A 4 V Li-Ion Battery using All-Spinel-Based Electrodes

Boosting the performance of rechargeable lithium-ion batteries (LIBs) beyond the state-of-the-art is mandatory toward meeting the future energy requirements of the consumer mass market. The replacement of conventional graphite anodes with conversion-type metal-oxide anodes is one progressive approach toward achieving this goal. Here, a LIB consisting of a highcapacity spinel NiMn₂ O₄ anode and a high-voltage spinel LiNi_0.5 Mn_1.5 O₄ cathode was proposed. Polyhedral-shaped NiMn₂ O₄ powder was prepared from a citrate precursor via the sol-gel method. Electrochemical tests showed that the NiMn₂ O₄ in a half-cell configuration could deliver reversible capacities of 750 and 303 mAh g^-1 at 0.1 and 3 C rates. Integrating the NiMn₂ O₄ anode into a full-cell configuration provided an estimated energy density of 506 Wh kg^-1 (vs. cathode mass) upon 100 cycles and excellent cycling performance over 150 cycles at the 0.1 C rate, which can be considered promising in terms of satisfying the demands for high energy densities in large-scale applications.

Probing the Sodium Insertion/Extraction Mechanism in a Layered NaVO3 Anode Material

For the realization of sodium-ion batteries (SIBs), high-performance anode materials are urgently required with the advantages of being low-cost and environment-friendly. In this work, layered-type NaVO₃ is prepared by the simple solid-state route with a rod-like morphology and used as an anode material for SIBs. The NaVO₃ electrode exhibits a high specific capacity of 196 mA h g^-1 during the first cycle and retains a capacity of 125 mA h g^-1 at the 80th cycle with a high Coulombic efficiency of >99%, demonstrating high reversibility. The sodium diffusion coefficient in NaVO₃ is measured using electrochemical impedance spectroscopy (1.368 × 10^-15 cm² s^-1), the galvanostatic intermittent titration technique (1.15715 × 10^-13 cm² s^-1), and cyclic voltammetry (2.7935 × 10^-16 cm² s^-1). Furthermore, the reaction mechanism during the sodiation/desodiation process is investigated using in situ X-ray diffraction and X-ray absorption near the edge structure analysis, which suggests the formation of an amorphous-like phase and reversible redox reaction of V⁴⁺ ↔ V⁵⁺, respectively.

Second-harmonic generation imaging of collagen in ancient bone

Second-harmonic generation imaging (SHG) captures triple helical collagen molecules near tissue surfaces. Biomedical research routinely utilizes various imaging software packages to quantify SHG signals for collagen content and distribution estimates in modern tissue samples including bone. For the first time using SHG, samples of modern, medieval, and ice age bones were imaged to test the applicability of SHG to ancient bone from a variety of ages, settings, and taxa. Four independent techniques including Raman spectroscopy, FTIR spectroscopy, radiocarbon dating protocols, and mass spectrometry-based protein sequencing, confirm the presence of protein, consistent with the hypothesis that SHG imaging detects ancient bone collagen. These results suggest that future studies have the potential to use SHG imaging to provide new insights into the composition of ancient bone, to characterize ancient bone disorders, to investigate collagen preservation within and between various taxa, and to monitor collagen decay regimes in different depositional environments.

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Second-Harmonic Generation (SHG) confocal laser scanning microscopy is used to investigate collagen remnants in ancient bone.

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Four independent techniques confirm the presence of collagen remnants in ancient bone samples with SHG-detected collagen.

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SHG imaging can visualise collagen remnants in ancient bone of various taxa, ages, and settings.

Self-Rearrangement of Silicon Nanoparticles Embedded in Micro-Carbon Sphere Framework for High-Energy and Long-Life Lithium-Ion Batteries

Despite its highest theoretical capacity, the practical applications of the silicon anode are still limited by severe capacity fading, which is due to pulverization of the Si particles through volume change during charge and discharge. In this study, silicon nanoparticles are embedded in micron-sized porous carbon spheres (Si-MCS) via a facile hydrothermal process in order to provide a stiff carbon framework that functions as a cage to hold the pulverized silicon pieces. The carbon framework subsequently allows these silicon pieces to rearrange themselves in restricted domains within the sphere. Unlike current carbon coating methods, the Si-MCS electrode is immune to delamination. Hence, it demonstrates unprecedented excellent cyclability (capacity retention: 93.5% after 500 cycles at 0.8 A g^-1), high rate capability (with a specific capacity of 880 mAh g^-1 at the high discharge current density of 40 A g^-1), and high volumetric capacity (814.8 mAh cm^-3) on account of increased tap density. The lithium-ion battery using the new Si-MCS anode and commercial LiNi_0.6Co_0.2Mn_0.2O₂ cathode shows a high specific energy density above 300 Wh kg^-1, which is considerably higher than that of commercial graphite anodes.

Missed opportunities for earlier HIV-testing in patients with HIV infection referred to a tertiary hospital, a cross-sectional study

INTRODUCTION

In Malaysia, the prevalence of missed opportunities for HIV-testing is unknown. Missed opportunities have been linked to late diagnosis of HIV and poorer outcome for patients. We describe missed opportunities for earlier HIV-testing in newly-HIV-diagnosed patients.

METHODS

Cross sectional study. Adult patients diagnosed with HIV infection and had at least one medical encounter in a primary healthcare setting during three years prior to diagnosis were included. We collected data on sociodemographic characteristics, patient characteristics at diagnosis, HIV-related conditions and whether they were subjected to risk assessment and offered HIV testing during the three years prior to HIV diagnosis.

RESULTS

65 newly HIV-diagnosed patients (male: 92.3%; Malays: 52.4%; single: 66.7%; heterosexual: 41%; homosexual 24.6%; CD4 <350 at diagnosis: 63%). 93.8% were unaware of their HIV status at diagnosis. Up to 56.9% had presented with HIV-related conditions at a primary healthcare facility during the three years prior to diagnosis. Slightly more than half were had risk assessment done and only 33.8% were offered HIV-testing.

CONCLUSIONS

Missed opportunities for HIV-testing was unacceptably high with insufficient risk assessment and offering of HIV-testing. Risk assessment must be promoted and primary care physicians must be trained to recognize HIV-related conditions that will prompt them to offer HIVtesting.

Study on the Electrochemical Reaction Mechanism of NiFe2O4 as a High-Performance Anode for Li-Ion Batteries

Nickel ferrite (NiFe₂O₄) has been previously shown to have a promising electrochemical performance for lithium-ion batteries (LIBs) as an anode material. However, associated electrochemical processes, along with structural changes, during conversion reactions are hardly studied. Nanocrystalline NiFe₂O₄ was synthesized with the aid of a simple citric acid assisted sol-gel method and tested as a negative electrode for LIBs. After 100 cycles at a constant current density of 0.5 A g^-1 (about a 0.5 C-rate), the synthesized NiFe₂O₄ electrode provided a stable reversible capacity of 786 mAh g^-1 with a capacity retention greater than 85%. The NiFe₂O₄ electrode achieved a specific capacity of 365 mAh g^-1 when cycled at a current density of 10 A g^-1 (about a 10 C-rate). At such a high current density, this is an outstanding capacity for NiFe₂O₄ nanoparticles as an anode. Ex-situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) were employed at different potential states during the cell operation to elucidate the conversion process of a NiFe₂O₄ anode and the capacity contribution from either Ni or Fe. Investigation reveals that the lithium extraction reaction does not fully agree with the previously reported one and is found to be a hindered oxidation of metallic nickel to nickel oxide in the applied potential window. Our findings suggest that iron is participating in an electrochemical reaction with full reversibility and forms iron oxide in the fully charged state, while nickel is found to be the cause of partial irreversible capacity where it exists in both metallic nickel and nickel oxide phases.

Clear cell changes in salivary gland neoplasms: A 20-year retrospective study

BACKGROUND

Clear cells are observed histopathologically in both benign and malignant neoplasms but their presence in salivary gland tumors has not been extensively documented.

MATERIAL AND METHODS

With IRB approval, the archive of the University of Florida College of Dentistry oral pathology biopsy service was retrospectively searched from 1994-2014 for all benign and malignant salivary tumors. Epidemiological data, tumor location and duration, and type of tumor were recorded. A four reviewer panel examined the original slides. Reviewers scaled each case as 0 (no clear cells present), 1 (few to focal clear cells), 2 (less than 50% clear cells), and 3 (greater than 50% clear cells).

RESULTS

A total of 535 cases were included of which 48% of tumors displayed 0 clear cells (257/535), 31.4% (168/535) scored 1, 13.6% (73/535) scored 2, and 7% (37/535) scored 3. Of the 251 (47%) malignant neoplasms, 64% (160/251) demonstrated 0-1 clear cell change, while 36% (91/251) showed a score of 2-3. For the total 284 (53%) benign tumors, 93% (265/535) scored 0-1 and 7% (19/535) scored a 2-3 range. No statistical difference was noted for gender, age, or duration of time present in regards to presence or absence of clear cells. Statistically significant differences in clear cell presence were found between location groups, between benign and malignant diagnosis, and between specific diagnostic groups.

CONCLUSIONS

This study demonstrates the frequent presence of increased numbers of clear cells in oral salivary malignancies and highlights salivary gland differential diagnoses when presented with clear cell changes.

MOLECULAR IDENTIFICATION AND ANTIBIOGRAM PROFILES OF ESCHERICHIA COLI ISOLATED FROM APPARENTLY HEALTHY AND DIARRHEIC GOATS

The present study was designed for the cultural, biochemical characterization and molecular detection of E. coli from apparently healthy and diarrheic goats in and around BAU campus including their antibiogram study. A total of 50 fecal samples were collected among which 13 originated from diarrheic goat and 37 from apparently healthy goats. Out of 50 samples, 35 were found positive for E. coli i.e., overall 70% occurrence. Occurrences of E. coli from diarrheic and apparently healthy goats were 92% and 62% respectively. Occurrences were 60%, 80% and 70% in case of BAU Goat Farm, Veterinary Teaching Hospital and Boyra respectively. On age basis 93%, 54%, 66% and 54% samples originated from 6 months, 7-12 months, 13-18 months and 19 months aged goats were found positive respectively. Occurrences of E. coli on the basis of sex were 78% for male and 62% for female. In case of breed, the occurrences were 69% in Black Bengal and 100% in for Jamunapari. Molecular detection was done by PCR and 13 out of 20 isolates tested gave the bands at the 585 bp specific for E. coli 16S rRNA gene. All the isolates (100%) were found sensitive to ciprofloxacin and norfloxacin; 100% and 35% were intermediately resistant to tetracycline and gentamicin respectively and 25% isolates were resistant to streptomycin. Ciprofloxacin and norfloxacin were found to be the best choice of antibiotics for the treatment of colibacillosis in goats in the study area.