Seroprevalence of HBV Infection Among Normal Population and Healthcare Workers in Baghdad

Objective: In this study we verified the epidemiology of HBV infection among normal population and healthcare workers (HCWs) in Baghdad by analyzing the prevalence of specific viral markers (anti-HBs, anti-HBc and HBsAg). Method: A total of 797 serum specimens (588-normal population, 209-HCWs) were tested using ELISA technique and positive HBsAg specimens were confirmed by VIDAS technique. Results: In normal population group, the HBsAg, anti-HBs and anti-HBc Total were 1.02%, 10.54%, 5.44%, respectively. The HBsAg result was significantly lower (P< 0.05) than previous studies were done in Iraq. Significant correlation (P < 0.05) in prevalence of HBsAg was found between age groups and males had higher positive HBsAg marker than females (P < 0.05). The prevalence of anti-HBs was insignificant (P＞0.05) between age groups but significant importance (P < 0.05) was recorded between both sexes. Highly significant (P＜0.01) was recorded between ages groups regarding to anti-HBc Total marker but insignificantly (P＞0.05) between both sexes were noticed. In HCWs group the HBsAg, anti-HBs, anti-HBc Total were 0.96%, 26.7%, 1.44% respectively and the prevalence of HBsAg was significantly less (P < 0.05) than previous studies. The comparison between normal population and HCWs groups showed significant correlation (P < 0.05) related to HBsAg and highly significant correlation (P＜0.01) regarding anti-HBs and anti-HBc Total. The HBsAg and anti-HBs among HCWs was significantly increased (P＜0.05) with advancing ages, whereas no such variation was observed between both sexes. The HBsAg was high among those with poor health education but it was with significantly importance (P< 0.05) among different occupational types as well as among vaccinated, incomplete vaccinated and unvaccinated HCWs groups. Additionally, HCWs who had only 1st, only 2nd and those who had 3rd doses showed significant correlation between number of vaccinated individuals and prevalence of anti-HBs. Keywords: Seroprevalence of HBV, HBsAg, anti-HBs, HCWs, normal population Abbreviations: anti-HBs, antibody anti-HBs; anti-HBc, antibody anti-HBc; HBsAg, antigen HB

Experimental and Theoretical Investigation of Droplet Evaporation on Heated Hydrophilic and Hydrophobic Surfaces

The evaporation characteristics of sessile droplets on heated hydrophobic and hydrophilic surfaces are investigated. Results are reported for the evaporation of water droplet volumes covering a range of shapes dominated by surface tension or gravity and over a range of temperatures between 40 and 60 °C. The weight evolution and total time of evaporation is measured using a novel self-contained heating stage on a high resolution analytical balance, which has advantages over visualization measurement techniques as it allows free choice of the initial droplet size and surface and the ability to record the droplet evaporation right through to the final stages of droplet life. Evaporation is modeled through a combination of a constant contact area and a constant contact angle model with the switch from the former to the latter occurring when the contact angle falls below its predetermined receding value. Theoretical results compare well with the experimental results for the hydrophobic substrate. However, a significant deviation is observed for the hydrophilic substrate due to the combined effects of the droplet surface cooling due to evaporation and buoyancy effects that are not included in the model. The proposed method of using the stick–slip model offers a convenient means of modeling droplet evaporation by mimicking the drying modes based on initial measurements of the static and receding contact angles

Rack Level Study of Hybrid Liquid/Air Cooled Servers: The Impact of Flow Distribution and Pumping Configuration on Central Processing Units Temperature

The flow distribution and central processing unit (CPU) temperatures inside a rack of thirty 1 U (single rack unit) Sun Fire V20z servers retrofitted with direct-to-chip liquid cooling and two coolant pumping configuration scenarios (central and distributed) are investigated using the EPANET open source network flow software. The results revealed that the servers in the top of the rack and close to the cooling distribution unit can receive up 30% higher flow rate than the servers in the bottom of the rack, depending on the pumping scenario. This results in a variation in the CPU temperatures depending on the position in the rack. Optimization analysis is carried out and shows that increasing the flow distribution manifold’s dimensions can reduce the flow variation through the servers and increase the total coolant flow rate in the rack by roughly 10%. In addition, activating the small pumps in the direct-to-chip liquid cooling loops inside the servers (distributed pumping) resulted in an increase of 2 °C in the CPU temperatures at the high computational workload

Alpha-particle-induced complex chromosome exchanges transmitted through extra-thymic lymphopoiesis in vitro show evidence of emerging genomic instability

Human exposure to high-linear energy transfer α-particles includes environmental (e.g. radon gas and its decay progeny), medical (e.g. radiopharmaceuticals) and occupational (nuclear industry) sources. The associated health risks of α-particle exposure for lung cancer are well documented however the risk estimates for leukaemia remain uncertain. To further our understanding of α-particle effects in target cells for leukaemogenesis and also to seek general markers of individual exposure to α-particles, this study assessed the transmission of chromosomal damage initially-induced in human haemopoietic stem and progenitor cells after exposure to high-LET α-particles. Cells surviving exposure were differentiated into mature T-cells by extra-thymic T-cell differentiation in vitro. Multiplex fluorescence in situ hybridisation (M-FISH) analysis of naïve T-cell populations showed the occurrence of stable (clonal) complex chromosome aberrations consistent with those that are characteristically induced in spherical cells by the traversal of a single α-particle track. Additionally, complex chromosome exchanges were observed in the progeny of irradiated mature T-cell populations. In addition to this, newly arising de novo chromosome aberrations were detected in cells which possessed clonal markers of α-particle exposure and also in cells which did not show any evidence of previous exposure, suggesting ongoing genomic instability in these populations. Our findings support the usefulness and reliability of employing complex chromosome exchanges as indicators of past or ongoing exposure to high-LET radiation and demonstrate the potential applicability to evaluate health risks associated with α-particle exposure.This work was supported by the Department of Health, UK. Contract RRX95 (RMA NSDTG)

Prospect and barrier of 3D concrete: a systematic review

This paper aims to explore the current state of the art and potential of 3D concrete printing and its use in large-scale applications. The study analysed 373 academic research, all of which were obtained from the Scopus database. The review conducted on some crucial issues on development of 3D concrete that included materials and their desirable properties, printer nozzle developments, reinforcement in printing, geopolymers as printing materials, and the use of coarse graded aggregates. This study provides researchers and institutions with an in-depth insight into 3D concrete printing and research trends worldwide and assesses the future of 3D concrete printing in large-scale applications. The requirement of more research on the mechanics of 3D printers, standardising a printer nozzle, the automation of reinforcing processes, and use of coarse graded aggregate for large-scale structural application were identified in this review. It also shows how 3D concrete printing has evolved and changed over time and gives an insight into the future of 3D concrete printing—making this scientometric review a framework for future studies

Investigating the Impact of Polymer and Portland Cement on the Crack Resistance of Half-Warm Bituminous Emulsion Mixtures

Cold mix asphalt (CMA) is emerging as an environmentally friendly alternative to traditional hot mix asphalt (HMA). It offers advantages such as lower costs, reduced energy demands, decreased environmental impacts, and improved safety aspects. Among the various types of CMA, the cold bitumen emulsion mixture (CBEM) stands out. The CBEM involves diluting bitumen through emulsification, resulting in lower bitumen viscosity. However, this process has certain drawbacks, including extended setting (curing) times, lower early strength, increased porosity, and susceptibility to moisture. This study focuses on enhancing CBEM properties through the utilization of low-energy heat techniques, such as microwave technology, and the incorporation of a polymeric additive, specifically acrylic. These innovations led to the development of a novel paving technology known as a half-warm bitumen emulsion mixture (HWBEM). The research was conducted in two phases. First, the study assessed the impact of low-energy heating on the CBEM. Subsequently, it explored the combined effects of low-energy heating and the addition of an acrylic polymer. CBEM samples containing ordinary Portland cement (OPC) as an active filler were utilized in the sample manufacturing process. The effectiveness of these techniques in enhancing crack resistance was evaluated by analysing the results of the indirect tensile strength test. Notably, CBEM samples containing an amount of 2.5% of acrylic polymer and OPC exhibited the highest resistance to cracking. Furthermore, significant improvements were observed in their volumetric and mechanical properties, comparable to those of HMA

Improving the Mechanical Properties and Durability of Cold Bitumen Emulsion Mixtures Using Waste Products and Microwave Heating Energy

Scientists have effectively demonstrated that the introduction of a waste product comprising cementitious chemical compositions can enhance the mechanical properties and durability of cold bitumen emulsion mixes (CBEMs). On the other hand, the high air void content of the CBEM mix remains a challenge that is considered unsatisfactory by paving engineers. As a result, this investigation highlights two major changes that were made. The first is the use of waste paper sludge ash (PSA) as a filler in CBEM instead of the conventional mineral filler (CMF). The second change was made to further improve the mixture by reducing the amount of CBEM air voids using microwave (MW) heating energy as a post-treatment method. When compared to typical hot mix asphalt (HMA), the new CBEMs showed great mechanical properties and durability. Moreover, the proposed method, using CBEMs, has lower environmental risks, is safer, and is more cost-effective than existing paving mix technologies. This study presents a method for controlling air voids within pavement specifications without affecting mechanical behaviour or generating additional environmental or economic considerations. When compared to typical mixtures, laboratory test results showed that MW-heating can enhance both the stiffness modulus and the air void content. Furthermore, these results revealed a minor reduction in creep stiffness and water sensitivity. Nevertheless, in terms of mechanical, volumetric, and economic properties, the suggested post-mix treatment was comparable to HMA. The findings point to the need to adopt CBEM post-heating approaches, particularly the MW treatment procedure

A Sustainable Cold Mix Asphalt Mixture Comprising Paper Sludge Ash and Cement Kiln Dust

Concerns about the environment, the cost of energy, and safety mean that low-energy cold-mix asphalt materials are very interesting as a potential replacement for present-day hot mix asphalt. The main disadvantage of cold bituminous emulsion mixtures is their poor early life strength, meaning they require a long time to achieve mature strength. This research work aims to study the protentional utilization of waste and by-product materials as a filler in cold emulsion mixtures with mechanical properties comparable to those of traditional hot mix asphalt. Accordingly, cold mix asphalt was prepared to utilize paper sludge ash (PSA) and cement kiln dust (CKD) as a substitution for conventional mineral filler with percentages ranging from 0–6% and 0–4%, respectively. Test results have shown that the incorporation of such waste materials reflected a significant improvement in the mixture’s stiffness and strength evolution. The cementitious reactivity of PSA produces bonding inside the mixtures, while CKD is used as an additive to activate the hydration process of PSA. Therefore, based on the results, it will be easier to build cold mixtures by shortening the amount of time needed to reach full curing conditions

Radiation-Induced Bystander Effects in Cultured Human Stem Cells

The radiation-induced "bystander effect" (RIBE) was shown to occur in a number of experimental systems both in vitro and in vivo as a result of exposure to ionizing radiation (IR). RIBE manifests itself by intercellular communication from irradiated cells to non-irradiated cells which may cause DNA damage and eventual death in these bystander cells. It is known that human stem cells (hSC) are ultimately involved in numerous crucial biological processes such as embryologic development; maintenance of normal homeostasis; aging; and aging-related pathologies such as cancerogenesis and other diseases. However, very little is known about radiation-induced bystander effect in hSC. To mechanistically interrogate RIBE responses and to gain novel insights into RIBE specifically in hSC compartment, both medium transfer and cell co-culture bystander protocols were employed.Human bone-marrow mesenchymal stem cells (hMSC) and embryonic stem cells (hESC) were irradiated with doses 0.2 Gy, 2 Gy and 10 Gy of X-rays, allowed to recover either for 1 hr or 24 hr. Then conditioned medium was collected and transferred to non-irradiated hSC for time course studies. In addition, irradiated hMSC were labeled with a vital CMRA dye and co-cultured with non-irradiated bystander hMSC. The medium transfer data showed no evidence for RIBE either in hMSC and hESC by the criteria of induction of DNA damage and for apoptotic cell death compared to non-irradiated cells (p>0.05). A lack of robust RIBE was also demonstrated in hMSC co-cultured with irradiated cells (p>0.05).These data indicate that hSC might not be susceptible to damaging effects of RIBE signaling compared to differentiated adult human somatic cells as shown previously. This finding could have profound implications in a field of radiation biology/oncology, in evaluating radiation risk of IR exposures, and for the safety and efficacy of hSC regenerative-based therapies