cultured until the eight-cell stage. Then these eight-cell embryos were vitrified by the SSV method and after thawing, cultured in melatonin added media at 37°C and 5 %CO2 conditions until the blastocyst stage. RESULT: In the experimental period, in vitro embryo development rates of the control, SSV and +10-12 M melatonin groups were observed as 97%, 86% and 93%, respectively. CONCLUSION: Our results indicated that melatonin addition slightly increased the development rates and total cell numbers of embryos vitrified by the SSV method.

How do arbidol and its analogs inhibit the SARS-CoV-2?

BACKGROUND: COVID-19 is not fully known and causes severe inflammation and cytokine storm. It has many symptoms, such as: fever, sore throat, headache, dyspnoea, and diarrhoea. Arbidol was used in the treatment of COVID19, which was the most critical health problem in the world. However, the desired recovery was not achieved with Arbidol. Many countries still use this drug in the treatment of COVID19. AIM: We aimed to determine whether Arbidol, the hemagglutinin esterase inhibitor used in the treatment of COVID-19, was effective against SARS Cov-2 in silico. RESULTS AND CONCLUSION: The similarity between hemagglutinin and spike proteins were reported due to the fact that inhibition properties of Arbidol and its 39 analogues were examined in detail against hemagglutinin esterase and spike glycoproteins. CID 1070884 and CID 1207786 were found to be more active against hemagglutinin esterase than in Arbidol, while these compounds were inactive against spike glycoproteins. The interaction mechanism was clarified between arbidol and spike proteins. Phenylalanine, tyrosine, glycine, lysine, and aspartic acid were found to be the headliner amino acids in the interactions between Arbidol and binding domains of spike glycoproteins in the SARS-CoV2 (Tab. 3, Fig. 8, Ref. 28).

Comparison of two different GnRH analogs' impact on final height in girls with early puberty: Triptorelin acetate vs. leuprolide acetate.

CONTEXT: GnRHa treatment has been a standard of care in progressive early puberty (EP). Choice of the GnRHa formulation is dependent on the preference of the clinician. OBJECTIVE: To compare the effects of triptorelin acetate (TA) and leuprolide acetate (LA) on anthropometry in girls with EP. DESIGN: A descriptive observational study. SUBJECTS AND METHODS: Girls diagnosed with central EP and treated with GnRHa at least for one year were included; treated with TA (n=46) and LA (n=35). First year anthropometric response and final height were evaluated. RESULTS: The mean age at the initiation of GnRHa treatment of girls was 8.5±0.5 years. The ratio of obesity and of overweight was 7.4 and 25.9%, respectively. In both TA and LA groups, anthropometric data of the patients at initiation and at the first year of treatment were similar. Although growth velocity was similar in each group, in LA group height SDS at the first year of the treatment showed a significant decrease (p=0.045), but not in TA group (p=0.317). No significant ΔBMI was observed with treatment. The differences between FH - PAH at initiation (height gain) in TA and LA groups were 2.9±4.7 and 4.0±5.8 cm, respectively (p=.316). Height gain per treatment year was 1.7±3.0 cm. CONCLUSIONS: There was a significant decrease in height SDS at the first year of leuprolid treatment, but not in triptorelin. Although these two analogs show similar effects on treatment, a not significant but slightly better benefit in leuprolide was observed.

Lycopene has a protective effect on septic shock­induced cardiac injury in rats.

OBJECTIVE: The aim of the present study is to investigate the cardioprotective effect of lycopene, known for its antioxidant and anti-inflammatory effect, in a rat sepsis model induced by lypopolysaccharide (LPS). METHODS: The oxidative stress parameters, antioxidant parameters and cytokine levels with or without lycopene treatment in LPS­induced septic rats as well as in controls were measured in serum and tissue. Histologic examinations of the cardiac tissues were also performed. The Kruskal-Wallis and the Bonferroni-adjusted Mann-Whitney U Test was used for analysis. A p value < 0.05 was considered significant. RESULTS: The data of this study showed that lycopene pretreatment reduced the oxidative stres parametersand , proinflammatory cytokines as well as increased the antoxidant enzyme activities in both serum and cardiac tissues in LPS­induced septic rats.. Moreover, hyperaemia and haemorrhage in the epicardium, myocardium and endocardium were lower in the lycopene pretreated group as compared to the LPS alone group. CONCLUSION: These results suggest that lycopene could be beneficial for the prevention of cardiac injury caused by sepsis through reducing the cytokine levels and oxidative stress parameters (Tab. 4, Fig. 1, Ref. 35).

Evaluation of intra-testicular injections of calcium chloride and 4-vinylcyclohexene 1,2 monoepoxide for chemical sterilization in guinea pigs.

This study was aimed at investigating the use of intra-testicular calcium chloride (CaCl2) and 4-vinylcyclohexene 1,2-monoepoxide (VCM) injections as a side effect-free alternative method for the control of reproduction in guinea pigs. Fifty male guinea pigs were randomly assigned to five groups. In all groups, the chemical agents were injected into both testes in 1% lidocaine hydrochloride. While Groups I, II and III were administered with a single dose (0.25 mL) of sterile physiological saline, 15 mg/100 g CaCl2, and 240 mg/kg VCM, respectively, Group IV and V received a daily dose of 15 mg/100 g CaCl2, and 240 mg/kg VCM for 3 days, respectively. On day 90 post-administration, all animals were weighed and later decapitated under ether anaesthesia. Blood and tissue (testis, liver, hypophysis and adrenal gland) samples were taken. Sperm samples from the cauda epididymis were examined for spermatological parameters. Blood was used for hormone analyses and tissue samples were examined histopathologically (haematoxylin-eosin) and immunohistochemically (Tunel staining). The epididymal sperm count decreased in all treatment groups. Excluding 2 animals, Group V displayed azoospermia. When compared to the control group, Group V displayed the highest prolactin and lowest testosterone levels, and Group III showed the highest testosterone level. Histopathological examination revealed no intoxication finding. Chemical castration with VCM may be a good alternative to surgical castration as it enables mass sterilization without postoperative risks in guinea pig.

Curcumin and dexmedetomidine prevents oxidative stress and renal injury in hind limb ischemia/reperfusion injury in a rat model.

Curcumin and dexmedetomidine have been shown to have protective effects in ischemia-reperfusion injury on various organs. However, their protective effects on kidney tissue against ischemia-reperfusion injury remain unclear. We aimed to determine whether curcumin or dexmedetomidine prevents renal tissue from injury that was induced by hind limb ischemia-reperfusion in rats. Fifty rats were divided into five groups: sham, control, curcumin (CUR) group (200 mg/kg curcumin, n = 10), dexmedetomidine (DEX) group (25 µg/kg dexmedetomidine, n = 10), and curcumin-dexmedetomidine (CUR-DEX) group (200 mg/kg curcumin and 25 µg/kg dexmedetomidine). Curcumin and dexmedetomidine were administered intraperitoneally immediately after the end of 4 h ischemia, just 5 min before reperfusion. The extremity re-perfused for 2 h and then blood samples were taken and total antioxidant capacity (TAC), total oxidative status (TOS) levels, and oxidative stress index (OSI) were measured, and renal tissue samples were histopathologically examined. The TAC activity levels in blood samples were significantly lower in the control than the other groups (p < 0.01 for all comparisons). The TOS activity levels in blood samples were significantly higher in Control group and than the other groups (p < 0.01 for all comparison). The OSI were found to be significantly increased in the control group compared to others groups (p < 0.001 for all comparisons). Histopathological examination revealed less severe lesions in the sham, CUR, DEX, and CUR-DEX groups, compared with the control group (p < 0.01). Rat hind limb ischemia-reperfusion causes histopathological changes in the kidneys. Curcumin and dexmedetomidine administered intraperitoneally was effective in reducing oxidative stress and renal histopathologic injury in an acute hind limb I/R rat model.

Effect of dietary restriction on sperm characteristic and oxidative status on testicular tissue in young rats exposed to long-term heat stress.

This study was conducted to evaluate the effects of dietary restriction on oxidative status and sperm parameters in rats exposed to long-term heat stress. Forty healthy Sprague-Dawley rats, aged 2.5 month, were divided into four groups of 10 with respect to feeding and temperature regimen (room temperature (22 °C)-ad libitum, room temperature-dietary restriction (40%), high temperature (38 °C)-ad libitum, high temperature-dietary restriction). At the end of the 9th week, some oxidants (lipid hydroperoxide, total oxidant status, oxidative stress index) and antioxidants (total antioxidant status, sulfhydryl groups, ceruloplasmin, paraoxonase and arylesterase activities) were measured in the testis tissue. The concentration, motility, volume, abnormal sperm count, acrosome and membrane integrity of epididymal spermatozoon and intratesticular testosterone levels were evaluated. High temperature did not change oxidative and antioxidative parameters except for sulfhydryl groups and ceruloplasmin, yet it impaired all sperm values. Neither sperm values nor oxidative status apart from sulfhydryl groups, ceruloplasmin and arylesterase was affected by dietary restriction in the testis tissue. These results suggest that long-term heat stress does not have a significant effect on testicular oxidative status, while the spermatozoa are sensitive to heat stress in young rats. Dietary restriction failed to improve the sperm quality and oxidative status except some individual antioxidant parameters; conversely, it decreased intratesticular testosterone level in the young rats exposed to long-term heat stress.

Effects of Boric acid as Maternal Feed Additives on the Development and Sex Ratio of Mouse pups.

Boron is primarily used in industrial applications, with recent interest revolving around its effects on metabolism. In this study, we administered boric acid (BA), which has positive effects on reproduction, in conjunction with feed supplementation to serve as a model for experimental animal development and breeding. The pregnancy performance, offspring development, and biochemical effects of mice given feed supplemented with BA at concentrations of 0 (control group), 250, and 500 ppm (BA groups) were investigated. A total of 18 female Balb-C mice were utilized for pregnancy. The mice were given the BA-supplemented feed during a period encompassing three weeks of pregnancy and three weeks of lactation. The numbers and weights of offspring born in cages on days 19-21 were determined. Blood and tissue samples were collected from the offspring during the third week postnatal, and the malondialdehyde (MDA) and total antioxidant and oxidant status (TAS, TOS, and OSI) levels were determined. A significant increase in female offspring was observed in the groups born to mice fed with BA compared to the control group. Positive development in organ weights was observed in the 250-ppm BA group. The 250-ppm group exhibited a significant increase in TAS compared to the control group, while TOS and MDA levels showed a decrease. Also, the levels of BA groups were found to decrease in both the OSI index serum and organ samples compared to the control group. Thus, the use of 250-ppm BA demonstrated positive effects on female offspring production, organ development, and antioxidant levels.

Fermiology of the strongly spin-orbit coupled superconductor Sn(1-x)In(x)Te: implications for topological superconductivity.

We have performed angle-resolved photoemission spectroscopy on the strongly spin-orbit coupled low-carrier density superconductor Sn(1-x)In(x)Te (x = 0.045) to elucidate the electronic states relevant to the possible occurrence of topological superconductivity, as recently reported for this compound based on point-contact spectroscopy. The obtained energy-band structure reveals a small holelike Fermi surface centered at the L point of the bulk Brillouin zone, together with a signature of a topological surface state, indicating that this material is a doped topological crystalline insulator characterized by band inversion and mirror symmetry. A comparison of the electronic states with a band-noninverted superconductor possessing a similar Fermi surface structure, Pb(1-x)Tl(x)Te, suggests that the anomalous behavior in the superconducting state of Sn(1-x)In(x)Te is related to the peculiar orbital characteristics of the bulk valence band and/or the presence of a topological surface state.

The association of serum prolidase activity with developmental dysplasia of the hip.

The purpose of this study was to evaluate serum prolidase activity in patients with developmental dysplasia of the hip (DDH). Prolidase enzyme activity was measured spectrophotometrically to pointing out the collagen metabolism. The prolidase activity in patients with DDH was significantly higher than that in the control group (p = 0.002). Furthermore, there was positive correlation between prolidase activity and dysplasia level. Increased serum prolidase activity may have played a role in the presence of DDH. We therefore hypothesized that the increased prolidase activity related to collagen turnover may be associated with etiopathogenesis and/or the progression of the disease.

Nitrosative stress-based specific evaluation of creatine use in combination with aerobic running exercise at different speeds: a preclinical study in mice.

OBJECTIVE: In acute and chronic aerobic exercise, skeletal muscle and liver are the main organs that adapt and regulate metabolic activity. The levels of nitrosative stress caused by exercise in these organs are extremely important in the continuity of exercise, its health-promoting benefits, and the evaluation of therapeutic efficacy. In this study, nitrosative stress levels were investigated in musculus quadriceps femoris tissue and liver tissue of mice that were given low and high-speed aerobic running exercise and also received Cr supplementation. MATERIALS AND METHODS: In this study, nitrosative stress levels were investigated in the muscle/liver tissue of 42 BALB/c mice that were given low and high-speed aerobic running exercise and creatine monohydrate (Cr) (40 mg/kg of diet daily) supplementation with exercise. The study included six groups with and without Cr supplementation, low-speed aerobic running, high-speed aerobic running, and no exercise. The mice in groups with low-speed and high-speed aerobic exercise with and without Cr supplementation were run on the treadmill for 8 weeks. Then, nitric oxide (NO·), nitric oxide synthase (NOS), and peroxynitrite (ONOO-) levels in muscle/liver tissue were measured by spectrophotometric method. RESULTS: It was found that the nitrosative stress level in the groups that did low and high-speed aerobic running exercises increased compared to the group that did not exercise. It was found that NO· decreased NOS activity and ONOO- level increased in muscle tissues of low and high-speed aerobic exercise groups that received Cr supplementation compared to those that did not. However, NO· and ONOO- levels in liver tissue decreased while NOS activity did not change. The lowest level of nitrosative stress in both muscle and liver tissue was found in the low-speed exercise group receiving Cr supplementation. CONCLUSIONS: Although supplements in exercise are an important component, the simultaneously measured nitrosative stress level is critical in determining the optimal exercise.

Boric Acid Improved Cryopreserved Mouse Embryo Development.

Boric acid (BA) is an essential trace element that is required to support the metabolic pathways in plants, humans, and animals. The present study investigates the in vitro development and quality of single-cell mouse embryos in a BA-added culture medium after cryopreservation using the solid-surface vitrification method. For this purpose, the pronuclear-stage embryos derived from superovulated C57Bl/6j mouse strains and the one-cell embryos were then cryopreserved using the solid-surface vitrification (SSV) method. After thawing, the embryos were cultured in a BA-added medium at 37 °C in a 5% CO2 environment until the blastocyst stage. The resulting in vitro development rates of the embryos in the control group, SSV group, and SSV + 1.62 × 10-4 µM BA group were 68.11% (36/59), 40.16% (16/48), and 64.92% (28/48) respectively, indicating that the BA supported the in vitro development of the embryos cryopreserved using the SSV method. Our results suggest that the addition of boric acid to the culture media increased the development rate of the embryos that were vitrified using the SSV method.

Manifestation of topological protection in transport properties of epitaxial Bi2Se3 thin films.

The massless Dirac fermions residing on the surface of three-dimensional topological insulators are protected from backscattering and cannot be localized by disorder, but such protection can be lifted in ultrathin films when the three-dimensionality is lost. By measuring the Shubnikov-de Haas oscillations in a series of high-quality Bi2Se3 thin films, we revealed a systematic evolution of the surface conductance as a function of thickness and found a striking manifestation of the topological protection: The metallic surface transport abruptly diminishes below the critical thickness of ~6 nm, at which an energy gap opens in the surface state and the Dirac fermions become massive. At the same time, the weak antilocalization behavior is found to weaken in the gapped phase due to the loss of π Berry phase.

Odd-parity pairing and topological superconductivity in a strongly spin-orbit coupled semiconductor.

The existence of topological superconductors preserving time-reversal symmetry was recently predicted, and they are expected to provide a solid-state realization of itinerant massless Majorana fermions and a route to topological quantum computation. Their first likely example, Cu(x)Bi(2)Se(3), was discovered last year, but the search for new materials has so far been hindered by the lack of a guiding principle. Here, we report point-contact spectroscopy experiments suggesting that the low-carrier-density superconductor Sn(1-x)In(x)Te is accompanied by surface Andreev bound states which, with the help of theoretical analysis, would give evidence for odd-parity pairing and topological superconductivity. The present and previous finding of possible topological superconductivity in Sn(1-x)In(x)Te and Cu(x)Bi(2)Se(3) suggests that odd-parity pairing favored by strong spin-orbit coupling is likely to be a common underlying mechanism for materializing topological superconductivity.

Giant magnetochiral anisotropy from quantum-confined surface states of topological insulator nanowires.

Wireless technology relies on the conversion of alternating electromagnetic fields into direct currents, a process known as rectification. Although rectifiers are normally based on semiconductor diodes, quantum mechanical non-reciprocal transport effects that enable a highly controllable rectification were recently discovered1-9. One such effect is magnetochiral anisotropy (MCA)6-9, in which the resistance of a material or a device depends on both the direction of the current flow and an applied magnetic field. However, the size of rectification possible due to MCA is usually extremely small because MCA relies on inversion symmetry breaking that leads to the manifestation of spin-orbit coupling, which is a relativistic effect6-8. In typical materials, the rectification coefficient γ due to MCA is usually ∣γ∣ ≲ 1 A-1 T-1 (refs. 8-12) and the maximum values reported so far are ∣γ∣ ≈ 100 A-1 T-1 in carbon nanotubes13 and ZrTe5 (ref. 14). Here, to overcome this limitation, we artificially break the inversion symmetry via an applied gate voltage in thin topological insulator (TI) nanowire heterostructures and theoretically predict that such a symmetry breaking can lead to a giant MCA effect. Our prediction is confirmed via experiments on thin bulk-insulating (Bi1-xSbx)2Te3 (BST) TI nanowires, in which we observe an MCA consistent with theory and ∣γ∣ ≈ 100,000 A-1 T-1, a very large MCA rectification coefficient in a normal conductor.

Observation of dirac holes and electrons in a topological insulator.

We show that in the new topological-insulator compound Bi(1.5)Sb(0.5)Te(1.7)Se(1.3) one can achieve a surfaced-dominated transport where the surface channel contributes up to 70% of the total conductance. Furthermore, it was found that in this material the transport properties sharply reflect the time dependence of the surface chemical potential, presenting a sign change in the Hall coefficient with time. We demonstrate that such an evolution makes us observe both Dirac holes and electrons on the surface, which allows us to reconstruct the surface band dispersion across the Dirac point.