Observation of short range order driven large refrigerant capacity in chemically disordered single phase compound Dy2Ni0.87Si2.95

In this work, we report the successful synthesis of a new intermetallic compound Dy2Ni0.87Si2.95 forming in single phase only with a chemically disordered structure. The random distribution of Ni/Si and crystal defects create a variation in the local electronic environment between the magnetic Dy ions. In the presence of both disorder and competing exchange interactions driven magnetic frustration, originating due to c/a ∼ 1, the compound undergoes spin freezing behaviour below 5.6 K. In the non-equilibrium state below the spin freezing behaviour, the compound exhibits aging phenomena and magnetic memory effects. In the magnetically short-range ordered region, much above the freezing temperature, an unusual occurrence of considerable magnetic entropy change, -ΔSmaxM ∼ 21 J kg-1 K-1 with large cooling power RCP ∼ 531 J kg-1 and adiabatic temperature change, ΔTad ∼ 10 K for a field change of 70 kOe, is observed for this short range ordered cluster-glass compound without any magnetic hysteresis loss.

Melatonin attenuates radiofrequency radiation (900 MHz)-induced oxidative stress, DNA damage and cell cycle arrest in germ cells of male Swiss albino mice

Increasing male infertility of unknown aetiology can be associated with environmental factors. Extensive use of mobile phones has exposed the general population to unprecedented levels of radiofrequency radiations (RFRs) that may adversely affect male reproductive health. Therefore, the present study investigated the effect of RFR Global System for Mobile communication (GSM) type, 900 MHz and melatonin supplementation on germ cell development during spermatogenesis. Swiss albino mice were divided into four groups. One group received RFR exposure for 3 h twice/day for 35 days and the other group received the same exposure but with melatonin ( N-acetyl-5-methoxytryptamine) (MEL; 5 mg/kg bw/day). Two other groups received only MEL or remain unexposed. Sperm head abnormality, total sperm count, biochemical assay for lipid peroxides, reduced glutathione, superoxide dismutase activity and testis histology were evaluated. Additionally, flow cytometric evaluation of germ cell subtypes and comet assay were performed in testis. Extensive DNA damage in germ cells of RFR-exposed animals along with arrest in pre-meiotic stages of spermatogenesis eventually leading to low sperm count and sperm head abnormalities were observed. Furthermore, biochemical assays revealed excess free radical generation resulting in histological and morphological changes in testis and germ cells morphology, respectively. However, these effects were either diminished or absent in RFR-exposed animals supplemented with melatonin. Hence, it can be concluded that melatonin inhibits pre-meiotic spermatogenesis arrest in male germ cells through its anti-oxidative potential and ability to improve DNA reparative pathways, leading to normal sperm count and sperm morphology in RFR-exposed animals.

Chemical disorder driven reentrant spin cluster glass state formation and associated magnetocaloric properties of Nd2Ni0.94Si2.94

In this work, we report the synthesis of a new ternary intermetallic compound, Nd₂Ni_0.94Si_2.94, that forms in single phase only in a defect crystal structure. The compound exhibits an antiferromagnetic transition below 7.2 K (T_N) followed by a spin cluster freezing behaviour below 2.85 K (T_f), which makes the compound a reentrant spin cluster glass system. The detailed studies of dc and ac magnetization, heat capacity, non-equilibrium dynamical behaviour, viz., aging effect, temperature and field dependent magnetic relaxation and magnetic memory effect establish the compound to be a cluster-glass material below freezing temperature. The interplay between competing exchange coupling (c/a ≃ 1.04 ⇒ J_NN ≃ J_NNN) and chemical disorder driven variation in the electronic environment among the Nd ions has been argued to be responsible for such a metastable state formation. A considerable value of MCE parameters (-ΔS ∼ 11.4 J kg^-1 K^-1, RCP ∼ 160 J kg^-1 and ΔT_ad ∼ 5.2 K for a field change of 70 kOe) is obtained for this magnetically frustrated glassy compound.

Initial experience with a dual-console robotic-assisted platform for training in colorectal surgery

BACKGROUND

Minimally invasive surgery is associated with several patient-related benefits, including reduced length of hospital stay and reduced blood loss. Robotic-assisted surgery offers many advantages when compared with standard laparoscopic procedures, including a stable three-dimensional binocular camera platform, motion smoothing and motion scaling, improved dexterity and ergonomics. There are limited data on the effectiveness of the dual-console DaVinci Xi platform for teaching resident surgeons. The goal of this study was to examine preliminary outcomes following the introduction of a dual-console robotic platform in our institution.

METHODS

A retrospective review of our prospectively maintained patient database was performed. The first ten dual-console resident-performed procedures in colorectal surgery were compared with matched cases performed on a single console by the trainer. Patient demographics, operative times and patient outcomes were compared.

RESULTS

Twenty patients were included in this study. There was no significant difference in console time (p = 0.46) or total operative time (p = 0.52) when residents and trainers were compared. Patient outcomes were equivalent, with no difference in length of stay, morbidity or mortality.

CONCLUSIONS

The DaVinci Xi dual-console platform is a safe and effective platform for training junior surgeons. The dual-console system has the potential to alter surgical training pathways.

Observation of ultrasharp metamagnetic jumps in polycrystalline Er2Cu2O5

The observation of ultrasharp metamagnetic jumps in the field variation of magnetization (M versus H) data for the highly insulating metal oxide Er₂Cu₂O₅ is investigated. The compound orders antiferromagnetically below about T _N1  =  28 K and shows conventional 'not-so-sharp' metamagnetism around 13 kOe on the field-increasing leg in the polycrystalline sample. The uniqueness of the ultrasharp jumps in Er₂Cu₂O₅ resides in the fact that they are only observed in the field-decreasing segment of the magnetization curve. We observe that the jumps are affected by the sweep rate of the magnetic field, similarly to several other systems that show such ultrasharp jumps. Er₂Cu₂O₅ shows a considerable amount of thermo-remanent magnetization when it is cooled in a field that is higher than the critical field of 13 kOe. Our analysis indicates that above 13 kOe the system remains phase separated, with the coexistence of antiferromagnetic and field-induced ferromagnetic-like phases. The jumps in the return leg occur because of the shear-dominated martensitic-like phase transition of the ferromagnetic-like phase to an antiferromagnetic phase, and interfacial strain plays a major role in the observed jumps.

Hypopituitarism presenting as congestive heart failure

Sheehan's syndrome (SS) develops as a result of ischemic pituitary necrosis due to severe postpartum hemorrhage and is characterized by various degrees of hypopituitarism. Although the occurrence of SS is now rare, it should still be considered in any woman with a history of peripartum hemorrhage who develops manifestations of pituitary hormone deficiency any time following the event. Appropriate hormone replacement therapy results in marked clinical improvement. We present an unusual case of SS in a young lady who continued to have normal menstruation after the index event, had two spontaneous pregnancies, and was diagnosed only 11 years later when she presented to us with acute heart failure.

Carbazole functionalized new bipolar ligand for monochromatic red light-emitting europium(iii) complex: combined experimental and theoretical study

Complete energy transfer observed from carbazole functionalized bipolar ligand as well as β-diketonate to Eu(iii) ion and Eu(iii) complex shows efficient PLQE (41.4%) with appropriate CIE color coordinates (x = 0.64, y = 0.36).

Universal institutional delivery among mothers in a remote mountain district of Nepal: what are the challenges?

Setting: Eight village development committees of Mugu District, a remote mountainous district of Nepal that has poor maternal health indicators. Objectives: 1) To assess the proportion of mothers who delivered in health facilities (institutional delivery); 2) among mothers who delivered at home, to understand their reasons for doing so; and 3) among mothers who delivered in health facilities, to understand their challenges. Design: Cross-sectional study involving semi-structured interviews with mothers conducted in 2015. Results: Of 275 mothers, 97 (35%) had an institutional delivery. Multivariate logistic regression analysis showed that women who resided within 1 h distance from the birthing centre, had adequate mass media exposure or had only one child were more likely to deliver in hospital. Reasons for non-institutional delivery (n = 178) were related to geographical access (49%), personal preferences (18%) and perceived poor quality care (4%). Mothers who accessed institutional delivery (n = 97) also reported difficulties related to travel (60%), costs (28%), dysfunctional health system (18%) and unfriendly attitudes of the health-care providers (7%). Conclusion: To improve access to institutional delivery, the government should establish a 24/7 emergency ambulance network, including air ambulance. Health system issues, including unfriendly staff attitudes, urgently need to be addressed to gain the trust of the mothers.

Non-communicable diseases at a regional hospital in Nepal: Findings of a high burden of alcohol-related disease

Recent global burden of disease reports find that a major proportion of global deaths and disability worldwide can be attributed to alcohol use. Thus, it may be surprising that very few studies have reported on the burden of alcohol-related disease in low income settings. The evidence of non-communicable disease (NCD) burden in Nepal was recently reviewed and concluded that data is still lacking, particularly to describe the burden of alcohol-related diseases (ARDs). Therefore, here we report on NCD burden and specifically ARDs, in hospitalized patients at a regional hospital in Nepal. We conducted a retrospective chart-review that included detailed information on all discharged patients during a four month period. A local database that included sociodemographic information and diagnoses at discharge was established. All doctor-assigned discharge diagnoses were retrospectively assigned ICD-10 codes. A total of 1,139 hospitalized adult patients were included in the study and one third of these were NCDs (n = 332). The main NCDs were chronic obstructive pulmonary disease (COPD) (n = 148, 45%) and ARDs (n = 57, 17%). Patients with ARD often presented with signs of liver cirrhosis and were typically younger men, with a median age at 43 years, from specific ethnic groups. These data demonstrate that severe alcohol-related organ failure in relatively young men contributed to a high proportion of NCDs in a regional hospital in Nepal. These findings are novel and alarming and warrant further studies that can establish the burden of ARDs and alcohol use in Nepal and other similar low-income countries.

Investigation of hydrogen induced fluorescence in C60 and its potential use in luminescence down shifting applications

Herein the photophysical properties of hydrogenated fullerenes (fulleranes) synthesized by direct hydrogenation utilizing hydrogen pressure (100 bar) and elevated temperatures (350 °C) are compared to the fulleranes C₆₀H₁₈ and C₆₀H₃₆ synthesized by amine reduction and the Birch reduction, respectively. Through spectroscopic measurements and density functional theory (DFT) calculations of the HOMO-LUMO gaps of C₆₀H_x (0 ≤ x ≤ 60), we show that hydrogenation significantly affects the electronic structure of C₆₀ by decreasing conjugation and increasing sp³ hybridization. This results in a blue shift of the emission maximum as the number of hydrogen atoms attached to C₆₀ increases. Correlations in the emission spectra of C₆₀H_x produced by direct hydrogenation and by chemical methods also support the hypothesis of the formation of C₆₀H₁₈ and C₆₀H₃₆ during direct hydrogenation with emission maxima of 435 and 550 nm respectively. We also demonstrate that photophysical tunability, stability, and solubility of C₆₀H_x in a variety of organic solvents make them easily adaptable for application as luminescent down-shifters in heads-up displays, light-emitting diodes, and luminescent solar concentrators. The utilizization of carbon based materials in these applications can potentially offer advantages over commonly utilized transition metal based quantum dot chromophores. We therefore propose that the controlled modification of C₆₀ provides an excellent platform for evaluating how individual chemical and structural changes affect the photophysical properties of a well-defined carbon nanostructure.

Effect of iron deficiency anemia and iron supplementation on HbA1c levels - Implications for diagnosis of prediabetes and diabetes mellitus in Asian Indians

BACKGROUND

We investigated the effect of iron deficiency anemia (IDA) on levels of glycated hemoglobin (HbA1c) and to compare its levels before and after iron supplementations.

METHODS

Age and sex matched subjects were enrolled and clustered in 2 groups: IDA (n=62) and healthy controls (HC; n=60). HbA1c levels were estimated by HPLC. Hemogram were estimated by hematology analyser. Serum ferritin (ELISA) and other parameters of iron profile were measured by standard guidelines of ICSH. HbA1c values and iron studies were repeated after 3months of iron supplementation to determine the effect of iron therapy on HbA1c levels.

RESULTS

Significantly higher HbA1c levels were observed in IDA subjects compared to HC (5.51±0.696 v/s 4.85±0.461%, p<0.001). A significant negative correlation was observed between HbA1c and hemoglobin, hematocrit, RBC count, MCH, MCHC and serum ferritin in IDA subjects (r=-0.632, -0.652, -0.384, -0.236, -0.192 and -0.441). Significant decline was noticed in HbA1c levels in IDA subjects after iron supplementation (5.51±0.696 before treatment v/s 5.044±0.603 post-treatment; p<0.001). Post treatment, 70% subjects (14/20) with HbA1c in pre-diabetes range normalised to normal glucose tolerance (NGT) range and out of 6 patients with pre-treatment HbA1c in diabetes range, 5 reverted to pre-diabetes range while 1 of them reverted to the NGT range.

CONCLUSIONS

Caution must be exercised in interpreting the results of HbA1c in patients of IDA and iron deficiency must be corrected before diagnosing diabetes and pre-diabetes solely on the basis of HbA1c criteria.

Magnetoelectric Coupling, Ferroelectricity, and Magnetic Memory Effect in Double Perovskite La3Ni2NbO9

We observe ferroelectricity in an almost unexplored double perovskite La3Ni2NbO9. Ferroelectricity appears below ∼60 K, which is found to be correlated with the significant magnetostriction. A reasonably large value of spontaneous electric polarization is recorded to be ∼260 μC/m(2) at 10 K for E = 5 kV/cm, which decreases signifi- cantly upon application of a magnetic field (H), suggesting considerable magnetoelectric coupling. The dielectric permittivity is also influenced by H below the ferroelectric transition. The magnetodielectric response scales linearly to the squared magnetization, as described by the Ginzburg-Landau theory. Meticulous studies of static and dynamic features of dc magnetization and frequency dependent ac susceptibility results suggest spin-glass state below 29 K. Intrinsic magnetic memory effect is observed from zero-field cooled magnetization and isothermal remanent magnetization studies, also pointing spin-glass state below 29 K. Appearance of ferroelectricity together with a significant magnetoelectric coupling in absence of conventional long-range magnetic order is promising for searching new magnetoelectric materials.

Magnetoelectric coupling and exchange bias effects in multiferroic NdCrO3

We report ferroelectricity around  ∼88 K that appears well below T N (∼25 K), unlike other members of RCrO3 series. A synchrotron diffraction study suggests that the occurrence of ferroelectricity in NdCrO3 is coupled to the structural transformation from centrosymmetric Pnma to a non-centrosymmetric Pna21 space group. A strong magnetoelectric coupling is observed in the electric polarization [P(T)]. This coupling is significantly influenced by the magnetic field cooling effect, suggesting an exchange bias effect in P(T). This exchange bias effect is also revealed by the systematic shift of the magnetic hysteresis loops below T(N). The rare occurrence of an exchange bias effect in both the magnetic and electric polarizations associated with a strong magnetoelectric coupling is of fundamental interest, as well as being attractive for technological applications close to liquid nitrogen temperature.

Arsenic and smokeless tobacco induce genotoxicity, sperm abnormality as well as oxidative stress in mice in vivo

BACKGROUND

Arsenic, a naturally occurring metalloid is a well-known water contaminant which causes a wide range of serious adverse health effects including cancer upon long-term exposure. Recent studies have shown high arsenic contamination in the ground water of North Eastern states of India including Southern Assam. Smokeless tobacco consumption locally known as "sadagura" is one of the most prevalent life style habit in southern Assam. The present study was undertaken in mice test system in vivo. Mice were exposed to smokeless tobacco (5 mg/kg body weight /day) and sodium arsenite (0.2 mg/kg body weight /day, 2 mg/kg body weight/day) independently and in combination for 90 days.

RESULTS

The results were compared with groups with only sodium arsenite exposure and groups which were exposed to only smokeless tobacco extract. Genotoxicity was evaluated by studying the incidence of micronucleated polychromatic erythrocytes from bone marrow. Both the tested doses of sodium arsenite induced statistically significant micronucleated polychromatic erythrocytes as compared to control group, however, sodium arsenite and smokeless tobacco extract could not increase the incidence of micronucleated polychromatic erythrocytes as compared to their individual counterparts when treated in combination in mice test system. Germ cell toxicity was evaluated by recording the sperm head abnormalities and total sperm count. Combined treatment of sodium arsenite and smokeless tobacco extract in lower dose induced a significant increase in sperm head abnormality as compared to only sodium arsenite and smokeless tobacco extract. Liver, kidney and intestine tissues were analyzed for various oxidative stress evaluations such as lipid peroxidation (MDA), Glutathione (GSH) and superoxide dismutase (SOD) assay. Sodium arsenite in combination with smokeless tobacco extract show higher genotoxic and germ cell toxic effects as compared to control but not when compared to their individual counterparts.

CONCLUSION

Impairment of the sperm head morphology by sodium arsenite and smokeless tobacco extract alone and in combination with lower dose of sodium arsenite could be oxidative stress mediated effects. Besides, combination treatment of both the agents may not produce additive effects related to micronucleated polychromatic erythrocytes induction and decline of total sperm count.