Innovative Low-Cost Plastic Optical Fiber Sensors for Gas Monitoring

In this study, a new simple and low-cost plastic optical fiber sensor for the measurements of low concentration HF vapors is described. The sensitivity to the HF vapors obtained by depositing a thin glass-like layer onto the PMMA core fiber after removing the fluorinated polymer cladding via dipping the fiber into ethyl acetate for a short period, not more than 40 second. Moreover, in order to enhance the fiber sensitivity, low pressure plasma treatments have been carried out in O2 and Ar gas mixtures on polymeric optical core fibers in order to increase the core surface area without damaging the PMMA core fiber. The reaction of glass-like layer with the HF vapor alters the fiber light transmission and is detected by means of a wide-band photodiode. POF sensors can find relevant applications for monitoring people exposed to unhealthy atmospheres in civil and industrial fields, and for monitoring the pollutants in gaseous mixtures. Several prototypes of fiber sensors have been fabricated and characterized in the reaction chamber. The obtained results demonstrating the capability to detect low concentration of HF vapors with high sensitivity

Design and Deployment of Low-Cost Plastic Optical Fiber Sensors for Gas Monitoring

This paper describes an approach to develop and deploy low-cost plasti optical fiber sensors suitable for measuring low concentrations of pollutants in the atmosphere. The sensors are designed by depositing onto the exposed core of a plastic fiber thin films of sensitive compounds via either plasma sputtering or via plasma-enhanced chemical vapor deposition (PECVD). The interaction between the deposited layer and the gas alters the fiber’s capability to transmit the light, so that the sensor can simply be realized with a few centimeters of fiber, an LED and a photodiode. Sensors arranged in this way exhibit several advantages in comparison to electrochemical and optical conventional sensors; in particular, they have an extremely low cost and can be easily designed to have an integral, i.e., cumulative, response. The paper describes the sensor design, the preparation procedure and two examples of sensor prototypes that exploit a cumulative response. One sensor is designed for monitoring indoor atmospheres for cultural heritage applications and the other for detecting the presence of particular gas species inside the RPC (resistive plate chamber) muon detector of the Compact Muon Solenoid (CMS) experiment at CERN in Geneva

BARRIERS TO ACCESSING AND CONSUMING MENTAL HEALTH SERVICES FOR PALESTINIANS WITH PSYCHOLOGICAL PROBLEMS RESIDING IN REFUGEE CAMPS IN JORDAN

Background: The Baqa’a refugee camp is the largest in Jordan, home to some 104,000 Palestine refugees. Barriers to accessing and consuming mental health services in Arab-refugees are well documented in the literature however few studies have been conducted hitherto to identify barriers for Palestine refugees with psychological problems residing in refugee camps in Jordan. Aim: To identify the barriers to accessing and consuming mental health services for Palestine refugees with psychological problems residing in Baqa’a refugee camp in Jordan and to formulate policy recommendations to overcome those barriers. Methods: 16 qualitative, semi-structured interviews were conducted with healthcare professionals working at health centres for Palestine refugees in Jordan, 14 of which were in health centres at Baqa’a refugee camp and the remaining two at the Field Office of the United Nations Relief and Works Agency (UNRWA) in Amman, Jordan. All the interviews were recorded and transcribed and thematic analyses conducted. Ethical approval was granted by the University of Leeds and UNRWA. Results: 16/16 (100%) respondents reported that resource and financial deficits were the most common barriers that contributed towards the treatment gap. Sex (15/16, (94%)), stigma and religion (12/16, (75%)) and culture (10/16, (63%)) were other major barriers identified. Discussion: Our findings help to elucidate the contributory factors towards the treatment gap between Palestine refugees with psychological problems residing in Baqa’a refugee camp in Jordan and mental health services therein. Policy recommendations based on our results are formulated and are discussed in this research paper

SiOx coated plastic fiber optic sensor for gas monitoring in RPC

This paper describes the development of a sensor designed to monitor the closed loop recirculation gas system of the Resistive Plate Counter (RPC) muon detectors which are used for the Compact Muon Solenoid (CMS) experiment installed at the Large Hadron Collider (LHC) accelerator of the European Center for Nuclear Research (CERN). The sensor is designed to detect low concentrations of hydrogen fluoride (HF) in the gas mixtures and employs a plastic optic fiber (POF) which is covered with a thin layer of a glass-like material. The fluoride ions attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coating is obtained by means of a low pressure plasma enhanced chemical vapor deposition (PECVD) that allows the glass-like film to be deposited at low temperature without damaging the fiber core

Antenatal care among Palestine refugees in Jordan: factors associated with UNRWA attendance.

BACKGROUND: Maternal and neonatal mortality is a global issue acknowledged by the Sustainable Development Goals (SDGs). Adequate ante-natal care (ANC) is pivotal to reducing these mortality rates, while understanding why women don't attend ANC is crucial to addressing the SDGs. AIMS: Using routine primary health care data to determine the factors associated with inadequate attendance by Palestine refugees (PR) to ANC seeking facilities provided by the United Nations Relief and Works agency for Palestine Refugees in the Near East (UNRWA), Jordan. METHODS: A backwards logistic regression model incorporating non-health system factors and health system factors, was performed using UNRWA data. RESULTS: A younger age of women was associated with inadequate ANC visits (P = 0.0009) in the non-health systems model. For health system factors, pregnancy risk status, having a gynaecologist review and the health centre attended were factors found to be significantly associated with ANC attendance (P < 0.0001). CONCLUSIONS: Understanding the health system factors associated with ANC attendance can lead to changes and improvements in UNRWA's operational policies

Dendrimers Based on 1,4-Phenylene Units: Synthesis, Reaction Chemistry, Reactivity, Structure and Bonding

In der vorliegenden Arbeit wird eine konvergente Synthesestrategie zum Aufbau von formstabilen dendritischen Carbosilanmolekülen mit 1,4-Phenyleneinheiten, welche als “Silicium-Silicium-Spacer” fungieren, vorgestellt. Zur Darstellung dieser Verbindungen kommen repetitive Lithiierungs-Silylierung-Zyklen zur Anwendung. Die Lithiierung von 1-Br-4-C6H4-Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)3 (n = 0, 1, 2, 3) mit nBuLi und die Umsetzung von in-situ generiertem 1-Li-4-Si(CH2CH=CH2)nMe3-nC6H4 mit SiCl4 liefert Dendrimere der 0. Generation Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)4 (n = 1, 2, 3). Wird 1-Li-4-Si(CH2CH=CH2)nMe3-nC6H4 mit 1-Br-4-SiCl3-C6H4 zur Reaktion gebracht, sind Dendronen der 0. Generation 1-Br-4-C6H4-Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)3 (n = 0; 1; 2; 3) zugänglich. Durch repetitive Lithiierungs-Silylierungs-Zyklen können ausgehend von 1-Br-4-C6H4-Si(C6H4-4- Si(CH2CH=CH2)nMe3-n)3 Dendrimere höherer Generationen aufgebaut werden. Bringt man die lithiierte Spezies 1-Li-4- C6H4-Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)3, welche ausgehend von 1-Br-4-C6H4-Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)3 durch Metallierung mit tBuLi zugänglich ist, in Anwesenheit von TMEDA mit SiCl4 zur Reaktion, so erhält man die Dendrimere der 1. Generation Si(C6H4-4-(C6H4-4-Si(CH2CH=CH2)nMe3-n)3)4 (G1b, n = 1; G1c n = 2). Erfolgt die Silylierung jedoch in Abwesenheit von TMEDA, werden die Chlorsilane ClSi(C6H4-4-(C6H4-4-Si(CH2CH=CH2)nMe3- n)3)3 (D1bCl, n = 1; D1cCl, n = 2) gebildet. Die Silylierung von 1-Li-4-C6H4-Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)3 mit 1-Br-4-SiCl3-C6H4 liefert die Dendronen der 1. Generation 1-Br-C6H4-4-Si(C6H4-4-(C6H4-4-Si(CH2CH=CH2)nMe3-n)3)3 (D1b, n = 1; D1c, n = 2; D1d, n = 3). Diese liegen in einem Gleichgewicht monomerer und komplementärer dimerer Spezies vor. Die Dimerisierung kann durch NMR-Untersuchungen sowie durch die Einkristallröntgenstruktur von D1bCl belegt werden. Die Darstellung von Carbosilanen des Typs PhMeSi((CH2)3B(OH)2)2 (2), Si(C6H4-4-SiMe2((CH2)3B(OH)2)4 (5), PhMeSi((CH2)3OH)2 (3) und Si(C6H4-4-SiMe3-n((CH2)3OH)n)4 (6a, n = 1; 6b, n = 2; 6c, n = 3) wird beschrieben. Die Boronsäuren 2 und 5 sind durch Umsetzung von PhMeSi(CH2CH=CH2)2 (1) und Si(C6H4-4-SiMe2(CH2CH=CH2))4 (4a) mit HBBr2·SMe2 und anschließender Hydrolyse zugänglich, während 3 und 6a - 6c durch Hydroborierung von 1 und 4a - c mit BH3·SMe2 und anschließender Oxidation mit H2O2 erhalten werden. Die Einkristallröntgenstruktur von 6a zeigt, dass das Molekül aufgrund von π-π-Wechselwirkungen und der Ausbildung von Wasserstoffbrückenbindungen Teil eines zweidimensionalen Netzwerks ist. Ein weiterer Schwerpunkt der Arbeit widmet sich der Synthese und Charakterisierung von Dendrimeren der 0. und 1. Generation mit symmetrisch substituiertem Porphyrin-Grundgerüst als multifunktionalem Kern. Hierbei werden zunächst die allyl-terminierten Bromide 1-Br-4-Si(CH2CH=CH2)nMe3-nC6H4 (n =1, 2) bzw. die Dendronen -Br-4-C6H4- Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)3 (n = 0, 1, 2) in die aromatischen Aldehyde 1-HOC-4-Si(CH2CH=CH2)nMe3-nC6H4 (2b, n = 1; 2c, n = 2) bzw. 1-HOC-4-C6H4-Si(C6H4-4-Si(CH2CH=CH2)nMe3-n)3 (4a, n = 0; 4b, n = 1; 4c, n =2) überführt. Aus diesen werden nach der Methode von Lindsey durch Umsetzung mit Pyrrol, BF3·OEt2 und DDQ die entsprechenden Porphyrine H2T(-4-Si(CH2CH=CH2)nMe3-nC6H4)P (5b, n = 1; 5c, n = 2) bzw. H2T(-4-C6H4-Si(C6H4-4- Si(CH2CH=CH2)nMe3-n)P (7a, n = 0; 7b, n = 1; 7c, n =2) aufgebaut. Deren Komplexierung mit Zn(OAc)2 liefert die Zn- Porpyrine Zn(II) T(-4-Si(CH2CH=CH2)nMe3-nC6H4)P (6a, n = 1; 6b, n = 2) bzw. Zn(II) T(-4-C6H4-Si(C6H4-4- Si(CH2CH=CH2)nMe3-n)P (8a, n = 0; 8b, n = 1; 8c, n =2). Ausgehend von 5b und 5c sind Porphyrine mit terminalen Hydroxyl-Carbosilan-Einheiten via Hydroborierung- Oxidation zugänglich. Diese Verbindungen einschließlich der entsprechenden Zn-Komplexe sind aufgrund ihrer Fähigkeit zur Ausbildung von Wasserstoffbrücken-Netzwerken in hohem Maße zum Aufbau von supramolekularen Strukturen geeignet. Anhand der Einkristallröntgenstruktur-Analyse von Zn[T(4-Si((CH2)3-OH)Me2-C6H4)P] 10a ist ersichtlich, dass dieses Metalloporphyrin aufgrund von dirigierenden Wasserstoffbrücken Teil eines selbst organisierenden Porphyrin-Netzwerks darstellt und darum einzigartige strukturelle Eigenschaften aufweist. Die Einkristallröntgenstrukturen von 5b, 5c, 6b und 7b werden ebenfalls vorgestellt

Development of Innovative Low Cost POF Sensors for Monitoring Chemical and Environmental Quantities

This work aims at the design and development of innovative sensing systems based on optical technology. Plastic Optical Fiber (POF) can be successfully employed for the development of highly sensitive and selective devices to be used in monitoring environmental and chemical quantity. This thesis presents the implementation of a prototype POF sensor which is able to detect low concentrations of hydrogen fluoride (HF) vapors. The sensor is based on plastic optical fibers whose surface is modified in such way to make it sensitive to the presence of specific contaminants (below to 0.1 ppm of HF). The approach proposed for the realization of the sensors foresees the surface modification of the plastic optic fiber in two steps: (i) etching of the cladding in an organic solvent (such as ethyl acetate); (ii) deposition of the sensitive film (glass-like) able to react with HF by using PECVD (Plasma Enhanced Chemical Vapor Deposition) and/or plasma sputtering. The fluoride ions attack the glass-like film and alter the transmission capability of the fiber so that the detection simply requires a LED and a photodiode. The sensor exploits a cumulative response which makes it suitable for direct estimation of the total exposure to the fluoride ions. This thesis describes the prototype sensor details by defining the way to prepare the plastic fiber, the design of the sensor assembly, the measurement set-up arrangement, and the sensor characterization. These sensors can be used both in civil and industrial fields, but have been designed to, i.e. the monitoring of the gas mixtures in the RPC (Resistive Plate Counters or Resistive Plate Chamber) which are employed detector in high energy physics experiments running at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland. This thesis also introduces a sulfide gas sensor, based on POF, that is able to monitor the low concentrations sulfide vapors (H_2S). This sensor is particularly suited for extensive use in the cultural heritage conservation monitoring, such as for precious artifacts in museum showcases, and can be used also for monitoring people exposed to unhealthy atmospheres. Also these sensors can be produced by depositing a sensing thin film onto the fiber surface and measuring the light transmittance change because of its reaction with the gas. The fiber sensors are made sensitive to sulfide vapors by deposition of an silver nanostructured sensing film by DC sputter coater. This thesis contains the design of the sensor assembly, the measurement set-up arrangement, and the sensor characterization

Clinical profile, prognosis and post COVID-19 Illnesses among attendants to private general practitioner (GP) clinic at Urban Amman Area: a clinical case-series study

Background: The clinical manifestations of Corona Virus Disease of 2019 (COVID-19) varied from patient to patient with evidence of multi-organ involvement. Many patients continue to have a wide range of symptoms for variable periods of time. The long-term effects of COVID-19 infection (post-COVID-19 illness or syndrome) are not yet been fully explored.This study aims to highlight the clinical manifestations of the acute COVID-19 infection and the longer-term manifestations of the disease among the attendants to a private GP clinic in the Urban Amman Area, Jordan.Methods: A clinical case-series study was conducted on a sample of 300 COVID-19-positive cases among patients attending my private GP clinic in the Urban Amman Area, Jordan. We used the structured questionnaire based mainly on World Health Organization (WHO) Case Report Form (CRF) verified tool for post-COVID-19. All patients with COVID-19 were included in the study. Data collection was conducted through phone calls and analyzed using the Statistical Package for Social Sciences (SPSS) software.&nbsp;Results: The incidence of COVID-19 among patients attending the clinic during the period of this study was 25%. Females were 135 (45%) of the study population and males were 165 (55%). The mean (SD) of age was 34.2 (5.0) years. Most of the infected staff (90%) were symptomatic and developed acute COVID-19 symptoms. Fever, Cough, Fatigue, joint pain and loss of smell and taste were the most common symptoms. 72% of the study population had fully recovered from the infection, while 28% of them continued to suffer from many long symptoms. Fatigue (28%), shortness of breath on activity (18%), Social withdrawal (18%), anxiety (17%), forgetfulness (16%), trouble concentrating (15) and depressed mood (14%) were the most frequently reported long symptoms.Conclusion: The prevalence of Post COVID-19 illness was 28% with a high public health burden calling for the public health system to address the medical and psychological needs of affected persons. Mental health and psychosocial support are recommended elements for the management of patients