Dead Area Research Articles

Automated Cell Viability Analysis in Tissue Scaffolds

Image processing techniques are frequently used for extracting quantitative information (cell area, cell size, cell counting, etc.) from different types of microscopic images. Image analysis of cell biology and tissue engineering is time consuming and requires personal expertise. In addition, evaluation of the results may be subjective. Therefore, computer-based learning applications have been rapidly developed in recent years. In this study, Confocal Laser Scanning Microscope (CLSM) images of the viable pre-osteoblastic mouse MC3T3-E1 cells in 3D bioprinted tissue scaffolds, captured from a bone tissue regeneration study, were analyzed by using image processing techniques. The goal of this study is to develop a reliable and fast algorithm for semi-automatic analysis of CLSM images. Percentages of live and dead cell areas in the scaffolds were determined with image correlation, and then, total cell viabilities were calculated. The other goal of this study is to determine the depth profile of viable cells in 3D tissue scaffold. Manual measurements of four different analysts were obtained. The measurement variations of analysts, also known as the coefficient of variation, were determined from 13.18% to 98.34% for live cell images and from 9.75% to 126.02% for dead cell images. To overcome this subjectivity, a semi-automatic algorithm was developed. Consequently, cross-sectional image sets of three different types of tissue scaffolds were analyzed. As a result, maximum cell viabilities were obtained at intervals of 63 µm and 90 µm from the scaffold surface.

Predicting the service life of road signs based on their retroreflectivity and color using Logistic Regression

Road signs play a vital role in providing drivers with crucial information for safe driving in both day and nighttime. The color of road signs enhances visibility during daylight hours, while retroreflectivity is essential for improving visibility during nighttime conditions. Road authorities, responsible for maintaining road signs, primarily consider the levels of retroreflectivity when deciding to replace them, ensuring optimal visibility for drivers. This study focuses on examining the degradation of road signs based on retroreflectivity and color to ensure safe driving through adequate visibility in both day and nighttime conditions. The study underscores the significance of regulating the deterioration of road sign colors to enhance visibility and legibility, while minimizing maintenance and replacement costs. The primary objective of this paper is to predict the age (service life) of road signs by considering both retroreflectivity and color status and using logistic regression. The results indicate that the age of road signs can be influenced by either retroreflectivity or color. For instance, approximately 50% of red road signs are projected to lose their color after 16 years, while their retroreflectivity remains acceptable. Similarly, around 50% of yellow and white road signs experience retroreflectivity degradation after 20 and 16 years, respectively, while their color remains acceptable. Finally, blue road signs demonstrate acceptable retroreflectivity and color levels even after 35 years.

Robust design and analysis for opto-mechanical two array laser warning system

In the past three decades, laser warning systems (LWS) have emerged in great importance, as the development of laser-guided weapons, such as airborne Hellfire missiles, has increased, posing an imminent threat to vital areas and VIPs. The laser warning station (LWS) can detect, classify, identify, and give alarm from laser threat at a very short time with high sensitivity. Therefore, the designers of this system must take into account the detectability and field of view to cover the area to be secured. The main contribution in this research is an analytical design of LWS that consists of 24 detector elements, distributed in two arrays (2 × 12) circularly. Also, calculating the best distance between the detectors according to the laser beam spot size. In addition, enhancement laser warring sensor detection capability and detection performance FOV between the detectors to increase coverage area up to 360°. Moreover, decreasing dead zone area between the laser detectors element. Mathematical calculations and illustrations made to reach the best systematic design.

Approaches of Finite Element Analysis to Study Fatigue Analysis of Rail-Wheel Contact for Light Rail Transit

Rolling contact fatigue (RCF) is oneof the main rail failure due ofrepeated stresses at rail-wheel contact. The types of defects of RCF such as spalling, squat and head checking occur at surface of rail as possible lead to catastrophic for train derailment. As to reduce the cost of maintenance in using preventative maintenance than corrective maintenance where it crucial to predict the rail fatigue failure through simulation. The objective of this research paper was to predict the cracks at rail surface in 3-dimensional through finite element analysis and in compared results with Hertz theory, alsoto count circlesof fatigue failure with 80000 N against rail.The rail profile selection was R260 as standard rail for light rapid transit. Results demonstrated that the highest von mises stress located at contact patch of rail-wheel, different percent of von mises stress & contact pressureand predicted the rail fatigue regards 339300 circles. Furthermore, this research study has not yet reported and discussed in previous studies for light rapid transit.

Cutaneous Nrf2-Keap1 pathway modulation by environmental factors: The Dead Sea area as a test case.

The skin is constantly exposed to exogenous environmental stressors and has to cope with excessive oxidative stress and tissue damage. However, exposure to moderate environmental stressors may be beneficial for the cutaneous tissue and assist in protecting against oxidative damage via the enhanced activation of the nuclear factor erythroid 2-related factor 2-Kelch-like ECH-associated protein 1 (Nrf2-Keap1) pathway. Such moderate stressors can be found in various locations around the globe. In this manuscript, we chose to focus on the Dead Sea (DS) area as a test case to study the effect of moderate stressors on the cutaneous tissue because of the unique combinations of moderate stressors in this area. The exceptional location of the DS at an altitude of -438 meters below sea level (the lowest place on earth) is responsible for its rare accumulation of moderate stressors such as high-water salinity, high atmospheric pressure, and unique solar radiation. In this manuscript, we hypothesized that the unique solar radiation in the DS area generates moderate oxidative stress in the skin leading to the induction of intracellular electrophiles, which in turn can activate the protecting Nrf2-Keap1 pathway. We showed that exposure of human skin organ culture from the same donor to solar radiation at the DS resulted in significant activation of the Nrf2-Keap1 pathway, induction of phase II enzymes, and lower apoptotic activity compared to a nearby location at a higher altitude (Jerusalem +700 m). This remarkable effect of activating the Nrf2 protecting pathway and the importance and characteristics of the solar irradiation at the DS is discussed.

Harvest Technique Does Affect the Quality of Osteochondral Grafts: Histologic Evaluation Comparing Commercial Standards versus Scalpel Blade Technique.

While the percentage of viable cells is a major determinant of graft performance during osteochondral allograft (OCA) transplantation, the baseline chondrocyte viability at the periphery of osteochondral plugs is defined at the time of harvest. In this laboratory study, we aimed to determine the optimal technique for OCA plug harvest by evaluating commercial standard techniques compared to sharp blade harvest technique. Osteochondral explants were harvested from bovine and human samples using 3 different techniques: (1) standard OATS manual punch device (Osteochondral Autograft Transplant System OATS; Arthrex, Naples, FL), (2) powered trephine device, and (3) fresh scalpel blade. Chondrocyte viability and the dead area at the periphery of the tissue were evaluated by LIVE/DEAD staining. Safranin-O and fast-green were performed for structural evaluation. For both bovine and human samples, the dead area at the periphery of the explant was significantly smaller after scalpel blade preparation compared to harvest with OATS (P < 0.001) and powered trephine devices (P < 0.001). In addition, while powered device had a smaller remaining dead area compared to the OATS device (P < 0.001), there was significantly greater tissue loss and peripheral contour change for plugs harvested with the powered trephine device. Our study demonstrated that OCA plugs harvested with OATS and powered device lead to a significant mechanical injury at the periphery of the explants compared to a scalpel. We propose that the optimal technique for OCA harvest utilizes a combined approach incorporating a scalpel blade/circular scalpel to prepare the chondral surface and a powered trephine to prepare the osseous surface.

Building and sustaining public and political commitment to the value of vaccination: Recommendations for the Immunization Agenda 2030 (Strategic Priority Area 2)

Vaccines have contributed to substantial improvements in health and social development outcomes for millions in recent decades. However, equitable access to immunization remains a critical challenge that has stalled progress toward improving several health indicators around the world. The COVID-19 pandemic has also negatively impacted routine immunization services around the world further threatening universal access to the benefits of lifesaving vaccines. To overcome these challenges, the Immunization Agenda 2030 (IA2030) focuses on increasing both commitment and demand for vaccines. There are three broad barriers that will need to be addressed in order to achieve national and subnational immunization targets: (1) shifting leadership priorities and resource constraints, (2) visibility of disease burden, and (3) social and behavioral drivers. IA2030 proposes a set of interventions to address these barriers. First, efforts to ensure government engagement on immunization financing, regulatory, and legislative frameworks. Next, those in subnational leadership positions and local community members need to be further engaged to ensure local commitment and demand. Governance structures and health agencies must accept responsibility and be held accountable for delivering inclusive, quality, and accessible services and for achieving national targets. Further, the availability of quality immunization services and commitment to adequate financing and resourcing must go hand-in-hand with public health programs to increase access to and demand for vaccination. Last, strengthening trust in immunization systems and improving individual and program resilience can help mitigate the risk of vaccine confidence crises. These interventions together can help ensure a world where everyone, everywhere has access to and uses vaccines for lifesaving vaccination.

Irrigation effects on elephant grass morphology, and its genotype‐dependent responses

AbstractThis study hypothesised that different elephant grass genotypes respond differently in terms of their morphological development to irrigation. The objective of this study was to evaluate how water availability could affect the morphological development of different genotypes of elephant grass. The treatments consisted of four genotypes of elephant grass [Cenchrus purpureus (Schumach.) Morrone], managed under irrigation or not, during a two‐year field trial. The experiment was arranged in a randomised block design in a split‐plot, with four replicates per treatment (n = 4). Between the genotypes, two of them were classified as tall‐sized (IRI 381 and Elephant B), and two as dwarfs (Taiwan A‐146 2.37 and Mott). A three‐way interaction between season, irrigation, and genotype affected the variables plant height, stem diameter, number of dead tillers, light interception (LI), and leaf area index (LAI) (p &lt; .05). The morphological development of all genotypes was negatively impacted by the dry season. All genotypes grew taller during the rainy season (p &lt; .05) and had a greater light interception (62%–80%) compared to the dry period (28%–59%). The genotype Mott, showed comparable LI and LAI to the tall‐sized genotypes, whilst Taiwan A‐146 2.37 was characterized by the lowest values, despite being the genotype with the greatest tiller density (60 tillers m−2) (p &lt; .05). The use of irrigation mitigated the negative effects of the dry season on the plants, however, the type and size (tall vs. dwarf) of the elephant grass genotypes defined the extent of the responses to the use of the irrigation during the dry period.

Investigation of Unexpected Crossing-Lane Activity on Curving Road Using Digital Human Modelling Analysis

This study investigates the truck driving posture, vision safety, and perception time safety for truck drivers adjusting their velocity at the curving road due to crossing lane activity. The investigation method starts defining the road contour of the target using Geospatial Information System software (QBase). After the road elevation projection was made, the line was drawn to the surface in CAD software. After that, Digital Human Modelling (DHM) was created on the Japanese population with Indonesian anthropometry properties of 50%ile. The environment scenario was assembled based on the 3D model road surface and 3D vehicle models, and DHM in series. The objective scenario used vision analysis and driver perception response analysis. The result shows that even if the truck and SUV blockage has not appeared, the truck driver will not see the motorcycle on the corner. After that, pillar-A also contributes to blocking the truck driver's vision. Since it contributes to construction safety, the trade-off cannot be negotiated. A speed trap shall be applied before the curving zone to increase safety. The speed trap could instantly reduce the truck and other vehicles' speed in both lanes.

Modeling and Performance Analysis of a Solar Pond Integrated with an Absorption Cooling System

Solar ponds are characterized by high storage capacity and the ability to provide a stable and continuous power source. Careful selection of the extraction rate helps to maintain supply temperature in a range suitable for the operation of an absorption unit. This study proposed a system in which a solar pond is coupled with an absorption chiller to investigate the resulting advantages. The chiller is cooled by using water of the upper convective zone, which ensures that the limit of deterioration of its performance is not reached and eliminates the need for an expensive cooling system. The key parameters in terms of ambient temperature, solar radiation, pond specifications, and cooling and refrigeration temperatures are investigated to optimize the proposed system design. The prediction of the model showed good agreement with the experimental results. By choosing the appropriate place to implement the system, such as the Dead Sea area, which enjoys favorable climatic conditions, it was found that a pond with an area of 3000 m2 can produce a heat rate at a temperature of 80 °C that can drive a chiller with 126.3 kW cooling capacity, with overall COP of 0.183. Based on this study, it appears that this type of system is feasible and suitable for cooling production, especially in hot regions.

Performance of triple-GEM detectors for the CMS Phase-2 upgrade measured in test beam

Triple-GEM detectors for the GE2/1 and ME0 stations of the endcap muon system for the Phase-2 upgrade of the CMS Experiment have been operated in a test beam to measure their efficiency and spatial resolution, together with a high spatial resolution triple-GEM tracker. A production module of GE2/1 detectors and a prototype ME0 detector show excellent local efficiency. A prototype detector with GEM foils employing random hole sectorization showed significant reduction of dead areas. The spatial resolution of the tracker has been measured and found close to the expected value of 75µm.

Numerical modeling of rolling contact fatigue cracks in the railhead

Rolling contact fatigue (RCF) crack is one of dominating damages on the rail surface due to repeated wheel and rail contact. RCF defects, including squats and head checks, can potentially cause rail fracture failure if not treated in time. It is critical to accurately predict the pertinent damage for different operational conditions. A two-stage simulation strategy was proposed to investigate the mechanisms of RCF-induced cracks on the rail, consisting of a dynamic FEM for wheel and rail interaction and a coupled static FEM/BEM for crack growth. It was found that there are two critical wheel positions for crack propagation during wheel approaching to and departing from the pre-existed crack. The different cracking mechanisms at these two critical wheel positions are correlated with the local physical phenomena, i.e., the traction at the wheel/rail interface, the relative distance between the contact patch and crack, and the sliding at crack faces. The twisting of the cracks from the transverse plane to the longitudinal plane at the railhead significantly reduces crack growth in mode I, enhances crack propagation in modes II and III, and shifts the dominant crack growth from the crack front center to the crack corners. The increased incline of the crack in the rolling direction promotes the crack to grow downward in opening mode I.

Cognitive Implementation of Metaverse Embedded Learning and Training Framework for Drivers in Rolling Stock

Public safety is prime concern in rail industry and driver training on hazard perception is crucial. Additionally, a new driver’s skill set determines the productivity and quality of existing driver training methods. Apprentice train drivers are required to complete massive hours under supervision of experienced drivers to attain the required skill sets causing productivity issues. Traditional driver training is paper based, and assessments are individually evaluated without any scientific rigor, resulting in quality challenges. This paper proposes a Metaverse embedded learning and training framework for drivers in rolling stock. The framework includes driver vision analysis by eye tracking and pupil dilation focusing on enhancing the productivity and quality of driver training and hazard detection for drivers in rolling stock. Metaverse embedded training and learning enhances experiential learning with unique benefits. In this paper, a metaverse-based training framework is proposed for train drivers to enhance productivity, quality, and safety aspects through case studies including: (i) driver sightline studies and (ii) vision analysis. The studies developed quantifying driver hazard perceptions and related comprehension rates based on eye tracking and vision studies. In conclusion, the overall savings on cost and time are 95% effective using Metaverse-based training method compared to traditional methods. Stakeholders need to supervise on driver tasks, knowledge retention, damage control due to the occurrence of hazards. The framework substantially reduced hazards to 50% with saving up to 3696 man-hours. The assessment was completely automated to provide real time assessment thus providing 93% more positive results compared to traditional methods.

Tristan—A 10 Million Pixel Large Area Time Resolved Detector for Synchrotron Use

This article describes the development of the Tristan 10 M detector for time-resolved synchrotron experiments. Tristan 10 M has an unprecedented time resolution (ns time scale) over long-duration continuous acquisition (days). The detector is constructed from an array of 160 Timepix3 readout application-specified integrated circuit (ASIC; about 10 million pixels) flip chip bonded to ten monolithic silicon sensors, which enable it to cover an area large enough to effectively carry out crystallography experiments. The large array of ASICs resulted in a number of severe technical challenges that had to be overcome during the development of the detector. The minimization of the dead area between sensors required the development of a very challenging mechanical and electronic packaging. Such a packaging had to be able to route the large number of data and power lines within the footprint of a sensor, had to effectively sink the heat generated by the ASICs, and had to be able to position the sensors accurately. In addition, the packaging of the detector was designed to be scalable in consideration of possible future larger versions of this detector, which added a further challenge. The data-driven nature of Timepix3 and the sheer data volume produced by the array of ASICs required us to devise a dedicated hardware, firmware, and software data acquisition architecture. This architecture proved very effective during the commissioning of Tristan 10 M when time-resolved crystallography experiments were carried out.

Investigating the effect of road lighting color temperature on road visibility in night foggy conditions

Night foggy road conditions limit visibility distance of drivers and are associated with higher accident and fatality rates than other weather conditions. Therefore, ensuring road visibility in night foggy road is critical. However, it is difficult to reproduce fog on a real road and only a few studies have researched foggy road conditions and visibility in a laboratory as a small scale. Previous studies have suggested that a color temperature of road lighting is related to visibility. However, many have only investigated the effects of relative transmittance in limited indoor experiments, and the impacts of differences in transmittance on visibility have thus far not been studied in real-scale conditions. In this study, a real-scale test involving 91 subjects was conducted to investigate how the visibility distance under night foggy conditions is affected by different lighting color temperatures. Based on the real scale experiments, the correlation between the visibility distance and lighting color temperature was derived. Road lighting with a low color temperature (i.e., yellow) was found to provide longer visibility distances than that with high color temperatures under night foggy conditions having measured visibility of approximately 102m. The impact of the differences in lighting color increased as the visibility distance decreased. In contrast, road lighting with a high color temperature (i.e., white) improved driver visibility in higher-visibility conditions. Therefore, this study confirmed the correlation between lighting color temperature and visibility distance for different visibility conditions and could serve as a foundation for the development of roadway design standards as well as future studies.

Comparison of Rail Head Checks Using Destructive and Non-Destructive Examination Methods

The development of railway transportation requires increased vehicle speeds and axle loads. The enhanced effects from the vehicle side and the new harder steel rails used in tracks lead to increased Rolling Contact Fatigue (RCF) crack initiation and propagation. One of the most frequently occurring RCF defects is the Head Checks (HC) around the rails’ gauge corner. These defects cause severe economic and safety issues. In-use maintenance is based on corrective and preventive approaches, which are neither cost-effective nor reliable. The development of new predictive methods and the improvement of the existing corrective and preventive approaches offer a solution to this issue. In this investigation, an HC-infected rail sample was examined with non-destructive Dye Penetration Testing, Eddy-current Testing, and Visual Microscopic Testing after the sectioning of the sample. In the future, an extensive HC database can be created from the results of the developed evaluation process, which may serve as the base validation tool for newly developed predictive maintenance methods.

Investigation of Scaling and Inhibition Mechanisms in Reverse Osmosis Spiral Wound Elements.

Understanding of crystal formation and growth conditions in reverse osmosis membrane channels enables us to develop efficient tools to control scaling in membrane facilities and increase their recoveries. Crystals are formed in “dead areas” and subsequently get out of them and sediment on membrane surface. Adsorption of polymeric inhibitor molecules to crystal surface was investigated as well as antiscalant behaviour throughout nucleation in “dead areas” and growth of crystals sedimented on membrane surface. Experimental dependencies of antiscalant adsorption rates on the antiscalant dosage values were determined. Examination of SEM images of crystals demonstrated that their size and amount depend on the supersaturation value reached in the “dead areas”. More efficient antiscalants delay the beginning of nucleation and reduce the rate of crystal growth due to adsorption and blockage of crystal growth process. Antiscaling property of inhibitors is also attributed to their ability to provide certain amount of adsorbent to block crystal growth during nucleation. A test procedure is described that enables us to predict concentrate composition in the “dead areas” and calculate supersaturation values that correspond to beginning of nucleation.

Faktor Penyebab dan Upaya Mengatasi Area Titik Buta pada Truk

Truck drivers cannot see the entire area around the vehicle. This area that cannot be seen is called a blind spot. This article aims to analyze the factors causing blind spot areas on trucks and discuss the efforts that have been made to address the blind spots on trucks. The writing method used is a literature study of the research that has been done. The keywords used in the reference search include blind spot, driver and anthropometry. The search results show that the blind spot area is on each side of the truck, either caused by the vehicle design or the driver's anthropometry. Various attempts have been made to address blind spot areas, such as the use of mirrors, cameras and sensors. In addition, expanding the driver's vision area from inside the cabin can also be a solution. Based on the results of the literature study, it is concluded that the blind spot area is influenced by vehicle design and driver anthropometry

Temperature Increase and Damage Extent at Retinal Pigment Epithelium Compared between Continuous Wave and Micropulse Laser Application.

Continuous wave (CW) and microsecond pulse (MP) laser irradiations were compared regarding cell damage and laser-induced temperature rise at retinal pigment epithelium (RPE). The RPE of porcine RPE-choroid-sclera explants was irradiated with a 577 nm laser in CW or MP mode (5% or 15% duty cycle (DC)) for 20 ms or 200 ms at an average laser power of 20–90 mW. Cell viability was investigated with calcein-AM staining. Optoacoustic (OA) technique was employed for temperature measurement during irradiation. For 200 ms irradiation, the dead cell area (DCA) increased linearly (≈1600 µm2/mW) up to the average power of 40 mW for all modes without significant difference. From 50 mW, the increase of DCA of MP-5% significantly dropped to 610 µm2/mW (p < 0.05), likely due to the detected microbubble formation. OA temperature measurement showed a monotonic temperature increase in CW mode and a stepwise increase in MP mode, but no significant difference in the average temperature increase at the same average power, consistent with the temperature modeling. In conclusion, there is no difference in the average temperature rise between CW and MP modes at the same average power regardless of DC. At lower DC, however, more caution is required regarding mechanical damage due to microbubble formation.

A power-law relation of surface roughness and ages of alluvial fans in a hyperarid environment: A case study in the Dead Sea area

Despite recent advances in mapping and dating alluvial fans, due to the availability of high-resolution remote sensing data and Quaternary dating techniques, quantifying surface features in remote sensing data remains a challenge. Surface roughness is a time-dependent feature under stable conditions, which indicates the relative age of alluvial fans in a hyperarid environment. Although surface roughness can be quantitatively inferred from remote sensing data, determining surface roughness in a uniform index remains a complex problem. Here, we used the normalized backscatter intensity (NBI) from high-resolution ALOS PALSAR data to quantify alluvial fan surface roughness, which is further used to quantitatively map alluvial fans. We established a robust power-law relation between the NBI value ( R) and the in-situ age ( T) as measured with independently dated alluvial fans. Based on the R-T relation, it can be further to apply the R measurement to T estimates as old as ∼540 ka with an average uncertainty of ∼25% on a regional scale. The NBI value, independent of atmospheric conditions and sensitive to surface roughness variability, is an effective criterion for quickly distinguishing alluvial fans and performing age estimation. We propose that insolation weathering is an important physical weathering pattern in the Dead Sea area, which mainly controls the surface roughness in this hyperarid region.