Beverage Consumption and Ulcerative Colitis: A Case-Control Study from Saudi Arabia.

BACKGROUND: The association between beverage intake and ulcerative colitis (UC) is not well-established, with no available data from Arab countries. Herein, we investigated the potential association of consuming coffee, tea, and carbonated soft drinks with UC among a population from Saudi Arabia. METHODS: This hospital-based case-control study used data of 171 newly diagnosed UC patients and 400 patients with other gastrointestinal conditions who served as controls. All UC cases were ascertained by endoscopy, while beverage intake was assessed by a questionnaire that was completed before diagnosis. We computed odds ratios (ORs) and 95% confidence intervals (95% CIs) of UC and UC extension for frequent versus infrequent intakes of coffee, tea, and carbonated soft drinks using logistic regression. RESULTS: Overall, 23.4% of UC patients had pancolitis, 21.1% extensive, 51.4% left-sided, and 4.1% proctitis. UC patients had a similar sex distribution to the controls but were older and had a lower BMI. After adjustment for age, sex, body mass index, and smoking history, frequent intakes of coffee and tea were associated with lower odds of UC: 0.62 (0.42, 0.91) and 0.53 (0.35, 0.79), respectively. On the other hand, frequent intakes of carbonated soft drinks were associated with increased odds of UC: 9.82 (6.12, 15.76). The frequency of beverage consumption was not associated with UC extension. CONCLUSION: UC was negatively associated with frequent coffee and tea consumption but positively associated with frequent carbonated soft drink intake in Saudi people. More population-based prospective cohort studies are needed to confirm our findings.

Perspectives on Telemedicine during the Era of COVID-19; What Can Saudi Arabia Do?

The coronavirus disease 2019 (COVID-19) pandemic has represented a challenge to medical practice in Saudi Arabia and worldwide. In contrary to the increasing numbers of COVID-19 patients, there was a limitation in the capacity of medical practices and access to healthcare. A growing body of evidence from healthcare settings in Saudi Arabia and worldwide has suggested a possible role for telemedicine in responding to this evolving need. Telemedicine can be used for triage, direct care, follow-up, and consultation. It could be delivered through synchronous, asynchronous, and mixed approaches. While telemedicine has several advantages, such as accessibility and cost-effectiveness, its diagnostic reliability should be further investigated. The Saudi Vision (2030) has drawn up a roadmap to invest in digital healthcare during the coming decade; however, some barriers related to using telemedicine in Saudi healthcare settings, including cultural issues and technical difficulties, should be openly discussed. In addition, before putting telemedicine in practice on a wide scale in Saudi Arabia, more efforts should be carried out to issue updated legislation and regulations, discuss and respond to ethical concerns, and ensure data security.

Prevalence of and Risk Factors for Nonprescription Antibiotic Use among Individuals Presenting to One Hospital in Saudi Arabia after the 2018 Executive Regulations of Health Practice Law: A Cross-Sectional Study.

Antibiotic resistance is a worldwide public health emergency. Nonprescription antibiotic use is a chief cause of antibiotic resistance. The Saudi Government, as a consequence, imposed in 2018 executive regulations to prevent the distribution of antibiotics without a prescription. Herein, we aimed to investigate the prevalence of and risk factors for nonprescription antibiotic use among individuals presenting to one hospital in Saudi Arabia after enacting these regulations. This cross-sectional study was conducted on people, aged ≥18 years, who presented to the primary healthcare clinics of King Khalid University Hospital in Riyadh during the period between 1/1/2019 and 28/2/2019. Participants were asked to fill out a self-administrated questionnaire assessing their nonprescription antibiotic use during the past year in addition to sociodemographic information. Then, logistic regression analyses were performed to calculate the odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for age, sex, education, and nationality of any nonprescription antibiotic use compared with no use within the past year. Out of 463 participants, 62.9% were females, 67.4% were <40 years, and 93.7% were Saudi citizens. Overall, 30.5% of participants reported nonprescription antibiotic use during the past year (19.7% one to two times and 10.8% more than two times). Male and non-Saudi participants were more likely to report any nonprescription antibiotic use, with HRs (95% CIs) of 1.99 (1.30, 3.04) and 3.81 (1.73, 8.35), respectively. The main reasons behind nonprescription antibiotic use were having previous experience with a health condition (69.2%), inaccessibility of healthcare (26.6%), and recommendation from a relative or a friend (16.1%). A major limitation of this study was that it included individuals attending one hospital. Individuals who seek medical consultation could be dissimilar to those who do not see doctors regarding nonprescription antibiotic use.

Sedentary lifestyle and Framingham risk scores: a population-based study in Riyadh city, Saudi Arabia.

BACKGROUND: Studies from Saudi Arabia have reported a continued increase in the prevalence of cardiovascular diseases and their associated risk factors. The objective of this study was to measure the gender differences in the cardiovascular disease (CVD) risk based on Framingham risk scores (FRS) and to explore the association of FRS with sedentary life style including physical inactivity, sitting time and central obesity among Saudi adults. METHODS: A cross-sectional survey was conducted on 2997 Saudi adults (males = 968, females = 2029) selected from 18 primary health care centres in Riyadh city, from December 2014 to August 2015. A detailed interview that evaluated lifestyle and past medical history was conducted; furthermore, anthropometric measurements and blood samples were collected for lipid profiling. The FRS were calculated based on the age, gender, systolic blood pressure, treatment for hypertension, diabetes, smoking status, total blood cholesterol and high-density lipoprotein levels. These scores were categorized into low risk (FRS < 10) and high/intermediate risk (≥10). A multivariable logistic regression analysis was performed. RESULTS: The mean (±SD) age of the males and females was 43.1(±11.7) vs 43.8(±10.9) years (p = 0.07), respectively. The number of Saudi male participants with intermediate-to-high FRS scores (≥10) was almost twice that of females (males 33% vs 17%). The multivariable logistic regression model after adjusting for education level and housing type, found that low physical activity (aOR & 95%CI for males 2.91 (1.45, 5.80); females 1.38 (1.06, 1.81); prolonged sitting time (aOR &95%CI for males 1.36 (0.98, 1.90) females 1.58 (1.20, 2.07), high central obesity (defined as waist circumference in males > 102 cms, and females > 88 cms) (aOR & 95%CI for males 2.38 (1.67, 3.41); females 3.35 (1.92, 5.87) were associated with high/ intermediate risk for CVD. CONCLUSIONS: A significant percentage of Saudi population revealed FRS ≥10. Females beyond the age of 50 were found to have a higher prevalence for CVD risk compared with males of the same age group. Modifiable risk factors like low physical activity, prolonged sitting time and central obesity have strong implications for primary prevention and management services that can change the risk profile of the Saudi population.

Correction: Incidence and contributing factors of glucose intolerance in Saudi postpartum women: Sub-group analysis from RAHMA study.

[This corrects the article DOI: 10.1371/journal.pone.0210024.].

Incidence and contributing factors of glucose intolerance in Saudi postpartum women: Sub-group analysis from RAHMA study.

OBJECTIVES: The objectives of this study were to determine incidence and risk factors of glucose intolerance one year after delivery in a sub-cohort of Riyadh Mother and Baby Cohort Study (RAHMA) study. METHODS: This is a follow-up study of a sub-cohort from RAHMA study from King Khalid University Hospital (KKUH). All women from RAHMA database who completed one year since delivery at KKUH were contacted by phone to participate in the study. Previously collected data from RAHMA registry for each participant were linked to this study data. Clinical data measured for each participant included current weight and height to calculate the BMI and waist circumference. Blood tests done for each participant were fasting blood glucose (FPG) and HbA1c. Based on the blood tests results, participants were classified into three groups; diabetic, pre-diabetic and normal. The incidence of diabetes and prediabetes was calculated for the whole cohort. Clinical, biochemical, and sociodemographic predictors of glucose intolerance were compared between the three groups. Risk factors with P-value less than 0.05 were tested in multivariate regression model with bootstrapping to calculate the relative risk (RR) and its 95% Bias corrected Confidence Interval (C.I.). RESULTS: From the sub-cohort, 407 women fulfilled the inclusion criteria and agreed to participate in the study. From the study participants; 250 (61.4%) women were normoglycemic, 142 (35%) women had prediabetes and 15 (3.6%) women were diabetic. Following multivariable regression analysis only history of gestational diabetes mellitus (GDM), (RR 1.74, 95% CI (1.06 to 2.84), P = 0.01), obesity (RR 1.69, 95% CI (1.01-3.11), P = 0.04) and diastolic blood pressure, (RR 1.04, 95% CI (1.01-1.09), P = 0.03) remained as predictors of postpartum glucose intolerance. CONCLUSION: The incidence of postpartum glucose intolerance (diabetes and prediabetes) is very high in Saudi women. Both GDM and obesity are strong predictors of glucose intolerance.

Knowledge, attitude and practice of secondary schools and university students toward Middle East Respiratory Syndrome epidemic in Saudi Arabia: A cross-sectional study.

This study was aiming to investigate the knowledge, practice and attitudes of secondary school and university students toward MERS-CoV infection. This is a cross-sectional study conducted in Riyadh, Saudi Arabia. Study participants were recruited from several constituent colleges of King Saud University and secondary schools in Riyadh. Data were collected using self-administered, closed-ended questionnaires. Frequencies and proportions were computed for descriptive purposes. Chi square test was utilized to depict statistical difference between groups. Among the 1109 students who answered the questionnaires, 53.1% were male, and 46.9% were female. Level of knowledge about clinical presentation of MERS is generally similar among university and school students. The most frequently reported source of transmission is entering crowded spaces and being exposed to coughing and sneezing. Additionally, hand washing was the most commonly reported method of protection against the infection. The localized spread of MERS in Saudi Arabia and the number of fatalities associated with it might have increased public interest in understanding how to maintain proper precautionary measures both on a community and on an individual level. More emphasis should be placed on educating the student participants about preventive measures such as using tissues when sneezing and coughing and proper tissue disposal.

Asthma quality of life in Saudi Arabia: Gender differences.

OBJECTIVES: To explore potential gender differences in the factors associated with asthma-specific quality of life (AQL). METHODS: A cross-sectional study of consecutive series of adult patients attending primary care centers at three major hospitals in Riyadh, Saudi Arabia, was performed. AQL was measured using a standardized version of the AQL questionnaire (min = 1, max = 7), with higher scores indicating a better AQL. Multiple linear regression analysis was performed. RESULTS: The mean AQL was 4.3 (standard deviation [SD] = 1.5) for males and 4.0 (SD = 1.3) for females (p = 0.113). With each unit increase in asthma control, the AQL improved by 0.19 points (95% confidence interval [CI] = 0.14-0.23) in men and by 0.21 points (95% CI = 0.16-0.25) in women. Daily tobacco smoking was associated with a 0.72 point (95% CI = 0.14-1.30) decrease in the AQL among males. Women who had a household member who smoked inside the house had a significantly lower AQL (B = -0.59, 95% CI = -1.0 - -0.19). A monthly household income of 25,000 Saudi Riyals or more was associated with a better AQL among men (B = 0.51, 95% CI = 0.01-1.01), whereas being employed exhibited a protective effect in women (B = 0.48, 95% CI = 0.11-0.84). Higher levels of perceived asthma severity were associated with better AQL in women (B = 0.82, 95% CI = 0.36-1.28). CONCLUSIONS: Our findings revealed gender-specific differences in the correlates of AQL in Saudi Arabia, particularly in tobacco exposure, socio-economic factors and perceived asthma severity.

Prevalence of Body Dysmorphic Disorder and its Association With Body Features in Female Medical Students.

BACKGROUND: Body dysmorphic disorder (BDD) is a distressing psychiatric disorder. So far there have not been any studies on BDD in Saudi Arabia. OBJECTIVES: The aim of this study was to determine the prevalence of body dysmorphic disorder in female medical students and to investigate whether there is an association between BDD and body features of concern, social anxiety and symptoms of BDD. MATERIALS AND METHODS: A cross sectional study was carried out on female medical students of the college of medicine, King Saud University, Riyadh, Saudi Arabia during January to April, 2015. Data were collected using the body image disturbance questionnaire, Body dysmorphic disorder symptomatology and social interaction anxiety scale. Descriptive statistics, bivariate and multivariate analysis were used to analyze the results. RESULTS: Out of 365 students who filled out the questionnaire, 4.4% (95% confidence intervals (CI): 2.54% to 7.04%) were positive for BDD with skin (75%) and fat (68.8%) as the most frequent body features of concern. Ten features (skin, fat, chest, hips, buttocks, arms, legs, lips, fingers, and shoulders) out of twenty-six were significantly associated with BDD. Arms and chest were independently associated with BDD. The odds of presence of body concern related to "arms" was 4.3 (95% C.I: 1.5, 12.1) times more in BDD subjects than non-BDD subjects, while concern about "chest" was 3.8 (1.3, 10.9) times more when compared to non-BDD subjects. No statistically significant association was observed between BDD and social anxiety (P = 0.13). CONCLUSIONS: This was the first study conducted in Kingdom of Saudi Arabia (KSA) on female medical students, which quantified the prevalence of BDD and identified the body features associated with it. Body dysmorphic disorder is prevalent in female medical students but it is relatively rare and an unnoticed disorder.

Challenges presented by MERS corona virus, and SARS corona virus to global health.

Numerous viral infections have arisen and affected global healthcare facilities. Millions of people are at severe risk of acquiring several evolving viral infections through several factors. In the present article we have described about risk factors, chance of infection, and prevention methods of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV), human coronaviruses (CoVs) frequently cause a normal cold which is mild and self-restricting. Zoonotic transmission of CoVs such as the newly discovered MERS-CoV and SARS-CoV, may be associated with severe lower respiratory tract infection. The present review provides the recent clinical and pathological information on MERS and SARS. The task is to transform these discoveries about MERS and SARS pathogenesis and to develop intervention methods that will eventually allow the effective control of these recently arising severe viral infections. Global health sector has learnt many lessons through the recent outbreak of MERS and SARS, but the need for identifying new antiviral treatment was not learned. In the present article we have reviewed the literature on the several facets like transmission, precautions and effectiveness of treatments used in patients with MERS-CoV and SARS infections.

Educational resources used by medical students in primary healthcare rotation: A cross sectional study.

OBJECTIVE: To identify what educational resources are used by medical students for their personal study during Primary health care (PHC) clinical rotation and the reasons for making these choices at King Saud University in Riyadh, Saudi Arabia. METHODS: A survey of 176 male and female medical students was conducted during PHC rotation. A self-administered questionnaire ascertained the type of educational source with reason and preferred type of teaching method. Responses by male and female students were compared by using Pearson's Chi-square tests. RESULTS: Of the 176 students, 85.8% used handouts, 77.3% used the internet, and 46.6% used textbooks. Of the three types of resources, 14.8% used one, 31.8% used all three sources, and 53.4% used two sources. Reasons for selecting a resource were; educational materials are up to the point (88.6%), convenient (85.2%), reliable (77.3%) fit the learning style (77.3%), exam focus (60.8%), recommended by seniors (57.4%), recommended by department (56.8%). The preferred teaching method was lecture (79.5%), and least preferred was student presentations (55.1%). Female medical students used internet related material greater than the males (86.9% versus 68.5%; p value <0.001), and tended to utilize more than one educational resource than male students. CONCLUSION: Medical students used multiple resources for relevance and convenience. Female students used network resources more than male students.

Comparison of Serum Fucose Levels in Leukoplakia and Oral Cancer Patients.

BACKGROUND: Tumor markers, designated as a broad group of substances produced by malignancies, could be in the form of biochemical substances, immunological substances, cell surface changes and genetic alterations. Cancer, a disorder of cellular behavior is characterized by alteration of serum glycoproteins. L-fucose, a hexose, which is the terminal sugar in most of the plasma glycoproteins, may be useful as a tumor marker for the detection, monitoring and prognostic assessment of malignancies. The aim of the study was to ascertain the role of serum fucose as a biomarker for early detection of oral cancer and to compare serum fucose levels in healthy controls, leukoplakia and oral cancer patients. MATERIALS AND METHODS: The study included 60 (100.0%) subjects, who were grouped as 20 (33.3%) control subjects, 20 (33.3%) squamous cell carcinoma patients and 20 (33.3%) leukoplakia patients. Fucose estimation was done using UV-visible spectrophotometry based on the method as adopted by Winzler using cysteine reagent. The results were analyzed statistically using ANOVA with Bonferroni post hoc tests. RESULTS: Results showed a high significance in serum fucose in oral squamous cell carcinoma (OSCC) and leukoplakia subjects compared to normal controls. There was a gradual increase in the values noted from control to leukoplakia and to squamous cell carcinoma. CONCLUSIONS: Estimation of serum fucose may be a reliable marker and can be used as an effective diagnostic biomarker in oral squamous cell carcinoma patients.

Evaluation of applied public health emergency system at Prince Mohammed International Airport in Almedinah during Hajj season 2014: a qualitative case study.

BACKGROUND: During the Hajj season 2014, several public health measures were applied by the Ministry of Health at Prince Mohammed International Airport in Almedinah. However, several operational defects affected the provision of preventive health services for passengers and airport workers. This study aims to evaluate the applied public health emergency system at the airport, detect any potential gaps and to provide appropriate operational solutions. METHODS: This is a qualitative case study conducted at Prince Mohammed International Airport in Almedinah during the 2014 Hajj season, September 2014. Data were collected via semi-structured interviews, focus groups and policy document reviews. Interviews were conducted with the 14 individuals of the airport's decision makers and relevant health practitioners. Data were recorded via taking notes during interviews and data coding was performed to produce the main themes and subthemes of the study. RESULTS: The main findings of the study revealed three main defects affecting the applied public health emergency system at the airport. The main themes were mainly related to shortage in logistics related to public health emergency systems, shortage in proper documentation of policies and lack of documented protocols of communications among airport stakeholders. CONCLUSIONS: The study highlighted the main factors hindering the application of public health emergency measures at the airport. A Public Health Emergency Contingency Plan was proposed as a method to regulate the process of providing logistics for public health preventive services, the method of producing documented policies and methods of producing Memoranda of Understandings as communication regulators.

Prevalence and causes of blindness and diabetic retinopathy in Southern Saudi Arabia.

OBJECTIVES: To determine the prevalence and causes of blindness and diabetic retinopathy (DR) in Jazan district, Southern Saudi Arabia. METHODS: Using the standardized Rapid Assessment for Avoidable Blindness (RAAB) and DR cross-sectional methodology, 3800 subjects were randomly selected from the population of ≥50 years of age in Jazan, Saudi Arabia between November 2011 and January 2012. Participants underwent screening comprised of interview, random blood glucose test, and ophthalmic assessment including visual acuity (VA) and fundus examination. Among participants with VA less than 6/18 in either eye, the cause(s) of visual impairment was determined. Participants were classified as diabetic if they had previous diagnoses of diabetes, or random blood glucose more than 200 mg/dl. Diabetic participants were assessed for DR using dilated fundus examination. All data were recorded using the RAAB + DR standardized forms. RESULTS: The prevalence of bilateral blindness less than 3/60 was 3.3% (95% confidence interval [CI]: 2.74 - 3.90). Cataract was the leading cause of blindness (58.6%); followed by posterior segment diseases (20%), which included DR (7; 3.3%). The prevalence of diabetes mellitus (DM) was 22.4%, (95% CI: 21.09 - 23.79]), among them; 27.8% had DR. The prevalence of sight-threatening DR was 5.7%. CONCLUSION: The prevalence of DM and the corresponding proportion of DR in this region is lower than that reported in other regions of Saudi Arabia. However, the prevalence of blindness not related to DR is relatively higher than the other studies.

Evaluation of knowledge and behavior of workers in Prince Mohammed International Airport in Western Saudi Arabia regarding public health emergency measures applied during Hajj season 2014.

OBJECTIVES: To evaluate the knowledge and behavior of workers at a Saudi airport regarding public health emergency measures applied during Hajj season. METHODS: This study is a cross-sectional study conducted at the Prince Mohammed International Airport in Al-Madinah Al-Munawwarah, Saudi Arabia between August and September 2014. Data were collected by semi-structured questionnaires during personal interviews. Non-random purposive sampling was conducted to target workers at higher risk of acquiring infection from travellers. RESULTS: One hundred and eighty-six participants were recruited of whom 92.5% were males. The study participants were workers in 8 different sectors. Twenty-six percent of the participants were health workers. Non-health workers were more likely to be concerned on acquiring infection while working at the airport compared with health workers (p=0.023). The most commonly feared disease was Ebola viral disease (EBV) among 30% of health workers, and 47% of non-health workers. Approximately 47% of non-health workers reported no knowledge of the procedures implemented during public health emergencies. The proportion of participants who received public health related training among non-health workers was significantly lower compared with health workers (p less than 0.00001). CONCLUSION: More emphasis should be given to educating airport workers on the potential health threats at the airport. Specific guidelines for public health emergencies at the airport should be established and communicated with airport sectors.

Evidence-Based Decision Making in Public Health: Capacity Building for Public Health Students at King Saud University in Riyadh.

Translation of research evidence into public health programs is lagging in Eastern Mediterranean Region. Graduate level public health curriculum at King Saud University (KSU), College of Medicine, Riyadh, is designed to equip students to integrate best available evidence in public health decision making. The objectives of study were to explore students' opinion about the evidence based public health (EBPH) courses and to survey the knowledge, opinion, and attitude of the students towards EBPH and perceived barriers for implementation of EBPH in decision making in public health. EBPH courses are designed based on a sequential framework. A survey was conducted at the completion of EBPH courses. Forty-five graduate students were invited to complete a validated self-administered questionnaire. It included questions about demography, opinion, and attitude towards EBPH and perceived barriers towards implementation of EBPH in the work environment. The response rate was 73%. Mean age of students was 30.1 (SD 2.3) years, and 51% were males. More than 80% had sound knowledge and could appreciate the importance of EBPH. The main perceived barriers to incorporate EBPH in decision making were lack of system of communication between researchers and policy makers and scarcity of research publications related to the public health problems.

trans-2-Tritylcyclohexanol as a chiral auxiliary in permanganate-mediated oxidative cyclization of 2-methylenehept-5-enoates: application to the synthesis of trans-(+)-linalool oxide.

The permanganate-mediated oxidative cyclization of a series of 2-methylenehept-5-eneoates bearing different chiral auxiliaries was investigated, leading to the discovery of trans-2-tritylcyclohexanol (TTC) as a highly effective chiral controller for the formation of the 2,5-substituted THF diol product with high diastereoselectivity (dr ∼97:3). Chiral resolution of (±)-TTC, prepared in one step from cyclohexene oxide, afforded (-)-(1S,2R)-TTC (er >99:1), which was applied to the synthesis of (+)-trans-(2S,5S)-linalool oxide.

Sickle cell disease in Middle East Arab countries.

The sickle cell (HbS) gene occurs at a variable frequency in the Middle Eastern Arab countries, with characteristic distribution patterns and representing an overall picture of blood genetic disorders in the region. The origin of the gene has been debated, but studies using ß-globin gene haplotypes have ascertained that there were multiple origins for HbS. In some regions the HbS gene is common and exhibits polymorphism, while the reverse is true in others. A common causative factor for the high prevalence and maintenance of HbS and thalassaemia genes is malaria endemicity. The HbS gene also co-exists with other haemoglobin variants and thalassaemia genes and the resulting clinical state is referred to as sickle cell disease (SCD). In the Middle Eastern Arab countries, the clinical picture of SCD expresses two distinct forms, the benign and the severe forms, which are related to two distinct ß-globin gene haplotypes. These are referred to as the Saudi-Indian and the Benin haplotypes, respectively. In a majority of the Middle Eastern Arab countries the HbS is linked to the Saudi-Indian haplotype, while in others it is linked to the Benin haplotype. This review outlines the frequency, distribution, clinical feature, management and prevention as well as gene interactions of the HbS genes with other haemoglobin disorders in the Middle Eastern Arab countries.

Synthesis, characterization and reactivity ratio study of poly(di(tri-n-butyltin) citraconate-co-N-vinylimidazole).

The organotin monomer di(tri-n-butyltin) citraconate (DTBTC, I) was synthesized. Subsequently this monomer was copolymerized with N-vinylimidazole (VI) using a free radical technique. The overall conversion was kept low (< or = 14% wt/wt) for all studied samples and the copolymer composition was determined from tin analysis using the Gilman and Rosenberg method. The synthesized monomer and copolymer were further characterized by elemental analysis, (1)H- and (13)C-NMR, and FTIR spectroscopy.

Reactivity ratios for organotin copolymer systems.

Di(tri-n-butyltin) itaconate (DTBTI) and monoethyl tributyltin fumarate (METBTF) were synthesized as organotin monomers. The organotin monomers were copolymerized with styrene (ST) and methyl methacrylate (MMA) via a free radical polymerization technique. The overall conversion was kept low (