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A mechanistic understanding of the principles governing the hierarchical organization of supramolecular polymers offers a paradigm for tailoring synthetic molecular architectures at the nano to micrometric scales. Herein, the unconventional crystal growth mechanism of a supramolecular polymer of superbenzene(coronene)-diphenylalanine conjugate (Cr-FFOEt ) is demonstrated. 3D electron diffraction (3D ED), a technique underexplored in supramolecular chemistry, is effectively utilized to gain a molecular-level understanding of the gradual growth of the initially formed poorly crystalline hairy, fibril-like supramolecular polymers into the ribbon-like crystallites. The further evolution of these nanosized flat ribbons into microcrystals by oriented attachment and lateral fusion is probed by time-resolved microscopy and electron diffraction. The gradual morphological and structural changes reveal the nonclassical crystal growth pathway, where the balance of strong and weak intermolecular interactions led to a structure beyond the nanoscale. The role of distinct π-stacking and H-bonding interactions that drive the nonclassical crystallization process of Cr-FFOEt supramolecular polymers is analyzed in comparison to analogous molecules, Py-FFOEt and Cr-FF forming helical and twisted fibers, respectively. Furthermore, the Cr-FFOEt crystals formed through nonclassical crystallization are found to improve the functional properties.
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A comprehensive molecular understanding of carbohydrate aggregation is key to optimize carbohydrate utilization and to engineer bioinspired analogues with tailored shape1s and properties. However, the lack of well-defined synthetic standards has substantially hampered advances in this field. Herein, we employ a phosphorylation-assisted strategy to synthesize previously inaccessible long oligomers of cellulose, chitin, and xylan. These oligomers were subjected to enzyme-triggered assembly (ETA) for the on-demand formation of well-defined carbohydrate nanomaterials, including elongated platelets, helical bundles, and hexagonal particles. Cryo-electron microscopy and electron diffraction analysis provided molecular insights into the aggregation behavior of these oligosaccharides, establishing a direct connection between the resulting morphologies and the oligosaccharide primary sequence. Our findings demonstrate that ETA is a powerful approach to elucidate the intrinsic aggregation behavior of carbohydrates in nature. Moreover, the ability to access a diverse array of morphologies, expanded with a non-natural sequence, underscores the potential of ETA, coupled with sequence design, as a robust tool for accessing programmable glycan architectures.
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Peptides and nucleic acids with programmable sequences are widely explored for the production of tunable, self-assembling functional materials. Herein we demonstrate that the primary sequence of oligosaccharides can be designed to access materials with tunable shapes and properties. Synthetic cellulose-based oligomers were assembled into 2D or 3D rod-like crystallites. Sequence modifications within the oligosaccharide core influenced the molecular packing and led to the formation of square-like assemblies based on the rare cellulose IVII allomorph. In contrast, modifications at the termini generated elongated aggregates with tunable surfaces, resulting in self-healing supramolecular hydrogels.
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Celulose , Oligossacarídeos , Celulose/química , Oligossacarídeos/química , Peptídeos/química , Hidrogéis/químicaRESUMO
MAIN CONCLUSION: A WRKY transcription factor identified through forward genetics is associated with sorghum resistance to the sugarcane aphid and through heterologous expression reduces aphid populations in multiple plant species. Crop plant resistance to insect pests is based on genetically encoded traits which often display variability across diverse germplasm. In a comparatively recent event, a predominant sugarcane aphid (SCA: Melanaphis sacchari) biotype has become a significant agronomic pest of grain sorghum (Sorghum bicolor). To uncover candidate genes underlying SCA resistance, we used a forward genetics approach combining the genetic diversity present in the Sorghum Association Panel (SAP) and the Bioenergy Association Panel (BAP) for a genome-wide association study, employing an established SCA damage rating. One major association was found on Chromosome 9 within the WRKY transcription factor 86 (SbWRKY86). Transcripts encoding SbWRKY86 were previously identified as upregulated in SCA-resistant germplasm and the syntenic ortholog in maize accumulates following Rhopalosiphum maidis infestation. Analyses of SbWRKY86 transcripts displayed patterns of increased SCA-elicited accumulation in additional SCA-resistant sorghum lines. Heterologous expression of SbWRKY86 in both tobacco (Nicotiana benthamiana) and Arabidopsis resulted in reduced population growth of green peach aphid (Myzus persicae). Comparative RNA-Seq analyses of Arabidopsis lines expressing 35S:SbWRKY86-YFP identified changes in expression for a small network of genes associated with carbon-nitrogen metabolism and callose deposition, both contributing factors to defense against aphids. As a test of altered plant responses, 35S:SbWRKY86-YFP Arabidopsis lines were activated using the flagellin epitope elicitor, flg22, and displayed significant increases in callose deposition. Our findings indicate that both heterologous and increased native expression of the transcription factor SbWRKY86 contributes to reduced aphid levels in diverse plant models.
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Afídeos , Sorghum , Animais , Estudo de Associação Genômica Ampla , Sorghum/genética , Fatores de Transcrição/genéticaRESUMO
In the nanomedicine field, there is a need to widen the availability of nanovectors to compensate for the increasingly reported side effects of poly(ethene glycol). Nanovectors enabling cross-linking can further optimize drug delivery. Cross-linkable polyoxazolines are therefore relevant candidates to address these two points. Here we present the synthesis of coumarin-functionalized poly(2-alkyl-2-oxazoline) block copolymers, namely, poly(2-methyl-2-oxazoline)-block-poly(2-phenyl-2-oxazoline) and poly(2-methyl-2-oxazoline)-block-poly(2-butyl-2-oxazoline). The hydrophilic ratio and molecular weights were varied in order to obtain a range of possible behaviors. Their self-assembly after nanoprecipitation or film rehydration was examined. The resulting nano-objects were fully characterized by transmission electron microscopy (TEM), cryo-TEM, multiple-angle dynamic and static light scattering. In most cases, the formation of polymer micelles was observed, as well as, in some cases, aggregates, which made characterization more difficult. Cross-linking was performed under UV illumination in the presence of a coumarin-bearing cross-linker based on polymethacrylate derivatives. Addition of the photo-cross-linker and cross-linking resulted in better-defined objects with improved stability in most cases.
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Poliaminas , Polímeros , Sistemas de Liberação de Medicamentos , MicelasRESUMO
BACKGROUNDS: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have improved survival for selected cases of peritoneal surface malignancy. In 2008, a CRS/HIPEC service was first established in Aotearoa New Zealand (AoNZ) at Waikato and Braemar Hospitals in the Waikato region. METHODS: This is a retrospective review of a prospectively maintained database of all patients undergoing CRS/HIPEC from 1 January 2008 to 1 November 2020 at Waikato and Braemar Hospitals. We analysed long-term survival and predictors of survival for each tumour type. RESULTS: 240 procedures were performed for 221 patients, including 22 re-do procedures. Cases had a median peritoneal cancer index of 16. Complete cytoreduction (CC0-1) was achieved in 196 cases (81.7%). All complete cytoreduction cases received HIPEC. There were 152 pseudomyxoma peritonei (PMP), 39 colorectal cancers (CRC), 29 appendiceal cancers, eight ovarian cancers, six peritoneal mesotheliomas, and six other cancers. The 5-year overall survival (OS) for PMP with acellular mucin, low-grade mucinous carcinoma peritonei, and high-grade mucinous carcinoma peritonei with or without signet cells were 91.6%, 80.5%, and 72.2%, respectively. 2- and 5-year OS in CRC were 56.7% and 40.4%. The achievement of complete cytoreduction improved the 5-year OS to 87.9% across all PMP and 45.1% in colorectal cancer. Incomplete cytoreduction predicted worse survival in appendiceal PMP. In colorectal cancer, worse survival was predicted in those who had incomplete cytoreduction, liver metastasis, and presentation with obstruction and perforation. CONCLUSION: Favourable long-term outcomes following CRS/HIPEC for peritoneal surface malignancy have been achieved in AoNZ through the Waikato peritonectomy service.
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Adenocarcinoma Mucinoso , Neoplasias do Apêndice , Neoplasias Colorretais , Hipertermia Induzida , Neoplasias Peritoneais , Pseudomixoma Peritoneal , Feminino , Humanos , Neoplasias Peritoneais/secundário , Quimioterapia Intraperitoneal Hipertérmica , Procedimentos Cirúrgicos de Citorredução/métodos , Nova Zelândia/epidemiologia , Hipertermia Induzida/métodos , Pseudomixoma Peritoneal/cirurgia , Neoplasias do Apêndice/patologia , Adenocarcinoma Mucinoso/patologia , Neoplasias Colorretais/patologia , Estudos Retrospectivos , Taxa de Sobrevida , Terapia CombinadaRESUMO
BACKGROUND: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is the standard of care for selected cases of peritoneal surface malignancy. However, due to its morbidity and learning curve, it is only delivered in six centres in Australia and Aotearoa New Zealand (AoNZ). In this study, we report peri-operative morbidity and mortality following CRS/HIPEC at Waikato and Braemar Hospitals, which have treated patients from all regions of AoNZ since 2008. METHODS: We retrospectively reviewed a database of all patients undergoing CRS and HIPEC from 01/01/2008 to 01/11/2020 at Waikato and Braemar Hospitals. RESULTS: Two-hundred and forty procedures were performed for 221 patients with a mean age of 55, including 22 (9.2%) re-do procedures. One hundred and eighty-six cases were European, 32 were Maori, and 16 were Pasifika. There were 152 pseudomyxoma peritonei, 39 colorectal adenocarcinomas, 29 appendiceal cancers, 8 ovarian cancers, 6 peritoneal mesothelioma, and 6 other tumour types. The median PCI was 16. HIPEC was administered to 196 out of 196 CC0/1 cases (100%) and 3 out of 44 CC2/3 cases (6.8%). Fifty-six cases (23.3%) had at least one major complication. There were two mortalities (0.8%) within 30 days. The median length of stay was 11 days. Operative duration was identified as an independent risk factor for major complications. There was considerable variation in the number of referrals from different regions of AoNZ. Over time, a decline in major complication rate is seen with increased case volume. CONCLUSION: The Waikato region has achieved favourable short-term outcomes following CRS/HIPEC.
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Procedimentos Cirúrgicos de Citorredução , Quimioterapia Intraperitoneal Hipertérmica , Neoplasias Peritoneais , Feminino , Humanos , Pessoa de Meia-Idade , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Combinada , Procedimentos Cirúrgicos de Citorredução/métodos , Nova Zelândia/epidemiologia , Neoplasias Peritoneais/patologia , Estudos Retrospectivos , Taxa de SobrevidaRESUMO
INTRODUCTION: Perception is an essential factor influencing smoking among adolescents. Thus, a valid tool for measuring perception is a requisite in smoking studies. This study further establishes the validity and reliability of a Malay language version of the Perception Towards Smoking Questionnaire (BM-PTSQ) for assessing the perception of smoking among secondary school-going adolescents in Malaysia. METHODS: We administered the BM-PTSQ to 669 secondary school students selected through multistage sampling; 60% of respondents were male (n=398), and 69.9% (n=463) were from rural areas. Respondents were aged 13-16 years, 36.4% (n=241) were 13 years, 40.0% (n=265) were 14 years, and 23.6% (n=156) were 16 years old. We used parallel and exploratory factor analysis (EFA) to determine the domains of the questionnaire. In addition, we also employed EFA, confirmatory factor analyses (CFA), and Cronbach's alpha to evaluate the construct validity and reliability of the BM-PTSQ. RESULTS: EFA and parallel analysis identified two domains in the BM-PTSQ that accounted for 62.9% of the observed variance, and CFA confirmed the two-domain structure. The two domains' internal consistency scores ranged from 0.702 to 0.80, which suggested adequate reliability. CONCLUSIONS: The BM-PTSQ has acceptable psychometric validity and is appropriate for assessing smoking perception and intention among Malaysian secondary school-aged youth. Researchers should further evaluate this tool's applicability in a more sociodemographically diverse population.
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Understanding the defect structure is fundamental to correlating the structure and properties of materials. However, little is known about the defects of soft matter at the nanoscale beyond their external morphology. We report here on the molecular-level structural details of kink defects of cellulose nanocrystals (CNCs) based on a combination of experimental and theoretical methods. Low-dose scanning nanobeam electron diffraction analysis allowed for correlation of the local crystallographic information and nanoscale morphology and revealed that the structural anisotropy governed the kink formation of CNCs. We identified two bending modes along different crystallographic directions with distinct disordered structures at kink points. The drying strongly affected the external morphology of the kinks, resulting in underestimating the kink population in the standard dry observation conditions. These detailed defect analyses improve our understanding of the structural heterogeneity of nanocelluloses and contribute to the future exploitation of soft matter defects.
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INTRODUCTION: The Fagerström test for nicotine dependence (FTND) was forward-backwards translated into the Malay language (FTND-M) and administered to 152 daily smokers who sought treatment for smoking cessation in government health clinics in Selangor state, Malaysia. METHODS: Using confirmatory factor analysis (CFA), four measurement models with the best relative fit were compared, one uni-dimensional model, and three different two-domain (morning and daytime smoking) models. RESULTS: The findings indicate that the best model of the FTND-M was a two-domain model, wherein domain one represented morning smoking (time to first cigarette of the day, smoking more in the morning, and which cigarette would you hate to give up) and domain two represented daytime smoking (cigarettes per day, difficulty refraining from smoking, and smoking when ill) which showed good model fit [χ2/df=1.932, goodness of fit (GFI) of 0.967, comparative fix index (CFI) of 0.945, incremental fit index (IFI) of 0.98, Tucker-Lewis index (TLI) of 0.95 and a real mean square end of approximation (RMSEA) of 0.079, and substantial reliability >0.70]. CONCLUSIONS: This study indicates that the FTND-M can be used to assess these two dimensions of nicotine addiction among daily smokers in a clinical setting.
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INTRODUCTION: Measuring the level of nicotine addiction among smokers is an integral part of enhancing smoking cessation as nicotine dependence is one of the barriers to smoking cessation. In this study, we compared the level of agreement between FTND and HSI in detecting high nicotine dependence among daily smokers. METHODS: We collected data from participants of a public smoking cessation clinic in Selangor. A trained pharmacist conducted face-to-face interviews with 152 daily smokers using a structured validated questionnaire. Respondents were classified as having high nicotine dependence using both the HSI (score ≥4) and the FTND (score ≥6), and concordance between the two measures, kappa statistics and sensitivity, specificity of the HSI were then determined with the FTND classification as the reference standard. RESULTS: The HSI had a substantial agreement with the FTND (Cohen's kappa=0.72) in measuring high levels of nicotine addiction, with good sensitivity (83.3%) and specificity (89.4%). CONCLUSIONS: The findings suggest that the HSI can be used instead of the FTND in clinical-based investigations to screen for high nicotine dependence among daily smokers in the clinical setting.
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INTRODUCTION: The Decisional Balance Inventory is a tool used to measure propensity to maintain or change a habit which takes into consideration the perceived advantages and disadvantages. This study aimed to establish the validity and reliability of a Malay language version of the DBI for assessing inclination for change in smoking behavior among secondary school-going adolescents in Malaysia. METHODS: We administered the MDBI to 669 secondary school students selected through multistage sampling. The sample consisted of 60.1% male (n=398) and 39.9% (n=264) female students, more than two-thirds (69.9%, n=463) of which were from rural areas. The majority of the respondents were aged 13-14 years [13 years, 36.4% (n=241), 14 years, 40.0% (n=265), 16 years, 23.6% (n=156)]. The construct validity of the MDBI was assessed using explanatory (EFA) and confirmatory factor analysis (CFA), and the reliability of the MDBI via Cronbach's alpha. RESULTS: EFA and parallel analysis extracted three factors in the MDBI that accounted for 65.4% of the observed variance, and this was supported by CFA. Internal consistency of the three factors ranged from 0.734 to 0.867, indicating acceptable reliability. CONCLUSIONS: The MDBI has good psychometric properties and is suitable for measuring smoking intention among Malaysian secondary school-going adolescents. However, it should continue to be tested to expand its usefulness and applicability among adolescents in other sociodemographic settings.
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Choanoflagellates are primitive protozoa used as models for animal evolution. They express a large variety of multi-domain proteins contributing to adhesion and cell communication, thereby providing a rich repertoire of molecules for biotechnology. Adhesion often involves proteins adopting a ß-trefoil fold with carbohydrate-binding properties therefore classified as lectins. Sequence database screening with a dedicated method resulted in TrefLec, a database of 44714 ß-trefoil candidate lectins across 4497 species. TrefLec was searched for original domain combinations, which led to single out SaroL-1 in the choanoflagellate Salpingoeca rosetta, that contains both ß-trefoil and aerolysin-like pore-forming domains. Recombinant SaroL-1 is shown to bind galactose and derivatives, with a stronger affinity for cancer-related α-galactosylated epitopes such as the glycosphingolipid Gb3, when embedded in giant unilamellar vesicles or cell membranes. Crystal structures of complexes with Gb3 trisaccharide and GalNAc provided the basis for building a model of the oligomeric pore. Finally, recognition of the αGal epitope on glycolipids required for hemolysis of rabbit erythrocytes suggests that toxicity on cancer cells is achieved through carbohydrate-dependent pore-formation.
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Coanoflagelados , Neoplasias , Animais , Carboidratos/química , Coanoflagelados/metabolismo , Glicoesfingolipídeos , Lectinas/química , Neoplasias/tratamento farmacológico , CoelhosRESUMO
INTRODUCTION: Dual/poly tobacco use is common among youths globally. However, in Malaysia information on dual/poly tobacco use is scarce, thus the present study examines the prevalence and factors associated with dual/poly tobacco users among school-going adolescents in Malaysia. METHODS: We derived data on tobacco and e-cigarette use among Malaysian adolescents from a nationwide school-based study conducted in 2016. A total of 13135 adolescents responded in the cross-sectional survey which used multi-stage sampling to select a representative sample of school-going adolescents aged 11-19 years. A standard validated questionnaire was used to obtain the data and multiple logistic regression was conducted to assess factors associated with dual/ poly tobacco use. RESULTS: The prevalence of dual/poly tobacco use was 6.5%, more than half of which were both conventional and e-cigarette users. Multivariable logistic regression revealed that the likelihood of dual tobacco use was significantly higher among males (AOR=14.73; 95% CI: 9.11-23.81), secondary school students, those aged 16-19 years (AOR=5.99; 95% CI: 4.04-8.87), natives of Sabah (AOR=7.41; 95% CI: 3.48-15.79), and those never been taught on the health hazards of tobacco at school, exposed to secondhand smoke (SHS) at home, school or other public areas, and had a positive perception of e-cigarettes and lower perception of the harms of tobacco smoking. CONCLUSIONS: Although the prevalence of dual/poly users was still low among Malaysian school-going adolescents, proactive measures should be taken to reduce dual tobacco use among youth in Malaysia with focus on the factors identified in this study.
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INTRODUCTION: Smoking is a known risk factor for many chronic diseases. Illness and death due to smoking are a significant public health burden in many countries. This study aims to address the information gap in smoking-related mortality in Malaysia by estimating the risk of cardiovascular disease and all-cause mortalities due to smoking among Malaysian adults. METHODS: We analyzed data on 2525 respondents, aged 24-64 years, of the Malaysian Non-Communicable Disease Surveillance survey conducted September 2005 to February 2006. Mortality records from the Malaysian National Registration Department were linked to the MYNCDS-1 data to determine respondents' mortality status over 12 years from 2006 to 2018. Associations between smoking and all-cause mortalities were assessed using Cox proportional hazards regression with adjustments for non-communicable disease and sociodemographic and lifestyle factors. RESULTS: The prevalence of daily smoking was 21.2% (95% CI: 19.0-23.7). During the 31668 person-years follow-up, 213 deaths from all causes occurred, where 68 deaths were among smokers (13.2%), and 452 were among non-smokers (6.3%). Smoking was associated with a significantly increased risk of all-cause mortality (adjusted hazard ration, AHR=1.79; 95% CI: 1.12- 2.97). These associations remained significant after excluding mortalities in the first two years of follow-up. CONCLUSIONS: Daily smoking is associated with a significantly higher risk of all-cause death. Behavioral and pharmacological smoking cessation interventions should be intensified among smokers to reduce the risk of mortality.
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INTRODUCTION: Secondhand (SHS) smoke exposure has caused various health problems. Therefore, continuous monitoring of SHS exposure is important to determine the efficacy of various anti-tobacco measure implemented. The study aims to compare the prevalence and factor(s) associated with SHS exposure among secondary school-going adolescents in Malaysia during 2012 and 2017. METHODS: We derived data from the Global School Health Survey (GSHS) 2012 and GSHS 2017, which was carried out in Malaysia using multistage sampling to select representative samples of secondary school-going adolescents. Both surveys used similar questionnaires to measure SHS exposure. Descriptive and multivariate logistic regression was used to determine the prevalence and factors associated with SHS exposure. RESULTS: Approximately four in ten respondents were exposed to SHS in the past week in both surveys (41.5% in GSHS 2012 and 42.0% in GSHS 2017, respectively). Both surveys revealed a significantly higher SHS exposure among respondents who smoked than among non-smokers and higher among males compared to females. The likelihood of SHS exposure in both surveys was also similar, with a higher likelihood of SHS exposure among smoking adolescents and non-smoking adolescents who had at least one smoking parent/guardian, regardless of their own smoking status. Male adolescents had a higher risk of SHS exposure compared to their female counterparts. Meanwhile, SHS risk also increased with age, regardless of smoking status. CONCLUSIONS: Our findings suggested that there were no changes in the prevalence of SHS exposure and recorded only a slight change in the factors associated with exposure to SHS among school-going adolescents in Malaysia between the years 2012 and 2017. A more pro-active, extensive and comprehensive programme should be implemented to address the problem of SHS exposure. Parents should be advised to stop smoking or abstain from smoking in the presence of their children, and smoking cessation interventions are necessary for smoking adolescents and their parents.
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INTRODUCTION: Studies have shown that the implementation of smoke-free policies at workplaces have shifted the social norms towards secondhand smoke (SHS) exposure at home. This study aimed to investigate whether working in a smoke-free workplace is associated with living in a smoke-free home (SFH). METHODS: The data were derived from the Malaysian Global Adult Tobacco Survey (GATS-M), collected in 2011-2012, involving 4250 respondents. Data analyses involved 1343 respondents reported to be in the working population. RESULTS: More than half of the respondents (58.5%) were reportedly working in smoke-free workplaces. Almost a quarter (24.8%) of those who worked in smoke-free workplaces stayed in smoke-free homes, which was more than two times higher than their counterparts who worked at non-smoke-free workplaces (24.8% vs 12.0%, p<0.001). Multivariable analyses further substantiated this finding (AOR=2.01, 95% CI: 1.11-3.61, reference group = worked at non-smoke-free workplaces). CONCLUSIONS: This study found an association between living in smoke-free homes and working at smoke-free workplaces, which could suggest a positive impact of implementing smoke-free workplaces.
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OBJECTIVE: The identification of susceptible non-smoking adolescents is an essential step in reducing smoking initiation among adolescents. The aim of this study was to examine the prevalence and factors associated with smoking susceptibility among non-smoking school-going adolescents in Malaysia. DESIGN: Cross-sectional study. SETTING: Primary and secondary schools in Malaysia. PARTICIPANTS: 11 246 non-smoking school-going adolescents. OUTCOME MEASURES: The prevalence and factors associated with smoking susceptibility among non-smoking school-going adolescents in Malaysia. RESULTS: Approximately 14% of non-smokers were susceptible to smoking, and the prevalence of susceptibility was significantly higher among males, ever-smokers and e-cigarette users. The odds of susceptibility to smoking were higher among males, e-cigarette users, those aged 12 years and under and those who had ever smoked or tried cigarettes. Students from schools with educational programmes on the health effects of second-hand smoke (SHS) and who perceived smoking to be harmful were less likely to be susceptible to smoking. CONCLUSION: Smoking susceptibility is prevalent among school-going adolescents. A comprehensive approach that enhances or reinforces health education programmes on the adverse health effects of smoking and SHS among school children, that considers multiple factors and that involves all stakeholders is urgently needed to reduce the prevalence of smoking susceptibility among vulnerable subgroups, as identified from the present findings.
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Atitude Frente a Saúde , Fumar Cigarros/prevenção & controle , não Fumantes/estatística & dados numéricos , Serviços de Saúde Escolar/estatística & dados numéricos , Prevenção do Hábito de Fumar , Vaping/epidemiologia , Adolescente , Criança , Fumar Cigarros/epidemiologia , Etnicidade , Feminino , Humanos , Malásia/epidemiologia , Masculino , Fatores de Risco , Fatores Sexuais , Poluição por Fumaça de Tabaco , Adulto JovemRESUMO
The photochemical oxidation of a (TAML)FeIII complex 1 using visible light generated Ru(bpy)33+ produces valence tautomers (TAML)FeIV (1+ ) and (TAMLË+)FeIII (1-TAMLË+ ), depending on the exogenous anions. The presence of labile Cl- or Br- results in a ligand-based oxidation and stabilisation of a radical-cationic (TAMLË+)FeIII complex, which subsequently leads to unprecedented C-H activation followed by nucleophilic substitution on the TAML aryl ring. In contrast, exogenous cyanide culminates in metal-based oxidation, yielding the first example of a crystallographically characterised S = 1 [(TAML)FeIV(CN)2]2- species. This is a rare report of an anion-dependent valence tautomerisation in photochemically accessed high valent (TAML)Fe systems with potential applications in the oxidation of pollutants, hydrocarbons, and water. Furthermore, the nucleophilic aromatic halogenation reaction mediated by (TAMLË+)FeIII represents a novel domain for high-valent metal reactivity and highlights the possible intramolecular ligand or substrate modification pathways under highly oxidising conditions. Our findings therefore shine light on high-valent metal oxidants based on TAMLs and other potential non-innocent ligands and open new avenues for oxidation catalyst design.
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@#Identification of the stages of smoking cessation among smokers is essential to improve the rate of smoking cessation. The aims of this study were to determine the prevalence and factors associated with stages of smoking cessation across the demographic distribution of adult smokers in Malaysia. Data were derived from a population-based study among Malaysian adults aged 18 years and above. Face-to-face interviews were carried out by trained staff using a validated questionnaire to obtain data related to smoking from 4,288 selected respondents. Of 4,288, 438 respondents are current smokers. Multivariable logistic regression analysis was used to determine factors associated with stage of smoking cessation. Approximately 60% (n=269/438) of the current smokers were in the pre-contemplation stage and 40% (n=169/438) were in the contemplation and preparation stages of smoking cessation. The proportion of pre-contemplators was higher among smokers with higher levels of nicotine addiction (71.3%), lower education attainment (71.4%), and those who were single/widowed/divorced (66.9%). Multivariable analysis showed that males, and those who reported low to high level of nicotine addiction were more likely to be in the pre-contemplation stage whilst those in the older age groups were more likely to be in the advanced stage of smoking cessation. The study revealed that the majority of current smokers in Malaysia had no intention to quit smoking within 6 months. Specific interventions targeting males, young adults and smokers with low to high nicotine addiction should be introduced to ensure the smokers proceed to the advanced stage of smoking cessation.