Sectorization of Macromolecular Single Crystals Unveiled by Probing Shear Anisotropy.

Polymer single crystals continue to infiltrate emerging technologies such as flexible organic field-effect transistors because of their excellent translational symmetry and chemical purity. However, owing to the methodological challenges, direct imaging of the polymer chains folding direction resulting in sectorization of single crystals has rarely been investigated. Herein, we directly image the sectorization of polymer single crystals through anisotropic elastic deformation on the surface of macromolecular single crystals. A variant of friction force microscopy, in which the scanning direction of the probe tip is parallel with the cantilever axis, allows for high contrast imaging of the sectorization in polymer single crystals. The lateral deflection of the cantilever resulting from shear forces transverse to the scan direction shows a close connection with the in-plane components of the elastic tensor of the polymer single crystals, which is of a fundamentally different origin than the friction forces. This allows for fast, facile, and nondestructive characterization of the microstructure and in-plane elastic anisotropy of compliant crystalline materials such as polymers.

A comparison of biofiltration performance based on bacteria and fungi for treating toluene vapors from airflow.

With increasing concerns about industrial gas contaminants and the growing demand for durable and sustainable technologies, attentions have been gradually shifted to biological air pollution controls. The ability of Pseudomonas putida PTCC 1694 (bacteria) and Pleurotus ostreatus IRAN 1781C (fungus) to treat contaminated gas stream with toluene and its biological degradation was compared under similar operating conditions. For this purpose, a biofilter on the laboratory scale was designed and constructed and the tests were carried out in two stages. The first stage, bacterial testing, lasted 20 days and the second stage, fungal testing, lasted 16 days. Inlet loading rates (IL) for bacterial and fungal biofilters were 21.62 ± 6.04 and 26.24 ± 7.35 g/m3 h respectively. In general, fungal biofilter showed a higher elimination capacity (EC) than bacterial biofilter (18.1 ± 6.98 vs 13.7 ± 4.7 g/m3 h). However, the pressure drop in the fungal biofilter was higher than the bacterial biofilter (1.26 ± 0.3 vs 1 ± 0.3 mm water), which was probably due to the growth of the mycelium. Fungal biofiltration showed a better performance in the removal of toluene from the air stream.

Novel and simple design of nanostructured, super-insulative and flexible hybrid silica aerogel with a new macromolecular polyether-based precursor.

This study reports a new strategy to fabricate a thermally super-insulative and flexible hybrid silica aerogel. A new generation of polymeric precursors was first synthesized for hybrid organic/inorganic silica aerogels from an epoxide ring containing a silica precursor. Ring opening polymerization (ROP) was used so as to insert flexible ether groups into the main chain. It has been demonstrated that the particulate structure of the polyether-based silica aerogel could be changed to a novel non-particulate and continuous one, by meticulous control of the thermodynamics, namely, through variations of the molecular weight of the polymeric precursor, the amount of the non-solvent, and the temperature. The study presents a new strategy to manufacture a polyether-based hybrid silica aerogel, which is fast and scalable, and also eliminates the aging process while accelerating the gelation time. This new strategy reduces the wet gel preparation time, including gelation, aging and solvent exchange, from several days to just a few seconds. However, this structure suffers from a low void fraction and wide pore size distribution. These drawbacks are then removed by chemically incorporating pre-polymerized vinyl trimethoxysilane chains. The resultant aerogels exhibit thermal superinsulation (λ = 15.9 mW·m-1·K-1) while providing good mechanical properties and flexibility. The polyether-based aerogels also demonstrated good performance as adsorbent material to remove organic solvents from water.

Robust, ultra-insulative and transparent polyethylene-based hybrid silica aerogel with a novel non-particulate structure.

Aerogels derived from pre-polymerized vinyl trimethoxy silane (VTMS) precursor with nano-size particles are known to exhibit outstanding mechanical and insulation properties. However, the density reduction has been limited by the poor connectivity. This paper presents an innovative technology to generate a new class of VTMS-based hybrid silica aerogels that possess outstanding non-particulate, reticulated structure and superior properties. This technology relies on spinodal decomposition instead of conventionally exploited binodal decomposition, which leads to a particulate structure. This new aerogel technology has significantly increased the void fraction of the pre-polymerized VTMS-based aerogel, which could not be achieved previously using binodal decomposition. The increased void fraction in the form of nano-pores with an average pore size of 21.75 nm nullifies the gas thermal conductivity effectively. Another consequence of the non-particulate structure is decreased processing time by removing the aging step. These improvements are due to the non-particulate structure's increased connectivity produced by spinodal decomposition. This novel structure was then compared to a particulate counterpart aerogel of the same material derived from the conventional binodal decomposition of the pre-polymerized VTMS precursor. To further decrease the processing cost, a lower molecular-weight polymeric precursor was synthesized under milder polymerization conditions. The effects of the polymeric precursor's molecular weight on the mechanical and thermal properties of the aerogel created via spinodal decomposition were also investigated.

The effect of graphene-nanoplatelets on gelation and structural integrity of a polyvinyltrimethoxysilane-based aerogel.

Aerogels suffer greatly from poor mechanical properties resulting from their particulate structure. They also experience noticeable pore shrinkage during drying due to their low structural integrity. These shortfalls limit their broad application. To enhance the mechanical properties and improve the structural integrity of silica-based aerogels, graphene nanoplatelets (GnPs), as a nanofiller, were embedded into the solution of polymerized vinyltrimethoxysilane (VTMS) to prepare P-VTMS-based silica/GnP (PE-b-Si/GnP) hybrid aerogel monoliths based on sol-gel synthesis and supercritical drying. The inclusion of GnPs in our polymer-based silica aerogel processes reinforced the nanostructure and suppressed PE-b-Si nanopore shrinkage during supercritical drying, thus acting as an effective anti-shrinkage nanofiller. Accordingly, the GnPs significantly contributed to the PE-b-Si solution's uniform gelation and to the change of the hydrophilic nature to a hydrophobic one even with 1 wt% addition. In this study, the influence of the GnP content on the sol-gel process, structure, and physical properties of PE-based silica aerogels is studied.

Synchronous Identification of Entamoeba histolytica, Giardia intestinalis, and Cryptosporidium spp. in Stool Samples Using a Multiplex PCR Assay.

BACKGROUND: Diarrheal disease annually causes 760000 deaths in children, and 1700 million new cases are reported each year worldwide. Among the parasites, Entamoeba histolytica, Giardia intestinalis, and Cryptosporidium spp. are the most important infectious agents leading to diarrhea. Clinical presentations due to these parasites are more or less similar, and microscopy is not as much as sensitive for the detection. The aim of this study was to set up and evaluate a Multiplex PCR Assay for Synchronous Identification of Entamoeba histolytica, Giardia intestinalis, and Cryptosporidium spp. in Stool Samples. METHODS: Samples were obtained from different sources such as culture media and patient stool samples. Primer pairs were designed using primer-BLAST, and for the extraction of DNA, the QIAamp DNA stool mini kit was used. The study was conducted in Tehran, Iran and completed in 2016. RESULTS: The current multiplex PCR assay for the detection of E. histolytica achieved sensitivity and specificity of 86.36% (95% CI: 65.09% to 97.09) and 95.74 % (95% CI: 85.46% to 99.48%), respectively. Sensitivity and specificity of the test for G. intestinalis was 90.91% (95% CI: 70.84% to 98.88%) and 95.74% (95%CI: 85.46% to 99.48%), respectively, and for the detection of Cryptosporidium, multiplex PCR showed a sensitivity of 90.91% (95% CI: 70.84% to 98.88%) and specificity of 95.74% (95%CI: 85.46% to 99.48%). CONCLUSION: Multiplex PCR in this study showed admissible sensitivity and specificity for the detection of E. histolytica, G. intestinalis, and Cryptosporidium spp. in fecal samples.

Subtype analysis of Giardia duodenalis isolates from municipal and domestic raw wastewaters in Iran.

A total of 54 raw wastewater samples collected from three urban treatment plants and two slaughterhouses in Tehran, Iran, were assessed for the presence of the Giardia cysts using immunofluorescence with monoclonal antibodies. To characterize the cysts at the molecular level, the three genetic loci were amplified and sequenced. The assemblages A (37.5 %) and E (58.3 %) were detected in livestock wastewater samples. Assemblage A, which is composed of only G. duodenalis genotype, was detected in 100 % of urban wastewater samples. The subassemblages A2, A3, A-I, A-II, and E3 were identified with ß-giardin, triose phosphate isomerase, and glutamate dehydrogenase genes. This study is the first to report on G. duodenalis genotypes in aquatic environmental samples in Iran.

Evaluation of a New Primer In Comparison With Microscopy for the Detection of Giardia lamblia Infection in Stool Samples.

BACKGROUND: Among the most important parasitic disease, causing diarrhea, Giardia lamblia is noteworthy. Nowadays detection methods for these parasites include parasitological methods such as microscopic examination. The sensitivity of these methods relies on the expertise and experience of examiners. In contrast, molecular methods such as PCR are less dependent on the expertise of the examiner. Here we developed a PCR for the detection of G. lamblia genome in stool samples in comparison with microscopy, which is the gold standard. METHODS: For the evaluation of primers, 22 positive samples and 47 negative samples were used. QIAamp DNA Stool Mini Kit (QIAGEN, Germany) was used for DNA extraction from feces. Primers for PCR were designed using Primer-BLAST which uses Primer 3 to designing specific primers (NCBI/Primer-BLAST). RESULTS: Sensitivity of the PCR was done with 100% (95%CI: 84.56-100) for the detection of G. lamblia DNA isolated from patients stool samples which were positive for G. lamblia cysts and/or trophozoites using microscopy as gold standard. In comparison with microscopy, PCR had showed the specificity of 97.87% (95%CI: 88.71-99.95). CONCLUSION: We designed new primers for the Giardia, and PCR method for the rapid and accurate identification of Giardia parasites established. With consideration to the routine diagnosis techniques in medical parasitology and their limitations such as time consuming, laborious, less sensitivity etc. This G. lamblia PCR is a sensitive and specific application for the diagnosis of G. lamblia and provides us a reliable method in the routine intestinal parasitic infection laboratory diagnosis.

Microscopic and Molecular Detection of Cryptosporidium andersoni and Cryptosporidium xiaoi in Wastewater Samples of Tehran Province, Iran.

BACKGROUND: As a waterborne pathogen, Cryptosporidium is one of the most common causes of gastroenteritis in human and hoofed livestock animals. This study aimed to investigate the distribution of Cryptosporidium spp. in human and livestock wastewaters in Iran, by the 18S rRNA sequence analysis. METHODS: A total of 54 raw wastewater samples collected from three urban treatment plants and two slaughterhouses during 2014-2015 in Tehran, Iran. The presence of the Cryptosporidium oocysts was assessed by immunofluorescence with monoclonal antibodies. To characterize the oocysts at the molecular level, the 18S rRNA gene of Cryptosporidium was PCR amplified and sequenced. RESULTS: Of the 54 wastewater samples examined, 34 (62.9%) were positive for Cryptosporidium oocysts using the IFA. Of these, 70.5% (24/34) were positive by PCR, that 91.6% (22/24) were successfully sequenced. The species of C. andersoni (95.4%) and C. xiaoi (4.6%) were detected in livestock wastewater samples. CONCLUSION: C. andersoni was the major Cryptosporidium sp. found in the aquatic environmental wastewater samples. The high rate of detection of C. andersoni in domestic wastewater was probably the result of the predominancy of this species in cattle herds in Iran. The current study is the first report of C. xiaoi in Iran.

Fungal rhino sinusitisin in tehran, iran.

BACKGROUND: Fungal rhino sinusitis (FRS) is an important infection of para nasal sinuses, which encompasses two main categories; invasive and noninvasive forms according to histopathological findings. Aspergillus spp are the most common species isolated from noninvasive form, while Mucorales are more frequently isolates from acute infections. METHODS: Four hundred fifty patients suspected to fungal rhino sinusitis were investigated in a cross-sectional prospective study from June 2009 to Sep 2013. All patients under went endoscopic sinus surgery of the middle meatus. Tissue biopsies were investigated for culture, histopathology and molecular examination. RESULTS: Totally, 87 patients were diagnosed with fungal rhinosinusitis. A. flavus was the most common etiological agent of chronic invasive form (CIFRS), allergic fungal rhino sinusitis (AFRS) and fungus ball (FB), while Rhizopus oryze (26.7%) was the most common cause of infection in acute invasive fungal rhino sinusitis (AIFR). However, a few rare species such as Shyzophyllum commune and Fusarium proliferatum were also isolated. CONCLUSION: Diabetes is the most important predisposing factor for patients with acute invasive form of sinusitis and the most involved sinuses were unilateral multiple sinuses and maxillary sinus.

Identifying differentially expressed genes in trophozoites and cysts of Acanthamoeba T4 genotype: Implications for developing new treatments for Acanthamoeba keratitis.

Acanthamoeba T4 genotype is the most prevalent genotype associated with amoebic keratitis. Acanthamoeba keratitis therapy is difficult due to transformation of trophozoite to cyst stage, which hinders the treatment of the disease. Although encystation assists the organism to survive against the chemotherapeutic compounds, the precise mechanism of encystation remains poorly understood. The purpose of this work was to identify differentially expressed genes in Acanthamoeba T4 genotype which might be useful for understanding of the encystment process and may thus help develop more efficient treatment. The mRNA profile of trophozoite and cyst of Acanthamoeba T4 genotype isolated from a soft contact lens wearer were analyzed using a cDNA amplified fragment length polymorphism (cDNA-AFLP) technique. Subsequently, a real time reverse transcriptase-PCR was performed to validate the cDNA-AFLP results. Three genes, heat shock protein70 (hsp70), actin-I and elongation factor-1alpha (EF-1α) were differentially expressed during Acanthamoeba differentiation. An in silico result predicted that transformation of trophozoite to cyst could be mediated through their cooperation with the protein partners interaction. Taken together, our experimental and bioinformatics findings suggested potential functions of hsp70, EF-1α and actin-I in differentiation of Acanthamoeba T4 genotype which may be useful in the design of an efficient therapeutic strategy in AK.

Preparation and characterization of kefiran electrospun nanofibers.

In this study, we report the first successful production of kefiran nanofibers through electrospinning process using distilled water as solvent. For this purpose, kefiran was extracted from cultured kefir grains, and homogenous kefiran solutions with different concentrations were prepared and then electrospun to obtain uniform nanofibers. The effect of main process parameters, including applied voltage, tip-to-collector distance, and feeding rate, on diameter and morphology of produced nanofibers, was studied. Scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were used to characterize electrospun mats. Rheological behavior of the kefiran solution was evaluated via a cone and plate rheometer too. The results exhibited that diameter of kefiran nanofibers increased with increasing polymer concentration, applied voltage, and polymer feeding rate, while tip-to-collector distance did not have significant effect on nanofiber diameter. ATR-FTIR spectra showed that kefiran has maintained its molecular structure during electrospinning process. Flow curves also demonstrated shear thinning behavior for kefiran solutions.

Direct diagnosis of Leishmania species on serosity materials punctured from cutaneous leishmaniasis patients using PCR-RFLP.

This study was aimed at identifying the Leishmania species using serosity materials punctured from skin lesions of cutaneous leishmaniasis (CL) patients by using internal transcribed spacer1 (ITS1) polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). We used the PCR-RFLP on 60 parasitological confirmed CL patients who referred to leishmaniasis laboratory from the School of Public Health, Tehran University of Medical Sciences. The PCR-RFLP could correctly detect 51 Leishmania species of the 60 confirmed positive specimens, where all the other 10 parasitological (microscopy and culture) negative samples that were prepared from other bacterial- and fungal-infected lesions had negative results. The results also revealed that Leishmania major was the dominant species (53.3%). This study suggests that the PCR-RFLP assay with serosity materials punctured from CL patients using Hae III enzyme is useful for the rapid identification of Leishmania species.