Competing magnetic states andM-Hloop splitting in core-shell NiO nanoparticles.

Magnetic relaxation in a nanoparticles system depends on the intra-particle interactions, reversal mechanism, the anisotropy field, easy axis distribution, particle volume, lattice defects, surface defects, materials composite, etc. Here we report the competing magnetic states between superparamagnetic blocking and Néel transition states in 14 nm core-shell NiO nanoparticles. A crossover temperature of 50 K was observed for both these states from the zero field cooled/field cooled magnetization curves taken at different fields. At crossover temperature, an interestingM-Hloop splitting is observed which is attributed to the slow spin relaxation. This anomalousM-Hloop splitting behaviour was found to be particle size dependent and suppressed for diameters above and below 14 nm which indicates a critical size for these competing magnetic states. Additional neutron diffraction experiments confirmed this observation. This experimental study provides a new insight for the understanding of intra-particle interactions in fine antiferromagnetic nanoparticles and obtained results are an important step towards deeper understanding of the competing/non-competing modes between superparamagnetic blocked and Néel transition states.

Magnetic homogeneity in Fe-Mn co-doped NiO nanoparticles.

The effect of Fe and Mn co-doping on the magnetic properties of the antiferromagnetic (AFM) NiO nanoparticles which offer large potential for different magnetic applications have been studied. The Rietveld refinement fitting of powder x-ray diffractometry (XRD) patterns confirmed the phase formation of face-centred cubic crystal structure of NiO and average crystallite size lies in the short range of 32-38 nm. The cavity and broadband ferromagnetic resonance (FMR) measurements taken at room temperature demonstrate the smaller local magnetic inhomogeneity for 4%Mn-4%Fe co-doped NiO nanoparticles as compared to undoped, single doped and co-doped with different concentration NiO nanoparticles. The M-H loops revealed the room temperature ferromagnetism-like behaviour for higher Fe doping concentration and lower Mn doping concentration. This can be attributed to the double exchange interaction. The zero field cooled (ZFC) and field cooled (FC) dc magnetization curves showed a small surface freezing peak (at[Formula: see text] at low temperatures and a blocking peak (at [Formula: see text] at higher temperatures. For samples with 4%Mn-4%Fe and 2%Mn-6%Fe, the blocking peak was found at a relatively high temperature in comparison to other samples. This can be attributed to the presence of magnetic exchange interactions which block the magnetic spins against a thermal increase. The ZFC AC-susceptibility showed three peaks; a surface freezing peak at Tf, a blocking peak at TB peak and an anomalous peak at Tx in between [Formula: see text] and [Formula: see text], which was found to be most prominent for the 4%Mn-4%Fe co-doped nanoparticles. The neutron diffraction pattern confirmed the AFM order of the core of the 4%Mn-4%Fe co-doped nanoparticles, which indicates an AFM coupling between the Fe2+ and Mn2+ ions and the Ni2+ ions through super-exchange interaction. Therefore, the origin of TX peak can be attributed to the ferromagnetic coupling between the Fe2+ and Mn2+ ions which has a maximum strength at equal concentration. Thus, small and equal doping concentration of Fe and Mn in NiO nanoparticles increase the magnetic homogeneity which makes them attractive for magnetic applications.

Municipal solid waste generation and its compositional assessment for efficient and sustainable infrastructure planning in an intermediate city of Pakistan.

It is imperative to design and operate sustainable solid waste management (SWM) systems in cities based on the results of waste amount and characterization study (WACS). In this work, WACS was conducted and results were used to design an SWM system for an intermediate city of Pakistan. The study revealed that about 110 tons of solid waste per day is generated with a per capita rate of 0.337 kg/day. Around 51.2% of mixed municipal solid waste (MSW) is organic in nature and its non-scientific disposal is resulting in higher greenhouse gas (GHG) emissions. It was also found that more than 80% of valuables are taken away by the informal sector during the transfer of MSW from the generation source to the dumping site. Ultimate analyses showed that the moisture content (MC) and carbon to nitrogen (C:N) ratio were 64.23% and 51.14%, respectively. Proximate analysis revealed that moisture and calorific values were 57 % and 3505 BTU/lb., respectively. Based on these results, a material sorting facility (MSF) was proposed, with an estimated investment cost of US $3.64 million. However, the efficiency of the existing collection system is limited to 32 % only. In order to improve the collection efficiency (>90 %), an additional investment of US $1.638 million was estimated with an operations and maintenance (O&M) cost of US $19.25 per ton. Existing non-scientific MSW disposal practices contribute 32,079.61 CO2e tons/year of GHG emissions. The proposed MSF followed by composting is estimated to reduce GHG emissions by 38% to 19,722.38 CO2e tons/year.

Post-vitrectomy secondary macular holes: Risk factors, clinical features, and multivariate analysis of outcome predictors.

Purpose: We report clinical characteristics, risk factors, treatment outcomes, and prognostic predictors of post-vitrectomy secondary macular holes (MHs). Methods: This was a retrospective observational case series from November 2014 to December 2020. Eyes that developed secondary MH, two weeks and beyond after primary vitrectomy for non-MH indications, were enrolled. Pre- and intraoperative records were screened to exclude pre-existence of MH. Eyes with multiple vitreoretinal surgeries prior to MH detection and tractional myopic maculopathy were excluded. Results: A total of 29 eyes of 29 patients with a mean age of 52 years developed secondary MH post-vitrectomy. The most common indications for primary vitrectomy were rhegmatogenous retinal detachment (RRD, 48.2%) and tractional retinal detachment (TRD, 24.1%). Time to MH detection after primary vitrectomy was 91.5 ± 117.6 days. The mean minimum hole diameter was 530 ± 298 microns. Epi-retinal membrane and cystoid degeneration was noted in 6 (20.7%) and 12 (41.3%) eyes, respectively (p = 0.088). The mean time from MH detection to MH repair was 34 ± 42 days. The surgical intervention included internal limiting membrane peeling with tamponade in 25 eyes. Overall, 80% showed anatomic hole closure, 90.9% versus 57.1% in the RRD and TRD (p = 0.092), respectively. The mean best-corrected visual acuity (BCVA) at the final visit was 0.71 logarithm of the minimum angle of resolution. Thirteen eyes (52%) had a BCVA of 20/100 or better. Minimal hole diameter (p = 0.029) only predicted final visual acuity. The interval between MH diagnosis and repair did not affect hole closure significantly (p = 0.064). Conclusion: Secondary MH post-vitrectomy closed successfully with limited visual improvement and trails behind idiopathic MH.

Morphometric analysis and roosting ecology of bat species Pteropus Medius in Mansehra, Khyber Pakhtunkhwa, Pakistan.

Morphometric measurement and roosting ecology of Pteropus medius were aimed to find out in Mansehra district of KP, Pakistan. Total 3149 numbers of bats were found in eight biological spots visited; Baffa Doraha, Darband, Dadar, Jallu, Hazara University, Garhi Habibullah Chattar Plain and Jabori, in total 299 numbers of different species of trees including; Morus alba, Pinus raxburghi, Eucalyptus camaldulensis, Morus nigra, Grevillea robusta, Brousonetia papyrifera, Platanus orientalis, Ailanthus altissima, Hevea brasiliensis and Populus nigra. Morphometric features were measured and found vary according to sex of the bats. The average wing span, wing`s length from tip of wing to neck, from thumb to tip of wing and the body`s length from head and claws were recorded to be 102.98 cm, 49.07cm, 28.7 cm and 22.78 cm respectively in males while 93.67 cm, 44.83cm, 24.78cm and 22.78 cm respectively in female bats. Mean circumference of the body including wings and without wing were measured as 22.78 cm and 17.29 cm in males and that of female were 20.07 cm and 16.9 cm. Average length of thumb 3.64 cm, ear`s length 3.1 cm, snout 5.62cm, eye length were 1.07 cm for both sexes and length between the feet in extended position were16.3 cm. Generally different measurement of males bodies were found to be greater than female such as mean body surface area, mass, volume and pressure were found to be 2691.79 cm2, 855.7gm,1236.4 ml and 295.77 dyne/ c m 3 for male and 2576.46 cm2, 852.71gm,1207 ml and 290.2 dyne/ c m 3 respectively for female. While weight and density for both males and females bats were same with mean of 8.59 newton and 0.701 g/m3. Findings of current reports can add valued information in literature about bats, which can be used for species identification and conservation.

Effects of microplastics in freshwater fishes health and the implications for human health.

The presence of microplastics in aquatic environments has raised concerns about their abundance and potential hazards to aquatic organisms. This review provides insight into the problem that may be of alarm for freshwater fish. Plastic pollution is not confined to marine ecosystems; freshwater also comprises plastic bits, as the most of plastic fragments enter oceans via rivers. Microplastics (MPs) can be consumed by fish and accumulated due to their size and poor biodegradability. Furthermore, it has the potential to enter the food chain and cause health problems. Evidence of MPs s ingestion has been reported in >150 fish species from both freshwater and marine systems. However, microplastic quantification and toxicity in freshwater ecosystems have been underestimated, ignored, and not reported as much as compared to the marine ecosystem. However, their abundance, influence, and toxicity in freshwater biota are not less than in marine ecosystems. The interaction of MPs with freshwater fish, as well as the risk of human consumption, remains a mystery. Nevertheless, our knowledge of the impacts of MPs on freshwater fish is still very limited. This study detailed the status of the toxicity of MPs in freshwater fish. This review will add to our understanding of the ecotoxicology of microplastics on freshwater fish and give subsequent research directions.

An investigation on protein and amino acid contents in scales and muscles of pomfret Parastromateus niger (Bloch, 1795) and Pampus argenteus (Eupharasen, 1788).

The present investigation was aimed to examine the percentage quantity of protein and amino acids in scales and muscles of Pampus argenteus and Parastromateus niger gathered from the local fish market of district Quetta of Balochistan. About 80 specimens of these two species, i.e., Pampus argenteus (N=40) and Parastromateus niger (N = 40), were collected from April 2017 to May 2018. In general, crude protein content was high in scales, that is, 71.03% in Parastromateus niger and 52.11% in Pampus argenteus, as well as in muscles of two Pomfret species of fishes i.e., 63.44% in Pampus argenteus and 60.99% in Parastromateus niger on a dry-weight basis, respectively. Likewise, the muscles and scales of Parastromateus niger reveal well compositions of amino acids that include proline was found to be high, and methionine was less than other amino acids, whereas threonine was found high in the scales of Pampus argenteus, but methionine was observed in lesser amount. However, the amino acids found in Pampus argenteus muscles also showed different compositions, such as lysine was found to be high, but histidine was less, respectively. In comparison, amino acids like tryptophan and cysteine were not detected in both scales and muscles of these Pomfret species of fishes. Thus, this study was based on analyzing the utilization of both Pomfret species of scales and meat whether they could have values as good supplements of both protein and certain kinds of essential amino acids in animal diets.

Numerical Simulation of a Biventricular Assist Device with Fixed Right Outflow Cannula Banding During Pulmonary Hypertension.

As a left ventricular assist device is designed to pump against the systemic vascular resistance (SVR), pulmonary congestion may occur when using such device for right ventricular support. The present study evaluates the efficacy of using a fixed right outflow banding in patients receiving biventricular assist device support under various circulatory conditions, including variations in the SVR, pulmonary vascular resistance (PVR), total blood volume (BV), as well as ventricular contractility. Effect of speed variation on the hemodynamics was also evaluated at varying degrees of PVR. Pulmonary congestion was observed at high SVR and BV. A reduction in right ventricular assist device (RVAD) speed was required to restore pulmonary pressures. Meanwhile, at a high PVR, the risk of ventricular suction was prevalent during systemic hypotension due to low SVR and BV. This could be compensated by increasing RVAD speed. Isolated right heart recovery may aggravate pulmonary congestion, as the failing left ventricle cannot accommodate the resultant increase in the right-sided flow. Compared to partial assistance, the sensitivity of the hemodynamics to changes in VAD speed increased during full assistance. In conclusion, our results demonstrated that the introduction of a banding graft with a 5 mm diameter guaranteed sufficient reserve of the pump speed spectrum for the regulation of acceptable hemodynamics over different clinical scenarios, except under critical conditions where drug administration or volume management is required.

Slow Spin Dynamics in Superconducting Ca0.9Ce0.1Fe2As2.

Slow spin dynamics has been observed in superconducting under-doped Ca0.9Ce0.1Fe2As2 single crystal. Below 100 K, the system exhibits hysteresis in the cooling and warming protocols of temperature dependent resistivity due to first order tetragonal to orthorhombic structural transition with simultaneous magnetic transition from paramagnetic to spin density wave antiferromagnetic state of the iron (Fe) ions. Zero field cooled/field cooled (ZFC/FC) magnetization curves showed splitting at 32 K followed by a sharp increase of the FC curve and then FC plateau at low temperatures. Slow spin relaxation in both the ZFC and FC protocols was observed which is typical for spin-glass system. The system also showed features analogue to spin-glass behavior such as ZFC peak, FC plateau, ZFC slow spin relaxation, magnetic hysteresis, and ZFC ac memory effect. The spin-glass like behavior was rather weak and vanished at higher fields. The origin of the slow spin dynamics could be the inhomogeneous distribution of the cerium (Ce) spins ordered along the c-axis OR interactions between Fe and Ce spins which lead to magnetic frustration of Ce spins. All these findings support the coexistence of slow spin dynamics of Ce spins and superconductivity in Ca0.9Ce0.1Fe2As2 single crystal.

Stability-indicating High-performance Liquid Chromatography Method for Simultaneous Determination of Aminophylline and Chlorpheniramine Maleate in Pharmaceutical Formulations.

The present work deals with the development and validation of method for simultaneous determination of antihistaminic drugs in pharmaceutical formulations. A precise, specific and accurate reverse phase-high-performance liquid chromatography method for the simultaneous measurement of aminophylline and chlorpheniramine maleate was developed. The separation of drugs was achieved on C-18 (5 µm, 250×4.6 mm) high-performance liquid chromatography column. The runtime for analysis was 10 min. Mobile phase is mixture containing dilute H2SO4:methanol (60:40% v/v) with flow rate adjusted at 1.5 ml/min. The detection of components was performed at a wavelength of 264 nm. Retention times of aminophylline and chlorphinramine maleate were found to be 2.00 and 3.25 min, respectively. Linearity was found in the range of 16-24 µg/ml for chlorpheniramine maleate and 102.4-153.6 µg/ml for aminophylline with a correlation coefficient of 0.9998 and 0.9996, respectively. High peak purity index of 99.99% indicated the complete separation of analytes in the presence of degradation products is justification of method stability. Linearity, accuracy, specificity, precision and robustness studies were performed for method validation.