Emergence of SARS-CoV-2 Delta Variant, Benin, May-July 2021.

Severe acute respiratory syndrome coronavirus 2 Delta variant epidemiology in Africa is unknown. We found Delta variant was introduced in Benin during April-May 2021 and became predominant within 2 months, after which a steep increase in reported coronavirus disease incidence occurred. Benin might require increased nonpharmaceutical interventions and vaccination coverage.

Mutations Associated with SARS-CoV-2 Variants of Concern, Benin, Early 2021.

Intense transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Africa might promote emergence of variants. We describe 10 SARS-CoV-2 lineages in Benin during early 2021 that harbored mutations associated with variants of concern. Benin-derived SARS-CoV-2 strains were more efficiently neutralized by antibodies derived from vaccinees than patients, warranting accelerated vaccination in Africa.

Optogenetics inspired transition metal dichalcogenide neuristors for in-memory deep recurrent neural networks.

Shallow feed-forward networks are incapable of addressing complex tasks such as natural language processing that require learning of temporal signals. To address these requirements, we need deep neuromorphic architectures with recurrent connections such as deep recurrent neural networks. However, the training of such networks demand very high precision of weights, excellent conductance linearity and low write-noise- not satisfied by current memristive implementations. Inspired from optogenetics, here we report a neuromorphic computing platform comprised of photo-excitable neuristors capable of in-memory computations across 980 addressable states with a high signal-to-noise ratio of 77. The large linear dynamic range, low write noise and selective excitability allows high fidelity opto-electronic transfer of weights with a two-shot write scheme, while electrical in-memory inference provides energy efficiency. This method enables implementing a memristive deep recurrent neural network with twelve trainable layers with more than a million parameters to recognize spoken commands with >90% accuracy.

Corrigendum: Control of Radiative Exciton Recombination by Charge Transfer Induced Surface Dipoles in MoS2 and WS2 Monolayers.

This corrects the article DOI: 10.1038/srep24105.

From Linear to Angular Isomers: Achieving Tunable Charge Transport in Single-Crystal Indolocarbazoles Through Delicate Synergetic CH/NH⋠⋠⋠π Interactions.

Weak intermolecular interaction in organic semiconducting molecular crystals plays an important role in molecular packing and electronic properties. Here, four five-ring-fused isomers were rationally designed and synthesized to investigate the isomeric influence of linear and angular shapes in affecting their molecular packing and resultant electronic properties. Single-crystal field-effect transistors showed mobility order of 5,7-ICZ (3.61 cm2 V-1 s-1 ) >5,11-ICZ (0.55 cm2 V-1 s-1 ) >11,12-ICZ (ca. 10-5  cm2 V-1 s-1 ) and 5,12-ICZ (ca. 10-6  cm2 V-1 s-1 ). Theoretical calculations based on density functional theory (DFT) and polaron transport model revealed that 5,7-ICZ can reach higher mobilities than the others thanks to relatively higher hole transfer integral that links to stronger intermolecular interaction due to the presence of multiple NH⋅⋅⋅π and CH⋅⋅⋅π(py) interactions with energy close to common NH⋅⋅⋅N hydrogen bonds, as well as overall lower hole-vibrational coupling owing to the absence of coupling of holes to low frequency modes due to better π conjugation.

[Anatomical study of pelvic colon]. / Étude anatomique du côlon pelvien.

OBJECTIVES: Identifying the different kinds of anatomical sigmoid colon in our environment and determine what exposes the most to the occurrence of pelvic colon volvulus. MATERIALS AND METHODS: This is a transverse prospective study from 1 January 2007 to 31 December 2012 on a series of 63 patients (33 men and 30 women) who underwent laparotomy for non-colonic pathologies. For all patients, the following parameters were recorded: C1: total length of the pelvic colon; C2: the length of the root of the meso-sigmoid; C3: the height of the meso-sigmoid; C4: maximum width of the meso-sigmoid. RESULTS: C1 through the entire series was 61,3cm. C2 average was 5.5cm. C3 height and maximum width C4 were on average 14,6cm and 7.6cm, respectively. Comparison of parameters in men and women showed no significant difference. CONCLUSION: This study allows us to know the different types of pelvic colons among the population of our operated patients. The measurements performed on the pelvic colon of patients presenting volvulus will help to attribute objectively the true authorship of this surgical emergency to an anatomical type of pelvic colon.

Control of Radiative Exciton Recombination by Charge Transfer Induced Surface Dipoles in MoS2 and WS2 Monolayers.

Due to the two dimensional confinement of electrons in a monolayer of 2D materials, the properties of monolayer can be controlled by electrical field formed on the monolayer surface. F4TCNQ was evaporated on MoS2 and WS2 monolayer forming dipoles between strong acceptor, F4TCNQ, and monolayers of MoS2 or WS2. The strong acceptor attracts electrons (charge transfer) and decreases the number of the ionized excitons. Free excitons undergo radiative recombination in both MoS2 and WS2. Moreover, the photoluminescence enhancement is stronger in WS2 where the exciton-phonon coupling is weaker. The theoretical model indicates that the surface dipole controls the radiative exciton recombination and enhances photoluminescence radiation. Deposition of F4TCNQ on the 2D monolayers enables a convenient control of the radiative exciton recombination and leads to the applications of these materials in lasers or LEDs.

[Zuckerkandl's tubercle: incidence and relationship with the inferior laryngeal nerve]. / Le tubercule de Zuckerkandl: incidence et rapport avec le nerf laryngé inférieur.

UNLABELLED: The iatrogenal lesion of the inferior laryngeal nerve (ILN) during thyroid surgery is an incident, which can have greatest functional after-effects. Its research is recommended during cervicotomy for thyroidectomy and it can be easily found by the presence of Zuckerkandl tubercle, which is a postero-lateral excrescence of the thyroid gland. OBJECTIVES: The main objective of our study was the researching of the presence of this Zuckerkandl tubercle and appreciating the reports with the ILN. PATIENTS AND METHODS: From 1st October 2010 to 30th September 2012, we realized a continuous prospective study on a mono-operator series of 48 patients operated on for thyroidectomy. The Zuckerkandl tubercle has been researched from all the patients and classified according to the classification of Pelizzo et al. RESULTS: From 21 patients (43.75%), the Zuckerkandl tubercle has been well identified and it was grade 3 and grade 2. In those cases, the ILN was very closed to the tubercle. For the 27 other patients (56.25%), the tubercle was practically undetectable or reduced to a small glandular mound (grades 0 and 1). The connections with the nerve in this case were less evident. CONCLUSION: The zuckerkandl tubercle is comparatively frequent and is refound more than one time over 3 in our study. Its presence makes easier the identification of the ILN, which entertains a dangerous connection with the thyroid gland.

Atomically flat, large-sized, two-dimensional organic nanocrystals.

Large-sized, 2D single crystals of perylene are grown by both solution-cast and physical vapor transport methods. The crystals have a atomically flat parallelogram morphology and the aspect ratios of the lateral extension compared to the thickness are up to 10(3) . The atomically flat feature leads to good interface contact, making a single-crystal field-effect transistor with higher mobility. The mobility of atomically flat crystals can be 10(3) -10(4) times higher than rough crystals.