Zero divisors and units with small supports in group algebras of torsion-free groups

We associate a graph to a possible non-zero zero-divisor in the group algebra of a torsion-free group.Comment: to appear in Communications in Algebra. arXiv admin note: substantial text overlap with arXiv:1612.0093

Zero divisors of support size 33 in group algebras and trinomials divided by irreducible polynomials over GF(2)GF(2)

A famous conjecture about group algebras of torsion-free groups states that there is no zero divisor in such group algebras. A recent approach to settle the conjecture is to show the non-existence of zero divisors with respect to the length of possible ones, where by the length we mean the size of the support of an element of the group algebra. The case length $2$ cannot be happen. The first unsettled case is the existence of zero divisors of length $3$. Here we study possible length $3$ zero divisors in rational group algebras and in the group algebras over the field with $p$ elements for some prime $p$

Efficacy of flour fortification with folic acid in women of childbearing age in Iran

Dieses ist die erste Bevölkerung gegründete Untersuchung über die Wirksamkeit der Mehlverstärkung mit Fol- Säure in den Frauen des Gebärenalters im Iran und eingeschlossen drei Bestandteilen, wie folgt: 1) Ermittlung der Ausdehnung von NTDs; 2) Fastende Blutanalyse; 3) Diätetische Einschätzung (24-hour-recall). Diese Studie war durchgeführte vorher und nachher Mehlverstärkung mit Fol- Säure. 2006 wurden Mehlverstärkung mit Eisen und Fol- Säure in einer der Nordprovinzen vom Iran (Golestan Provinz) eingeführt und abschließende Auswertung wurde 2008 durchgeführt. Die Mustergröße war 580 gesunde Frauen in der ersten Phase (vor Mehlverstärkung) und 580 Frauen nach Mehlverstärkung in der zweiten Phase (nach Mehlverstärkung), die zu 600 Frauen rundete, wie die Repräsentativprobe der Frauen im Gebärenalter in der Golestan Provinz. Daten wurden durch ein Interview auf dem Haushalt Niveau gesammelt. Serumkonzentrationen des Folats und des Vitamins B12 wurden mit Radioimmunoprobe- und Plasmahomocysteinkonzentrationen von HPLC mit Fluoreszenzabfragung gemessen. Daten bezüglich des NTDs Vorherrschens schlossen Phasen alle mit ein und Neugeborene des Stillbirths, die in der neugeborenen Maßeinheit der intensiven Obacht Dezyani des unterrichtenden Empfehlung Krankenhauses in Gorgan zugelassen wurden, die Hauptstadt der Golestan Provinz, wurden erfaßt. Die Resultate zeigen, daß das Mittelserumfolat, das von nmol 13.5 /L auf 18.1 nmol/L und Vorherrschenrate des Serumfolatmangels erhöht wurde, erheblich von 14.3% bis 2.3% verringerte, nach Mehlverstärkung (p = 0.000). Die Entdeckungen zeigen an, daß Vorherrschenrate von hyperhomocycteinemia von 38.3% bis 7.3% verringerte (p = 0.000). In dieser Forschung wurde Möglichkeit der Maskierung des Mangels des Vitamins B12 auch studiert. Das Mittel von MCV war (p =0.04) in der Periode von nachdem die Verstärkung (83.5fl) verglichen mit der Periode von erheblich niedriger, bevor Verstärkung (84.3%) der Anteil Frauen mit niedrigem Serumvitamin B12 ohne macrocytosis höher war, nachdem Verstärkung aber der Unterschied nicht bedeutend waren. Die Ausdehnung von NTDs wurde zwischen den ären vor Mehlverstärkung (September 2006 bis Juli 2007) und den Ohren nach Verstärkung (Dezember 2007 bis Dezember 2008) verglichen. Eine Abnahme in der NTD Ausdehnung (31%) wurde nach Mehlverstärkung mit Fol- Säure beobachtet. Die Resultate der vorliegenden Untersuchung zeigen, daß Fol- saurer Einlaß um ein durchschnittliches 226μg/day zugenommen hat an, wegen des Verbrauchs des verstärkten Brotes in den Frauen des Gebärenalters. Vom Gesichtspunkt des öffentlichen Gesundheitswesens würde Mehlverstärkung mit Fol- Säure eine wirkungsvolle Strategie sein, zum von Folatstatus der Frauen im Kindlageralter im Iran zu verbessern.This is the first population based study on the efficacy of flour fortification with folic acid in women of childbearing age in Iran and included three components as follows: 1) Determination of incidence of NTDs; 2) Fasting blood analysis; 3) Dietary assessment (24-hour-recall).This study was carried out before and after flour fortification with folic acid. In 2006, Flour fortification with iron and folic acid was implemented in one of the northern provinces of Iran (Golestan province) and final evaluation was carried out in 2008. The sample size was 580 healthy women in the first phase (before flour fortification) and 580 women after flour fortification in the second phase( after flour fortification) ,which rounded to 600 women, as the representative sample of women in childbearing age in Golestan province . Data were collected by an interview at the household level. Serum concentrations of folate and vitamin B12 were measured with radioimmunoassay and plasma homocysteine concentrations by HPLC with fluorescence detection. Data on the NTDs prevalence included all live and stillbirth's newborns who were admitted in neonatal intensive care unit of Dezyani teaching referral hospital in Gorgan, the capital city of the Golestan province, were gathered. The results show that the mean serum folate increased from 13.5 nmol /L to 18.1 nmol/L and prevalence rate of serum folate deficiency decreased significantly from 14.3 % to 2.3% , after flour fortification (p = 0.000) . The findings indicate that prevalence rate of hyperhomocycteinemia reduced from 38.3% to 7.3% (p = 0.000). In this research, possibility of masking vitamin B12 deficiency was also studied. The mean of MCV was significantly lower (p =0.04) in the period of after fortification (83.5fl) compared to the period of before fortification (84.3%) The proportion of women with low serum vitamin B12 without macrocytosis was higher after fortification but the difference was not significant. The incidence of NTDs was compared between the eras before flour fortification (September 2006-July 2007) and the ears after fortification (December 2007-December 2008). A decline of in NTD incidence (31%) was observed after flour fortification with folic acid. The results of the present study indicate that folic acid intake has increased by an average 226μg/day, due to consumption of fortified bread in women of childbearing age. From public health point of view, flour fortification with folic acid would be an effective strategy to improve folate status of women in child bearing age in Iran

A GIS-Based Spatiotemporal Impact Assessment of Droughts in the Hyper-Saline Urmia Lake Basin on the Hydro-Geochemical Quality of Nearby Aquifers

Urmia Lake is a hyper-saline lake in northwestern Iran that has been drying up since 2005. The main objective of this study was to evaluate the water quality in aquifers that are the main source of fresh water for the eastern plains Urmia Lake, which has been drying up due to intensive land use/cover changes and climate change. We evaluated hydro-geochemical data and factors contributing to aquifer pollution and quality variation for nine aquifers in the vicinity of Urmia Lake during the dry and wet seasons from 2000–2020. Our methodology was based on the analysis of 10 years of data from 356 deep and semi-deep wells using GIS spatial analysis, multivariate statistical analysis, and agglomerative hierarchical clustering. We developed a Water Quality Index (WQI) for spatiotemporal assessment of the status of the aquifers. In doing so, we highlighted the value of combining Principal Component Analysis (PCA), WQI, and GIS to determine the hydro-geochemical attributes of the aquifers. We found that the groundwater in central parts of the study area was unsuitable for potable supplies. Anthropogenic sources of contamination, such as chemical fertilizers, industrial waste, and untreated sewage water, might be the key factors causing excessive concentrations of contaminants affecting the water quality. The PCA results showed that over 80% of the total variance could be attributed to two principal factors for most aquifers and three principal factors for two of the aquifers. We employed GIS-based spatial analysis to map groundwater quality in the study area. Based on the WQI values, approximately 48% of groundwater samples were identified as poor to unsuitable for drinking purposes. Results of this study provide a better hydro-geochemical understanding of the multiple aquifers that require preventive action against groundwater damage. We conclude that the combined approach of using a multivariate statistical technique and spatial analysis is effective for determining the factors controlling groundwater quality.University of TabrizAlexander von Humboldt FoundationHumboldt-Universität zu BerlinPeer Reviewe

Intra-operative optical monitoring of bowel tissue viability based on photoplethysmography and laser doppler flowmetry

Determination of bowel viability in patients undergoing bowel resection is essential in gastrointestinal surgery. One of the most common operations in gastrointestinal surgery is bowel resection for patients who have different kinds of bowel cancer or any other occlusion in which anastomosis has to be carried out following the removal of an unhealthy segment of the bowel. Monitoring blood flow in abdominal surgery especially intraoperatively would be a valuable tool for prevention of a postoperative anastomosis complication (e.g. anastomotic leak, which is the main complication after colorectal resection). The development of a continuous method for monitoring perfusion of bowel tissue would assist in early detection of inadequate blood supply which then help to reduce the occurrence of an anastomosis complication. Although various monitoring techniques have been proposed to assess intestinal viability intraoperatively, none of these techniques have proved to be reliable enough to replace visual observation. Therefore, to date there is no widely accepted and readily available intraoperative technique to reliably assess the viability of bowel tissue. The aim of this study was to combine the established techniques, laser Doppler flowmetry (LDF) and Photoplethysmography (PPG), into one probe intended for assessment of perfusion in abdominal tissue during bowel resection intraoperatively. In PPG, changes in transmission of light through tissue due to pulsation of small arteries can be monitored whereas in LDF microcirculatory blood cell velocity and flux can be studied. Such a probe could alert the surgeon immediately of any compromise in blood flow so further investigation and, if necessary, therapeutic steps can be applied immediately to prevent severe consequences. Therefore, custom reflectance PPG along with LDF sensor was designed and built in the form of a probe to investigate the changes in blood volume, blood flow and arterial oxygen saturation in patients undergoing bowel resection. The instrumentation was designed successfully and the data was saved for the further analysis. Twenty-four patients undergoing bowel resection were recruited for monitoring of perfusion and blood flowintraoperatively; twenty had undergone laparoscopy and the remainder had a laparotomy operation. Eight different measurements were performed during each trial. The results revealed that the probe could be an indicator of evaluating perfusion and blood flow changes at different stages of the surgery. The results also suggest that laser Doppler is more sensitive to artefact compared to PPG. Differences in amplitude of PPG between different measurements reveal that the sensor does detect changes in blood volume and flow confirming that it has the ability to verify that pulsatile flow is being preferentially preserved at the last step of the resection procedure (at the edges of the anastomosis sites after anastomosis is been constructed

Effect of slow stroke back massage on anxiety in patients with stroke- A randomized clinical trial

زمینه و هدف: سکته ی ‌مغزی یک بیماری ناتوان کننده می‌باشد که استقلال بیمار را در انجام فعالیت های روزمره به شدت محدود نموده و باعث اضطراب بیمار می شود. ماساژ درمانی به عنوان یک هنر مفید و مؤثر در حرفه پرستاری شناخته شده است که یکی از انواع آن، ماساژ استروک سطحی پشت (SSBM) می باشد. لذا پژوهش حاضر به منظور تعیین تأثیر ماساژ SSBM بر اضطراب بیماران مبتلا به سکته ی مغزی انجام شده است. روش بررسی: در این پژوهش کارآزمایی بالینی که به صورت نیمه تجربی انجام شد، تعداد 34 بیمار از میان 70 بیمار مراجعه کننده به مرکز توانبخشی تبسم شهر تهران در سال 1389 انتخاب شدند و به روش تصادفی در دو گروه مداخله و شاهد قرار گرفتند. ابزار گرد آوری داده ها شامل پرسشنامه های مشخصات دموگرافیک و اضطراب آشکار اسپیل‌برگر بود. میزان اضطراب قبل و 24 ساعت پس از آخرین جلسه ماساژ SSBM در گروه ها ارزیابی و مورد مقایسه قرار گرفت. یافته ها: میانگین نمره اضطراب قبل از مداخله در گروه آزمون 8/25±61/40 و در گروه شاهد 3/85±61/80 بود که از لحاظ آماری تفاوت معناداری را نشان نداد (P>0/05). پس از مداخله میانگین نمره اضطراب گروه آزمون 4/62±34/60 و گروه شاهد 3/44±58/80 بدست آمد که تفاوت معناداری را نسبت به قبل از آزمون نشان داد (0/001>P). نتیجه گیری: بکارگیری ماساژ SSBM توسط پرسنل درمانی و مراقبتی می‌تواند گام مؤثری در پیشگیری یا کاهش اضطراب مبتلایان به سکته ی مغزی محسوب گردد

In Vitro Sealing Properties of Calcium-Enriched Mixture and Mineral Trioxide Aggregate Orifice Barriers during Intra-Coronal Bleaching

Introduction: This study aimed at evaluating the sealing properties of calcium-enriched mixture (CEM) compared to mineral trioxide aggregate (MTA) as a cervical barriers in intra-coronal bleaching. Methods and Materials: In this in vitro study, endodontic treatment was performed on 60 extracted human incisors and canines without canal calcification, caries, restorations, resorption or cracks. The teeth were then randomly divided into two experimental groups and two control groups (n=15). Then, CEM cement and MTA were applied as 3-mm intra-orifice barriers in the test groups; a mixture of sodium perborate and 30% hydrogen peroxide bleaching agents were placed within the pulp chamber for one week. Dye penetration method was used to evaluate the sealing ability of agents. Statistical analysis was performed using SPSS software. The Kendall coefficient was used to evaluate inter-observer agreement. The chi-squared test was used for statistical analysis. Results: The results showed that the penetration rates of CEM and MTA were the same as positive control group, with no significant differences (P=0.673 and P=0.408, respectively). However, there was a significant difference between the negative control group and CEM and MTA groups (P=0.001 for both groups). In addition, the sealing ability of MTA and CEM cement were not significantly different (P=0.682). Conclusion: During intra-coronal bleaching procedures CEM cement can be used as a cervical barrier with sealing properties comparable to that of MTA.Keywords: Calcium-Enriched Mixture Cement; Cervical Barrier; Intra-Coronal Bleaching; Mineral Trioxide Aggregat

Knowledge, attitude and practice of urban and ruarl households towards principles of nutrition in Iran: results of NUTRIKAP Survey.

Background: The aim of this study was to assess knowledge, attitude and practice of urban and rural households toward principles of nutrition in Iran. Methods: The study population was Iranian households who live in rural and urban areas in all provinces of the country. The sampling method at households’ level in each province was single stage cluster sampling with equal size clusters. The incumbent data was collected by a structured questionnaire and through the interview with the eligible subject in each household. Results: A total of 14,136 Iranian households were selected as total sample size, 9,149 urban households, and 4,987 rural households. Around 57.2% of urban and 49.5% of rural households was aware of food groups. Respectively in urban and rural households, about 35.1% and 39.7% had correct knowledge toward roles of food groups. Approximately 41.5% and 39.9% of households had accurate knowledge about reason of food eating in urban and rural areas, respectively. The results showed that 79.6% of them had favorable attitudes. The most of the households consumed red meat and poultry weekly whereas fish was eaten rarely. Fruits, vegetables and dairy were consumed daily in the most of households. Sugar intake was daily in the most of households and cream and butter intake was weekly. Conclusion: The most of households had moderate knowledge and good attitudes. Practice of families about food consumption was good. The results of this study can be used for proper intervention for improving of health society

An improved method for fabrication of Ag-GO nanocomposite with controlled anti-cancer and anti-bacterial behavior; a comparative study

In this study, two green procedures for Silver-Graphene Oxide (Ag-GO) nanocomposite synthesis were investigated. As a common method, AgNO3 was first loaded on the GO surface and then was reduced and stabilized by walnut green husk extract, producing Ag-GO-I. As an innovative approach, GO was first exposed to the extract and then the AgNO3 was added as the second step, producing Ag-GO-Pi. Physicochemical properties, antibacterial and cytotoxicity activity of both nanocomposites were subsequently studied comparing with free silver nanoparticles (AgNPs) and pure GO. Based on the results, exposure of GO to the extract, as a reducing agent, at the first/last step of the synthesis process resulted in the fundamental differences in the final products. So that, high amounts of agglomerated silver nanoparticles were formed between the GO sheets, when using the common method, whereas in Ag-GO-Pi, small AgNPs were formed on the GO sheets without aggregation, entirely covering the sheets. Antibacterial and cytotoxic behavior of these nanomaterials could be compared as AgNPs > AgGO-Pi > Ag-GO-I. It is assumed that these differences are due to control of unwanted nucleation in the synthesis process that Ag nanoparticles are smaller with less agglomeration when the GO surfaces are pre-treated with reducing agent