From Unregulated Networks to Designed Microstructures: Introducing Heterogeneity at Different Length Scales in Photopolymers for Additive Manufacturing.

Photopolymers have been optimized as protective and decorative coating materials for decades. However, with the rise of additive manufacturing technologies, vat photopolymerization has unlocked the use of photopolymers for three-dimensional objects with new material requirements. Thus, the originally highly cross-linked, amorphous architecture of photopolymers cannot match the expectations for modern materials anymore, revealing the largely unanswered question of how diverse properties can be achieved in photopolymers. Herein, we review how microstructural features in soft matter materials should be designed and implemented to obtain high performance materials. We then translate these findings into chemical design suggestions for enhanced printable photopolymers. Based on this analysis, we have found microstructural heterogenization to be the most powerful tool to tune photopolymer performance. By combining the chemical toolbox for photopolymerization and the analytical toolbox for microstructural characterization, we examine current strategies for physical heterogenization (fillers, inkjet printing) and chemical heterogenization (semicrystalline polymers, block copolymers, interpenetrating networks, photopolymerization induced phase separation) of photopolymers and put them into a material scientific context to develop a roadmap for improving and diversifying photopolymers' performance.

Mechanical upcycling of single-use face mask waste into high-performance composites: An ecofriendly approach with cost-benefit analysis.

The COVID-19 pandemic created an unprecedented demand for PPE, with single-use face masks emerging as a critical tool in containing virus transmission. However, the extensive use and improper disposal of these single-use face masks, predominantly composed of non-biodegradable plastics, has exacerbated environmental challenges. This research presents an innovative method for mechanically upcycling PPEs used in medical sectors i.e. single use face masks. The study investigates a facile approach for reclamation of infection-free and pure polypropylene (PP) plastic from discarded single use face masks (W-PP) and blends it with various vegetable oil percentages (5, 10 and 20 %), resulting in a versatile material suitable for various applications. Melt flow index, rheological behaviour, DSC and FTIR were employed to investigate the effect of vegetable oil/radical initiator through chemical grafting on W-PP properties. The results demonstrate significant enhancements in the tensile strength and modulus of W-PP when blended with vegetable oil and a radical initiator. There was a marked increase in tensile strength (33 %) and strain (55 %) compared to untreated W-PP, rendering W-PP both robust and flexible. Furthermore, we employed this upcycled W-PP in the fabrication of glass fibre-reinforced composites, resulting in notable enhancements in both tensile strength and impact resistance. The upcycled W-PP demonstrates excellent potential for various applications, such as sheet forming and 3D printing, where the non-brittleness of plastics plays a pivotal role in manufacturing high-quality products. The cost-benefit analysis of this approach underscores the potential of upcycling PPE waste as a sustainable solution to mitigate plastic pollution and conserve valuable resources. The applications of this upcycled material span a wide range of industries, including automotive composites, packaging, and 3D printing.

Advancing structural batteries: cost-efficient high-performance carbon fiber-coated LiFePO4 cathodes.

Structural batteries (SBs) have gained attention due to their ability to provide energy storage and structural support in vehicles and airplanes, using carbon fibers (CFs) as their main component. However, the development of high-performance carbon fiber-based cathode materials for structural batteries is currently limited. To address this issue, this study proposes a cost-efficient and straightforward method for creating a high-performance structural lithium iron phosphate (LiFePO4) positive electrode by coating carbon fibers at mild temperatures and pressures. The resulting cathode demonstrated a high LiFePO4 loading (at least 74%) and a smooth coating, as confirmed by X-ray spectroscopy, scanning electron microscopy, and Raman spectroscopy. This structural cathode exhibited a capacity of 144 mA h g-1 and 108 mA h g-1 at 0.1 C and 1.0 C, respectively. Additionally, the LiFePO4 cathode displayed excellent electrochemical properties, with a capacity retention of 96.4% at 0.33 C and 81.2% at 1.0 C after 300 cycles. Overall, this study presents a promising approach for fabricating high-performance structural batteries with enhanced energy storage and structural capabilities.

RT-qPCR Analysis of LAMP3 (CD208) Gene Expression in Oral Lichen Planus and Oral Squamous Cell Carcinoma.

Background: Many new studies have been conducted on cellular proteins to use them as prognostic markers or in target therapy through determining the increase or decrease in their expression in the lichen planus and OSCC. LAMP3 protein is one of these proteins which has been recently considered. Thus, considering the unknown etiology of lichen planus, significance of their early diagnosis and treatment and lack of a suitable and final treatment for this disease and oral cancers, and preventing the progression of lichen planus, which can turn into OSCC, we decided to investigate the level of expression of this gene and its effect on the progression, study the connection between these two conditions and the probable factors contributing to their etiopathogenesis. Methods: In this study, ninety-four paraffin blocks tissue samples of patients were obtained together with their demographic documents. LAMP3 expression was measured RT-qPCR method. Results: The results show that there is not any significant difference between age and sex population of our study. in squamous cell carcinoma the amount of expression of LAMP3 was higher than lichen planus and healthy margin. Average LAMP3 Gene expression in grade III was higher than group grade I & II in which considering significant level of 5%, it is statistically significant. Conclusions: According to the findings of this study, it can be concluded that the expression of the LAMP3 gene in SCC lesions is higher than in healthy tissue. Hence, LAMP3 gene expression can be used as a diagnostic biomarker.

Comprehensibility of pharmaceutical pictograms: Effect of prospective-user factors and cognitive sign design features.

BACKGROUND: The people's comprehensibility regarding the meaning of internationally recommended pictograms is an important factor in the correct usage of medications. OBJECTIVE: To investigate the relationship between the guessability of the pharmaceutical pictograms, the cognitive sign features, and prospective-user factors. METHODS: A total of 351 Iranian people participated in this study. Two questionnaires were used to measure guessability and cognitive design features regarding the pharmaceutical pictograms. A single-sheet questionnaire was also developed to collect demographic data. RESULTS: According to the 67% correctness criterion suggested by ISO 3864:P3, 18 pictograms were understandable by the participants. Moreover, of the five cognitive features, "semantic closeness" and "meaningfulness" had the most correlation with the guessability score. In terms of personal factors, understanding of the pictograms' meaning was negatively correlated with age, while it had no association with the occupation. CONCLUSIONS: Some pharmaceutical pictograms developed by reliable international organizations can be used in a community only after redesigning and testing among the prospective users. The findings indicated that some pharmaceutical pictograms were not comprehensible for most participants. It is therefore expected that using a combination of pictograms with written messages and training could help in conveying the messages by pharmaceutical pictograms.

Circumferential wrinkling of polymer nanofibers.

Surface wrinkles are commonly observed in soft polymer nanofibers produced in electrospinning. This paper studies the conditions of circumferential wrinkling in polymer nanofibers under axial stretching. A nonlinear continuum mechanics model is formulated to take into account the combined effects of surface energy and nonlinear elasticity of the nanofibers on wrinkling initiation, in which the soft nanofibers are treated as incompressible, isotropically hyperelastic neo-Hookean solid. The critical condition to trigger circumferential wrinkling is determined and its dependencies upon the surface energy, mechanical properties, and geometries of the nanofibers are examined. In the limiting case of spontaneous circumferential wrinkling, the theoretical minimum radius of soft nanofibers producible in electrospinning is determined, which is related closely to the intrinsic length l_{0}=γ/E of the polymer (γ: the surface energy; E: a measure of the elastic modulus), and compared with that of spontaneous longitudinal wrinkling in polymer nanofibers. The present study provides a rational understanding of surface wrinkling in polymer nanofibers and a technical approach for actively tuning the surface morphologies of polymer nanofibers for applications, e.g., high-grade filtration, oil-water separation, tissue scaffolding, etc.

The effectiveness of acceptance and commitment therapy for social anxiety disorder: a randomized clinical trial.

OBJECTIVE: Acceptance and commitment therapy has been used to treat anxiety disorders recently. The purpose of this study was to investigate the effectiveness of acceptance and commitment therapy for psychological symptoms in students with social anxiety disorder, including difficulty in emotion regulation, psychological flexibility based on experiential avoidance, self-compassion, and external shame. METHODS: This study was a semi-experimental clinical trial. Twenty four students with social anxiety disorder were randomly divided into two groups after initial evaluations: an experimental group (12 subjects) and a control group (12 subjects). The experimental group received 12 treatment sessions based on a protocol of acceptance and commitment therapy for anxiety disorders, and the control group was put on a waiting list. Self-Compassion (SCS), Difficulty in Emotion Regulation (DERS), External Shame (ESS), Social Anxiety (SPIN), and Acceptance and Action (AAQ-II) questionnaires were used to assess participants. Data were analyzed using SPSS. RESULTS: Acceptance and commitment therapy was shown to be effective at the post-test and follow up stages for reducing external shame, social anxiety, and difficulty in emotion regulation and its components, and for increasing psychological flexibility and self-compassion (p < 0.05). The largest effect size of treatment was for increase of psychological flexibility and the lowest efficacy was for the components "difficulty in impulse control" and "limited access to emotional strategies" at the post-test and follow-up stages, respectively. CONCLUSION: Acceptance and commitment therapy may be an appropriate psychological intervention for reducing the symptoms of students with social anxiety disorder and helping them to improve psychological flexibility. Emotion and related problems can be identified as one of the main targets of this treatment. CLINICAL TRIAL REGISTRATION: Iranian Registry of Clinical Trials, IRCT20180421039369N1.

The effectiveness of acceptance and commitment therapy for social anxiety disorder: a randomized clinical trial

Abstract Objective Acceptance and commitment therapy has been used to treat anxiety disorders recently. The purpose of this study was to investigate the effectiveness of acceptance and commitment therapy for psychological symptoms in students with social anxiety disorder, including difficulty in emotion regulation, psychological flexibility based on experiential avoidance, self-compassion, and external shame. Methods This study was a semi-experimental clinical trial. Twenty four students with social anxiety disorder were randomly divided into two groups after initial evaluations: an experimental group (12 subjects) and a control group (12 subjects). The experimental group received 12 treatment sessions based on a protocol of acceptance and commitment therapy for anxiety disorders, and the control group was put on a waiting list. Self-Compassion (SCS), Difficulty in Emotion Regulation (DERS), External Shame (ESS), Social Anxiety (SPIN), and Acceptance and Action (AAQ-II) questionnaires were used to assess participants. Data were analyzed using SPSS. Results Acceptance and commitment therapy was shown to be effective at the post-test and follow up stages for reducing external shame, social anxiety, and difficulty in emotion regulation and its components, and for increasing psychological flexibility and self-compassion (p < 0.05). The largest effect size of treatment was for increase of psychological flexibility and the lowest efficacy was for the components "difficulty in impulse control" and "limited access to emotional strategies" at the post-test and follow-up stages, respectively. Conclusion Acceptance and commitment therapy may be an appropriate psychological intervention for reducing the symptoms of students with social anxiety disorder and helping them to improve psychological flexibility. Emotion and related problems can be identified as one of the main targets of this treatment. Clinical trial registration: Iranian Registry of Clinical Trials, IRCT20180421039369N1.

A Hydrothermal-Assisted Ball Milling Approach for Scalable Production of High-Quality Functionalized MoS2 Nanosheets for Polymer Nanocomposites.

The most known analogue of graphene, molybdenum disulfide (MoS2) nanosheet, has recently captured great interest because it can present properties beyond graphene in several high technological applications. Nonetheless, the lack of a feasible, sustainable, and scalable approach, in which synthesizing and functionalization of 2H-MoS2 nanosheets occur simultaneously, is still a challenge. Herein, a hydrothermal treatment has been utilised to reduce the effect of breaking mechanisms on the lateral size of produced nanosheets during the ball milling process. It was demonstrated that the hydrothermal pre-treatment led to the initial intercalation of an organic molecule such as 4,4'-diaminodiphenyl sulfone (DDS) within the stacked MoS2 sheets. Such a phenomenon can promote the horizontal shear forces and cause sliding and peeling mechanisms to be the dominated ones during low energy ball milling. Such combined methods can result in the production of 2H functionalized MoS2 nanosheets. The resultant few layers showed an average lateral dimension of more than 640 nm with the thickness as low as 6 nm and a surface area as high as 121.8 m2/g. These features of the synthesised MoS2 nanosheets, alongside their functional groups, can result in fully harnessing the reinforcing potential of MoS2 nanosheets for improvement of mechanical properties in different types of polymeric matrices.

BDNF Val66Met genetic variation and its plasma level in patients with morbid obesity: A case-control study.

Obesity is a major public health concern worldwide. Genetic, behavioral, and environmental factors contribute to the multifactorial etiology of obesity. Evidence suggests an association between human Brain-Derived Neurotrophic Factor (BDNF) Val66Met single nucleotide polymorphism (SNP) and obesity. Reduced plasma BDNF levels have also been reported in patients with eating disorders and obesity. We aimed to evaluate the BDNF Val66Met (rs6265) SNP and also plasma BDNF levels in morbidly obese patients compared with healthy normal controls in southern Iran. One hundred morbidly obese patients and one hundred eight healthy normal controls were enrolled. Blood-derived DNA samples were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and confirmed by DNA sequencing. Plasma BDNF levels were evaluated using a commercially available sandwich enzyme-linked immunosorbent assay (ELISA) kit for human BDNF. Data analysis was performed by SPSS software, version 18.0. Genotype distribution was not significantly different between obese patients and controls. However, plasma BDNF levels were significantly lower in obese patients compared with controls. Interestingly, a significant association was found between BDNF Val66Met SNP and plasma BDNF levels. No relationship was observed between BDNF Val66Met SNP and all assessed demographic and clinical characteristics of obese patients. It seems that plasma BDNF levels were associated with both obesity and BDNF Val66Met SNP. However, this association was not found between BDNF Val66Met SNP and obesity. Further studies with larger sample sizes are needed for more detailed assessment of this genetic variation as a potential biomarker for obesity.

Low-Cost Carbon Fibre Derived from Sustainable Coal Tar Pitch and Polyacrylonitrile: Fabrication and Characterisation.

Preparation of high-value pitch-based carbon fibres (CFs) from mesophase pitch precursor is of great importance towards low-cost CFs. Herein, we developed a method to reduce the cost of CFs precursor through incorporating high loading of coal tar pitch (CTP) into polyacrylonitrile (PAN) polymer solution. The CTP with a loading of 25% and 50% was blended with PAN and their spinnability was examined by electrospinning process. The effect of CTP on thermal stabilization and carbonisation of PAN fibres was investigated by thermal analyses methods. Moreover, electrospun PAN/CTP fibres were carbonised at two different temperatures i.e., 850 °C and 1200 °C and their crystallographic structures of resulting such low-cost PAN/CTP CFs were studied through X-ray diffraction (XRD) and Raman analyses. Compared to pure PAN CFs, the electrical resistivity of PAN/25% CTP CFs significantly decreased by 92%, reaching 1.6 kΩ/sq. The overall results showed that PAN precursor containing 25% CTP resulted in balanced properties in terms of spinnability, thermal and structural properties. It is believed that CTP has a great potential to be used as an additive for PAN precursor and will pave the way for cost-reduced and high-performance CFs.

The Effects of UV Light on the Chemical and Mechanical Properties of a Transparent Epoxy-Diamine System in the Presence of an Organic UV Absorber.

Despite several excellent properties including low shrinkage, good chemical resistance, curable at low temperatures and the absence of byproducts or volatiles, epoxy resins are susceptible to ultra violet (UV) damage and their durability is reduced substantially when exposed to outdoor environments. To overcome this drawback, UV absorbers have been usually used to decrease the rate of UV degradation. In this present study, the effects of UV light on the chemical, mechanical and physical properties of cured epoxy structure, as well as the effect of an organic UV absorber, Tinuvin 1130, on the epoxy properties were investigated. Chemical changes in a cured epoxy system as a result of the presence and absence of Tinuvin 1130 were determined using Fourier transform infrared spectroscopy (FT-IR) analyses. The effect of Tinuvin 1130 on the surface morphology of the epoxy systems was also investigated by scanning electron microscopy (SEM) imaging. Additionally, the glass transition temperatures (Tg) before and during UV radiation were measured. After an 800 h UV radiation, mechanical test results revealed that the lack of the UV absorber can lead to a ~30% reduction in tensile strength. However, in the presence of Tinuvin 1130, the tensile strength was reduced only by ~11%. It was hypothesized that the use of Tinuvin 1130, as an organic UV absorber in the epoxy-amine system, could decrease the undesirable effects, arising from exposure to UV light.

Collision-induced activation: Towards industrially scalable approach to graphite nanoplatelets functionalization for superior polymer nanocomposites.

Scale-up manufacturing of engineered graphene-like nanomaterials to deliver the industry needs for development of high-performance polymer nanocomposites still remains a challenge. Herein, we introduce a quick and cost-effective approach to scalable production of functionalized graphite nanoplatelets using "kitchen blender" approach and Diels-Alder chemistry. We have shown that, in a solvent-free process and through a cycloaddition mechanism, maleic anhydride can be grafted onto the edge-localized electron rich active sites of graphite nanoplatelets (GNP) resulting from high collision force, called "graphite collision-induced activation". The mechanical impact was modelled by applying the point charge method using density functional theory (DFT). The functionalization of GNP with maleic anhydride (m-GNP) was characterized using various spectroscopy techniques. In the next step, we used a recyclable process to convert m-GNP to the highly-reactive GNP (f-GNP) which exhibits a strong affinity towards the epoxy polymer matrix. It was found that at a low content of f-GNP e.g., 0.5 wt%, significant enhancements of ~54% and ~65% in tensile and flexural strengths of epoxy nanocomposite can be achieved, respectively. It is believed that this new protocol for functionalization of graphene nanomaterials will pave the way for relatively simple industrial scale fabrication of high performance graphene based nanocomposites.

Catalyzed Synthesis and Characterization of a Novel Lignin-Based Curing Agent for the Curing of High-Performance Epoxy Resin.

In this study, lignin, an aromatic compound from the forestry industry, was used as a renewable material to synthesize a new aromatic amine curing agent for epoxy resin. Firstly, lignin was separated from black liquor and hydroxyl groups were converted to tosyl groups as leaving groups. Then, primary amination was conducted using an ammonia solution at high pressure and temperature, in the presence of a nano-alumina-based catalyst. The structure of the nanocatalyst was confirmed by FT-IR, ICP, SEM, and XPS analyses. According to the FT-IR spectra, a demethylation reaction, the substitution of hydroxyl groups with tosyl groups, and then an amination reaction were successfully performed on lignin, which was further confirmed by the 13C NMR and CHNS analyses. The active hydrogen equivalent of aminated lignin was determined and three samples with 9.9 wt %, 12.9 wt %, and 15.9 wt % of aminated lignin, as curing agents, were prepared for curing the diglycidyl ether of bisphenol A (DGEBA). The thermal characteristics of the curing process of these epoxy samples were determined by DSC and TGA analyses. Moreover, the mechanical performance of the cured epoxy systems, e.g., the tensile strength and Izod impact strength, were measured, showing that in the presence of 12.9 wt % aminated lignin, the mechanical properties of the aminated lignin-epoxy system exhibited the best performance, which was competitive, compared to the epoxy systems cured by commercial aromatic curing agents.

Two Different Endotracheal Tube Securing Techniques: Fixing Bandage vs. Adhesive Tape.

INTRODUCTION: Emergency physicians should secure Endotracheal tubes (ETT) properly in order to prevent unplanned extubation (UE) and its complications. Despite various available endotracheal tube holders, using bandages or tape are still the most common methods used in this regards. OBJECTIVE: This study aimed to compare adhesive tape (AT) versus fixing bandage (FB) method in terms of properly securing ETT. METHODS: This was an observational longitudinal trial. All patients older than 15-years-old admitted to the ED who had indication for ETT insertion were eligible. Patients were randomly assigned to one of the two groups in which AT or FB was applied. All patients were observed thoroughly in the first 24 hours after intubation. Using a pre-prepared checklist, encountered UE rate and other data were recorded. RESULTS: Seventy-two patients with the mean age of 55.98 18.39 years were finally evaluated of which 38 cases (52.8%) were male. In total, 12% of patients in our study experienced unplanned extubation. Less than 12% of the patients experienced complete UE; there was no statistically significant difference between the two groups (p = 0.24). Comparison of UE with age showed no significant difference (p = 0.89). Male patients experienced more UE, but this was not statistically significant (p = 0.44). CONCLUSION: It is likely that whether the AT method or FB was applied for securing the ETT in emergency departments, there was no significant difference in rates of unplanned extubation.

Fish DNA-modified clays: Towards highly flame retardant polymer nanocomposite with improved interfacial and mechanical performance.

Deoxyribonucleic Acid (DNA) has been recently found to be an efficient renewable and environmentally-friendly flame retardant. In this work, for the first time, we have used waste DNA from fishing industry to modify clay structure in order to increase the clay interactions with epoxy resin and take benefit of its additional thermal property effect on thermo-physical properties of epoxy-clay nanocomposites. Intercalation of DNA within the clay layers was accomplished in a one-step approach confirmed by FT-IR, XPS, TGA, and XRD analyses, indicating that d-space of clay layers was expanded from ~1.2 nm for pristine clay to ~1.9 nm for clay modified with DNA (d-clay). Compared to epoxy nanocomposite containing 2.5%wt of Nanomer I.28E organoclay (m-clay), it was found that at 2.5%wt d-clay loading, significant enhancements of ~14%, ~6% and ~26% in tensile strength, tensile modulus, and fracture toughness of epoxy nanocomposite can be achieved, respectively. Effect of DNA as clay modifier on thermal performance of epoxy nanocomposite containing 2.5%wt d-clay was evaluated using TGA and cone calorimetry analysis, revealing significant decreases of ~4000 kJ/m2 and ~78 kW/m2 in total heat release and peak of heat release rate, respectively, in comparison to that containing 2.5%wt of m-clay.

Molecular Epidemiology Analysis of TB in Five Regional States of Iran.

BACKGROUND: The increasing prevalence of TB drug resistant strains in absence of recent transmission evidence, highlights the need for an improved control program, coupled with a need to improve detection rate and early diagnosis. IS6110-RFLP is a means of genotyping TB clinical samples. In this study IS6110- RFLP was used for specification and quick tracking of TB infection source, transmission and reactivation of infection, in Iran. MATERIALS AND METHODS: This study was carried out on 258 TB patients from Tehran, Mashhad, Isfahan, Shiraz and Ahwaz. DNA from positive cultures was extracted and digested by PVUII restriction enzyme. The digested sequences were separated based on the size on agar gel and then southern Blot was transferred on the membrane. IS6110 probe was marked by HRD and hybridized to the target parts along genome. RESULTS: Sixty-one strains (24%) showed similar patterns (Recent transmission) and 197 strains (76%) showed different IS6110 patterns (Reactivation). Average number of IS6110 copies was between 10-11 bands. Frequency of IS6110 similar pattern was 11.46 in Afghan immigrants and 10.68 in Iranians. CONCLUSION: High diversity of IS6110, indicates that 76% of the patients have been infected through reactivation by different sources, while 24% have been infected due to recent transmission. Observing different antibiogram patterns in patients infected with the same strain indicated vast transmission of a single strain in the society. A susceptible strain can be changed into mono drug resistant and MDR strain in the transition period.

Rapid Detection of Isoniazid Resistance in Mycobacterium tuberculosis by a Single Multiplex Allele-specific Polymerase Chain Reaction Assay.

OBJECTIVE: Global surveillance has shown that drug resistant (DR) tuberculosis (TB) is widespread. Prompt detection of Mycobacterium tuberculosis drug resistance is essential for effective control of TB. The most frequent mutations associated with Isoniazid (INH) resistance in Mycobacterium are substitutions at codons 315 in the katG gene and the mabA-inhA promoter region (-15). This survey evaluated INH resistant-associated mutations in order to determine rapid detection of TB resistance. MATERIALS AND METHODS: Through a descriptive cross- sectional study total of 96 sputum specimens were digested, examined microscopically for acid-fast bacilli and inoculated into Löwenstein-Jensen slants. Thereafter, the susceptibility and identification tests were performed on culture positive specimens. Subsequently, the strains were subjected to multiplex allele-specific polymerase chain reaction (MAS-PCR) targeting in the codons 315 in the katG gene and the mabA-inhA promoter region. Distinct PCR banding patterns were observed for different mutation profiles. RESULTS: Drug susceptibility testing revealed that out of 96 available isolates, 30 (31.3%) were susceptible, 36 (37.5%) had multi-drug resistance (MDR-TB) and 30 (31.3%) showed mono- drug resistance. In comparison with the culture-based phenotypic drug susceptibility test, the sensitivity and specificity of MAS-PCR assay for drug resistance-related genetic mutations were 76.7% and 71.4%, respectively. The correlation between MAS-PCR and culture-based phenotypic drug susceptibility testing findings was 99.4%. CONCLUSION: The profile of the isolates suggests a significant number of different DR strains with a high frequency of mutations at codon 315 of the katG gene. MAS-PCR provides a rapid, simple and cost-effective method for detecting MDR-TB.

Synchronous Comparison of Mycobacterium tuberculosis Epidemiology Strains by "MIRU-VNTR" and "MIRU-VNTR and Spoligotyping" Technique.

Molecular epidemiology analyses are frequently used in determining epidemiology of tuberculosis. Recently, Mycobacterial Interspersed Repetitive Unit Variable Number Tandem Repeat (MIRU-VNTR) and Spoligotyping has become an important method, as it allows high-through put, discriminatory and reproducible analysis of clinical isolate. The purpose of this study is to compare techniques of "MIRU-VNTR" versus "MIRU-VNTR and Spoligotyping" together for study of genetic pattern of Mycobacterium tuberculosis (M. tuberculosis) strains. Sixty M. tuberculosis (MTB) isolates were selected (30 susceptible, 30 multi-drug resistant) for this study. Thereafter, the "MIRU-VNTR and Spoligotyping" were performed to identify their genetic patterns. The frequency of unknown genetic pattern of MTB was compared using technique of "MIRU-VNTR" alone versus "MIRU-VNTR and Spoligotyping" together. The MIRU-VNTR allelic diversity at each of the loci was calculated by Hunter - Gaston Discriminatory Index (HGDI). Based on differentiation index of all strains 10, 16, 26, 31 and 40 loci were identified as the most distinctive (HGI ≥0.6) and 2, 4, 20 and 24 as the weakest distinctive locus (HGI ≤0.3). By using MIRU-VNTR technique 38% (n = 23) of isolates could not be typed, whereas by applying "MIRU-VNTR and Spoligotyping" together only 15% (n = 9) of isolates remained unknown (p = 0.004). For sensitive strains, the difference was significant (67% vs. 90%, p = 0.028), but only marginally significant for drug resistant strains (57% vs. 80%, p = 0.052). The discrimination power of 12-locus MIRU-VNTR and Spoligotyping was equal to that of MIRU-VNTR analysis. If appropriate loci are added to the standard MIRU analysis, MIRU-VNTR genotyping could be a valuable tool for strain typing and epidemiological research of M. tuberculosis. With this approach a more clear understanding about genetic pattern of MTB can be achieved.

The recent-transmission of Mycobacterium tuberculosis strains among Iranian and Afghan relapse cases: a DNA-fingerprinting using RFLP and spoligotyping.

BACKGROUND: Relapse of tuberculosis (TB) may develop as the result of reactivation of the endogenous primary infection, or as a result of a exogenous reinfection. This survey evaluated the rate of reactivation versus recent transmission among Iranian and Afghan relapse cases. METHODS: The sputum specimens were digested, examined microscopically for acid-fast bacilli, and inoculated into Löwenstein-Jensen slants by standard procedures. Thereafter, the susceptibility and identification tests were performed on culture positive specimens. Subsequently, the strains that were identified as Mycobacterium tuberculosis (258 isolates) were subjected to IS6110 restriction fragment length polymorphism (RFLP) and spoligotyping. Additional patient's information was collected for further epidemiological analysis. Patients whose isolates had identical genotyping patterns were considered a cluster with recent transmission episode. RESULTS: Out of 258 available isolates, 72(28%) had multi-drug resistant (MDR-TB) in ratio and 42 (16.2%) had other resistant. Notably, 38 of MDR-TB cases (52%) were isolated from Afghan patients. By IS6110-RFLP typing method, 65 patients (25%) were clustered in 29 clusters. In cluster cases, the intra-community transmissions between Iranian and Afghan patients were 41%. All MDR-TB patients in clusters had either Haarlem I or Beijing characteristic. The risk factors like sex, family history, close contact, living condition, PPD test result and site of TB infection were not associated with clustering. Although, the MDR-TB strains were more frequent in non-cluster cases (31%) than cluster one(18%) (P < 0.05). Majority of M. tuberculosis strains isolated from non-cluster cases were belong to EAI3 (51; 30%) and CASI(32;18.6%) superfamilies. CONCLUSION: During the studied period, reactivation of a previous infection remain the more probable cause of recurrence. Although, the evidence of intra- community transmission between Iranian and Afghan TB cases, highlighted the impact of afghan immigrants in national tuberculosis control program (NTP) of Iran.