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.

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.

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.

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.

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.

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.

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.

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.

Driver Gene Mutations in Stools of Colorectal Carcinoma Patients Detected by Targeted Next-Generation Sequencing.

Detection of driver gene mutations in stool DNA represents a promising noninvasive approach for screening colorectal cancer (CRC). Amplicon-based next-generation sequencing (NGS) is a good option to study mutations in many cancer genes simultaneously and from a low amount of DNA. Our aim was to assess the feasibility of identifying mutations in 22 cancer driver genes with Ion Torrent technology in stool DNA from a series of 65 CRC patients. The assay was successful in 80% of stool DNA samples. NGS results showed 83 mutations in cancer driver genes, 29 hotspot and 54 novel mutations. One to five genes were mutated in 75% of cases. TP53, KRAS, FBXW7, and SMAD4 were the top mutated genes, consistent with previous studies. Of samples with mutations, 54% presented concomitant mutations in different genes. Phosphatidylinositol 3-kinase/mitogen-activated protein kinase pathway genes were mutated in 70% of samples, with 58% having alterations in KRAS, NRAS, or BRAF. Because mutations in these genes can compromise the efficacy of epidermal growth factor receptor blockade in CRC patients, identifying mutations that confer resistance to some targeted treatments may be useful to guide therapeutic decisions. In conclusion, the data presented herein show that NGS procedures on stool DNA represent a promising tool to detect genetic mutations that could be used in the future for diagnosis, monitoring, or treating CRC.

Mean Polyp per Patient Is an Accurate and Readily Obtainable Surrogate for Adenoma Detection Rate: Results from an Opportunistic Screening Colonoscopy Program.

BACKGROUND The incidence of colorectal cancer is rising in several developing countries. In the absence of integrated endoscopy and pathology databases, adenoma detection rate (ADR), as a validated quality indicator of screening colonoscopy, is generally difficult to obtain in practice. We aimed to measure the correlation of polyp-related indicators with ADR in order to identify the most accurate surrogate(s) of ADR in routine practice. METHODS We retrospectively reviewed the endoscopic and histopathological findings of patients who underwent colonoscopy at a tertiary gastrointestinal clinic. The overall ADR and advanced-ADR were calculated using patient-level data. The Pearson's correlation coefficient (r) was applied to measure the strength of the correlation between the quality metrics obtained by endoscopists. RESULTS A total of 713 asymptomatic adults aged 50 and older who underwent their first-time screening colonoscopy were included in this study. The 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 good correlations between polyp detection rate (PDR) and ADR (r=0.93), and mean number of polyp per patient (MPP) and ADR (r=0.88) throughout the colon. There was a positive, yet insignificant correlation between advanced ADRs and non-advanced ADRs (r=0.42, p=0.35). CONCLUSION MPP is strongly correlated with ADR, and can be considered as a reliable and readily obtainable proxy for ADR in opportunistic screening colonoscopy programs.

Physicians' Knowledge and Attitude Towards Fecal Microbiota Transplant in Iran.

BACKGROUND Fecal microbiota transplant (FMT) is employed to replace the 'unhealthy' microbiota of the patient with the 'healthy' microbiota of a pre-screened healthy donor. Given the growing importance of gut microbiota dysbiosis in the pathogenesis of intestinal or extraintestinal diseases; it is conceivable that FMT becomes integrated in the routine clinical practice. Our objective was to assess the knowledge and attitude of the Iranian physicians towards FMT. METHODS We surveyed the participants of Iranian gastroenterology and hepatology 2014 conference. RESULTS Overall, 146 (68.5%) were familiar with FMT; of whom 132 (94.28%) were willing to accept FMT if scientifically and ethically approved and 115 (88.46%) were willing to refer their patients for FMT if indicated. In total, 42 (30.7%) had identified stool preparation as the most unappealing aspect of FMT, while 17 (11.6%) reported the therapeutic use of fecal material as the most unappealing and 39 (28.5%) indicated that both are equally unappealing. The doctors who had an overall positive opinion toward FMT reported less negative feelings towards FMT. CONCLUSION Iranian physicians are willing to accept FMT as a therapeutic option if it is scientifically justified and ethically approved. Nevertheless, physicians prefer to skip the stool preparation phase; as they are more in favour of synthetic microbiota as opposed to fecal microbiota.

Is the Prevalence of Celiac Disease Higher than the General Population in Inflammatory Bowel Diseaese?

BACKGROUND In some studies inflammatory bowel disease (IBD) and celiac disease were considered to be associated and some belive that this association may influence the prognosis of IBD. However, there is a cosiderable controversy regarding this association. Therefore ,we aimed to assess the association of these two common digestive diseases and evaluate the complications of this association. METHODS In this comparative study, 200 patients with ulceritive colitis (UC) and 206 patients with Crohn's disease (CD) were evaluated for celiac disease using relevant diagnostic tests and pathologic studies. Total IgA, IgA tissue transgulaminase antibody and specific IgA anti endomysial antibody were asseyed. In cases of IgA deficiency, total IgG and IgG tissue TG and IgG anti endomyseal Ab were measured. Patients with increased specific IgA and IgG antibodies for celiac disease, underwent endoscopy and 4 standard samples were obtained. Our results were compared with the results of the prevalence study of celiac disease in the general population. Data were analyzed using analytic and descriptive statistics at a significance level of 5%. RESULTS Among the studied patients, 1 patient with UC had elevated IgA anti tTG antibody and IgA anti-endomysial antibody who underwent endoscopy and celiac was confirmed on pathology. Hence, of the 200 patientswith UC, the diagnosis of celiac disease was confirmed in 1 patient (1:200) with no significant difference with the prevalence of celiac disease in the general population (1:166). However, none of our patients with Crohn's disease had celiac disease (0:206). CONCLUSION We found no significant difference in the prevalence of celiac disease between patients with UC and the general population. Since most of our participants had a mild level of Crohn's activation, none of those with Crohn's disease had celiac disease. Complications of IBD including sclerosing cholangitis, may be more common in patients with concurrent celiac disease. Therefore, it is recommended that celiac disease be considered in patients with severe and complicated IBD.

Severe Lower Gastrointestinal Bleeding in a Patient with Crohn's Disease: a Case Report and the Review of Literature.

Crohn's disease (CD) is rarely presented with lower GI bleeding (LGIB) which eludes the clinician. A 25-year-old lady with severe rectorrhagia was presented with no history of constipation, diarrhea or abdominal pain. Colonoscopy revealed ulcers in the rectum, sigmoid colon, and terminal ileum. Crohn's pathologic features were detected in the terminal ileum. The bleeding was controlled via supportive care and IV corticosteroid. Recurrent LGIB was managed by prednisolone and azathioprine. The patient had an uneventful recovery. The clinicians should consider CD as a possible diagnosis in severe LGIB. Prednisolone and azathioprine efficiently control acute bleeding episodes and prevent the recurrence.

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.

Characteristics of colorectal polyps and cancer; a retrospective review of colonoscopy data in iran.

BACKGROUND Early diagnosis and endoscopic resection of adenomatous polyps is the main approach for screening and prevention of colorectal cancer (CRC). We aimed to assess polyp detection rate (PDR) and to characterize demographic, clinical, and pathological features of colorectal polyps in an Iranian population. METHODS We retrospectively analyzed the data from 5427 colonoscopies performed during 2007-2012 at Masoud Clinic, the main endoscopy center associated with Sasan Alborz Biomedical Research Center, in Tehran, Iran. RESULTS Our sample included 2928 (54%) women and 2499 (46%) men, with the mean age of 48.3 years (SD=16.1). The most common reasons for colonoscopy included screening in 25.0%, and gastrointestinal bleeding in 15.2%. Cecal intubation was successful in 86% of patients. The quality of bowel preparation was fair to excellent in 78.1% (n=4235) of colonoscopies. Overall PDR was 42.0% (95% CI: 40.6-43.3). The PDR in men (51.1%, 95% CI: 49.1-53.1) was significantly higher than women (34.2%, 95% CI: 32.4-35.9, p<0.001). Polyps were more frequently observed in patients after the 6(th) decade of life (F=3.2; p=0.004). CRC was detected in 2.9% (73/2499) of men and 1.9% (57/2928) of women (p=0.02). The mean age for patients with cancer was significantly higher than that for individuals with polyps, 60.9 (SD=13.4) year vs. 56.9 (SD=13.7) year, respectively (p=0.001). Almost 82.8% of the lesions were precancerous with tubular type predominance (62.3%) followed by tubulo-villous (10.3%), villous (6.6%), and serrated (3.6%). Hyperplastic/inflammatory polyps comprised 17.2% of lesions. CONCLUSION Distal colon was more prone to develop polyps and cancer than proximal colon in our series. These findings provide a great infrastructure for next preventive programs and have implications for colorectal cancer screening at population-level.