Structural, thermodynamic, and magnetic properties of SrFe12O19 hexaferrite modified by co-substitution of Cu and Gd.

A hard magnetic system of SrFe12O19 nanomaterial was modified according to the composition of Sr0.95Gd0.05Fe12-xCuxO19 with x = 0.0, 0.30, and 0.60 using the sol-gel technique. The structures of the samples were evaluated using X-ray diffraction (XRD) along with Rietveld refinement, and an M-type hexaferrite with a hexagonal structure was confirmed with a trace amount of the α-Fe2O3 phase. In addition, transmission electron microscopy (TEM) analysis revealed polycrystalline nanoplates in all samples. Furthermore, the bond structures of the octahedral and tetrahedral sites along with the thermodynamic properties of these ferrites were extracted from the FTIR spectra at room temperature. The Debye temperature (θD) decreased from 755.9 K to 749.3 K due to the co-substitution of Gd3+ at Sr2+ and Cu2+ at Fe3+. The magnetic hysteresis (M-H) measurements revealed that the coercivity decreased from 5.3 kOe to 1.5 kOe along with the highest magnetization saturation (Ms) of 65.2 emu g-1 for the composition Sr0.95Gd0.05Fe11.7Cu0.3O19, which is suitable for industrial application. The effect of local crystalline anisotropy in magnetization was explored using the law of approach to saturation (LAS). Finally, thermo-magnetization was recorded in the range from 400 K to 5 K for cooling under zero field and in the presence of a 100 Oe field, and magnetic transitions were tracked due to the introduction of the foreign atoms of Gd and Cu into SrFe12O19.

Exploration of the structural, vibrational, electronic, mechanical and thermal properties of Ru4Al3B2 and Ru9Al3B8: a DFT study.

The structural, dynamical, electro-optical, mechanical, and thermal characteristics of the newly synthesized intermetallic compounds Ru4Al3B2 and Ru9Al3B8 have been studied under ambient and elevated pressure through density functional theory (DFT). The obtained lattice parameters of the compounds are consistent with the experimental values. The metallic character of these compounds is established by the band structure and density of states (DOS). The electronic charge density distribution and bond analysis imply that Ru4Al3B2 and Ru9Al3B8 have mainly both ionic and covalent bonding. The non-negative phonon dispersion frequency of the compounds reaffirms their dynamical stability. Both compounds are tough as well as have high melting points, and hence, can be applied in harsh conditions. Mechanical properties are significantly improved under pressure. Thermal barrier coating (TBC) is a possible field of application for both compounds. The different thermal properties such as the Debye temperature (ΘD), Grüneisen parameter (γ), melting temperature (Tm), minimum thermal conductivity (Kmin) and lattice thermal conductivity (κph) of these compounds have been studied to figure out the suitable application areas in thermally demanding situations. The pressure and temperature dependent bulk modulus (B) and other thermodynamic properties have also been analyzed, which suggested that the present compounds are strong candidates for device applications at high temperature and pressure. Owing to their high optical absorptivity and reflectivity in the UV region, they are also candidates for UV-based applications. Furthermore, they also have applicability in the fields of electronics, aviation, energy storage, and supercapacitor devices for their superior electronic, thermal and mechanical properties.

Evaluation of Pre-peritoneal (Sublay) Mesh Repair for Treatment of Ventral Hernia.

Ventral hernia after abdominal surgery is a common complication. Several techniques for the repair of ventral hernia have been described from time to time and it is a great challenge for a surgeon. The mesh placement by sublay technique authorized by Rives and Stoppa in Europe has been reported to be effective with low recurrence rate. The objective of this study was to evaluate the efficacy of sublay technique of mesh placement in ventral hernia. This prospective study was carried out in the Department of Surgery, Dhaka Dental College, Bangladesh from January 2017 to December 2018. A total of 21 patients with ventral hernia were included in this study. Data collected in data collection sheet regarding demographic data, severity of symptoms and post operative complains of patients which were then analyzed. Age ranged from 21-60 years. Male were 5(23.80%) and female were 16(76.20%). Dragging pain were 7(33.33%), irreducibility were 4(19.05%) but swelling were 100%. Incisional hernia was 18(85.71%) and para-umbilical hernia was 3(14.29%). Post-operative complication were seroma1 (4.76%), major wound infection 1(4.76%), minor infection 1(4.76%) but no recurrence. Sublay mesh repair in ventral hernia was found to be a better and effective technique with minimal complication rate.

Effect of yttrium(Y) on structural, morphological and transport properties of CdO thin films prepared by spray pyrolysis technique.

Cadmium oxide (CdO) and yttrium (Y) doped CdO (Y: CdO) thin films have been prepared onto glass substrate at temperature 300 °C by spray pyrolysis technique. The effects of yttrium (Y) doping on the structural, morphology, optical and electrical properties were studied systematically. The X-ray diffraction (XRD) study confirms that CdO films are polycrystalline in nature with cubic structure having lattice parameter of 0.4658 nm. Surface topographic and nano-structural analysis indicates cluster grain size and porosity decreased substantially with increase of yttrium (Y) content in CdO films. The optical transmittance exhibits excellent optical transparency, with an average transmittance of >70% in the visible range for 2 to 4% yttrium (Y) doping. The optical band gap widens in Y: CdO film from 2.24 to 2.62 eV through Burstein- Moss shift. Hall measurement confirms that material is of n type with a minimum resistivity of 4.7 × 10-4 Ω-cm with carrier concentration of 4.2 × 1021 cm-3 were achieved for 2% yttrium (Y) doping.

Mechanical property and quality aspects of rice dried in industrial dryers.

The influence of drying methods on selected mechanical properties and qualities of MR219 rice variety has been investigated. The results showed significant effects of drying methods on bending strength and head rice yields while the average bending strength of paddy were 28.6-31.8 MPa. The effect of drying methods on apparent modulus of elasticity of rice was not significant (204.5-222.4 MPa). The fracture energy of rice varied significantly under control drying but not with industrial drying methods. Higher temperature in drying by IBD contributed in making the grains tougher, where the effect of FBD temperature was positive toward the development of fracture energy inside rice kernel. IBD at temperature above 40 °C resulted in lower bending strength in rice kernels which affected head rice yield. Two stage paddy drying practices with FBD using temperature of 115-125 °C as first stage is still acceptable, and inclined bed dryer either as single stage or as second stage after FBD should be operated at temperature of <40 °C to maintain head rice yield. The whiteness and milling recovery of rice achieved from different drying methods were comparable.

Smear Positive Tuberculosis amongst Suspects Reported to DOTS Corner of Mymensingh Medical College Hospital, Bangladesh.

Sputum microscopy still remains the primary tool for the laboratory diagnosis of tuberculosis. A retrospective study was conducted in the directly observed treatment, short-course (DOTS) corner of Mymensingh Medical College Hospital (MMCH), in Bangladesh from May 2013 to May 2014. The study was designed to evaluate the extent of smear positive microscopy including multi-drug resistance (MDR) amongst tuberculosis suspected cases. A total of 2,361 Pulmonary Tuberculosis (PTB) suspects were noticed to DOTS corner during this period, with the mean age of 43 years. The male female ratio was 2.02:1 and the smear positivity rate was about 10%. Study found majority of the suspects were in the economically productive year of life 20-70 years. Smear negative suspects were not re-evaluated further, though smear negativity does not rule out absence of tuberculosis. Extra pulmonary or non tuberculous mycobacteria were not evaluated in this study. Twenty two patients 0.9% of total 2361 were identified as MDR during the study period where 61 clinically highly suspected cases were sent for GeneXpert that seems to be much lesser than the national rate (3.6% in new cases and 19% in retreated cases). The smear positivity rate of all three (1st, 2nd and 3rd) smear was 94.5%, all the second smear was 100% positive and the third were 95.47% positive. It is evident from this study that two smear microscopy was found sufficiently reliable to diagnose TB. However, further in depth prospective study might be undertaken to ascertain the scenario of this chronic diseases.

Immune response of Bangladeshi children with acute diarrhea who subsequently have persistent diarrhea.

BACKGROUND: Because altered immune responses may be a risk factor for persistent diarrhea, various aspects of the immune response were examined to elucidate the underlying immune mechanisms that may be involved in the development of persistent diarrhea. METHODS: Children (7-12 months of age) with watery diarrhea for 6 to 8 days from the Dhaka Hospital of the International Centre for Diarrheal Disease Research, Bangladesh (ICDDR,B), were enrolled. Children were classified as having acute diarrhea (AD) or persistent diarrhea (PD) if diarrhea resolved within 14 days or persisted for more than 14 days, respectively. Uninfected control children (n = 13), from the Nutrition Follow-Up Unit of ICDDR,B were also enrolled. Of the 123 children with diarrhea who were enrolled, 85 had AD and 38 had PD. Comparisons were performed for clinical features, nutritional status (weight for age, plasma transferrin, and serum albumin levels), and immune responses: neutrophil function; peripheral blood mononuclear cell function, delayed-type hypersensitivity (DTH) responses, plasma levels of immunoglobulins, tumor necrosis factor-alpha, and interferon-gamma. Univariate analyses were conducted to assess differences among the three groups of children and between children with AD and PD. Logistic regression was performed to determine risk factors for PD. RESULTS: There were no differences in clinical features and nutritional status among the groups of children studied. More children in whom PD developed had a negative DTH response to tuberculin than those with AD (P = 0.021). Also, a negative DTH response to tuberculin was a significant risk factor for PD (odds ratio [OR] = 3.8, 95% confidence interval [CI] = 1.5-9.9). CONCLUSIONS: Children with acute diarrhea with a negative DTH response to tuberculin are more likely to have development of persistent diarrhea.