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Thirty years ago, the small molecules we now know as microRNAs (miRNAs) would have been regarded as “junk” genetic material. Today, miRNAs have been hailed as promising biomarkers for diseases including cancer, neurological disorders, heart conditions, and infections. Although progress has been made toward characterizing the role of miRNAs in different diseases, there remain challenges in bringing them into clinical use. Researchers continue to explore where miRNAs will make the most impact. [ABSTRACT FROM AUTHOR]

The structure of modified foamed polyurethane used as a multilayer composite filler for building envelopes has been studied. The effect of flame retardants on the geometrical parameters of gas-structural elements of foamed polyurethane is considered. The presence of macroelements and microelements, the ratio of which is different in various modifications, has been studied. The linear dimensions and shape of the cells and geometric coefficients characterizing the mechanical work of the cell structure are determined. [ABSTRACT FROM AUTHOR]

ABSTRACT The pathogenic yeast Cryptococcus neoformans causes nearly 200,000 deaths annually in immunocompromised individuals. Cryptococcus cells can undergo substantial morphological change during mammalian infection, including increased capsule and cell size, the release of shed capsule, and the production of titan (>10 μm), micro (

The primo vascular system (PVS) is observed in different parts of the body under different physiological and disease conditions. Previously, the PVS was not observed in the vagina. The vaginal samples of this study were collected from the female genitalia of healthy New Zealand white rabbits from the animal house, Faculty of Medicine, Assiut University. The vaginal samples were fixed in Bouin's solution. The sections were stained with hematoxylin and eosin and Crossmon's trichrome. Additionally, the sections were immunohistochemically stained with neuron‐specific enolase (NSE) and vascular endothelial growth factor (VEGF). A primo node was observed on the lymph vessel of the vagina and has several characteristics that resemble those of the previously discovered primo nodes. The primo node in this study was surrounded by mesothelial cells that provide positive immunoreactivity to NSE and VEGF. Sinuses of different sizes, floating cells, telocyte‐like cell, and primo microcells were observed as the main constituents of the primo node. Additionally, migratory cells were detected, which passed from the primo node to the enclosing lymph vessel. [ABSTRACT FROM AUTHOR]

Micro‐concentrator photovoltaic (CPV), incorporating micro‐scale solar cells within concentrator photovoltaic modules, promises an inexpensive and highly efficient technology that can mitigate the drawbacks that impede standard CPV, such as resistive power losses. In this paper, we fabricate micro‐scale multijunction solar cells designed for micro‐CPV applications. A generic process flow, including plasma etching steps, was developed for the fabrication of complete InGaP/InGaAs/Ge microcells with rectangular, circular, and hexagonal active areas down to 0.089 mm2 (0.068‐mm2 mesa). Large cells (>1 mm2) demonstrate good electrical performance under one sun AM1.5D illumination, but a degradation in the open‐circuit voltage (VOC) is observed on the smallest cells. This effect is attributed to perimeter recombination for which a passivation effect by the antireflective coating partially recovers the VOC. The VOC penalty for small cells is also reduced under high‐intensity illumination, from 3.8% under sun to 1.0% at 974 suns. High intensity illumination yields an efficiency of 33.8% under 584 suns for a 0.25‐mm2 and microcells are expected to show higher efficiency than standard cells under very high concentration. [ABSTRACT FROM AUTHOR]

A core issue in concentrator photovoltaic technology (CPV) is the resistive losses in cells that usually limits the maximum photoconversion efficiency under high concentration. We propose the use of three‐junction monolithic interconnected modules (MIM) to mitigate resistive losses by providing high‐voltage low‐current power. First, we present the fabrication of InGaP/InGaAs/Ge front‐contacted microcells with various designs and dimensions. Front‐contacted cells are the key enabler for the MIM fabrication and demonstrate good electrical characteristics under one sun, similar to standard‐contacted cells. The base front contact size is minimized to limit the unutilized area on the wafer. Second, fabrication techniques for interconnecting cells in MIM are described. Finally, electrical measurements show a record conversion efficiency of 35.1% under 798 suns for the first three‐junction MIM reported (17.8% when considering the entire device area). Versatility and further optimization of the devices are discussed to enlarge their field of application. [ABSTRACT FROM AUTHOR]

The ability to resolve the dynamic evolution of electrocatalytically induced processes with electrochemical liquid-phase electron microscopy (EM) is limited by the microcell configuration. Herein, a free-standing tri-layer graphene is integrated as a membrane and electrode material into the electrochemical chip and its suitability as a substrate electrode at the high cathodic potentials required for CO 2 electroreduction (CO 2 ER) is evaluated. The three-layer stacked graphene is transferred onto an in-house fabricated single-working electrode chip for use with bulk-like reference and counter electrodes to facilitate evaluation of its effectiveness. Electrochemical measurements show that the graphene working electrode exhibits a wider inert cathodic potential range than the conventional glassy carbon electrode while achieving good charge transfer properties for nanocatalytic redox reactions. Operando scanning electron microscopy studies clearly demonstrate the improvement in spatial resolution but reveal a synergistic effect of the electron beam and the applied potential that limits the stability time window of the graphene-based electrochemical chip. By optimizing the operating conditions, in situ monitoring of Cu nanocube degradation is achieved at the CO 2 ER potential of -1.1 V versus RHE. Thus, this improved microcell configuration allows EM observation of catalytic processes at potentials relevant to real systems., (© 2024 The Authors. Advanced Materials published by Wiley‐VCH GmbH.)

Definition of the most relevant ways of magnesium deficiency correction and prevention of magnesium-deficiency states complications is an important task. Application of peroral magnesium preparations corrects magnesium deficiency in the pregnant, reduces probability of miscarriage and eclampsy, development of gestational diabetes and obesity

Inverted metamorphic (IMM) multijunction solar cells represent a promising material platform for ultrahigh efficiency photovoltaic systems (UHPVs) with a clear pathway to beyond 50% efficiency. The conventional device processing of IMM solar cells, however, typically involves wafer bonding of a centimeter‐scale die and destructive substrate removal, thereby imposing severe restrictions in achievable cell size, type of module substrate, spatial layout, as well as cost effectiveness. Here, we report material design and fabrication strategies for microscale triple‐junction IMM (3J IMM) Ga0.51In0.49P/GaAs/In0.26Ga0.74As solar cells that can overcome these difficulties. Specialized schemes of delineation and undercut etching enable the defect‐free release of microscale IMM solar cells and printed assemblies on a glass substrate in a manner that preserves the growth substrate, where efficiencies of 27.3% and 33.9% are demonstrated at simulated AM1.5D one‐ and 351 sun illumination, respectively. A composite carrier substrate where released IMM microcells are formed in fully functional, print‐ready configurations allows high‐throughput transfer printing of individual IMM microcells in a programmable spatial layout on versatile choices of module substrate, all desired for CPV applications. [ABSTRACT FROM AUTHOR]

Reinforcement corrosion is the risk most frequently cited to justify concrete durability research. The number of studies specifically devoted to corrosion propagation, once the object of most specialised papers, has declined substantially in recent years, whilst the number addressing initiation, particularly where induced by chlorides, has risen sharply. This article briefly describes the characteristics of steel corrosion in concrete that need to be stressed to dispel certain misconceptions, such as the belief that the corrosion zone is a pure anode. That is in fact seldom the case and as the zone is also affected by microcells, galvanic corrosion accounts for only a fraction of the corrosion rate. The role of oxygen in initiating corrosion, the scant amount required and why corrosion can progress in its absence are also discussed. Another feature addressed is the dependence of the chloride threshold on medium pH and the buffering capacity of the cement, since corrosion begins with acidification. Those general notions are followed by a review of the techniques for measuring corrosion, in particular polarisation resistance, which has proved to be imperative for establishing the processes involved. The inability to ascertain the area affected when an electrical signal is applied to large-scale elements is described, along with the concomitant need to use a guard ring to confine the current or deploy the potential attenuation method. The reason that measurement with contactless inductive techniques is not yet possible (because the area affected cannot be determined) is discussed. The method for integrating corrosion rate over time to find cumulative corrosion, Pcorr, is explained, together with its use to formulate the mathematical expressions for the propagation period. The article concludes with three examples of how to use corrosion rate to assess cathodic protection, new low-clinker cements or determine the chloride threshold with an integral accelerated service life method. [ABSTRACT FROM AUTHOR]

In this article, we present a real-time 3D hybrid beamforming approach for 5G wireless networks. One of the key concepts in 5G cellular systems is the small cell network, which settles the high mobile traffic demand and provides uniform user-experienced data rates. The overall capacity of the small cell network can be enhanced with the enabling technology of 3D hybrid beamforming. This study validates the feasibility of 3D hybrid beamforming, mostly for link-level performance, through the implementation of a real-time testbed using a SDR platform and fabricated antenna array. Based on the measured data, we also investigate system-level performance to verify the gain of the proposed smart small cell system over LTE systems by performing system-level simulations based on a 3D ray-tracing tool. [ABSTRACT FROM PUBLISHER]

Steady-state voltammetry is easily attained in narrow cells. Here we develop an exact mathematical description of one of the simplest instances, in which a redox pair is present, but without supporting electrolyte. The Nernstian oxidation that depolarizes the anode is partnered at the nearby cathode by the converse reduction. The resulting voltammogram is sigmoidal in overall shape but, generally, no explicit analytic expression describes the current-potential relationship, or even the height of the limiting-current plateau. Such limiting currents arise either by exhaustive oxidation of one member of the redox pair at the anode or by exhaustive cathodic reduction of the other member. For a critical composition, which this study identifies, both exhaustions occur concurrently. The ionic strength plays a paramount role in unravelling the conditions during the experiment. Although no direct analytical application of this 'closed' experiment suggests itself, there are implications of the theory for microgap cells and electroanalytical methods in 'open' configurations, as well as separatory possibilities. [ABSTRACT FROM AUTHOR]

Despite improvements and expansion of cellular coverage in developing regions, a substantial qualitative divide remains. Maps that display the presence or absence of cellular coverage mask critical differences in infrastructure performance and client load. In order to illuminate challenges faced by users of such mobile networks, we collect and analyze GSM network measurements at the local scale. We discover higher network congestion in developing regions as well as performance differences between available carriers in each location. Based on our findings, we propose an app, called SmartCell, that informs and empowers users in near real time to seek out improved mobile connectivity. [ABSTRACT FROM PUBLISHER]

Recent years have witnessed a massive penetration of cellular systems in developing countries. However, isolated rural areas (sparsely inhabited by low-income population) have been disregarded because classical access and backhaul technologies do not ensure the return on investment. This article presents innovative techno- economical solutions to provide these areas with cellular voice and data services. We first analyze the general characteristics of isolated rural communities, and based on this information, low-cost solutions are designed for both access (using 3G access points) and backhaul networks (using non-carrier grade equipment as WiFi for long distances or WiMAX in non-licensed bands). Subsequently, a study of population- dependent income vs. costs is presented, and a new business model is proposed involving mobile network operators, rural operators, and infrastructure providers. In order to test these solutions, we have built two demonstration platforms in the Peruvian jungle that have allowed validation of the technical feasibility of the solution, verifying the business model assumptions and the scalability of the initiative. [ABSTRACT FROM PUBLISHER]

Due to the pervasive demand for mobile services, next generation wireless networks are expected to be able to deliver high data rates while wireless resources become more and more scarce. This requires the next generation wireless networks to move toward new networking paradigms that are able to efficiently support resource-demanding applications such as personalized mobile services. Examples of such paradigms foreseen for the emerging 5G cellular networks include very densely deployed small cells and device-to-device communications. For 5G networks, it will be imperative to search for spectrum and energy-efficient solutions to the resource allocation problems that i) are amenable to distributed implementation, ii) are capable of dealing with uncertainty and lack of information, and iii) can cope with users? selfishness. The core objective of this article is to investigate and establish the potential of the MAB framework to address this challenge. In particular, we provide a brief tutorial on bandit problems, including different variations and solution approaches. Furthermore, we discuss recent applications as well as future research directions. In addition, we provide a detailed example of using an MAB model for energy-efficient small cell activation in 5G networks. [ABSTRACT FROM PUBLISHER]

Information of multi-cells is big data because of the enormous quantities of various cells as well as their parameters and status. To securely and efficiently integrate all the cells' information and trace multi-cells are challenging due to varying number of the multi-cells, as well as the complicacy of the multi-cells' movement. In this paper, an automatic big data integration algorithm based on the optical transfer function is proposed. The experimental results show that the algorithm can securely and efficiently integrate all the cell information and simultaneously track a large quantity of cells. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The concentrating approach was applied on Cu(In,Ga)Se 2 to develop photovoltaic devices with increased efficiency using less rare materials. To withstand the operating conditions, Cu(In,Ga)Se 2 devices are miniaturized. Compared to previous generations of microcells, with only window layer structuration, microcells with a mesa design are fabricated. These microcells are created by etching ZnO, CdS and Cu(In,Ga)Se 2 layers. The crucial issue addressed in this study is the electrical behavior of the device edges, to determine if microcells suffer from perimeter recombination. We analyze the influence of different etching techniques on the edge recombination signal. It is found that bromine etch result in well passivated surfaces, and devices as small as 50 × 50 μm do not experience edge recombination efficiency limitations. This behavior is remarkable compared to that of the microcells made of crystalline materials. For devices where the edges are deteriorated by a chemical post-treatment, a quasi-shunting signal coming from the edges is seen. We tested these microcells under concentrated illumination and important open-circuit voltage and efficiency gains are seen. [ABSTRACT FROM AUTHOR]

The cell part of a cellular mobile communication system is determined where the radio signal level exceeds the reception threshold value with allowance for multibeam radiowave propagation (with the Rayleigh fading distribution). [ABSTRACT FROM AUTHOR]

Abstract: This paper demonstrates spherical vapor cells intended to be used in chip-scale atomic devices. A micro glass blowing process is introduced, in which multiple glass spheres are simultaneously shaped on the top of a silicon wafer and subsequently filled with rubidium. In the presented fabrication process, an array of cylindrical cavities is first etched in silicon. Next, a thin glass wafer is anodically bonded to the silicon wafer. The bonded wafers are then placed inside a furnace set to 850 C. At this elevated temperature, the viscosity of the glass is decreased and the heated trapped gas in the cavities expands, thus causing the glass to be blown into spherical cells. Microscopic alkali vapor cells are achieved by evaporation of through a small glass nozzle into the cell cavities. The cells are then sealed by anodic bonding. The fabricated cells are characterized and the presence of rubidium vapor inside the cells is verified by observing an absorption spectrum. [Copyright &y& Elsevier]

It is an essential question for acupuncture whether the acupuncture meridians form an anatomically distinctive system of threadlike ducts that spread throughout an animal body. We observed the threadlike structures on the surface of internal organs of animals. This threadlike structure may be the physical basis of the meridian-like network of internal organs as detected by the Bi-Digital O-Ring test imaging method. One of the characteristics of the threadlike structures is the presence of DNA containing granules or Bonghan granules that flow through the ducts. The aim of this study was to separate and characterize their morphology and ultrastructural features. Using confocal laser-scanning microscopy (CLSM) and transmission electron microscopy (TEM), we found that Bonghan granules were round and measure 1.7-2.5 µm in diameter. They had a small nucleus surrounded by a layer of cytoplasm and a trilaminar plasma membrane. TEM also showed that they had cytoplasmic protrusions like pseudopodia. They contained fragmented DNA with a significant amount of 3′-OH ends. We compared their properties with the cell structure and general morphology of apoptotic bodies, bacteria, and the microcells. The motion of these granules was influenced by light, which may be related to the photo-therapy on the acupuncture points. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new technique for the performance analysis of cellular mobile communication networks based on a frequency division multiple access/time division multiple access scheme (such as global system for mobile communications), in which the utilization of two separate frequency bands leads to a complex cellular structure with overlapping microcells and macrocells. Call durations and dwell times are described by random variables with general distributions; the call duration distribution is then approximated by a two-phase hyper-exponential distribution with the same first and second moments as the original general distribution. The analysis technique is based on Markovian assumptions as regards the traffic flows entering both microcells and macrocells, as well as an assumption of flow balance between handovers into and out of any cell. The analytical model is validated against results of detailed simulation experiments for various system configurations, and shown to provide quite accurate predictions. [ABSTRACT FROM PUBLISHER]

Special optical sensors require thin film devices with a layer structure of the type glass/Al/Al2O3 with thicknesses of oxide and metal in the range of some nm. Structures comparable with a printed circuit board were written by electrochemical potential control with a scanning droplet device. Dots, lines, or areas of different thickness ratios Al/Al2O3 or even with gradients can be written. Insulating lines become possible by complete oxidation of the Al metal. [Copyright &y& Elsevier]

Microcellular propagation follows different laws than the well-known traditional models, and it is strongly affected by the street and building layout. A well-known and evident phenomenon is the street-corner effect, which consists of a sudden decrease of received field strength as soon as a mobile turns into a side street. Predictions based on ray optics, which can be applied to this case, are accurate but time-consuming. Hence, they cannot be used extensively, e.g., to plan a microcellular network in a city. In many cases, a simplified model would be suitable to give account of field strength behaviour in the transition region between line-of-sight (LOS) and non-line-of-sight (NLOS) propagation, and could be used as a basis of a complete microcellular field prediction tool. Following this approach, we propose a simple parametrical model for propagation around a corner: the parameter values have been tuned to fit the considered environment. The tuning process can be accomplished by means of either measurements or simulations. In order for the model to be as general as possible, it needs a large amount of reference data: for this reason, we used simulations performed with a validated ray-tracing software tool in a variety of situations. These simulations allow one to derive values of the various parameters as functions of the local topology (e.g., street width, distance from the street corner, etc.). The model thus tuned is compared with measurements, showing a good agreement between estimated and measured path loss. This model is shown to behave satisfactorily when compared with measurements, and it is suitable to characterise the street-corner effect in a variety of cases. Finally, this model, along with a simple model for LOS propagation (double slope, with a breakpoint caused by reflections on the ground and on building walls), is aimed at building a complete, modular prediction tool for the microcellular environment. [ABSTRACT FROM AUTHOR]

The pathogenic yeast Cryptococcus neoformans causes nearly 200,000 deaths annually in immunocompromised individuals. Cryptococcus cells can undergo substantial morphological change during mammalian infection, including increased capsule and cell size, the release of shed capsule, and the production of titan (>10 μm), micro (<2 μm)-, and irregular cells. We examined phenotypic variation under conditions designed to simulate in vivo stress in a collection of nine lineages derived from the C. neoformans type strain H99. These lineages are highly genetically similar but have a range of virulence levels. Strains from hypervirulent lineages had a larger average capsule size, greater variation in cell size, and an increased production of microcells and shed capsule. We tested whether disruption of SGF29 , which encodes a component of the SAGA histone acetylation complex that has previously been implicated in the hypervirulence of some lineages, also has a role in the production of morphological variants. Deletion of SGF29 in a lineage with intermediate virulence substantially increased its production of microcells and released capsule, consistent with a switch to hypervirulence. We further examined SGF29 in a set of 52 clinical isolates and found loss-of-function mutations were significantly correlated with patient death. Expansion of a TA repeat in the second intron of SGF29 was positively correlated with cell and capsule size, suggesting it also affects Sgf29 function. This study extends the evidence for a link between pleomorphism and virulence in Cryptococcus, with a likely role for epigenetic mechanisms mediated by SAGA-induced histone acetylation. IMPORTANCE Cryptococcosis is a devastating cause of death and disease worldwide. During infection, Cryptococcus cells can undergo substantial changes to their size and shape. In this study, we used a collection of C. neoformans strains that are highly genetically similar but possess differing levels of virulence to investigate how morphological variation aligns with virulence. We found hypervirulent strains on average had larger capsules and greater variation in cell size and produced more microcells and shed capsule. These hypervirulent strains possessed a mutation in SGF29 , which encodes a component of the SAGA complex involved in epigenetic regulation. Analysis of the SGF29 gene in a set of clinical isolates found strains with loss-of-function mutations were associated with higher patient death rates. The capacity to vary appears to be linked with virulence in Cryptococcus, and this can occur in the absence of genetic variation via epigenetic mechanisms.

A method is described to generate microcells from human lymphobalsts for use in microcell-mediated chromosome transfer (MMCT). Micronuclei were induced in cells from a human lymphoblastic cell line by prolonged colcemid treatment, and were separated from these lymphoblasts by: (a) attaching the cells to Concanvalin A coated plastic slides designed for enucleation, and (b) centrifuging the slides in medium containing cytochalasin B. Microcells of less than 3 μm in diameter were fused with thymidine kinase negative mouse fibroblast (LMTK). HAT medium (hypoxanthine, aminopterin and thymidine) was used to select microcell hybrids expressing thymidine kinase activity. Positive clones were isolated and Q-banded for chromosome analysis. Unlike previous methods this procedure permits microcells to be easily generated from lymphoid cells. This methodology of enucleation of microcells may be extended to a variety of other donor cell types which can be micronucleated but which do not adhere tightly to enucleation slides and do not exhibit extrusion subdivision. This feature makes our methodology particularly useful for constructing a library of hybrid clones containing one or a few human chromosomes. [ABSTRACT FROM AUTHOR]

Adaptive antenna technology is now regarded as one of the key system components in future generation cellular networks. This paper considers the performance of a DS-CDMA system which employs adaptive antennas at the base station sites of both microcell and mixed micro/umbrella cell operational environments. A microcellular ray tracing propagation tool has been employed in order to ascertain site specific propagation data. Results for a typical small cell environment highlight both the propagation characteristics and the behaviour of the adaptive antenna, as well as the sensitivity of the system upon parameters such as the mutual coupling effect. This work does not assume idealised propagation conditions or antenna radiation patterns for the small cell analysis. In summary, the results indicate that microcellular base stations employing adaptive antenna signal processing can offer a significant capacity enhancement and improved channel characteristics when compared with their omnidirectional counterparts. In addition, it is shown that umbrella cells overlaying microcells within the same RF bandwidth allocation, do not impact upon system capacity providing that adaptive antenna technology is employed at the umbrella cell site. [ABSTRACT FROM AUTHOR]

This paper presents a new interference model for microcellular networks which integrates radio propagation parameters and user terminal mobility. This model uses a parameter denoted the “interference to noise ratio” (INR) to obtain a simplified description of mobile link outage contours as a function of the location of the fixed and mobile radio ports. The INR is used to demonstrate that microcell networks are more interference limited than macrocell networks, and thus are more affected by user terminal mobility. Expressions are derived for the INR and user terminal cell radius distributions. It is shown that in microcell systems a significant proportion of terminals may not be able to meet a contiguous coverage criterion, and that closer microcell spacing can reduce rather than improve the coverage quality. Examination of cochannel and adjacent channel reuse ratios in DCA microcell systems suggest that the closer frequency reuse is primarily responsible for these coverage effects. Monte Carlo simulations are used to test the analytical theory. These results may form the basis of a design methodology for microcell systems. [ABSTRACT FROM AUTHOR]