A subbands study on the resistivity of field-effect CNT-based piezoresistive nanocomposites.

In this paper, an analytical model based on the percolation theory has been developed to predict the subbands effect on the effective electrical resistivity of carbon nanotubes (CNT)-based polymer nanocomposites. The CNTs are considered as randomly distributed or aligned channel material in the polymer transmitting electrons through tunneling. The tunneling effect takes into account the electron transmission between each connected pair of CNTs to evaluate electrical resistivity. The modeling approach contains two steps of primary prediction of resistivity and further calculation of CNTs' displacements and subsequent change of the resistance. A good agreement is found between the analytical model predictions and experimental data when the tunneling behavior was considered in the percolation transition region. The effect of CNT diameter, orientation state, and subbands on the resistivity has been investigated. The results depict that subbands increment is a collateral benefit to the aspect ratio in decreasing the resistivity. The analytical results demonstrate that a random CNT dispersion leads to a decreased piezoresistivity, while an increased strain range depicts a more non-linear behavior.

Voltammetric aptasensor for bisphenol A based on the use of a MWCNT/Fe3O4@gold nanocomposite.

The present study describes an electrochemical aptamer-based method for the determination of bisphenol A (BPA). It is making use of gold nanoparticles (AuNPs) immobilized on a conjugate between multiwalled carbon nanotubes and thiol-functionalized magnetic nanoparticles (MWCNT/Fe3O4-SH) that are modified with an aptamer. The nanocomposite was characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, elemental mapping analysis and energy dispersive X-ray diffraction. The aptasensor, typically operated at 0.20 V (vs. Ag/AgCl), has a linear response in the 0.1 to 8 nM BPA concentration range, a low detection limit (0.03 nM), and high sensitivity (86.43 µA nM-1 cm-2). Voltammetric experiments were performed by using the hexacyanoferrate redox system as an electrochemical probe. The results indicate that the presence of AuNPs, magnetic nanoparticles and MWCNTs results a synergistic electrochemical augmentation. The method is highly selective, sensitive, efficient and environmentally friendly. The method was successfully applied to the determination of BPA in spiked real samples. Graphical abstract Aptasensor fabricated by MWCNT/Fe3O4-SH@Au nanocomposite and anti-BPA aptamer. The conformation of aptamer change after BPA binding, triggering a decrease in the electron transfer of Fe(CN)63-/4- on the electrode surface. The observed decline was detectable as a function of BPA concentration.

Advanced colonic neoplasia in the first degree relatives of colon cancer patients: A colonoscopy-based study.

We aimed to determine the risk of advanced neoplasms among a cohort of asymptomatic first degree relatives (FDRs) of patients with sporadic colorectal cancer (CRC) compared with matched controls. Data for patients with a diagnosis of CRC made between September 2013 and August 2014 were obtained from a population-based cancer registry system in Tehran. Screening colonoscopies were done for 342 FDRs and the findings were compared to those from 342 age- and gender-matched healthy controls without a family history of CRC. We reported the association as conditional Odds Ratio (OR) using Mantel Hazel and Logistic regression. The prevalence of advanced neoplasia was 13.2% among FDRs and 3.8% in controls (matched OR [mOR], 4.0, 95% confidence interval [CI], 2.1 - 7.6; p < 0.001). In FDRs aged 40-49 years, the prevalence of advanced neoplasia was significantly higher than in their matched controls (mOR, 6.8, 95% CI, 1.5-31.4; p = 0.01). Family history of CRC in at least one FDR was the strongest predictor of advanced neoplasia (adjusted OR, 4.0, 95% CI: 2.1-7.6; p < 0.001). The age of the index case at diagnosis did not predict the presence of advanced colonic neoplasms in their FDRs. Our study indicates a high risk of advanced neoplasia in FDRs of CRC cases, where only eight colonoscopies are needed to detect one advanced neoplasia. Our data suggest that all FDRs, regardless of the age of CRC diagnosis in their index case, should be considered for a targeted early screening.

Adenoma detection rates in an opportunistic screening colonoscopy program in Iran, a country with rising colorectal cancer incidence.

BACKGROUND: Data on the quality of colonoscopies in populations with rising colorectal cancer (CRC) incidence is scarce. We aimed to calculate the adenoma detection rates (ADR), and assess the quality of colonoscopies in an opportunistic screening colonoscopy program in Iran. METHODS: All the colonoscopy and pathology reports of asymptomatic adults over age 50 who underwent screening colonoscopy between June 2007 and March 2013 were reviewed. The colonoscopy quality indicators including ADR were calculated, and patient factors associated with the adenoma detection were determined. RESULTS: A total of 713 asymptomatic adults aged 50 years and older who underwent their first-time screening colonoscopy were included in this study. ADR and advanced-ADR were 33.00% (95% CI: 29.52-36.54) and 13.18% (95% CI: 10.79-15.90), respectively. We observed a significantly higher rate of cecal intubation in patients with fair or better bowel preparation compared to those with poor prep, 90.00% vs. 70.45%, respectively (P < 0.001). Bowel preparation (adjusted OR: 2.49, 95% CI: 1.75-3.55), older age (≥60) (adjusted OR: 1.70, 95% CI: 1.22-2.36), and male gender (adjusted OR: 1.39, 95% CI: 1.01-1.92) were associated with the adenoma detection. CONCLUSIONS: Our ADR in both genders meets and exceeds the recommended colonoscopy quality benchmarks. The polyp and adenoma detection rates in the current study are comparable to those reported from Western countries where the incidence of CRC is traditionally high. These data are in line with the epidemiologic transition of CRC in Iran.

Evaluation of health related quality of life in irritable bowel syndrome patients.

BACKGROUND: Quality of life (QOL) is an important measure in the management of Irritable Bowel Syndrome (IBS). Controversy exists in the findings of studies evaluating QOL in IBS subtypes, and little is known about this issue in Iranian patients. Determination of the factors affecting QOL in IBS patients may influence treatment outcomes. The aims of this study are to: 1) compare QOL between subtypes in a sample of Iranian IBS patients, 2) determine the factors associated with QOL in IBS. METHODS: This cross sectional study included two hundred and fifty IBS patients with the mean age (± standard deviation) of 31.62 (± 11.93) years that were referred to outpatient gastroenterology clinic. IBS patients were diagnosed based on Rome-3 criteria by a gastroenterologist, and then they were categorized into three subtypes according to the predominant type of bowel habit. The "QOL specific for IBS", "Stait-trait anxiety inventory", and "Beck depression inventory-2" questioners were used to evaluate QOL, anxiety, and depression symptoms, respectively. RESULTS: The mean QOL scores in IBS mixed subtype (71.7 ± 25.57), constipation predominant subtype (80.28 ± 25.57), and diarrhea predominant subtype (76.43 ± 19.13) were not different. (P value: 0.05) In multivariate linear regression analysis, anxiety symptom scores were inversely correlated with QOL scores. [Standardized beta: -0.43, (95% confidence interval: -0.70, -0.39), P value: < 0.01] CONCLUSION: It seems reasonable to manage anxiety symptoms properly in IBS patients since this might increase their QOL.

Poorly differentiated laryngeal neuroendocrine neoplasm with high serum calcitonin level, a case report, with literature review.

Neuroendocrine neoplasm (NEN) of the larynx consists of 0.6% of laryngeal cancer and is the second most common type after squamous cell carcinoma (SCC). Laryngeal NEN rarely secret calcitonin and should be differentiated from medullary thyroid carcinoma. It makes a diagnostic and therapeutic challenge. We describe a case of a laryngeal NEN with calcitonin hypersecretion. A 59-year-old man presented to our clinic with recurrent cough, dysphonia, hoarseness, cervical mass, and significant weight loss. Diagnostic workup showed a supraglottic mass. Biopsy of the lesion revealed large-cell neuroendocrine neoplasm. Further diagnostic workup showed elevated serum calcitonin level. The patient underwent total laryngectomy, thyroidectomy, and modified radical neck dissection. During his follow-up, new subcutaneous nodules appeared that were biopsy-proven metastases. Then adjuvant chemoradiotherapy was performed. Laryngeal NEN with hypersecretion of calcitonin is a rare entity. In patients with elevated serum calcitonin levels and head and neck tumors, it should be considered a differential diagnosis of medullary thyroid carcinoma. As the management and prognosis of these two neoplasms are entirely different.

Core Needle Biopsy in Suspicious Malignant Thyroid Nodules with Repeated Nondiagnostic Fine Needle Aspiration.

Key message: The clinician could have CNB in mind for thyroid nodules when FNA results were nondiagnostic. Our study would suggest CNB a safe and efficient method for investigating thyroid nodules. Abstract: Usefulness of preoperative tissue sampling and pathology diagnoses in thyroid tumors were accepted worldwide. We investigate the role of Core needle biopsy (CNB) in the thyroid nodules lesions when FNA results are nondiagnostic. We conducted a cross-sectional study to evaluate twenty-six CNBs results of suspicious malignant thyroid nodules with nondiagnostic repeated fine needle aspiration. 25 from 26 CNBs were diagnostic. Twenty-one needle biopsy reports were papillary thyroid carcinoma, three CNB samples diagnosed medullary thyroid carcinoma and one of them had anaplastic results. All diagnostic needle biopsies results were compatible with final pathology. Our study would suggest CNB a safe and efficient method for investigating thyroid nodules while repeated FNA yielded nondiagnostic results.

Structural and mechanical properties of antimonene monolayers doped with transition metals: a DFT-based study.

In the current study, the elastic and plastic properties of the 2 × 2 and 3 × 3 pristine and transition metal (TM)-doped antimonene are studied through DFT calculations. Sc, Ti, V, Cr, Fe, Co, Ni, Cu, and Zn atoms are selected as the doping atoms. It was observed that Young's and bulk moduli of both 2 × 2 and 3 × 3 pristine structure would decrease while affected by the doping atoms. The highest reduction in the Young's and bulk moduli of the 2 × 2 nanosheets has occurred in the Cr- and Ti-doped structures, respectively, while the same reduction was observed in the V- and Ti-doped structures in the 3 × 3 nanosheets. In addition, it was shown that all of the investigated structures express isotropic behavior since the obtained Young's moduli of these nanostructures have negligible difference along armchair and zigzag directions. Finally, the loading is further increased to investigate the plastic behavior of these structures. The results showed that except for 2 × 2 Sc-doped structure under biaxial loading, the yield strain of all doped nanosheets would decrease under uniaxial and biaxial loadings. The highest reduction in the yield strain of the 2 × 2 nanosheets under biaxial loading has been observed in Cu-doped nanosheet while in 3 × 3 nanosheets, the highest reduction has occurred in Cu-, Fe-, and Zn-doped nanosheets under the same condition. As for the yield strain of the doped 2 × 2 nanosheets while affected by the uniaxial loading, Cu- and Zn-doped nanosheets experienced the highest reduction while in 3 × 3 nanosheets, the highest reduction has been observed for Cr-doped nanosheet under the same condition.

Effects of geometrical parameters and functionalization percentage on the mechanical properties of oxygenated single-walled carbon nanotubes.

The mechanical properties of oxygen-functionalized single-walled carbon nanotubes (CNTs) are studied herein by molecular dynamics (MD) simulations. An analysis of the random distribution of oxygen atoms on CNTs of various functionalization percentages is presented in this study. The influences of the nanotube length, diameter, and the percentage of functionalization on longitudinal Young's modulus, failure stress, strain, and toughness are investigated. The results show that for both zigzag and armchair chiralities, Young's modulus decreases by increasing the nanotube diameter and length-to-diameter ratio. Also, the values of all studied properties including Young's modulus, stress, strain, and toughness are reduced by increasing the functionalization percentage until the nanotube reaches failure. Moreover, the reason for the alteration of the mechanical properties of nanotubes and the behavior of the stress-strain diagram are discussed.

Subacute Thyroiditis in COVID-19 Patients.

INTRODUCTION: Since December 2019, novel coronavirus (COVID-19) infection has been identified as the cause of an outbreak of respiratory illness in Wuhan, China. The classic presentation of COVID-19 infection was described as fever, myalgia, cough, and fatigue. Whether coronavirus can directly attack the endocrine glands is unclear. OBJECTIVE: Post-viral subacute thyroiditis (SAT, de Quervain thyroiditis) has been reported following other viral infection. A limited number of SAT after COVID-19 infection have been reported up to now. METHODS: Here, we reported 6 patients with SAT and positive COVID-19 serology tests. Demographic, clinical, biochemical, and imaging data were presented. RESULTS: In this study, 6 patients (4 women and 2 men) with clinician manifestations and physical examination in favor of SAT were described. Cervical ultrasonography showed bilateral hypoechoic areas in the thyroid gland which was suggestive of SAT. Elevated C-reactive protein, erythrocyte sedimentation rate, free thyroxine, free tri-iodothyronine, and undetectable thyrotropin were found in laboratory evaluations. Both IgM and IgG were positive for COVID-19 infection, but the PCR tests were negative in all patients. Patients had history of working in a COVID center and/or family member hospitalized due to COVID-19 pneumonia. Patients were followed up for 1 month and were treated effectively with steroids. CONCLUSION: This report may help physicians to identify lesser-known manifestations and complications of COVID-19. Early diagnosis of COVID-19 infection results in the prevention of further transmission.

The effect of enteric-coated, delayed-release peppermint oil on irritable bowel syndrome.

Herbal remedies, particularly peppermint, have been reported to be helpful in controlling symptoms of irritable bowel syndrome (IBS). We conducted a randomized double-blind placebo-controlled study on 90 outpatients with IBS. Subjects took one capsule of enteric-coated, delayed-release peppermint oil (Colpermin) or placebo three times daily for 8 weeks. We visited patients after the first, fourth, and eighth weeks and evaluated their symptoms and quality of life. The number of subjects free from abdominal pain or discomfort changed from 0 at week 0 to 14 at week 8 in the Colpermin group and from 0 to 6 in controls (P < 0.001). The severity of abdominal pain was also reduced significantly in the Colpermin group as compared to controls. Furthermore, Colpermin significantly improved the quality of life. There was no significant adverse reaction. Colpermin is effective and safe as a therapeutic agent in patients with IBS suffering from abdominal pain or discomfort.

Epidemiology and molecular genetics of colorectal cancer in iran: a review.

Although the incidence of colorectal cancer in Iranian older age subjects is currently very low compared to Western population, the younger generation is experiencing an accelerated rate approaching the Western rates and the burden of disease will increase dramatically in near future. The high frequency of positive family history of colorectal cancer in Iranian patients indicates that a significant number of colorectal cancers in Iran arise in family members and relatives of colorectal cancer patients. It is clear that the familial clustering of colorectal cancer is more often seen in younger probands and cancer located in the right side of the colon. These epidemiologic findings call for a broader attempt to promote public awareness and screening strategies in those families with a member affected by colorectal cancer, especially at younger age or with proximal tumors. Based on our present understanding, the possibility of preventing or curing most colon and rectal cancers is now plausible. The molecular biology of colon cancer has been the subject of many researches and is better understood than those for any other solid cancer and have established an important example for cancer research. It is now clear that colorectal cancer develops as the result of genetic and epigenetic alterations that lead to malignant transformation of normal mucosa. In spite of these scientific progresses and the fact that screening can reduce the rate of death by detecting early cancer or premalignant polyps, the rate of screening is very low globally and negligible in Iran and many other developing countries which is due to cost, resistance by physicians, patients, and the healthcare system. In Iran screening should at least be started in family members at earlier age with colonoscopy as the preferred modality of screening method.

Synthesized Nano particle derivation of poly (Styrene - co- Maleic Anhydride) and sour cherry Rock for removing nickel (II) ion from aqueous solutions.

In this study, Prunus Cerasus Rock (PCR) and Poly (Styrene - co- Maleic Anhydride) modified with Melamine-Oxalic acid (SMA-MO) were used to prepare a cheap adsorbent through chemical modification. The maximum removal was observed at pH = 6.0 and adsorbent dose 1.5 g/L for initial Nickel -ions concentration 30 mg/L. Study of temperature effect proved that the process is endothermic. Langmuir and Freundlich isotherm models were used for equilibrium adsorption data. Langmuir isotherm proved to be a better fit. Pseudo first order and pseudo second order kinetic models were applied to analyze the kinetic mechanism of adsorption.

P53 mutations in colorectal cancer from northern Iran: Relationships with site of tumor origin, microsatellite instability and K-ras mutations.

CRC-associated P53 mutations have not been studied extensively in non-Western countries at relatively low CRC risk. We examined, for the first time, 196 paraffin-embedded CRC cases from Northern Iran for mutations in P53 exons 5-8 using PCR-direct sequencing. P53 status and mutation site/type were correlated with nuclear protein accumulation, clinicopathologic variables and data on K-ras mutations and high-level microsatellite instability (MSI-H). We detected 96 P53 mutations in 87 (44.4%) cases and protein accumulation in 84 cases (42.8%). P53 mutations correlated directly with stage and inversely with MSI-H. Distal CRCs were more frequently mutated at major CpG hotspot codons [248 (8/66, 12.1%), 175 (7/66, 10.6%), and 245 (7/66, 10.6%)], while in proximal tumors codon 213, emerged as most frequently mutated (5/28, 17.9% vs. 3/66, 4.5%, P = 0.048). Transitions at CpGs, the most common mutation type, were more frequent in non-mucinous (25% vs. 10.4% in mucinous, P = 0.032), and distal CRC (27% vs. 12.5% in proximal, P = 0.02), and correlated with K-ras transversions. Transitions at non-CpGs, second most common P53 mutation, were more frequent in proximal tumors (15.6% vs. 4.7% in distal, P = 0.01), and correlated with K-ras transitions and MSI-H. Overall frequency and types of mutations and correlations with P53 accumulation, stage and MSI-H were as reported for non-Iranian patients. However P53 mutation site/type and correlations between P53 and K-ras mutation types differed between proximal and distal CRC. The codon 213 P53 mutation that recurred in proximal CRC was previously reported as frequent in esophageal cancer from Northern Iran.

Ulcerative colitis and irritable bowel syndrome: relationships with quality of life.

OBJECTIVES: Quality of life is reduced in inflammatory bowel disease. Irritable bowel syndrome (IBS)-like symptoms seem to be common in inflammatory bowel disease patients during the remission phase. We aimed to (i) assess the prevalence of IBS-like symptoms in ulcerative colitis (UC) patients during the remission phase and (ii) evaluate the impact of IBS symptoms on health-related quality of life (HRQOL) of UC patients in remission compared with the HRQOL of those in the active phase. METHODS: Ninety-five patients with UC (45 patients in the active phase and 50 in remission for at least 12 months) and 100 selected controls (recruited from among those who visited the orthopedic minor trauma outpatient clinic during 2004-2005) completed questionnaires to evaluate IBS-like symptoms according to ROME II criteria: the influence of these symptoms on the HRQOL of UC patients in remission was compared with that on the HRQOL of those in the active phase. Chi square and nonparametric tests were used. RESULTS: The prevalence of IBS-like symptoms in UC patients in remission and controls were 46 and 13%, respectively (P<0.001). HRQOL seemed to be significantly reduced in both active UC patients and UC patients in remission with IBS, compared with UC patients in remission without IBS and with controls (P<0.001). In active UC patients, the mean scores for most elements (as measured by SF36) were considerably lower than for UC patients in remission (P<0.05). CONCLUSION: The prevalence of IBS-like symptoms in UC patients in remission is about three times higher than in controls, and these patients have impaired HRQOL comparable with that of UC patients in the active phase.

The prevalence of polyp in colon of patients with acromegaly.

Several studies have shown that patients with acromegaly are at increased risk of developing colorectal polyps and cancer. The prevalence of polyp in colon of patients with acromegaly was variously reported between 23% and 53%. This study was conducted to determine the prevalence of polyp and cancer of colon in patients with acromegaly. Twenty-three patients with acromegaly were evaluated with colonoscopy for the presence of colonic polyps and cancer. Three patients were found to have colonic polyps. This translates to a prevalence rate of 13%. We recommend that screening colonoscopy be carried out once every three years in all acromegalic patients over the age of 40 years.

Mesalazine Has No Effect on Mucosal Immune Biomarkers in Patients with Diarrhea-Dominant Irritable Bowel Syndrome Referred to Shariati Hospital: A Randomized Double-Blind, Placebo-Controlled Trial.

BACKGROUND Intestinal mast cells may cause gastrointestinal symptoms in patients with diarrhea-dominant irritable bowel syndrome (IBS). The objective of this study was to determine the effect of mesalazine on the number of lamina propria mast cells and clinical manifestations of patients with diarrhea-dominant IBS referred to Shariati Hospital affiliated to Tehran University of Medical Sciences. METHODS This was a randomized placebo-controlled double-blind trial conducted on 49 patients with diarrhea-dominant IBS. The patients were randomly assigned to one of the experiment or control groups. The patients in experiment group took 2400 mg mesalazine daily in three divided doses for 8 weeks and the patient in control group took placebo on the same basis. Our first targeted outcome was an assigned downturn of mast cells number to the safe colonic baseline and the next one was a marked palliation of disease symptoms. Data were analyzed conforming intention-to-treat method. We used MANCOVA test to compare our both assigned outcomes in the two groups. We also compared the data with baseline values in both groups.All statistical tests were performed at the significance level of 0.05. RESULTS There was no significant difference between Mesalazine and placebo groups regarding the number of mast cells (p value=0.396), abdominal pain (p value=0.054), bloating (p value=0.365), defecation urgency (p value=0.212), and defecation frequency (p value=0.702). CONCLUSION Mesalazine had no significant effect either on the number of mast cells or on the severity of disease symptoms. This finding seems to be inconsistent with the hypothesis indicating immune mechanisms as potential therapeutic targets in IBS. The possible difference in this effect of Mesalazine should be evaluated in further studies among populations varying in race, ethnic, and geographical characteristics.

Incidence and age distribution of colorectal cancer in Iran: results of a population-based cancer registry.

Epidemiologic patterns of colorectal cancer (CRC) in Iran have not been studied adequately. In a recent cancer registry and active cancer surveillance, we collected data on the incidence of colorectal tumors in five provinces of Iran from 1996 to 2000. In total, 2055 were registered in this study. Age-adjusted rates of CRC in Iranian males and females were 8.2 and 7.0/100,000, respectively. Seventeen percent of the cases were younger than 40 years of age at the time of diagnosis. This proportion was similar to proportions seen in many other Middle-Eastern countries, but much higher than those seen in Western countries. A comparison of age-specific rates between Iran and the US showed similar rates in young (<40 years) Iranians and Americans, but much lower rates in older (>/=40) Iranians. We conclude that Iran is still a country with low-risk of CRC, particularly for older individuals. The high proportions of young CRC cases seen in Iran, and probably many neighboring countries, are due to the young age-structure of these countries and relatively low rates of CRC in older individuals.