Gram-scale bottom-up flash graphene synthesis.

Most bulk-scale graphene is produced by a top-down approach, exfoliating graphite, which often requires large amounts of solvent with high-energy mixing, shearing, sonication or electrochemical treatment1-3. Although chemical oxidation of graphite to graphene oxide promotes exfoliation, it requires harsh oxidants and leaves the graphene with a defective perforated structure after the subsequent reduction step3,4. Bottom-up synthesis of high-quality graphene is often restricted to ultrasmall amounts if performed by chemical vapour deposition or advanced synthetic organic methods, or it provides a defect-ridden structure if carried out in bulk solution4-6. Here we show that flash Joule heating of inexpensive carbon sources-such as coal, petroleum coke, biochar, carbon black, discarded food, rubber tyres and mixed plastic waste-can afford gram-scale quantities of graphene in less than one second. The product, named flash graphene (FG) after the process used to produce it, shows turbostratic arrangement (that is, little order) between the stacked graphene layers. FG synthesis uses no furnace and no solvents or reactive gases. Yields depend on the carbon content of the source; when using a high-carbon source, such as carbon black, anthracitic coal or calcined coke, yields can range from 80 to 90 per cent with carbon purity greater than 99 per cent. No purification steps are necessary. Raman spectroscopy analysis shows a low-intensity or absent D band for FG, indicating that FG has among the lowest defect concentrations reported so far for graphene, and confirms the turbostratic stacking of FG, which is clearly distinguished from turbostratic graphite. The disordered orientation of FG layers facilitates its rapid exfoliation upon mixing during composite formation. The electric energy cost for FG synthesis is only about 7.2 kilojoules per gram, which could render FG suitable for use in bulk composites of plastic, metals, plywood, concrete and other building materials.

The significance of low titer serum cryptococcal antigen testing from 2017 to 2023 performed in a tertiary care center.

Several false positive low serum cryptococcal antigen (SCrAg) reports by lateral flow assay (LFA) were identified in late 2016 at our tertiary care hospital. After the recall and correction of the problem in the reagent, we studied the significance of SCrAg LFA ≤ 1:10 from January 2017 to October 2023. Of 20 patients with 31 samples of SCrAg LFA ≤ 1:10, 14 patients (70%) were classified as true positives, four (20%) were indeterminate, and only two (10%) patients were false positives. If a new SCrAg LFA ≤ 1:10 is detected, it should be repeated, and additional workup should be pursued.

We studied the significance of low serum cryptococcal antigen (SCrAg) titer lateral flow assay (LFA) ≤ 1:10 from January 2017 to October 2023. Of 20 patients with SCrAg LFA ≤ 1:10, only two patients (10%) were false positives. If a new SCrAg ≤ 1:10 is detected, it should be repeated, and additional workup should be done.

Theoretical insights into the mechanism of oxygen evolution reaction (OER) on pristine BiVO4(001) and BiVO4(110) surfaces in acidic medium both in the gas and solution (water) phases.

Monoclinic scheelite bismuth vanadate is an efficient photocatalyst for water splitting. In this paper, we perform DFT + Ucalculations to investigate the structural, electronic, and optical properties, water adsorption and the oxygen evolution reaction processes on BiVO4(001) and BiVO4(110) surfaces in acidic medium both in the gas and solution (water) phases. The structural, electronic, optical, and water adsorption properties reveal that BiVO4(001) surface is energetically more stable than BiVO4(110) surface in vacuum. On other hand, the water oxidation mechanisms reveal that BiVO4(110) surface in water and in strained form in vacuum is energetically more stable than BiVO4(001) surface in water and in strained form in vacuum bothU = 0 and 2.1 V. The free energy of adsorption for all systems atU = 2.1 V reduce about 2 times than that atU = 0 V. Such analyzes provide important insights into the role of different facets on BiVO4surface for photocatalytic reactions.

Changing demographics and risk factors for cryptococcosis: A 12-year review at a tertiary care centre.

BACKGROUND: Cryptococcosis is classically associated with the immunocompromised patients but there is a rising appreciation for its impact on the immunocompetent hosts. We sought to analyse the trends, diagnosis, treatment of different hosts and the effect of immunodeficiency and chronic liver disease on relapse and in-house mortality. METHODS: This is a retrospective study of 12 years of patients with cryptococcosis, divided into three different groups: HIV-infected, transplant and non-HIV non-transplant (NHNT). Data were analysed with Chi-square, unpaired parametric t test, simple and multivariate logistic regression analysis. RESULTS: Of 114 identified patients, 23 (20.2%) had HIV infection, 11 (9.6%) had transplant, 80 (70.2%) were NHNT patients. Overall, mortality was 28.1% (32/114) and relapse occurred in 10.5% (12/114) of patients. The mortality trend was higher (OR = 2.346, p = .287) in the transplant group (45.5%, 5/11) than in HIV (26.1%, 6/23) and NHNT groups (26.3%, 21/80). HIV was associated with relapse; 30.4% (7/23) for HIV-positive patients and 5.5% (5/91) for HIV-negative patients (OR = 7.525, p = .002). Chronic liver disease had a large and statistically significant association with mortality on multivariate analysis (OR = 3.583, p = .013) which was more pronounced than the HIV or transplant groups. It was independently associated with mortality by chi-square analysis (OR 3.137, p = .012). CONCLUSION: Chronic liver disease represented 30.7% (35/114) of all studied patients. It was a risk factor for in-hospital mortality. HIV infection and transplant were not statistically significant for mortality. Relapse was highest in the HIV-infected patients at 30.4% (7/23). These data highlight the effect of type and degree of immunocompromise on cryptococcosis.

Recent progress in theoretical and computational investigations of Li-ion battery materials and electrolytes.

There is an increasing worldwide demand for high energy density batteries. In recent years, rechargeable Li-ion batteries have become important power sources, and their performance gains are driving the adoption of electrical vehicles (EV) as viable alternatives to combustion engines. The exploration of new Li-ion battery materials is an important focus of materials scientists and computational physicists and chemists throughout the world. The practical applications of Li-ion batteries and emerging alternatives may not be limited to portable electronic devices and circumventing hurdles that include range anxiety and safety among others, to their widespread adoption in EV applications in the future requires new electrode materials and a fuller understanding of how the materials and the electrolyte chemistries behave. Since this field is advancing rapidly and attracting an increasing number of researchers, it is crucial to summarise the current progress and the key scientific challenges related to Li-ion batteries from theoretical point of view. Computational prediction of ideal compounds is the focus of several large consortia, and a leading methodology in designing materials and electrolytes optimized for function, including those for Li-ion batteries. In this Perspective, we review the key aspects of Li-ion batteries from theoretical perspectives: the working principles of Li-ion batteries, the cathodes, anodes, and electrolyte solutions that are the current state of the art, and future research directions for advanced Li-ion batteries based on computational materials and electrolyte design.

Key scientific challenges in current rechargeable non-aqueous Li-O2 batteries: experiment and theory.

Rechargeable Li-air (henceforth referred to as Li-O2) batteries provide theoretical capacities that are ten times higher than that of current Li-ion batteries, which could enable the driving range of an electric vehicle to be comparable to that of gasoline vehicles. These high energy densities in Li-O2 batteries result from the atypical battery architecture which consists of an air (O2) cathode and a pure lithium metal anode. However, hurdles to their widespread use abound with issues at the cathode (relating to electrocatalysis and cathode decomposition), lithium metal anode (high reactivity towards moisture) and due to electrolyte decomposition. This review focuses on the key scientific challenges in the development of rechargeable non-aqueous Li-O2 batteries from both experimental and theoretical findings. This dual approach allows insight into future research directions to be provided and highlights the importance of combining theoretical and experimental approaches in the optimization of Li-O2 battery systems.

Radiation dose analysis of computed tomography coronary angiography in Children with Kawasaki disease.

BACKGROUND: There is evolving role of computed tomography coronary angiography (CTCA) in non-invasive evaluation of coronary artery abnormalities in children with Kawasaki disease (KD). Despite this, there is lack of data on radiation dose in this group of children undergoing CTCA. AIM: To audit the radiation dose of CTCA in children with KD. METHODS: Study (December 2013-February 2018) was performed on dual source CT scanner using adaptive prospective electrocardiography-triggering. The dose length product (DLP in milligray-centimeters-mGy.cm) was recorded. Effective radiation dose (millisieverts-mSv) was calculated by applying appropriate age adjusted conversion factors as per recommendations of International Commission on Radiological Protection. Radiation dose was compared across the groups (0-1, 1-5, 5-10, and > 10 years). RESULTS: Eighty-five children (71 boys, 14 girls) with KD underwent CTCA. The median age was 5 years (range, 2 mo-11 years). Median DLP and effective dose was 21 mGy.cm, interquartile ranges (IQR) = 15 (13, 28) and 0.83 mSv, IQR = 0.33 (0.68, 1.01) respectively. Mean DLP increased significantly across the age groups. Mean effective dose in infants (0.63 mSv) was significantly lower than the other age groups (1-5 years 0.85 mSv, 5-10 years 1.04 mSv, and > 10 years 1.38 mSv) (P < 0.05). There was no significant difference in the effective dose between the other groups of children. All the CTCA studies were of diagnostic quality. No child required a repeat examination. CONCLUSION: CTCA is feasible with submillisievert radiation dose in most children with KD. Thus, CTCA has the potential to be an important adjunctive imaging modality in children with KD.

Electronic properties-morphology correlation of a rod-rod semiconducting liquid crystalline block copolymer containing poly(3-hexylthiophene).

The influence of the solvent and annealing temperature on the field-effect mobilities and morphologies of poly(3-hexylthiophene)-b-poly(γ-benzyl-L-glutamate) (P3HT-b-PBLG) rod-rod diblock copolymer has been investigated. Thin film X-ray diffraction studies show peaks originating from both P3HT and PBLG indicating that the crystalline nature of both the blocks is conserved after the formation of the block copolymer. It has been observed that the field-effect mobilities of the diblock copolymer are independent of the annealing temperatures for thin films deposited from both 1,2,4-trichlorobenzene and chloroform solvents. The correlation between the field-effect mobility and morphology indicates that the P3HT block self-assembles at the surface SiO(2) dielectric.

Various defects in graphene: a review.

Pristine graphene has been considered one of the most promising materials because of its excellent physical and chemical properties. However, various defects in graphene produced during synthesis or fabrication hinder its performance for applications such as electronic devices, transparent electrodes, and spintronic devices. Due to its intrinsic bandgap and nonmagnetic nature, it cannot be used in nanoelectronics or spintronics. Intrinsic and extrinsic defects are ultimately introduced to tailor electronic and magnetic properties and take advantage of their hidden potential. This article emphasizes the current advancement of intrinsic and extrinsic defects in graphene for potential applications. We also discuss the limitations and outlook for such defects in graphene.

Central Nervous System Blastomycosis With Multiple Brain Abscesses Presenting as Right Upper Extremity Weakness.

Blastomycosis is a mycotic infection that typically affects the lung, but that can have dermatologic, orthopedic, genitourinary, and central nervous system manifestations. Blastomyces dermatitidis is a true human pathogen, which can produce disease in immunocompetent hosts. Risk factors for infection include residence in or travel to endemic areas and outdoor occupation, particularly those activities near open bodies of water and that disrupt soil. Immunosuppressed patients are also at increased risk for severe and disseminated disease. We present a case of a 79-year-old male who presented with a 2-week history of progressive right upper extremity weakness and severe odontogenic disease. He was found to have multiple brain abscesses with positive cultures from a cerebral abscess incision and drainage for B dermatitidis. He underwent an incision and drainage of the largest cerebral abscess and was treated with intravenous liposomal amphotericin B, which he tolerated poorly. He was subsequently switched to voriconazole, which was well tolerated, and his neurological deficits improved throughout his hospitalization.

Orientation mapping of semicrystalline polymers using scanning electron nanobeam diffraction.

We demonstrate a scanning electron nanobeam diffraction technique that can be used for mapping the size and distribution of nanoscale crystalline regions in a polymer blend. In addition, it can map the relative orientation of crystallites and the degree of crystallinity of the material. The model polymer blend is a 50:50w/w mixture of semicrystalline poly(3-hexylthiophene-2,5-diyl) (P3HT) and amorphous polystyrene (PS). The technique uses a scanning electron beam to raster across the sample and acquires a diffraction image at each probe position. Through image alignment and filtering, the diffraction image dataset enables mapping of the crystalline regions within the scanned area and construction of an orientation map.

Management of infants with large, unrepaired ventricular septal defects and respiratory infection requiring mechanical ventilation.

OBJECTIVES: We sought to describe the hospital management and early outcome of critically ill infants presenting with large ventricular septal defects and pneumonia requiring mechanical ventilation at a referral center in a developing country. Infants with large ventricular septal defects who have pneumonia might present with respiratory failure requiring mechanical ventilation. In the developing world this presentation is relatively common, but few data exist describing patient management strategies. METHODS: Hospital data of consecutive infants admitted with large ventricular septal defects and pneumonia requiring mechanical ventilation were reviewed and analyzed. RESULTS: We identified 18 infants (mean age, 3.6 +/- 3.0 months). On admission, all the infants were significantly malnourished, and echocardiography showed bidirectional shunting (predominantly right-to-left shunting) in 6 infants. Thirteen (72%) patients improved with intensive medical management that included mechanical ventilation for 1 to 16 days (median, 6.5 days); unequivocal left-to-right shunting was subsequently documented by means of echocardiography in all 13 patients. Twelve patients underwent surgical repair, and 11 (91.6%) were discharged after median mechanical ventilation of 100 hours (range, 42-240 hours) and intensive care unit stay of 8 days (range, 4-15 days). Five of 6 unoperated patients died, 4 of them within a few hours of admission. One child with multiple ventricular septal defects was discharged and subsequently underwent pulmonary artery banding. CONCLUSION: Corrective cardiac surgery for selected critically ill infants with large ventricular septal defects, severe malnutrition, and pneumonia requiring mechanical ventilation is feasible and should be considered a viable management strategy.

Neonatal Kawasaki disease.

The authors report a case of Kawasaki disease that manifested in a newborn and presented at the age of 6 weeks of age with coronary artery aneurysms.

Spontaneous coronary artery dissection with multiple coronary artery aneurysms in a patient with diabetic ketoacidosis.

Spontaneous coronary artery dissection (SCAD) is a very rare and commonly fatal condition that typically presents with signs and symptoms of an acute myocardial infarction and cardiogenic shock. We herein present a case of a 54-year-old woman who was diagnosed with diabetic ketoacidosis (DKA) as the first manifestation of her underlying diabetes mellitus, while being hospitalized for treatment, she was found to have a non ST-elevation myocardial infarction (NSTEMI), an urgent cardiac catheterization revealed a complete dissection of the right coronary artery (RCA) with an intraluminal thrombus formation and multiple aneurismal dilatations in the left anterior descending (LAD) and left circumflex (LC) arteries. The patient underwent coronary artery bypass grafting with a favorable outcome.