Congenital Nasal Pyriform Aperture Stenosis as a rare manifestation of Trisome 8 Mosaicsm: a case report

Congenital Nasal Pyriform Aperture Stenosis (CNPAS) is an extremely rare cause of nasal airway obstruction. Clinically, it mimics choanal atresia in neonate. It needs to be differentiated because management differs from each. Pyriform aperture is located at the most anterior part of the nose and is always the narrowest region of the nasal cavity. Therefore, nasal obstruction can easily occur if there is slight decrease in its cross sectional area. CNPAS rarely presents alone. Usually, it arises together with a midline developmental defect such as holoprosencephaly or pituitary defect. We present the first ever reported case of CNPAS, in association with Trisomy 8 Mosaicsm (T8M)

Bell’s palsy in pregnancy as a prodromal sign of preeclampsia: A report of three cases, pregnancy outcome, and literature review

Bell’s palsy is a less common neurological disorder in the general population. Its occurrence during pregnancy can be used as a predictor of adverse obstetric outcomes including preeclampsia and its complications. We report cases of three pregnant women from Botswana who presented with Bell’s palsy in the third trimester coexisting with preeclampsia and multiple complications. One of the patient was a case of maternal near-miss with multiple life threating complications including stage 3 acute kidney injury (AKI) and required hemodialysis. The second and third patients developed Bell`s palsy and preeclampsia at term, management of preeclampsia commenced with immediate delivery resulting in good maternal and neonatal outcome. In all the three patients preeclampsia and Bell`s palsy completely resolved post-delivery. Therefore, new onset Bell’s palsy in pregnancy may be used as a prodromal sign of preeclampsia. Such patients deserve close follow up for preeclampsia or gestational hypertension for a better obstetric outcome. La paralysie de Bell est un trouble neurologique moins fréquent dans la population générale. Son apparition pendant la grossesse peut être utilisée comme un prédicteur d'issues obstétricales défavorables, y compris la prééclampsie et ses complications. Nous rapportons les cas de trois femmes enceintes du Botswana qui ont présenté une paralysie de Bell au troisième trimestre coexistant avec une prééclampsie et de multiples complications. L'un des patients était un cas de quasi-accident maternel avec de multiples complications potentiellement mortelles, notamment une insuffisance rénale aiguë (IRA) de stade 3 et une hémodialyse nécessaire. Les deuxième et troisième patientes ont développé une paralysie de Bell et une prééclampsie à terme, la prise en charge de la prééclampsie a commencé avec l'accouchement immédiat, ce qui a donné de bons résultats maternels et néonatals. Chez les trois patientes, la prééclampsie et la paralysie de Bell ont complètement disparu après l'accouchement. Par conséquent, une nouvelle paralysie de Bell pendant la grossesse peut être utilisée comme signe prodromique de prééclampsie. Ces patientes méritent un suivi rapproché de la prééclampsie ou de l'hypertension gestationnelle pour un meilleur résultat obstétrica

Au plasmonics in a WS2-Au-CuInS2 photocatalyst for significantly enhanced hydrogen generation

Promoting the activities of photocatalysts is still the critical challenge in H2 generation area. Here, a Au plasmon enhanced photocatalyst of WS2-Au-CuInS2 is developed by inserting Au nanoparticles between WS2 nanotubes and CuInS2 (CIS) nanoparticles. Due to the localized surface plasmonic resonance properties from Au nanoparticles, WS2-Au-CIS shows the best performance as compared to Au-CIS, CIS, WS2-CIS, CIS-Au, WS2-Au, and WS2-CIS-Au. The surface plasmonic resonance effects dramatically intensify the absorption of visible light and help to inject hot electrons into the semiconductors. Our findings open up an efficient method to optimize the type-II structures for photocatalytic water splitting

Efficient Photocatalytic Hydrogen Evolution via Band Alignment Tailoring: Controllable Transition from Type-I to Type-II

Considering the sizable band gap and wide spectrum response of tin disulfide (SnS2), ultrathin SnS2 nanosheets are utilized as solar-driven photocatalyst for water splitting. Designing a heterostructure based on SnS2 is believed to boost their catalytic performance. Unfortunately, it has been quite challenging to explore a material with suitable band alignment using SnS2 nanomaterials for photocatalytic hydrogen generation. Herein, a new strategy is used to systematically tailor the band alignment in SnS2 based heterostructure to realize efficient H2 production under sunlight. A Type-I to Type-II band alignment transition is demonstrated via introducing an interlayer of Ce2S3, a potential photocatalyst for H2 evolution, between SnS2 and CeO2. Subsequently, this heterostructure demonstrates tunability in light absorption, charge transfer kinetics, and material stability. The optimized heterostructure (SnS2–Ce2S3–CeO2) exhibits an incredibly strong light absorption ranging from deep UV to infrared light. Significantly, it also shows superior hydrogen generation with the rate of 240 µmol g−1 h−1 under the illumination of simulated sunlight with a very good stability

The Role of Active Oxide Species for Electrochemical Water Oxidation on the Surface of 3d-Metal Phosphides

Transition metal phosphides (TMPs) have recently been utilized as promising electrocatalysts for oxygen evolution reaction (OER) in alkaline media. The metal oxides or hydroxides formed on their surface during the OER process are hypothesized to play an important role. However, their exact role is yet to be elucidated. Here unambiguous justification regarding the active role of oxo(hydroxo) species on O-Ni(1−x)FexP2 nanosheet with pyrite structure is shown. These O-Ni(1−x)FexP2 (x = 0.25) nanosheets demonstrate greatly improved OER performance than their corresponding hydroxide and oxide counterparts do. From density function theory (DFT) calculations, it is found that the introduction of iron into the pyrite-phased NiP2 alters OER steps occurred on the surface. Notably, the partially oxidized surface of O-Ni(1−x)FexP2 nanosheets is vital to improve the local environment and accelerate the reaction steps. This study sheds light on the OER mechanism of the 3d TMP electrocatalyst and opens up a way to develop efficient and low-cost electrocatalysts

High Crystal Quality 2D Manganese Phosphorus Trichalcogenide Nanosheets and their Photocatalytic Activity

Transition metal phosphorus trichalcogenides (MPX3, X = S, Se) are layered materials possessing high chemical diversity and wide range of applications in a broad wave length spectrum. Theoretical studies reveal that auspicious activity of photocatalytic water splitting can be realized from them. However, experimental efforts have so far been challenged with the synthesis bottleneck. Described herein is the general chemical vapor deposition (CVD) growth method and photocatalytic activity of these materials. A novel route to systematically grow MnPX3 nanosheets on flexible carbon fiber substrate is reported. The temperature profile of the CVD process is carefully optimized that confer a facile and successful conversion of oxide precursor to phospho-trichalcogenide with high crystallinity. Moreover, the obtained manganese-based phosphorus trichalcogenide nanosheets demonstrate promising activity in sacrificial agent-free photocatalytic water splitting under simulated solar light (AM 1.5G). This study provides a significant stepping stone in exploring the fascinating world of functional 2D materials and pursuing performance enhancement

Efficient Catalysis of Hydrogen Evolution Reaction from WS2(1−x)P2x Nanoribbons

The rational design of Earth abundant electrocatalysts for efficiently catalyzing hydrogen evolution reaction (HER) is believed to lead to the generation of carbon neutral energy carrier. Owing to their fascinating chemical and physical properties, transition metal dichalcogenides (TMDs) are widely studied for this purpose. Of particular note is that doping by foreign atom can bring the advent of electronic perturbation, which affects the intrinsic catalytic property. Hence, through doping, the catalytic activity of such materials could be boosted. A rational synthesis approach that enables phosphorous atom to be doped into WS2 without inducing phase impurity to form WS2(1−x)P2x nanoribbon (NRs) is herein reported. It is found that the WS2(1−x)P2x NRs exhibit considerably enhanced HER performance, requiring only −98 mV versus reversible hydrogen electrode to achieve a current density of −10 mA cm−2. Such a high performance can be attributed to the ease of H-atom adsorption and desorption due to intrinsically tuned WS2, and partial formation of NRs, a morphology wherein the exposure of active edges is more pronounced. This finding can provide a fertile ground for subsequent works aiming at tuning intrinsic catalytic activity of TMDs

High-performance, multifunctional devices based on asymmetric van der Waals heterostructures

Two-dimensional materials are of interest for the development of electronic devices due to their useful properties and compatibility with silicon-based technology. Van der Waals heterostructures, in which two-dimensional materials are stacked on top of each other, allow different materials and properties to be combined and for multifunctional devices to be created. Here we show that an asymmetric van der Waals heterostructure device, which is composed of graphene, hexagonal boron nitride, molybdenum disulfide and molybdenum ditelluride, can function as a high-performance diode, transistor, photodetector and programmable rectifier. Due to the asymmetric structure of the device, charge-carrier injection can be switched between tunnelling and thermal activation under negative and positive bias conditions, respectively. As a result, the device exhibits a high current on/off ratio of 6 × 108 and a rectifying ratio of 108. The device can also function as a programmable rectifier with stable retention and continuously tunable memory states, as well as a high program/erase current ratio of 109 and a rectification ratio of 107

CoS2xSe2(1-x) nanowire array: An efficient ternary electrocatalyst for the hydrogen evolution reaction

Binary transition metal dichalcogenides (TMDs) have emerged as efficient catalysts for the hydrogen evolution reaction (HER). Co-based TMDs, such as CoS2 and CoSe2, demonstrate promising HER performance due to their intrinsic metallic nature. Recently, the ternary electrocatalysts were widely acknowledged for their prominent efficiency as compared to their binary counterparts due to increased active sites caused by the incorporation of different atoms. Herein, we successfully grew the ternary CoS2xSe2(1-x) (x = 0.67) nanowires (NWs) on a flexible carbon fiber. As a superior electrocatalyst, ternary CoS2xSe2(1-x) NWs arrays demonstrated excellent catalytic activity for electrochemical hydrogen evolution in acidic media, achieving current densities of 10 mA cm-2 and 100 mA cm-2 at overpotentials of 129.5 mV and 174 mV, respectively. Notably, the high stability of CoS2xSe2(1-x) NWs suggested that the ternary CoS2xSe2(1-x) NWs are a scalable catalyst for electrochemical hydrogen evolution

Carbon dots decorated vertical SnS2 nanosheets for efficient photocatalytic oxygen evolution

Metal sulfides are highly desirable materials for photocatalytic water splitting because of their appropriate energy bands. However, the poor stability under light illumination in water hinders their wide applications. Here, two-dimensional SnS2 nanosheets, along with carbon dots of the size around 10 nm, are uniformly grown on fluorine doped tin oxide glasses with a layer of nickel nanoparticles. Significantly, strong light absorption and enhanced photocurrent density are achieved after integration of SnS2 nanosheets with carbon dots. Notably, the rate of oxygen evolution reached up to 1.1 mmol g-1 h-1 under simulated sunlight irradiation featuring a good stability