Mechanophore-linked hydroxyl-terminated polybutadiene for the remote detection and quantification of mechanical stress

Polymers containing chromophores often exhibit mechanoresponsive behaviour, allowing the remote detection of stress in components such as rocket motors without taking the rockets out of service. Here we describe a polymer comprising a difunctional spiropyran chromophore and methyl methacrylate cross-linked with hydroxyl-terminated polybutadiene (HTPB). This polymer was developed as a sensor for the non-destructive monitoring of mechanical stress by using the force-induced colour changes as a quantitative readout. After about 40 N of load was applied there was a gradual colour changes proportional to the compressive forces on the sample, as revealed by in-situ monitoring using a video camera and UV–Vis spectrometry. The tests highlighted a gradual decrease in the transmitted light intensity at 675 nm with increasing load, due to the opening of the spiropyran rings and their conversion to the coloured merocyanine forms. A reversible change to the initial colour occurred 72 h after the load was removed, but only under artificial fluorescent lighting, confirming that visible light is required for the ring-closing reaction. This new polymer is an ideal candidate for the remote detection of stress-induced damage in inaccessible structures or essential equipment that cannot be withdrawn from service for testing

Implementation of Carbon Dioxide Gas Injection Method for Gas Recovery at Rashidpur Gas Field, Bangladesh

Natural gas plays an important role for the economic development of Bangladesh. It is the primary options to satisfy the environmentally clean energy, whereas coal is a dirty energy source and oil creates an unhealthy environment. Bangladesh is the seventh-largest producer of natural gas in Asia. Gas supplies meet 56% of domestic energy demand. The proven natural gas reserve in Bangladesh is only 19.73 Tcf. The Rashidpur Gas Field (RGF) is located in the Sylhet Basin, Northeast Bangladesh. It is 35 km long and 7 km anticlinal structure and asymmetric in nature with steeper eastern flank (22˚ to 25˚) and gentler western flank (8˚ to 12˚). There are two gas zones in depth between 1380m to 2787m below surface. Sandstone reservoirs of Miocene-Pliocene age and are considered to have been originated shallow marine depositional environment. The reservoir porosity-permeability values are very good, with estimated gas initially in place (GIIP) of the RGF was 2.242 Tcf with 58% recovery, thus recording an initial gas reserve is 1.309 Tcf. Five gas producing wells (RP-1, 3, 4, 6 and 7) in the RGF are producing 50 MMscf gas per day. Due to the demand of natural gas with decreasing production rate, this enhanced natural gas plays a vital role in the national economy of the country. This research depicts the development of the daily production of the RGF from 50 MMscfd to 99 MMscfd using software from the existing production wells. Thus the natural gas in the RGF would be enhanced/recovered using carbon dioxide (CO2) gas injection by Enhanced Gas Recovery (EGR) method from the RGF reservoir. Applying this method would play a vital role to increase the daily production rate of the RGF

Cognitive Functioning in a Pilot Sample of Childhood Cancer Patients in Egypt

Abstract A subset of cancer survivors experience cognitive deficits that can last for many years after the completion of chemotherapy. The etiology of this problem is largely unknown, so the present study aimed to assess cognitive functioning in childhood patients with cancer and to investigate the proposed disposing factors including variables related to disease, treatment, and some socio-demographic characteristics. In a case control study parents of 67 cancer patients aged 8-12 years, completed the parent proxy report of PedsQL™ 3.0 Cognitive Functioning Scale (Arabic versions), as well as a separate sheet for socio-demographic data. Control group consisted of 37 healthy subjects from the same age group were subjected to the same methodology for comparison. All patients under the study have successfully accomplished their treatment protocol and were in complete remission during the evaluation. Hematological malignancies represented 70.1% of the patients sample, with the highest proportion for ALL (52.2%). Brain tumors represented 40% of the solid malignancies (29.9% of the study patients). Cognitive functioning score was significantly lower in the solid group (69.6±37.3) compared to the hematologic group (85.1±22.2) (t = 2.1, p =0.038). Cognitive functioning score was also lower in solid group versus control subjects (p =0.047), while it showed no significant difference between hematological malignancies and control group. Older age at diagnosis, urban residence, illiterate mothers, higher duration of treatment as well as long duration of hospital admission were associated with a lower cognitive score in the solid tumors group compared to hematological group

Impact of measurement backaction on nuclear spin qubits in silicon

Phosphorus donor nuclear spins in silicon couple weakly to the environment making them promising candidates for high-fidelity qubits. The state of a donor nuclear spin qubit can be manipulated and read out using its hyperfine interaction with the electron confined by the donor potential. Here we use a master equation-based approach to investigate how the backaction from this electron-mediated measurement affects the lifetimes of single and multi-donor qubits. We analyze this process as a function of electric and magnetic fields, and hyperfine interaction strength. Apart from single nuclear spin flips, we identify an additional measurement-related mechanism, the nuclear spin flip-flop, which is specific to multi-donor qubits. Although this flip-flop mechanism reduces qubit lifetimes, we show that it can be effectively suppressed by the hyperfine Stark shift. We show that using atomic precision donor placement and engineered Stark shift, we can minimize the measurement backaction in multi-donor qubits, achieving larger nuclear spin lifetimes than single donor qubits

Do ‘passive’ medical titanium surfaces deteriorate in service in the absence of wear?

Globally, more than 1000 tonnes of titanium (Ti) is implanted into patients in the form of biomedical devices on an annual basis. Ti is perceived to be ‘biocompatible’ owing to the presence of a robust passive oxide film (approx. 4 nm thick) at the metal surface. However, surface deterioration can lead to the release of Ti ions, and particles can arise as the result of wear and/or corrosion processes. This surface deterioration can result in peri-implant inflammation, leading to the premature loss of the implanted device or the requirement for surgical revision. Soft tissues surrounding commercially pure cranial anchorage devices (bone-anchored hearing aid) were investigated using synchrotron X-ray micro-fluorescence spectroscopy and X-ray absorption near edge structure. Here, we present the first experimental evidence that minimal load-bearing Ti implants, which are not subjected to macroscopic wear processes, can release Ti debris into the surrounding soft tissue. As such debris has been shown to be pro-inflammatory, we propose that such distributions of Ti are likely to effect to the service life of the device

Vulnerability and Weaknesses of Eating Habits of Overweight School Children as an Entry Risk for COVID-19

BACKGROUND: In developing countries, overweight among children becomes an alarming problem and a health concern. Obesity is a factor in disease severity of coronavirus disease (COVID-19) having the greatest impact on patients. AIM: The aim of this study was to determine the prevalence of overweight in some of the Egyptian governmental primary school children, its nutritional and socioeconomic determinants. Special focus was directed to identify the current dietary practices including risky nutritional habits of overweight children as a weak point leading to increasing their vulnerability to catching COVID-19 infection. METHODS: A cross-sectional observational study was conducted on primary school children aged 6–12 years. General demographic data, socioeconomic data, dietary pattern, intake of a diversity of nutrient-rich food versus calorie-dense food, and anthropometrical data were collected. RESULTS: Of 1600 child, there were 8% overweight who are considered at risk of COVID-19 infection. Considering the weekly share of the stomach, only one-third of the food consumed by overweight children is nutrient-rich, with high consumption of French fries and Candies (once per day among 95% and 78 % of overweight children, respectively). Moreover, 90% of them consume sugar-sweetened beverages (SSB) more than once per day. The majority of overweight children belonged to small, middle- income families, and had illiterate or read and write mothers. CONCLUSION: Overweight children eat narrow diversity of nutrient-rich food that includes vegetables, fruits, protein, and dairy products. They eat more calorie-dense foods, every day. The increase of family income increased the likelihood of having overweight children with a high intake of SSB, candies, and chips; consumption of snacks between meals and before sleep. Protective predictors against overweight were highly educated mothers, taking breakfast before school, having dinner, and taking meals on time. RECOMMENDATION: Nutritional behavioral education aiming at choosing nutritious and varied options of food that is effective for improving children’s nutritional status is the key to decreasing vulnerability toward COVID 19

Identification and Characterization of Human Monoclonal Antibodies for Immunoprophylaxis Against Enterotoxigenic Escherichia coli Infection

Background. Enterotoxigenic Escherichia coli (ETEC) cause diarrheal illness in infants in the developing world and travelers to endemic countries including military personnel. ETEC infection of the host involves colonization of the small intestinal epithelium and toxin secretion leading to watery diarrhea. There is currently no vaccine licensed to prevent ETEC. CFA/I is one of the most common colonization factor antigens (CFAs). The CFA/I adhesin subunit, CfaE, is required for ETEC adhesion to host intestinal cells. Human antibodies against CfaE have potential to block colonization of ETEC and serve as an immunoprophylactic against ETEC-related diarrhea. Methods. Mice transgenic for human immunoglobulin genes were immunized with CfaE to generate a panel of human monoclonal IgG1 antibodies (HuMAbs). The most potent IgG1 identified in the in vitro functional assays were selected and isotype switched to secretory IgA (sIgA) and tested in animal colonization assays via oral administration. Results. Over 300 unique anti-CfaE IgG1 HuMabs were identified. The lead IgG1 anti-CfaE HuMAbs completely inhibited hemagglutination and blocked adhesion of ETEC to Caco-2 cells. Epitope mapping studies revealed that HuMAbs recognized epitopes in the N-terminal domain of CfaE near the putative receptor binding site. Oral administration of anti-CfaE antibodies in either IgG or secretory IgA isotypes inhibited intestinal colonization in mice challenged with ETEC. A two to four log decrease of colony forming units was observed as compared to irrelevant isotype controls. Conclusions. We identified fully human monoclonal antibodies against CfaE adhesion domain that can be potentially employed as an immunoprophylaxis to prevent ETEC-related diarrhea

Academic Achievement and Psychosocial Profile of Egyptian Primary School Children in South Sinai

BACKGROUND: Population of South Sinai has suffered from negligence for many years. Solving educational problems of this population is the main concern nowadays.AIM: To assess academic achievement in primary school children in South Sinai in relation to intelligence and psychosocial profile.SUBJECTS AND METHODS: A descriptive cross-sectional survey was conducted on 407 Bedouin and urban students randomly selected from twelve public primary schools in six cities in South Sinai. Intelligence was assessed using Goodenough-Harris test. The midyear Arabic language and Arithmetic scores were used to assess academic achievement. The teachers completed a Pediatric-Symptom Checklist for evaluation of children behaviour.RESULTS: A statistically significant difference in academic achievement (P < 0.001), total psychosocial scores, (P < 0.05), and externalization (P < 0.05) was found between urban and Bedouin students with significant gender differences (P < 0.05). Highly significant positive correlations were observed between IQ percentile and mid-year Arabic language scores and Arithmetic scores (P < 0.001), and significant negative correlations with the total score of PSCL and its subscale scores (externalising, inattention, and internalising behaviour) (P < 0.001) among the students.CONCLUSION: Comorbid academic and psychosocial dysfunction in primary school children were observed in South Sinai. A national strategy to minimise the educational gap between Bedouin and urban areas should be implemented