Recent advances in natural polymer-based hydroxyapatite scaffolds:Properties and applications

New materials that mimic natural bone properties, matching functional, mechanical, and biological properties have been continuously developed to rehabilitate bone defects. Desirably, 'tissue engineering' has been a multidisciplinary ground that uses the principles of life sciences and engineering for the biological replacements that restore or replace the tissue function or a whole organ. Nevertheless, the bone grafting treatment has numerous restrictions, counting the major hazards of morbidity from the sites where donor bone grafts are removed, the likelihood for an immune rejection or bacterial transport from the donor site (in case of allogeneic grafting), and the inadequate availability of donor bone grafts that can meet the current demands. Since the proper growth of synthetic materials for implantable bones encourages the reconstruction of bone tissues by providing strong structural support without any damages to the interferences of biological tissue. To serve for such behavior, the biodegradable matrices provide temporary scaffolds within which the bone tissues can be regenerated. Typically, the thermoplastic aliphatic polyesters are found to serve this purpose. The great significance of this field lies in the in vitro growth of precise cells on porous matrices (scaffolds) to generate three-dimensional (3D) tissues that can be entrenched into the location of tissue/bone damage. Numerous gifts have been gifted by our nature to advance and preserve the well-being of all living things either directly or indirectly. This review focuses on the recent advances in polymer-based hydroxyapatite scaffolds including their properties and applications

Facteurs de Risque, Epidémiologie et Prise en Charge de la Grossesse Extra-utérine Rompue (GEUR) au Service de Gynécologie et d’Obstétrique de l’Hôpital National Ignace Deen du CHU de Conakry en 2022

Introduction : urgence gynécologique fréquente, découverte fortuite aux urgences médicales et ou chirurgicales dans un tableau d’anémie. L’objectif de ce travail était d’étudier les facteurs de risque, épidémiologie, et prise en charge de la grossesse extra-utérine rompue au service de gynécologie et d’obstétrique de l’hôpital national Ignace Deen du CHU de Conakry en 2022. Méthodes : il s’agissait d’une étude descriptive transversale à recrutement rétrospectif. Elle a été menée au service de gynécologie et d’obstétrique de l’hôpital national Ignace Deen du CHU de Conakry du 1er janvier  2019 au 31 Décembre 2022 soit une période de trois ans. Ont été étudiées les variables se rapportant aux facteurs de risque, épidémiologie, et la prise en charge de la GEUR dans notre contexte de travail. Nous avons utilisé le logiciel Excel pour l’analyse des données. Résultats : fréquence de la GEUR dans notre étude était 1,26 % sur l’ensemble des interventions gynécologiques, les tranches d’âge les plus représentées étaient celles de 20-24 ans et 30-34 ans dans 32,69%, plus de la moitié était célibataire 69,23%, sans profession, non scolarisé respectivement 64,23% et 42,31%, primipares dans 49,04%.  Parmi les facteurs de risque (FDR) retrouvés dans notre série, figuraient les antécédents de :  l’infection génitale 46,15%, les fausses couches spontanées 10,58%, la contraception par microprogestatif 16,34%. La prise en charge a été exclusivement chirurgicale (100%), associée à la transfusion sanguine comme moyen de réanimation dans 95,16%. Conclusion : la grossesse extra-utérine rompue est une urgence médicochirurgicale fréquente, le diagnostic précoce traine les pas dans les pays à faibles ressources.   Introduction : a frequent gynecological emergency, discovered incidentally in medical and/or surgical emergencies in the setting of anemia. The aim of this study was to investigate the risk factors and management of ectopic pregnancy in the gynecology and obstetrics department of the Ignace Deen National Hospital of Conakry University Hospital in 2022. Methods : This was a descriptive study with retrospective recruitment. It was conducted at the gynecology and obstetrics department of the CHU Ignace Deen national hospital in Conakry from January 1, 2019 to December 31, 2022, a three-year period. Variables relating to risk factors, epidemiology and management of GEUR in our working context were studied. We used Excel software for data analysis. Results : The frequency of GEUR in our study was 1.26% of all gynaecological procedures, the most represented age groups were 20-24 and 30-34 years with 32.69%, more than half were single 69.23%, without profession, not in school respectively 64.23% and 42.31%, primiparous in 49.04%.  Among the risk factors found in our series were a history of : genital infection 46,15%, spontaneous miscarriage 10.58%, microprogestogen contraception 16.34%. Management was exclusively surgical (100%), associated with blood transfusion as a means of resuscitation in 95.16% Conclusion : Ruptured ectopic pregnancy is a frequent medico-surgical emergency, early diagnosis is lagging behind in low-resource countries

Phases and geometry of the N=1 A_2 quiver gauge theory and matrix models

We study the phases and geometry of the N=1 A_2 quiver gauge theory using matrix models and a generalized Konishi anomaly. We consider the theory both in the Coulomb and Higgs phases. Solving the anomaly equations, we find that a meromorphic one-form sigma(z)dz is naturally defined on the curve Sigma associated to the theory. Using the Dijkgraaf-Vafa conjecture, we evaluate the effective low-energy superpotential and demonstrate that its equations of motion can be translated into a geometric property of Sigma: sigma(z)dz has integer periods around all compact cycles. This ensures that there exists on Sigma a meromorphic function whose logarithm sigma(z)dz is the differential. We argue that the surface determined by this function is the N=2 Seiberg-Witten curve of the theory.Comment: 41 pages, 2 figures, JHEP style. v2: references adde

Analysis of different characteristics of smile

Introduction: Analysis of smile is imperative in the diagnosis and treatment planning phases of aesthetic dentistry.Aim: To evaluate the components of smile among students of a dental institution.Methods: Frontal view digital photographs with posed smile of 157 dental students were assessed using Adobe Photoshop7.0. Smile characteristics evaluated included; smile line, smile arc, smile design, upper lip curvature, labiodental relationship and number of teeth displayed. Data were analyzed using SPSS version 23.0. Pearson chi-square test was used to determine the gender based differences for various parameters.Results: Average smile line (43.3%), consonant smile arcs (45.2%), cuspid smiles (45.9%), upward lip curvature (43.9%), maxillary anterior teeth not covered by lower lip (60.5%) and teeth displayed up to first premolars (35.7%). Gender based differences were not statistically significant except for smile arc (p value = 0.02) and number of teeth displayed (p value \u3c 0.001). There was a significant relationship between lip curvature and smile pattern (p value \u3c 0.001) and lip curvature and smile arc (p value = 0.01) revealing that upward lip curvature was associated with commissure type smiles and consonant smile arcs.Conclusions: The smile characteristics should be considered before beginning the aesthetic treatment of the patient to obtain adequate results in oral rehabilitation

Hybrid spectrum access with relay assisting both primary and secondary networks under imperfect spectrum sensing

This paper proposes a novel hybrid interweave-underlay spectrum access for a cognitive amplify-and-forward relay network where the relay forwards the signals of both the primary and secondary networks. In particular, the secondary network (SN) opportunistically operates in interweave spectrum access mode when the primary network (PN) is sensed to be inactive and switches to underlay spectrum access mode if the SN detects that the PN is active. A continuous-time Markov chain approach is utilized to model the state transitions of the system. This enables us to obtain the probability of each state in the Markov chain. Based on these probabilities and taking into account the impact of imperfect spectrum sensing of the SN, the probability of each operation mode of the hybrid scheme is obtained. To assess the performance of the PN and SN, we derive analytical expressions for the outage probability, outage capacity, and symbol error rate over Nakagami-m fading channels. Furthermore, we present comparisons between the performance of underlay cognitive cooperative radio networks (CCRNs) and the performance of the considered hybrid interweave-underlay CCRN in order to reveal the advantages of the proposed hybrid spectrum access scheme. Eventually, with the assistance of the secondary relay, performance improvements for the PN are illustrated by means of selected numerical results

Car make and model recognition under limited lighting conditions at night

Car make and model recognition (CMMR) has become an important part of intelligent transport systems. Information provided by CMMR can be utilized when license plate numbers cannot be identified or fake number plates are used. CMMR can also be used when a certain model of a vehicle is required to be automatically identified by cameras. The majority of existing CMMR methods are designed to be used only in daytime when most of the car features can be easily seen. Few methods have been developed to cope with limited lighting conditions at night where many vehicle features cannot be detected. The aim of this work was to identify car make and model at night by using available rear view features. This paper presents a one-class classifier ensemble designed to identify a particular car model of interest from other models. The combination of salient geographical and shape features of taillights and license plates from the rear view is extracted and used in the recognition process. The majority vote from support vector machine, decision tree, and k-nearest neighbors is applied to verify a target model in the classification process. The experiments on 421 car makes and models captured under limited lighting conditions at night show the classification accuracy rate at about 93 %

An Integrated-Photonics Optical-Frequency Synthesizer

Integrated-photonics microchips now enable a range of advanced functionalities for high-coherence applications such as data transmission, highly optimized physical sensors, and harnessing quantum states, but with cost, efficiency, and portability much beyond tabletop experiments. Through high-volume semiconductor processing built around advanced materials there exists an opportunity for integrated devices to impact applications cutting across disciplines of basic science and technology. Here we show how to synthesize the absolute frequency of a lightwave signal, using integrated photonics to implement lasers, system interconnects, and nonlinear frequency comb generation. The laser frequency output of our synthesizer is programmed by a microwave clock across 4 THz near 1550 nm with 1 Hz resolution and traceability to the SI second. This is accomplished with a heterogeneously integrated III/V-Si tunable laser, which is guided by dual dissipative-Kerr-soliton frequency combs fabricated on silicon chips. Through out-of-loop measurements of the phase-coherent, microwave-to-optical link, we verify that the fractional-frequency instability of the integrated photonics synthesizer matches the $7.0*10^{-13}$ reference-clock instability for a 1 second acquisition, and constrain any synthesis error to $7.7*10^{-15}$ while stepping the synthesizer across the telecommunication C band. Any application of an optical frequency source would be enabled by the precision optical synthesis presented here. Building on the ubiquitous capability in the microwave domain, our results demonstrate a first path to synthesis with integrated photonics, leveraging low-cost, low-power, and compact features that will be critical for its widespread use.Comment: 10 pages, 6 figure

Functionalized graphene-based nanocomposites for smart optoelectronic applications

The recent increase in the use of graphene and its derivatives is due to their exceptional physicochemical, electrical, mechanical, and thermal properties as the industrial materials developed by involving graphene structures can fulfill future needs. In that view, the potential use of these graphene-containing nanomaterials in electronics applications has encouraged in-depth exploration of the electronic, conducting, and other functional properties. The protecting undifferentiated form of graphene has similarly been proposed for various applications, for example, as supercapacitors, photovoltaic and transparent conductors, touch screen points, optical limiters, optical frequency converters, and terahertz devices. The hybrid composite nanomaterials that undergo stimulus-induced optical and electrical changes are important for many new technologies based on switchable devices. As a two-dimensional smart electronic material, graphene has received widespread attention, and with that view, we aim to cover the various types of graphene oxide (GO)-based composites, linking their optical and electrical properties with their structural and morphological ones. We believe that the topics covered in this review can shed light on the development of high-yield GO-containing electronic materials, which can be fabricated as the field moves forward and makes more significant advances in smart optoelectronic devices