mohammadjavad kazemi

This study was conducted on the feasibility of improving processes of thickening, anaerobic digestion, and sludge dewatering at wastewater treatment plants on a laboratory pilot scale, aiming to reduce polyelectrolyte consumption by 50% and replace it with chemical sludge. Parameters of Sludge Volume Index (SVI), Specific Filtration Resistance (SRF), compressibility coefficient, filtration rate, and biogas production rate were investigated. It is shown that by applying 200 mg/g of water treatment plant sludge to wastewater sludge, the compressibility coefficient was decreased by 27%, the filtration rate was increased by 70%, and SVI and SRF were decreased by 64.9% and 43.3%, respectively. Therefore, it has facilitated the sludge sedimentation and release of its free water. On the other hand, adding the sludge from a water treatment plant led to the proper access of microorganisms to micronutrients and improvement of their performance resulting in an increase of 7.77% in the total biogas production. The iron present in the digestion process caused an increase in biogas production by increasing the activity of enzymes, reducing oxidation-reduction potential, and improving the direct interspecies electrons transfer. In conclusion, adding the optimal amount of water treatment plant sludge, along with the environmental management of a meaningful portion of water and wastewater residuals, may play an important role in significantly reducing polyelectrolyte consumption and improving biogas production.

The issue of optimal disposal of sludge in water treatment plants is among the important issues in line with the principles and goals of sustainable development. In this study, the possibility of applying activated carbon and water treatment sludge with the purpose of reducing the consumption of cationic polyelectrolytes in the thickening stage of wastewater treatment sludge on a laboratory pilot scale was investigated. For this purpose, the effect of these additives on SVI, TTF, DS, pH, and the dosage of polyelectrolytes used was evaluated. SVI and TTF of conditioned sludge at a dose of 300 mg/g along with 1 mg/l of cationic polyelectrolyte decreased to less than 100 ml/g and 100 s-1, respectively, and also increased the amount of sewage sludge solids to at least 5%. Large flocs formation, particles size distribution change, and increasing the porosity of the sludge have become as a result of adding the conditioning materials, and facilitating the thickening and releasing of free water. In addition to improving the efficiency of sewage sludge thickening, these industrial wastes reduce polyelectrolyte consumption by 50%, protecting the environment from the negative impacts of their disposal.

One of the layers that is applied on the base layer in asphalt pavements and increases the cohesion between the two layers, is the prime coat layer. Due to the fact that there are usually problems with the prime coat penetration into the base layer and penetration is not usually done well, there is a need to identify the factors affecting the penetration into the base layer. In this study, the penetration rate of prime coat coatings made of emulsified bitumen CSS-1h on the grain base level with different aggregate grading (aggregation close to the lower, middle and upper limits in two different types of aggregate grading) and different compaction levels were examined. Optimum water content, density, California Bearing Ratio (CBR) and the permeability of the samples were also examined. According to the results, the compressive strength of stone materials samples increases with approaching the upper limit (fine grain) and increasing the compaction. Also, increasing the grain size and decreasing compaction, increases the prime coat penetration rate, so that the 90% compacted sample with aggregate grading Type 3 has the highest penetration rate. The effect of moisture is obvious on the prime coat penetration, so that prime coat penetration rate is greatly reduced in saturation mode, but moisture in the base layer can help the prime coat to penetrate into the base layer.

The genus Lactobacillus contains several Gram-positive bacteria that are microaerophilic or facultatively anaerobic. These are the main groups of lactic acid bacteria. Some lactobacilli are used in the production of yogurt, cheese, and other fermented products. The purpose of this study was to isolate, identify, and characterize the technological characteristics of lactic acid isolated from a single-humped camel in the city of Tabas, Iran,by standard technological properties tests. From a total of 12 raw milk samples, 60 isolates were investigated by morphological and Gram studies. Thirty-six isolates of catalase-negative and Gram-positive selected for genus identification were compared using the Bergey Book. All examined isolates were analyzed to determine the carbohydrate fermentation pattern and CO2 production. The results showed that 23 isolates of Lactobacillus (with a 63.88% frequency) were found in five groups, including Lactobacillus gasseri isolates (L1-L7), Lactobacillus gallotix isolates (L8-L13), Lactobacillus xiangfangensis isolates (L14-L16), Lactobacillus salivarius isolates (L17-L21), and Lactobacillus paracasei isolates (L22, L23). Additionally, five Pediococcus isolates, P1-P5 (13.99%), and eight Enterococcus isolates, E1-E8 (2.22%), were obtained. Seven isolates were evaluated for molecular identification using 16S rRNA. Finally, five Lactobacillus, one Pediococcus, and one Enterococcus were identified. These seven isolates were examined by complementary tests including proteolytic, lipolytic and autolytic activities, and antibiotic and acid resistance. Two isolates, K030508 (L. salivarius) and K020704 (L. xiangfangensis), exhibited the highest potential for future commercial use as a starter culture.

Abortion is the most common complication in the first trimester of pregnancy. Infections are reported as the etiology of abortions. Some species of Mycoplasmas are seen in the lower genital tract. The aim of this study was to investigate the frequency and the molecular identity of Mycoplasma species in women with a history of idiopathic recurrent abortion.

This study was carried out on 68 women with a history of recurrent abortion. Detecting 16S rRNA to identify the infection of Mycoplasma was done by polymerase chain reaction (PCR) on cervical samples. Furthermore, the sequencing of positive samples was performed to identify the species of Mycoplasma.

The results showed that only one woman with history of three times abortions was infected by Mycoplasma. Her gestational age was six weeks and she had apparent signs of infection. After sequencing, Mycoplasma genitalium was diagnosed as the infectious agent. The prevalence rate of Mycoplasma was 1.47% and 0% in the case and control groups, respectively. There was no significant association betweenabortion and Mycoplasma infection.

It seems more studies are necessary to evaluate the relationship between Mycoplasma infection and abortion. Moreover the increase in the level of public health due to better education and the improvement of contraceptive methods compared to the past has created a significant reduction in Mycoplasma infection.

On commercial contracts, firstly, parties agree to resolve their disputes through amicable negotiations before referring to an arbitrator or the judiciary in a bid to settle their disputes at the lowest possible cost as well as in the shortest possible time and also the least possible damage to their commercial relationship. From the perspective of economic analysis, negotiation is considered as an economic behavior that parties with regard to its results, perform cost and benefit analysis as well as organize their behavior in a bid to achieve maximum benefits as well as resolve their disputes.The main question which is raised in this paper is whether the initial settlement of disputes through negotiation is consisted with economic basis or not. The following hypothesis which is proposed is that the peaceful settlement of disputes (negotiation) not only is complied with the economic theories but also is strongly consistent with the economic formulas such as cost-benefit, efficiency and welfare

Helicobacter pylori-associated gastritis is regarded as the most prevalent gastrointestinal infection, as well as the major cause of several other diseases. Despite being
discovered over 30 years ago, no golden diagnostic method has yet been suggested for this microorganism.

The present study aimed to compare two common diagnostic methods of histology and serology.

This cross-sectional study began in July, 2016, and was conducted at Imam Jafar Sadegh Hospital (a university hospital) in Maybod, Yazd, Iran, on 70 patients. All the patients underwent endoscopy, and biopsy samples were taken for histology, as well as blood samples for ELISA test. Finally, sensitivity, specificity, NPV (negative predictive values), and PPV (positive predictive values) were calculated and analyzed.

The sensitivity, specificity, accuracy, PPV, and NPV of the ELISA method with histology as the gold standard were 87.5%, 36.9%, 54.2%, 42%, and 85%, respectively. Still, the histology method appears to be the most reliable test for the diagnosis of H. pylori in Iran.

Regarding the high prevalence of H. pylori in Iran, the present study recommends the use of histology as a diagnostic method in combination with other diagnostic methods for detecting H. pylori infection.

Pharmaceuticals and micro pollutions have been regularly flushing into water resources through municipal and industrial wastewater plants. This problem therefore, needs more attention. Conventional water and wastewater treatment plants couldn’t eliminate these pollutions and it needs advanced treatment, otherwise humans and animals’ health would be in danger by them. Advance oxidation processes have the ability of removal of Pharmaceuticals like Carbamazepine. And in this study, Carbamazepine removal has been examined through Electrochemical Peroxidation process at optimum pH(e.g. pH=3), also other effective operation conditions include contact time, current density, hydrogen peroxide and proportion of iron to hydrogen peroxide have been optimized through surface response method by Design Expert software. After experiments was completed, results have been analyzed and correlation coefficient of 94 percent computed, and proportion of iron to hydrogen peroxide has been identified as the most effective parameter in Carbamazepine removal. To achieve a removal more than 90%, 13 solutions have been predicted by different operation conditions. The best scenario with 98% desirability, was 67.5 minutes contact time, 26 mM hydrogen peroxide concentration, 14.75 mA current density and 0.002 proportion of iron to hydrogen peroxide.

Disposal of micro-plastics to land, oceans, lakes and rivers has become a global environmental problem. The sources of micro-plastics in the environment are divided into two primary sources, such as cosmetic and sanitary and secondary materials, such as plastic bags which may degrade slowly by the time. The importance of micro-plastics and their effects in aqueous media and other environments are discussed in the present study. The present study is a review on the results of the search in the Iranian and international bases of Elsevier, Springer, Pubmed, Science Direct, Google Scholar, SID, CIVILICA, Google, Irandoc, Magiran. In English, the combination of the words "Micro Plastic", "Environment", "Water Resource," and in Persian "Micro Plastic", "Water Resources" and "Environment" were used. The results were categorized in three sections: micro-plastics in water and environments, micro-plastics in the soil and beaches, and micro-platics in food and the related health concerns. According to the findings and observations of these materials, they can have adverse effects on the environment and living organisms due to their inherent toxicity, chemical composition, being non-degradable in nature and having the potential of bioaccumulation of pathogenic microorganisms and cause the changes in ecosystems. It is therefore suggested that the production and supply of cosmetics, plastics, and the use of plastic bags be reduced to the possible extent, or rigorous laws should be adopted. In addition, scientific study is necessary to achieve the potential for micro-plastic to enter the country's water resources.

In commercial contracts, the parties usually agree to settle their disputes through amicable negotiations prior to refereeing them to arbitration or judiciary and hereby they will be achieved a settlement by maintaining their commercial relations with the lowest cost, time and damages. Although these agreements are very prevalent in commerce, their legal status, especially in respect of obligations of the parties and legal consequences of their breach, has not thoroughly been discussed. In this research paper, the legal status of these agreements will be first studied as an obligation on the parties to negotiate before refereeing their disputes to arbitration or judiciary. Based on such agreements, the parties are banned from referring their disputes to arbitration or judiciary before they first try to settle their disputes via amicable negotiations on a bona fide basis and on an organized manner. The breach of this obligation would also lead to a contractual liability.

In current study, three dimensional numerical analysis has been employed to investigate the flow and thermal fields, for different geometry of the hole injection of the film cooling over a flat plate. The computational methodology includes the use of a structured, non-uniform hexahedral grid consisting of the main flow channel, the coolant delivery tube and the feeding plenum, applying the SIMPLE algorithm for pressure-velocity coupling. The two sister holes injection located in the vicinity of to the main injection the cylindrical and the fan-shaped hole by angles of 15, 0 and -15 degree to decrease the strength of counter rotating vortex pairs of the main injection hole and the film cooling performance investigated for two blowing ratios of 0.5 and 1 and density ratio of 1.6. The results show that for blowing ratio of 1, the using of sister holes with the angle of 15 degree with fan-shaped hole injection has the best film cooling performance and increases the performance of film cooling about 37.44% more than the base case which is used from sister holes with the angle of 0 degree with cylindrical hole injection.

The emergence of Pseudomonas aeruginosa as a multiple drug resistant bacteria has renewed efforts to identify alternative antibacterial materials, such as medicinal plants..
The aims of this study were to investigate the antibacterial effects of a Rumex dentatus methanol extract against drug resistant P. aeruginosa isolates and to analyze the chemical composition of this extract..
Sixty strains of P. aeruginosa were isolated from urine and wound samples and identified using conventional tests, as well as 16S rDNA gene sequencing..
The isolates were completely resistant to the tested antibiotics, with minimum inhibitory concentration (MIC) values for ceftazidime, imipenem, and gentamicin between 256 to > 256 μg/mL, 8 to > 256 μg/mL, and 64 to > 256 μg/mL, respectively. The R. dentatus extract had a broad spectrum activity against all tested isolates and maximum growth inhibition against isolates from burn wound and urinary tract infections occurred at 200 mg/mL (22.43mm and 22.86mm, respectively). The means of the MIC and minimum bactericidal concentration (MBC) values were 25 and 50 mg/mL, respectively. The effects of a combination of the methanol extract and ceftazidime, imipenem, and gentamicin antibiotics were antagonistic. The GC-MS analysis of the methanol extract revealed a high probable presence percentage of alpha-pinene, sabinene, and eucalyptol (1, 8-cineole) that have confirmed antimicrobial activity..
The R. dentatus methanol extract with broad spectrum activity can be viewed as an alternative to antibiotics for treatment of P. aeruginosa infection..

One of the most common diseases worldwide is urinary tract infection (UTI). The main agents causing these infections are bacteria. Urinary tract infections occur when uropathogens colonize the urethra, migrate to the bladder and invade urinary tract cells.
The purpose of this study was the detection of uropathogens causing UTIs, as well as serotyping and antibiotic susceptibility of the most common bacteria.
The study was performed on 300 urine samples collected from patients referred to Koohdasht Imam Khomeini hospital of Lorestan province. After culturing the samples and determination of uropathogens, antibiotic susceptibility test was performed by the Kirby-Bauer disk diffusion method. Serotyping was performed for the most common uropathogens by polyvalent and monovalent antisera.
Of the 300 samples, 61 samples (20.33%) were positive for UTIs. Among these, 49 samples (80.33%) were Gram-negative bacteria and 12 (19.67%) Gram-positive. The most common uropathogens in UTIs were Escherichia coli (55.74%), Proteus species (11.47%), Staphylococcus epidermidis (11.47%), Citrobacter species (8.20%), Staphylococcus aureus (8.20%) and Klebsiella species (4.92%), respectively. The rate of UTI in females (83.61%) was more than males (16.39%). The highest level of resistance was towards trimethoprim/sulfamethoxazole and the lowest to ampicillin, ciprofloxacin and nitrofurantoin. The most common uropathogen was Escherichia coli and the most common serotypes were O142:K86 and O25:K11, respectively.
The treatment of UTIs and resistance control in bacteria should be done based on common strains and choosing an effective antibiotic. Therefore, the determination of prevalent bacterial strains in UTIs of each region based on laboratory tests is very important.

Chlamydia trachomatis is one of the most common causes of genital infection in men and women. Genital chlamydial infections in women are clinically asymptomatic in 70-80% of the cases; therefore, the lack of timely diagnosis and treatment leads to complications such as infertility and ectopic pregnancy. The aim of this study was to evaluate the frequency of chlamydial infection in symptomatic and asymptomatic women in the Golestan province.
This cross-sectional study was conducted on 150 cervical swab samples obtained from 150 women referred to the clinic, after obtaining written consent and completion of questionnaires. The swab samples were transferred to laboratory in phosphate-buffered saline solution and DNA extraction was carried out using phenol-chloroform and boiling methods. The frequency of chlamydial infection was evaluated by PCR.
None of the tested samples were found as Chlamydia-positive.
The findings require that some more extensive research with larger sample sizes and dispersed population be performed to determine the true prevalence. Considering the serious complications of chlamydial infections and its asymptomatic nature, a highly sensitive and specific method such as PCR should be used to detect Chlamydia. It is suggested that this method be used along with a complementary test to obtain the results that are more accurate. Furthermore, conducting simultaneous studies on other populations at risk will be very helpful in obtaining representable national data.

Cirrhosis is one of the most severe liver complications, with multiple etiologies. The torque teno virus (TTV), also known as transfusion transmitted virus, which has a high incidence in the world population, is one of the possible increasing risk factors in patients with idiopathic fulminant hepatitis and cryptogenic cirrhosis.. The aim of this study was to evaluate solitary and co-infection with TTV, in patients with cryptogenic and determined cause of cirrhosis..Patients and In this cross-sectional study, 200 liver transplant patients were consecutively recruited between years 2007 and 2011. Patients were classified, based on recognition of the etiology of cirrhosis to determined (n = 81) and cryptogenic (n = 119) patient groups. The existence of TTV infection was analyzed, using a semi-nested polymerase chain reaction method. The presence of hepatitis B virus (HBV) infective markers, including HBV DNA, hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B core antibody (HBcAb), and hepatitis B e antibody (HBeAb), was evaluated using qualitative polymerase chain reaction and enzyme linked immunosorbent assay protocols, respectively.. The TTV infection was found in 37 of 200 (18.5%) and 53 of 200 (26.5%) plasma and tissue samples of studied liver transplanted patients, respectively. The TTV genomic DNA was found in 32 (26.9%) and 28 (23.5%) of 119 liver tissue and plasma samples of transplanted patients with cryptogenic cirrhosis, respectively. The genomic DNA of TTV was also diagnosed in 21 (25.9%) and nine (11.1%) of the 81 liver tissue and plasma samples of patients with determined cirrhosis, respectively. Significant associations were found between TTV infection with HBV molecular and immunologic infective markers, in liver transplanted patients, with determined and cryptogenic cirrhosis.. The diagnosis of the high frequency of solitary TTV and co-infection with HBV, in both liver transplanted patients with cryptogenic and determined cirrhosis, emphasized on the importance of TTV infection in the development of cirrhosis, especially in the cases of cryptogenic ones, prompting for further studies the confirm this agent in the etiology of determined cirrhosis..

Nosocomial infections are primarily caused by Klebsiella bacteria, which lead to an increase in healthcare costs and the mortality rate. Concerning the alarming increased antibiotic resistance of Klebsiella species, the purpose of this study was to compare the frequency and determine the antibiotic resistance pattern of Klebsiella species isolated from nosocomial infections using Kirby Bauer method.

This study was done on 80 specimens of Klebsiella isolates from 480 hospitalized patients in three different units of Khorramabad Shohadaye Ashayer hospital. After determining the bacterial species, antibiotic-resistance test of Klebsiella species was performed for 15 antibiotics using the disk diffusion method. The results were recorded based on Clinical and Laboratory Standards Institute (CLSI) standard guidelines.

The frequency rates of Klebsiella species were determined as follows: Klebsiella pneumoniae (91%), Klebsiella oxytoca (5%), Klebsiella rhinoscleromatis (3%), and Klebsiella ozaenae (1%). The frequency of Klebsiella species on the basis of sources of infection and type of sample respectively were: urine (42%), lung and sputum (36%), wound (15%), blood (6%), and cerebro-spinal fluid (CSF) (1%). The resistance of all Klebsiella species to studied antibiotics were respectively as follows: ceftriaxone (92%), ciprofloxacin (82%), nitrofurantoin (80%), ofloxacin (75%), cefotaxime (70%), imipenem (67%), ticarcillin (66%), nalidixic acid (60%), gentamicin (52%), azithromycin (40%), cefepime (31%), polymyxin B (22%), colistin (17%), amikacin (7%), and meropenem (1%).

According to the obtained results, meropenem and amikacin with the lowest resistance are the most effective antibiotics against all Klebsiella strains, and although ceftriaxone antibiotic does not help in the treatment of Klebsiella infections, but it may cause antibiotic resistance.