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Anisotropy in mechanical, optical and thermal sensors in a spatial direction has many applications in health care, robotics, aerospace, and tissue engineering. In particular, wearable and implantable sensors respond to stretching and bending strains that probe mechanical energy and track physiological signals. Hence, the development of anisotropic pressure sensors with true piezoelectric (PE) signals is of utmost importance to achieve efficient devices. Herein, a simple and efficient method is developed for high longitudinal and transverse responses, with an approach to isolating a true piezoelectric signal. The electrospun (ES) polarity of oriented dipoles inside flexible fibers gives rise to a high longitudinal/transverse PE response of both lateral and transverse strains. Nanofibers of poly(vinylidene-chlorotrifluoroethylene) copolymers contain poled dipoles, up to 86%, that promote an enhanced PE coefficient of 42 pm V-1 in the case of negative polarity-based electrospinning. It is 40% higher in composition than the commonly adopted positive polarity-biased electrospinning process. We demonstrated the advantage of such a high PE coefficient by the enhanced sensitivity of the longitudinal (VLs = 0.3 V kPa-1, ILs = 0.07 µA kPa-1) as well as transverse (VTs = 1.0 V kPa-1, ITs = 0.8 µA kPa-1) PE response. To counter the ambiguity of high transverse response as compared to longitudinal in electrospun fiber-based devices, a facile method is proposed to isolate the ferroelectret, triboelectric and piezoelectric signals in a fiber-based hybrid device with their independent charge generation mechanisms.
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In view of the depletion of natural energy resources, harvesting energy from waste is a revolution to simultaneously capture, unite, and recycle various types of waste energies in flexible devices. Thus, in this work, a spin-charge-regulated pyro-magneto-electric nanogenerator is devised at a well-known ferroelectric P(VDF-TrFE) copolymer. It promptly stores thermal-magnetic energies in a "capacitor" that generates electricity at room temperature. The ferroelectric domains are regulated to slip at the interfaces (also twins) of duly promoting polarization and other properties. An excellent pyroelectric coefficient p â¼ 615 nC·m-2·K-1 is obtained, with duly enhanced stimuli of a thermal sensitivity â¼1.05 V·K-1, a magnetoelectric coefficient αme â¼8.8 mV·cm-1·Oe-1 at 180 Hz (resonance frequency), and a magnetosensitivity â¼473 V/T. It is noteworthy that a strategy of further improving p (up to 41.2 µC·m-2·K-1) and αme (up to 23.6 mV·cm-1·Oe-1) is realized in the electrically poled dipoles. In a model hybrid structure, the spins lead to switch up the electric dipoles parallel at the polymer chains in a cohesive charged layer. It is an innovative approach for efficiently scavenging waste energies from electric vehicles, homes, and industries, where abundant thermal and magnetic energies are accessible. This sustainable strategy could be useful in next-generation self-powered electronics.
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The MnBi alloys is a model series of rare-Earth free magnets for surge of technologies of small parts of automobiles, power generators, medical tools, memory systems, and many others. The magnetics stem primarily at unpaired Mn-3d5spins (a 4.23µBmoment) align parallel via an orbital moment 0.27µBof Bi-5d106s2p3in a crystal lattice. Thus, using a surplus Mn (over Bi) in a Mn70Bi30type alloy designs a spin-rich system of duly tailored properties useful for magnetics and other devices. In this view, we report here a strategy of a refined alloy powder Mn70Bi30can grow into small crystals of hexagonal (h) plates at seeds as annealed in magnetic fields (in H2gas). So, small h-plates (30 to 50 nm widths) are grown up at (002) facets, wherein the edges are turned down in a spiral (≤2.1 nm thicknesses) in a core-shell structure. The results are described with x-ray diffraction, lattice images and magnetic properties of a powder Mn70Bi30(milled in glycine) is annealed at 573 K for different time periods, so to the Mn/Bi order at the permeable facets (seeds). Duly annealed samples exhibit an enhanced magnetization,Msâ 70.8 emu g-1, with duly promoted coercivityHcâ 10.810 kOe (15.910 kOe at 350 K), energy-product 14.8 MGOe, and the crystal-field-anisotropy,K1â 7.6 × 107erg cm-3, reported at room temperature. Otherwise,Msshould decline at any surplus 3d5-Mn spins order antiparallel at the antisites. Enhanced Curie point 658.1 K (628 K at Mn50Bi50alloy) anticipates that a surplus Mn does favor the Mn-Bi exchange interactions. Proposed spin models well describe the spin-dynamics and lattice relaxations (on anneals) over the lattice volume (with twins) and spin clusters.
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BACKGROUND: Drug-resistant tuberculosis is a major public health problem throughout the world and accounts for substantial morbidity and mortality rates in India, too. Early diagnosis is the corner stone of tuberculosis treatment. State-level and cluster-wise variations in drug resistance is a possibility and should be regularly checked in from time to time. MATERIALS AND METHODS: The present prospective cohort study (January 2019 to May 2022) was conducted in Darbhanga Medical College and Hospital on drug-resistant pulmonary tuberculosis patients. Sputum specimens were collected from designated centers. Rapid molecular drug-resistance testing (genotypic tests) and growth-based drug-susceptibility testing (DST) (phenotypic tests) were performed in the National Tuberculosis Elimination Program certified Laboratory. RESULTS: A total of 268 patients with drug-resistant pulmonary tuberculosis were included in the study group. The treatment outcomes revealed as cured in 100 (37.31%); treatment completed in 43 (16.04%); died in 56 (20.89%); treatment failed in 22 (8.21%); loss of follow up in 34 (12.69%); and transferred out in 13 (4.85%) drug-resistant pulmonary tuberculosis patients. Adverse events were recorded in 199 (74.25%) of the drug-resistant pulmonary tuberculosis patients. CONCLUSIONS: Drug-resistant pulmonary tuberculosis patients are a matter of concern and need to be addressed.
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A spin Mn3d5-rich Mn60Bi40alloy reveals a model system in order to tailor profound magnetic properties at unpaired 3d5spins in such alloys of a core-shell structure. As annealed (at a critical temperature 573 K in H2gas), a refined powder (in glycine) grows onα-MnBi seeds (crystallites) present in it at Mn/Bi atoms order over topological layers, preferentially along (110) planes, at a self-confined structure at seeds of an anisotropic shape of hexagonal (h) plates (25-85 nm widths). In terms of the HRTEM images, the atoms turn down at edges (at the plates grow up) in a spiral layer, ≤ 2.1 nm thickness, of small core-shells. A spin model is proposed to delineate a way at the spins can pin down at the edges, form single magnetic domains, and raise coercivity (Hc), with no much loss of net magnetic moment. The X-ray diffraction and HRTEM images corroborate the results of topological pacing of atoms at the h-plates at anneals. A novelty is that a core-shell leads to tailor a superbHc, as much as 11.110 kOe (16.370 kOe at 350 K), with a fairly large magnetization, 76.5 emu g-1, at near 300 K. An enhanced Curie point 650.1 K (628 K at Mn50Bi50alloy) confers a surplus 3d5-Mn spin sensitively tunesα-MnBi stoichiometry and so its final magnetic structure. A refined alloy powder so made is useful to make powerful magnets and devices in the forms of films and bonded magnets in different shapes for uses as small tools, tweezers, and other devices.
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The binary alloy Mn0.5+xBi0.5-x, x ⩽ 0.05, is a promising rare-earth-free magnetic material, with high-energy-density (a critical characteristic for electric motors and power electronics), low cost, and significant magnetic properties for multiple uses at room temperature. In this article, we report how a free Bi, when precipitated over Mn0.5+xBi0.5-x (x ⩽ 0.05) of small crystallites, diffuses back into a stable Mn0.5+xBi0.5-x, x â 0, via a peritectic reaction, which facilitates preferential growth of small core-shell crystallites with multiple facets, having the potential for tailored magnetic properties. This growth travels slowly in the anisotropic channels of vacancies on annealing the reactive nanopowder at a critical 573 K temperature in Ar gas. Thus, an initial crystallite size of D â¼ 27 nm grows to only 38 nm in a reaction extended over a period of 96 h. A transient phase, x > 0, which has Bi vacancies, primarily grows in the (101) and (110) facets, filling the vacancies over a 6.41% larger crystal density. If any excess Mn is present, it segregates over a saturated phase, combines with free Bi, and ultimately forms a stable alloy phase. The small crystallites contain an inbuilt surface Bi-layer (shell), with a 1-2 nm thickness, in a core-shell of nanoplates (20-60 nm width), as shown in the high resolution transmission electron microscope images. In the proposed microscopic model, with hybridized Mn-d5 and Bi-p3 electrons (also spins), the magnetic properties are readily controlled. Thus, at 300 K, a maximum coercivity Hc = 9.850 kOe (14.435 kOe at 350 K) develops (Hc = 5.010 kOe in the initial) in critical single domains (D â¼ 33 nm). A net 72.5 emu g-1 magnetization occurs, with an enhanced TC = 641.5 K (600.5 K at x â¼ 0.05) on an order of enhanced anisotropy constant K1, demonstrating the significant effects of this core-shell structure of small crystallites.
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BACKGROUND: Sickle cell disease (SCD), one of the most common inherited disorders, is associated with vaso-occlusive pain episodes and haemolysis leading to recurrent morbidity, hospital admissions and work or school absenteeism. The crises are conventionally treated with opioids, non-opioids and other adjuvants with the risk of developing complications, addictions and drug-seeking behaviour. Different non-pharmacological treatments, such as transcutaneous electrical nerve stimulation (TENS) have been used for managing pain in other painful conditions. Hence, the efficacy of TENS for managing pain in SCD needs to be reviewed. OBJECTIVES: To assess the benefits and harms of TENS for managing pain in people with SCD who experience pain crises or chronic pain (or both). SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Register, comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries and the reference lists of relevant articles and reviews. Date of the last search: 26 Febraury 2020. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs, where TENS was evaluated for managing pain in people with SCD. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the eligibility of the trials identified by the literature searches according to the inclusion criteria. Two review authors then independently extracted data, assessed for risk of bias using the Cochrane standard tool and rated the quality of evidence using the GRADE guidelines. MAIN RESULTS: One double-blind cross-over RCT with 22 participants with SCD (aged 12 to 27 years) was eligible for inclusion. Following stratification into four pain crises severity grades, participants were then randomised to receive TENS or placebo (sham TENS). The trial was concluded after 60 treatment episodes (30 treatment episodes of each treatment group). There is a lack of clarity regarding the trial design and the analysis of the cross-over data. If a participant was allocated to TENS treatment for an episode of pain and subsequently returned with a further episode of a similar degree of pain, they would then receive the sham TENS treatment (cross-over design). For those experiencing a pain episode of a different severity, it is not clear whether they were re-randomised or given the alternate treatment. Reporting and analysis was based on the total number pain events and not on the number of participants. It is unclear how many participants were crossed over from the TENS group to the sham TENS group and vice versa. The trial had a high risk of bias regarding random sequence generation and allocation concealment; an unclear risk regarding the blinding of participants and personnel; and a low risk regarding the blinding of the outcome assessors and selective outcome reporting. The trial was small and of very low quality; furthermore, given the issue with trial design we were unable to quantitatively analyse the data. Therefore, we present only a narrative summary and caution is advised in interpreting the results. In relation to our pre-defined primary outcomes, the included trial did not report pain relief at two to four weeks post intervention. The trial authors reported that no difference was found in the changes in pain ratings (recorded at one hour and four hours post intervention) between the TENS and the placebo groups. In relation to our secondary outcomes, the analgesic usage during the trial also did not show any difference between groups. Given the quality of the evidence, we are uncertain whether TENS improves overall satisfaction as compared to sham TENS. The ability to cope with activities of daily living was not evaluated. Regarding adverse events, although one case of itching was reported in the TENS group, the site and nature of itching was not clearly stated; hence it cannot be clearly attributed to TENS. Also, two participants receiving 'sham' TENS reported a worsening of pain with the intervention. AUTHORS' CONCLUSIONS: Since we have only included one small and very low-quality trial, with a high risk of bias across several domains, we are unable to conclude whether TENS is harmful or beneficial for managing pain in people with SCD. There is a need for a well-designed, adequately-powered, RCT to evaluate the role of TENS in managing pain in people with SCD.
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Dolor Crónico/terapia , Manejo del Dolor/métodos , Estimulación Eléctrica Transcutánea del Nervio/métodos , Analgésicos/uso terapéutico , Anemia de Células Falciformes/fisiopatología , Dolor Crónico/etiología , Humanos , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
A simple approach of template growth of graphitic-carbon nitride (g-CN), a polymeric unit consisting of C, N, O, and H elements derived from extracts of green plant Aloe vera, which are rich in several chemical constituents, has been successfully experimented in this work. Comparing several other methods used for synthesizing g-CN involving a large amount of toxic components, here, we propose the simplest route economically and environmentally highly viable for near future. Green plants are highly rich in natural carbon and nitrogen compounds, such as acemannan, glucose, aloin, protein, etc. Way before g-CN research, many carbon-based materials have been synthesized for multifunctional properties, but g-CN has much benefit over them due to the presence of elements such as C, N, O, and H, thus making it electron-rich. Multifunctional properties of graphitic-carbon nitride interface bonding as a supercapacitor or as a metal-free catalyst thus help degrade dyes. Violet-blue broad band emission was even noticed when excited at 240 nm via C-C bonding (π-π* transition) in the absorption band with an extinction coefficient of â¼104 M-1 cm-1. With our research, we want to pave new ways of synthesizing such materials present in our nature in a biological form, which can protect our environment, thus causing less harm to mankind.
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The two-dimensional (2D) semiconductor molybdenum disulfide (MoS2) has attracted widespread attention for its extraordinary electrical-, optical-, spin-, and valley-related properties. Here, we report on spin-polarized tunneling through chemical vapor deposited multilayer MoS2 (â¼7 nm) at room temperature in a vertically fabricated spin-valve device. A tunnel magnetoresistance (TMR) of 0.5-2% has been observed, corresponding to spin polarization of 5-10% in the measured temperature range of 300-75 K. First-principles calculations for ideal junctions result in a TMR up to 8% and a spin polarization of 26%. The detailed measurements at different temperature, bias voltages, and density functional theory calculations provide information about spin transport mechanisms in vertical multilayer MoS2 spin-valve devices. These findings form a platform for exploring spin functionalities in 2D semiconductors and understanding the basic phenomena that control their performance.
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Cerium(III)-N,N-dimethylformamide-bisulfate [Ce(DMF)(HSO4)3] complex is doped into poly(vinylidene fluoride) (PVDF) to induce a higher yield (99%) of the electroactive phases (ß- and γ-phases) of PVDF. A remarkable enhancement of the output voltage (â¼32 V) of a nanogenerator (NG) based on a nonelectrically poled cerium(III) complex containing PVDF composite film is achieved by simple repeated human finger imparting, whereas neat PVDF does not show this kind of behavior. This high electrical output resembles the generation of self-poled electroactive ß-phase in PVDF due to the electrostatic interactions between the fluoride of PVDF and the surface-active positive charge cloud of the cerium complex via H-bonding and/or bipolar interaction among the opposite poles of cerium complex and PVDF, respectively. The capacitor charging capability of the flexible NG promises its applicability as piezoelectric-based energy harvester. The cerium(III) complex doped PVDF composite film exhibit an intense photoluminescence in the UV region, which might be due to a participation of electron cloud from negative pole of bipolarized PVDF. This fact may open a new area for prospective development of high-performance energy-saving flexible solid-state UV light emitters.
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BACKGROUND: It is known that simulation training is associated with stress for the trainees, at all levels of trainee experience. We explored the factors which were perceived by the trainees to cause them the maximum stress related to their simulation experience and their temporal changes over three simulation sessions. METHODS: Ninety-seven final year medical students were administered a Likert-type questionnaire on perceived stressors after trauma simulation training. These stressors were classified as intrapsychic (relating to internal feelings); interpersonal (relating to interaction with others) and interactive (related to interaction with the simulated patient). Non-parametric tests were used for statistical analysis. RESULTS: Death of the simulated patient scored highest of all stressors. When the median scores for intrapsychic, interpersonal or interactive items were plotted session-wise, three distinct types of graphs were obtained. Eight of 13 items had a decrease in perceived stress scores from the first to the second session. Only 'death of the simulated patient' showed a significant increase in the score from the second to the third session. CONCLUSION: Undergraduate medical trainees experienced stress due to various factors during their first simulation session, which reduced with repeated sessions. However, perceived stress related to simulated death of a patient continued to remain high even after two repetitions. We suggest that simulation training programmes for undergraduate medical students should have at least one repeat session to reduce the stress and that facilitators should consider keeping the simulated patient alive throughout the training sessions.
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Maniquíes , Estrés Psicológico/epidemiología , Estudiantes de Medicina/psicología , Traumatología/educación , Adulto , Femenino , Humanos , Malasia/epidemiología , Masculino , Factores de Riesgo , Encuestas y CuestionariosRESUMEN
BACKGROUND: The psychological stress after diagnosis of breast cancer is often severe. Most of the women with breast cancer and their families suffer from emotional, social, financial and psychological disturbances. MATERIALS AND METHODS: A cluster non-randomized trial was conducted at a Cancer Society in Melaka, Malaysia to assess the effectiveness of psycho-education on well-being status and depression among breast cancer patients. The study period was for one month (11(th) June 2011 and 16(th) July 2011). Participants in this study were 34 adult women suffering from non-metastatic breast cancer and on appropriate allopathic medication. The WHO-five Well-being Index (1998 version) was used as the screening instrument for the assessment of well-being and depression. The data collected were tabulated and analyzed by using the Statistical Package for Social Sciences (SPSS) version 11.0. Wilcoxon Signed-rank Test was applied for comparison between pre-test and post-test scores. A P value <0.05 was considered as statistically significant. RESULTS: This study revealed that majority of the participants was in the state of adequate well-being after the psycho-education 33 (97.1%). The proportion of depressed individuals had also reduced from 8 (23.5%) to 1 (2.9%) after the psychological intervention. The post-test results significantly improved after the intervention for the items related to "I have felt calm and relaxed", "I woke up feeling fresh and rested" and "my daily life has been filled with things that interest me" along with the "overall impression" in the WHO-5 Well-being Index. CONCLUSION: Group psycho-education played a significant role in improving the well-being status and reducing depression of breast cancer survivors.
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Ni39+x Mn50Sn11-x (x = 0.5, 1.0, 1.5 and 2) alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, â¼15 mm diameter and 8 mm width. A single martensite phase with a L10 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% (x = 2), whereas an austenite cubic L21 phase turns up at smaller x ⩽ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips (x â½ 1.5) with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite-austenite (or reverse) phase transition. A net residual enthalpy change ΔHMâA = -0.12 J g-1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (-)26% at 10 T is observed together with a large entropy change of 11.8 mJ g-1 K-1, nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The ΔHMâA irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features.
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A chemical method with small polymer templates is explored to obtain single magnetic domain La0.67Ca0.33MnO3 particles of thin nanoplates (25-35 nm thickness). The sample is light-emitting (480-800 nm) in multiple bands with two prominent bandgroups in the 570 nm green and 762 nm red emissions. The green emission consists of four bands 555.1, 565.7, 573.4, and 584.7 nm in the O2- -2p--> Mn3+ / Mn4+ -3d interband electronic transitions. Two excited-electronic levels G, (565.7 nm) and G2 (555.1 nm), which are exchange coupled via a phonon level v2* (678 cm(-1)), exhibit the four bands in the transitions to the ground state G0 and a phonon level v1 (575 cm(-1)). The bands v1 and v2 are well-resolved in the IR spectrum. A similar phonon assisted Mn3+ --> Mn4+ charge transfer transition results in the red emission. Both the green and red bandgroups appear in a common excitation over 350-450 nm from a xenon source. Evidently, as proposed with a model energy level diagram, the electron-phonon coupling governs a multiple light-emission in this example of the single domain particles. Otherwise, such specific ceramics of half-metallic ferromagnets hardly allows a light-emission at room temperature.
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The thrust to develop environmental friendly procedures for production of Nanoparticles arises from the very fact that current nanotechnology research uses a lot of chemicals, which are potential threat to both environment and public health. Tea (Camellia Sinensis) with its rich source of polyphenolic compounds has been exploited for the reduction and capping of silver nanoparticles (Ag-NPs), making it a complete green chemical route. The reduction of Ag+ to Ag0 was observed by the color change from pale yellow to dark yellow. The reaction was followed with the help of UV-Visible spectrometer. Crystal structure was obtained by carrying out X-ray diffraction studies and it showed face centered cubic (fcc) structure. The particle size and morphology were obtained from transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) studies. An average particle size of 25 nm silver particles could be obtained using this method and the TEM and SAXS data corroborate with each other.
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Peridinin is known as the main light-harvesting pigment in photosynthesis in the sea and exhibits exceptionally high energy transfer efficiencies to chlorophyll a. This energy transfer efficiency is thought to be related to the intricate structure of peridinin, which possesses allene and ylidenbutenolide functions in the polyene backbone. There are, however, no studies on the relationship between the structural features of peridinin and its super ability for energy transfer. We then focused on the subjects of why peridinin possesses a unique allene group and how the allene function plays a role in the exceptionally high energy transfer. Toward elucidation of the exact role of the allene function, we now describe the syntheses of three relatively unstable allene-modified derivatives of peridinin along with the results of the Stark spectroscopy of peridinin and the synthesized peridinin derivatives.
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Alcadienos/química , Alcadienos/metabolismo , Carotenoides/síntesis química , Transferencia de Energía , Fotosíntesis , Acetileno/química , Alquenos/química , Carotenoides/química , Carotenoides/metabolismo , Clorofila/química , Clorofila/metabolismo , Clorofila A , Modelos Moleculares , Conformación Proteica , Solventes/química , Análisis EspectralRESUMEN
Iron oxide nanoparticles (IONPs) can play a significant role in the cycling of heavy metals. Arsenite [As(III)] is highly toxic, mobile, and predominant species in arsenic-contaminated groundwater. IONPs have been synthesized and tested for the removal of As(III) from arsenic contaminated water. In this work, we synthesized IONPs, as a finely divided loose nanopowder, using a chemical method involving a dispersion of the metal cations (Fe3+) through polymer molecules of polyvinyl alcohol (PVA) in an aqueous medium. X-ray diffraction (XRD) analysis confirmed the formation of a single phase rhombohedral crystal structure of R3c space group. Transmission electron microscopic images corroborate the result of IONPs of 45 nm average size and the rhombohedral shape. Selective experiments, conducted with an initial concentration of 0.25 ppm of As(III), have demonstrated the maximum As(III) adsorption capacity (96%) in 2.0 gL(- 1) IONPs in water at pH 4.5-7.5. At room temperature, the adsorption isotherm studies have revealed a better correlation with the Langmuir isotherm than the Freundlich isotherm. Characteristic surface hydrolysis of IONPs as = Fe-OH species has been studied in terms of the vibration bands. The results reveal that the removal of the As(III) species from water is associated with the As(III) adsorption onto the IONPs followed by a surface hydrolysis of the iron species.
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Arsénico/aislamiento & purificación , Compuestos Férricos/química , Nanopartículas del Metal , Adsorción , Cristalografía por Rayos X , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Transmisión , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
BACKGROUND: Pilomatricoma, a benign skin adnexal tumor, frequently leads to false positive diagnosis cytologically. We report a rapidly growing nodular swelling misdiagnosed as round cell tumor cytologically and found to be pilomatricoma histopathologically. CASE: A 32-year-old man presented with a rapidly growing, mobile nodule on his left arm for 4 months with fixed, shiny overlying skin. Fine needle aspiration cytology (FNAC) sample was cellular, showing round to ovoid cells dispersed or in clusters with occasionally rosette-like appearance. Cells displayed round, granular nuclei, single to multiple small nucleoli, absent to scant cytoplasm, a moderate amount of granular cytoplasm and apoptotic and mitotic figures in places. Nuclear moldings were encountered occasionally. Cytologically the diagnosis of blue round cell tumor was made. Histopathologic examination showed islands of basaloid cells with scant cytoplasm and shadow cells and occasional giant cells. The diagnosis was pilomatricoma bistopathologically. Rapidly growing, early lesions of pilomatricoma are predominantly composed of basaloid cells and mostly devoid of other diagnostic clues, leading to a false impression of malignancy. To avoid misdiagnosis, all skin-based nodules should undergo extensive cytologic sampling from diferent sites. Pilomatricoma should be considered in diferential diagnosis when primitive-appearing cells are aspirated, especially in rapidly growing early lesions.
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Carcinoma de Células de Merkel/diagnóstico , Carcinoma de Células Pequeñas/diagnóstico , Enfermedades del Cabello/diagnóstico , Pilomatrixoma/diagnóstico , Neoplasias Cutáneas/diagnóstico , Adulto , Biomarcadores de Tumor/metabolismo , Biopsia con Aguja Fina , Colágeno Tipo II/metabolismo , Proteínas de Unión al ADN/metabolismo , Diagnóstico Diferencial , Errores Diagnósticos , Enfermedades del Cabello/metabolismo , Humanos , Queratina-3/metabolismo , Masculino , Pilomatrixoma/metabolismo , Neoplasias Cutáneas/metabolismo , Factores de TranscripciónRESUMEN
allo-Threonine-derived O-acyl-B-phenyl-oxazaborolidinones are demonstrated to be powerful and highly enantioselective Lewis acid catalysts for the Diels-Alder reaction of simple acyclic enone dienophiles, expanding the scope of ketone dienophiles and dienes. With 10 to 20 mol % of catalyst, the Diels-Alder adducts are obtained in 76-98% ee with high endo-selectivity. The catalyst exhibits high activity for the reaction with the less reactive beta-substituted dienophiles and the less reactive 1,3-cycohexadiene and 1,3-butadiene derivatives. The application of the catalysts to the Diels-Alder reaction of furan is also described.
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Compuestos Heterocíclicos con 1 Anillo/química , Cetonas/química , Cetonas/síntesis química , Boranos , Catálisis , Ciclización , Estructura Molecular , EstereoisomerismoRESUMEN
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has been used extensively for the analysis of -intact proteins and for proteomics. Proteins or proteomics analyses with low molecular mass range have some limitations because of background interference from the salt or surfactant ions. Lanthanum-calcium- manganate La(0.67)Ca(0.33)MnO(3) nanoparticles (LCMONPs) have been used as the matrix-assisting material after surface modification to reduce the salt or surfactant interference. The detectable mass range was tested in the range of 800-16,000 Da. The surface-modified LCMONPs have affinity with protein molecules through ionic or electrostatic interaction at pH 4.0. The nanoparticles mixed with proteins give a spectrum with a large signal-to-noise ratio for the analytes, and effectively eliminate the noise from interfering salt or surfactant ions. The results indicate that surface-modified La(0.67)Ca(0.33)MnO(3) nanoparticles can be used with MALDI matrix for proteins to eliminate the excessive noise of selective surfactants or salt ions from the MALDI spectrum.