Standard Bag Research Articles

Experimental research on influence of curing environment on mechanical properties of coal gangue cementation

Abstract To investigate the impact of curing environments on the mechanical properties of coal gangue cementation (CGC), various curing methods were established, including standard bag curing, standard curing, natural sealing curing, natural curing, water curing, and varying curing ages. By examining the uniaxial compressive strength (UCS) and stress–strain relationship of CGC by applying axial loads, the influence mechanism was analyzed in terms of both physical and chemical reactions. Furthermore, a mechanistic structural model was established to illustrate the impact of the curing environment on the mechanical properties of CGC. The primary substances and reasons affecting the mechanical properties of CGC were analyzed through the use of scanning electron microscopy and X-ray diffraction techniques. Evaluation of influence factors on CGC mechanical properties by grey correlation degree. The findings indicate that curing temperature, humidity, and carbonization are the principal factors influencing the UCS. Maintaining constant temperature and humidity while isolating CO2 is conducive to improving the UCS. The hydration products, such as needle-like ettringite and white fibrous calcium silicate hydrogel, fill the internal voids of CGC and are the primary substances affecting UCS. The hydration products formed during standard curing and natural curing of CGC can undergo carbonation with CO2 to form CaCO3, which interacts with ettringite and hydrated calcium silicate to provide strength support for CGC. However, beyond a certain age, CO2 will progressively diminish the UCS; the larger the contact area and the longer the exposure time to the gel materials in CGC, the faster the UCS decreases.

Spatial bagging to integrate spatial correlation into ensemble machine learning

We propose a novel spatial bagging workflow for predictive ensemble machine learning that improves on standard bagging models. Our proposed method integrates spatial bootstrap for bagging with the number of effective sample size, neff, for integration of the spatial context of the dataset. We benchmark the improved performance over standard machine learning bagging models with a large number of two-dimensional synthetic datasets with varying degrees of Gaussian noise. For noise free datasets, both methods demonstrate equivalent accuracy; however, spatial bagging achieves this with a significantly smaller sample size, showcasing its improved efficiency. As data noise increases, spatial bagging consistently outperforms standard bagging, displaying an improved Mean Squared Error (MSE) and robustness against overfitting. Our proposed spatial bagging method computes the optimal effective sample size for spatial data, reducing model overfitting. Furthermore, our proposed method requires only the additional step of variogram calculation and modeling, and can be implemented with any predictive machine learning bagging model with minimal code modification. i.e., specification of the number of bootstrap samples as the number of effective data. We recommend using spatial bagging for improved predictions for any spatial data setting across diverse scientific fields, e.g., atmospheric, agricultural, subsurface resources etc.

Does apneic oxygenation with nasopharyngeal cannula during intubation improve the oxygenation in patients with acute hypoxemic respiratory failure compared to the standard bag valve mask preoxygenation? An open-labeled randomized control trial.

In the context of acute hypoxemic respiratory failure (AHRF), ensuring effective preoxygenation and apneic oxygenation emerges as the pivotal approach ensuring for averting hypoxemic adverse events during endotracheal intubation. To investigate this, we conducted an open-label randomized controlled trial, aiming to assess the comparative effectiveness of nasopharyngeal high-flow oxygenation in conjunction with Bag-Valve-Mask (BVM) versus standard BVM preoxygenation in patients experiencing AHRF within the emergency department (ED). This prospective single-center, open-labeled, randomized controlled trial enrolled patients aged 18 years and above requiring rapid sequence intubation due to AHRF in the ED. Participants were randomly assigned in a 1:1 ratio to either the intervention arm (involving nasopharyngeal high-flow oxygenation and BVM preoxygenation) or the control arm (involving BVM preoxygenation alone). A total of 76 participants were enrolled in the study, evenly distributed with 38 individuals in each arm. Median (interquartile range [IQR]) SpO2 at 0 min postintubation was 95.5 (80%-99%) versus 89 (76%-98%); z-score: 1.081, P = 0.279 in the intervention and control arm, respectively. The most common postintubation complications included hypoxia (intervention arm: 56.7% vs. control arm: 66.7%) and circulatory/hypoxic arrest (intervention arm: 39.5% vs. control arm: 44.7%). There were no adverse complications in 36.7% (n = 11) of patients in the intervention arm. Despite the best possible medical management, almost half (52.6%) of patients in the intervention arm and 47.4% of patients in the control arm succumbed to their illnesses in the ED. The primary outcome revealed no statistically significant difference between the two arms. However, patients in the intervention arm exhibited fewer intubation-related adverse effects.

ZOOMICS : comparative metabolomics of red blood cells from dogs, cows, horses and donkeys during refrigerated storage for up to 42 days.

The use of omics technologies in human transfusion medicine has improved our understanding of the red blood cell (RBC) storage lesion(s). Despite significant progress towards understanding the storage lesion(s) of human RBCs, a comparison of basal and post-storage RBC metabolism across multiple species using omics technologies has not yet been reported, and is the focus of this study. Blood was collected in a standard bag system (CPD-SAG-Mannitol) from dogs (n=8), horses, bovines, and donkeys (n=6). All bags were stored at 4°C for up to 42 days (i.e., the end of the shelf life in Italian veterinary clinics) and sampled weekly for metabolomics analyses. In addition, data comparisons to our ongoing Zoomics project are included to compare this study's results with those of non-human primates and humans. Significant interspecies differences in RBC metabolism were observed at baseline, at the time of donation, with bovine showing significantly higher levels of metabolites in the tryptophan/kynurenine pathway; dogs showing elevated levels of high-energy compounds (especially adenosine triphosphate and S-adenosyl-methionine) and equine (donkey and horse) RBCs showing almost overlapping phenotypes, with the highest levels of free branched chain amino acids, glycolytic metabolites (including 2,3-diphosphoglycerate), higher total glutathione pools, and elevated metabolites of the folate pathway compared to the other species. Strikingly, previously described metabolic markers of the storage lesion(s) in humans followed similar trends across all species, though the rate of accumulation/depletion of metabolites in energy and redox metabolism varied by species, with equine blood showing the lowest degree of storage lesion(s). These results interrogate RBC metabolism across a range of mammalian species and improve our understanding of both human and veterinary blood storage and transfusion.

High efficiency closed-system gene transfer using automated spinoculation

BackgroundGene transfer is an important tool for cellular therapies. Lentiviral vectors are most effectively transferred into lymphocytes or hematopoietic progenitor cells using spinoculation. To enable cGMP (current Good Manufacturing Practice)-compliant cell therapy production, we developed and compared a closed-system spinoculation method that uses cell culture bags, and an automated closed system spinoculation method to decrease technician hands on time and reduce the likelihood for microbial contamination.MethodsSepax spinoculation, bag spinoculation, and static bag transduction without spinoculation were compared for lentiviral gene transfer in lymphocytes collected by apheresis. The lymphocytes were transduced once and cultured for 9 days. The lentiviral vectors tested encoded a CD19/CD22 Bispecific Chimeric Antigen Receptor (CAR), a FGFR4-CAR, or a CD22-CAR. Sepax spinoculation times were evaluated by testing against bag spinoculation and static transduction to optimize the Sepax spin time. The Sepax spinoculation was then used to test the transduction of different CAR vectors. The performance of the process using healthy donor and a patient sample was evaluated. Functional assessment was performed of the CD19/22 and CD22 CAR T-cells using killing assays against the NALM6 tumor cell line and cytokine secretion analysis. Finally, gene expression of the transduced T-cells was examined to determine if there were any major changes that may have occurred as a result of the spinoculation process.ResultsThe process of spinoculation lead to significant enhancement in gene transfer. Sepax spinoculation using a 1-h spin time showed comparable transduction efficiency to the bag spinoculation, and much greater than the static bag transduction method (83.4%, 72.8%, 35.7% n = 3). The performance of three different methods were consistent for all lentiviral vectors tested and no significant difference was observed when using starting cells from healthy donor versus a patient sample. Sepax spinoculation does not affect the function of the CAR T-cells against tumor cells, as these cells appeared to kill target cells equally well. Spinoculation also does not appear to affect gene expression patterns that are necessary for imparting function on the cell.ConclusionsClosed system-bag spinoculation resulted in more efficient lymphocyte gene transfer than standard bag transductions without spinoculation. This method is effective for both retroviral and lentiviral vector gene transfer in lymphocytes and may be a feasible approach for gene transfer into other cell types including hematopoietic and myeloid progenitors. Sepax spinoculation further improved upon the process by offering an automated, closed system approach that significantly decreased hands-on time while also decreasing the risk of culture bag tears and microbial contamination.

PARENTERAL NUTRITIONAL ALGORITHM - A NEW WEB-BASED CALCULATOR TO PRESCRIBE STANDARD OR PERSONALIZED PARENTERAL NUTRITION

The use of standard all-in-one bags is increasingly widespread in patients of all ages across all care settings, in particular for pediatric patients. There are no tools, to our knowledge, that guides parenteral nutrition prescription from estimation of energy needs to the selection of the best fitting standard bag. We present a tool that helps the choice of the best standard bag based on the estimation of the patient's needs. The software considers: age, weight, sex, metabolic phase and type of venous access; energy and macro-micronutrient requirements. It contains a database of the compatible electrolyte and minerals that can be added to the PN bags. The software selects suitable PN bags, helping to reduce the time of PN prescription. The software limits or eliminates prescription or transcription errors while offering an evidence based prescription process. According to ESPEN/ESPGHAN guidelines, standard PN bags are suitable to most of the adult and paediatric patients. Using all-in-one standard bags in paediatric patients may be complex due to a wide range of patient ages and variable requirements. Several studies have shown that calculators are more accurate than traditional calculations. Using our tool, over and under feeding can be avoided and PN can be safe. The software is free and works on all fix and mobile devices.

The "folded" glove-finger in minimally invasive surgery: easy, quick and cheap specimen retrieval.

Laparoscopic and thoracoscopic surgery often require extraction of surgical specimens. The use of standard retrieval bag can be expensive, especially in case of multiple specimens during the same operation. We describe the use of a folded glove-finger as cheap alternative and easily reproducible means of specimen extraction. The medium finger of a glove, cut at its base, was used to locate several types of specimens. The edge of the glove was folded to allow an easier insertion and retrieval of the specimens. Using this technique in the last 5 years, we have retrieved hundreds of different types of specimens (including omentum, lymph nodes, appendix, peritoneal or pleural biopsies) during laparoscopic and thoracoscopic procedures. All the retrieval fingers were safely pulled outside and were intact when extracted through the ports with no fragmentation of the specimens. In conclusion, we suggest that a folded glove-finger can be used as an easy, quick and cheap strategy for specimen extraction during laparoscopic and thoracoscopic surgery.

Vacuum-Assisted Hot-Forming Using Tailored Laminate Temperature

A non-isothermal vacuum assisted hot-forming process using tailored laminate temperature is introduced. By using process simulation and manufacturing experiments, improved laminate quality is achieved compared to the standard hot-forming process. Furthermore, it is also shown that the manufacturing time in the clean room can be reduced to one tenth of the standard process time. In this study 8.4 mm thick quasi-isotropic laminates from unidirectional prepreg were laid up flat with an automatic tape laying machine and hot-formed to a U-shaped laminate. The laminates were then cured in a concave mould with standard bag on the inside. A complete tailored temperature hot-forming cycle of 7.5 min produced a very good final laminate quality with a total thickness variation as low as 4.0% and without wrinkles or indications of porosity. With a 4 min hot-forming cycle the thickness variation was also acceptable at 8%.

Coronavirus Disease 2019: Anesthesia Machine Circuit Pressure During Use as an Improvised Intensive Care Unit Ventilator.

Use of anesthesia machines as improvised intensive care unit (ICU) ventilators may occur in locations where waste anesthesia gas suction (WAGS) is unavailable. Anecdotal reports suggest as much as 18 cm H2O positive end-expiratory pressure (PEEP) being inadvertently applied under these circumstances, accompanied by inaccurate pressure readings by the anesthesia machine. We hypothesized that resistance within closed anesthesia gas scavenging systems (AGSS) disconnected from WAGS may inadvertently increase circuit pressures. An anesthesia machine was connected to an anesthesia breathing circuit, a reference manometer, and a standard bag reservoir to simulate a lung. Ventilation was initiated as follows: volume control, tidal volume (TV) 500 mL, respiratory rate 12, ratio of inspiration to expiration times (I:E) 1:1.9, fraction of inspired oxygen (Fio2) 1.0, fresh gas flow (FGF) rate 2.0 liters per minute (LPM), and PEEP 0 cm H2O. After engaging the ventilator, PEEP and peak inspiratory pressure (PIP) were measured by the reference manometer and the anesthesia machine display simultaneously. The process was repeated using prescribed PEEP levels of 5, 10, 15, and 20 cm H2O. Measurements were repeated with the WAGS disconnected and then were performed again at FGF of 4, 6, 8, 10, and 15 LPM. This process was completed on 3 anesthesia machines: Dräger Perseus A500, Dräger Apollo, and the GE Avance CS2. Simple linear regression was used to assess differences. Utilizing nonparametric Bland-Altman analysis, the reference and machine manometer measurements of PIP demonstrated median differences of -0.40 cm H2O (95% limits of agreement [LOA], -1.00 to 0.55) for the Dräger Apollo, -0.40 cm H2O (95% LOA, -1.10 to 0.41) for the Dräger Perseus, and 1.70 cm H2O (95% LOA, 0.80-3.00) for the GE Avance CS2. At FGF 2 LPM and PEEP 0 cm H2O with the WAGS disconnected, the Dräger Apollo had a difference in PEEP of 0.02 cm H2O (95% confidence interval [CI], -0.04 to 0.08; P = .53); the Dräger Perseus A500, <0.0001 cm H2O (95% CI, -0.11 to 0.11; P = 1.00); and the GE Avance CS2, 8.62 cm H2O (95% CI, 8.55-8.69; P < .0001). After removing the hose connected to the AGSS and the visual indicator bag on the GE Avance CS2, the PEEP difference was 0.12 cm H2O (95% CI, 0.059-0.181; P = .0002). Displayed airway pressure measurements are clinically accurate in the setting of disconnected WAGS. The Dräger Perseus A500 and Apollo with open scavenging systems do not deliver inadvertent continuous positive airway pressure (CPAP) with WAGS disconnected, but the GE Avance CS2 with a closed AGSS does. This increase in airway pressure can be mitigated by the manufacturer's recommended alterations. Anesthesiologists should be aware of the potential clinically important increases in pressure that may be inadvertently delivered on some anesthesia machines, should the WAGS not be properly connected.

Can we meet patients’ energy and nitrogen requirements with standard peripheral parenteral nutrition bags?

Can we meet patients’ energy and nitrogen requirements with standard peripheral parenteral nutrition bags?

The Peritoneal Dialysis Transfer Set Replacement Procedure

Peritoneal dialysis transfer sets (extension lines) are replaced every six to nine months to minimize peritoneal dialysis catheter complications. The aim of this study was to compare a revised non-bag transfer set exchange procedure with the standard bag exchange procedure on nursing time, costs, and safety. Thirty-three people were randomized to two groups - a standard bag exchange procedure group (n = 16) and a non-bag transfer set exchange procedure group (n = 17). The standard bag exchange procedure took a median of 32 minutes (interquartile range [IQR] 25 to 38 minutes) compared to the non-bag transfer set exchange procedure of 6 minutes (IQR 4 to 8 minutes) (p Ò 0.0001). There was one episode of peritonitis in each group within the 72-hour follow-up period. The average cost of the non-bag transfer set exchange procedure was $24.54 lower, a 37% cost reduction. This study has shown the revised non-bag transfer set replacement procedure appears to be safe, consume less participant and staff time, and decreases costs.

USE ASSESSMENT AND COST ANALYSIS OF PARENTERAL NUTRITION FOR ADULTS IN A PUBLIC HOSPITAL

The Parenteral Nutrition (PN) is a high-alert medication, with high-cost, indicated for patients in which oral or enteral nutrition is not possible, is insufficient or contraindicated. There are two PN systems currently available, the custom system, prepared in hospital pharmacies or outsourced to specialized clinics, and the standardized compartmentalized bag system. Currently, it is fundamental that the application of financial resources in health be performed efficiently, considering effectiveness, safety and economy. The aim of this study was to evaluate the effectiveness of industrialized NP in the supply of energy and to perform a pharmacoeconomic analysis of cost minimization comparing standardized and custom bags. For this, was determined the total energy expenditure of patient and then determined the adequacy of the prescriptions of PN. For cost analysis was used the values of the standardized bags used for the patient in relation with the hypothetical cost if the same formulation were custom manipulated. 28 patients and 296 PN prescriptions were identified in the study period. The rates of adequacy to the energy expenditure were 39.3% on the 1st day, 34.6% on the 2nd day, 44.65% on the remaining days of treatment, and 33.33% on the last day. As for the analysis cost, the cost of standardized bags was lower in relation to manipulated bags (p <0.05). It was therefore verified that this was a high level of the inadequacy of the prescriptions of industrialized PN bags and that the same is more cost effective for the hospital in question.

Production of cement in Peru: Understanding carbon-related environmental impacts and their policy implications

Cement production is one of the main drivers of the construction sector worldwide. While cement demand has plateaued in many developed nations recently, several emerging and developing economies have experienced important increases in demand. This is the case of Peru, a nation with a growing economy and a high demand for seismic-resistant infrastructures and housing. Recent estimates have shown that cement is responsible for approximately 5–10% of worldwide anthropogenic CO2 emissions, of which more than half are linked to the production of clinker, due to the use of fossil fuels and direct clinkering emissions. To face this concern in the Peruvian context, producing a more sustainable product with improved environmental performance, it is necessary to first understand the environmental profile of current production standards. Therefore, this study analyzed the environmental impacts, specifically climate change, of cement production in three relevant national cement plants to identify the main greenhouse gas mitigation strategies throughout the whole supply chain. Three different types of cement produced in the three different plants were analyzed: ordinary Portland cement, cement with added natural pozzolan and cement with added blast furnace slag. Life Cycle Assessment was used to quantify the GHG emissions linked to the production of one standard bag of cement. Although results were in the lower range as compared to the literature, these varied significantly across the cement plants, reaffirming that Portland cement tends to have higher global warming impacts than when blended cement is produced, although the energy carrier for the kiln or the import of clinker can have an influence on the final results.

The use of standard parenteral nutrition bags in advanced cancer patients

The use of standard parenteral nutrition bags in advanced cancer patients

VIABILITY OF OAT AND BARLEY SEEDS DURING STORAGE

The work presents the evaluation results of the viability of oat and barley collection varieties during storage in the laboratory conditions at the temperature of 20-25o C. Seed storage covered the period of 2006-2017. The research included 24 varieties of barley and 29 varieties of chaffy oats of domestic and foreign breeding collection. The seeds were stored in different packaging materials such as standard paper package; glass bottles of 0.25 liter and plastic bottles of 0.5 liter. The initial seed moisture content was 8.5-9.0 per cent. The varieties were divided into groups taking into account the initial laboratory seed germinating ability. For oats the fi rst group included 10 varieties with initial germination of 96-99%; the second group included 12 varieties with initial germination of 91-95%; the third group included 7 varieties with initial germination of 86-90%. For barley the fi rst group consisted of 5 varieties with initial germination of 91-99%; the second group consisted of 10 varieties with initial germination of 81-90%; the third group consisted of 9 varieties with initial germination of 71-80%. Determination of seed quality was carried out in 7 and 11 years’ time. The initial moisture content of seeds remained without signifi cant changes in all packaging types during the storage period of 11 years. It was also noted that germination of oat and barley seeds during 7 years of storage did not differ in any type of package. The average value in all three groups of oats was 93.2%. After 11 years of storage, germination of oat differed a little, depending on the type of package. In a paper bag it was 80.4%; in a glass bottle – 88.2%; in a plastic bottle – 85.1%. The average initial germination of three groups of barley in 7 years’ time of storage was 84.7%. After 11 years of storage, germination of barley was 53.2% in a paper bag; 63.3% in a glass bottle; 61.8% in a plastic bottle It was revealed that oat and barley seed germination in 7 years’ time did not differ in any type of package. After 11 years, germination of oats was 5.8% higher, and germination of barley was 8.6% higher in a sealed plastic bottle than in a standard paper bag. Differences in seed germinating ability between the glass and plastic bottles were not observed.

Warming the premature infant in the delivery room: Quantification of the risk of hyperthermia

AimThe efficacy and safety of three polyethylene bags commonly used to prevent hypothermia in premature infants was assessed. MethodsTo simulate transfer from the delivery room to a secondary care unit, a thermally stable, bonneted mannequin (skin temperature: 34.4 °C) was placed in a climate chamber under different conditions: with a radiant warmer, with various polyethylene bags (open on one side, closed by a draw-string at the neck, or a “life support pouch” with several access points) or without a bag. ResultsWith the radiant warmer turned on, the mean reduction in heat loss from the nude mannequin was 50.8 ± 1.7% (p < 0.0001, vs. warmer off). The mean reduction in heat loss (vs. no bag) was 55.0 ± 0.9% for the drawstring bag, 49.0 ± 2.2% for the standard bag (p = 0.0001), and 48.1 ± 0.7% for the life support pouch (p = 0.006). When a radiant warmer + polyethylene bag were used, heat stress (body temperature: 38 °C) and severe hyperthermia (40 °C) occurred after 11 and 34 min, respectively. ConclusionCaution must be taken when using a radiant warmer and polyethylene bag with a premature infant. Heat stress can occur in only 11 min. Continuous body temperature monitoring is therefore required.

Impact of resuscitation fluid bag size availability on volume of fluid administration in the intensive care unit.

Iatrogenic fluid overload is associated with increased mortality in the intensive care unit (ICU). Decisions on fluid therapy may, at times, be based on other factors than physiological endpoints. We hypothesized that because of psychological factors volume of available fluid bags would affect the amount of resuscitation fluid administered to ICU patients. We performed a prospective intervention cross-over study at 3 Swedish ICUs by replacing the standard resuscitation fluid bag of Ringer's Acetate 1000mL with 500mL bags (intervention group) for 5 separate months and then compared it with the standard bag size for 5months (control group). Primary endpoint was the amount of Ringer's Acetate per patient during ICU stay. Secondary endpoints were differences between the groups in cumulative fluid balance and change in body weight, hemoglobin and creatinine levels, urine output, acute kidney failure (measured as the need for renal replacement therapy, RRT) and 90-day mortality. Six hundred and thirty-five ICU patients were included (291 in the intervention group, 344 in the control group). There was no difference in the amount of resuscitation fluid per patient during the ICU stay (2200mL [1000-4500 median IQR] vs 2245mL [1000-5630 median IQR]), RRT rate (11 vs 9%), 90-day mortality (11 vs 10%) or total fluid balance between the groups. The daily amount of Ringer's acetate administered per day was lower in the intervention group (1040 (280-2000) vs 1520 (460-3000) mL; P=.03). The amount of resuscitation fluid administered to ICU patients was not affected by the size of the available fluid bags. However, altering fluid bag size could have influenced fluid prescription behavior.

English

The permanence of harvested fruits in the plantation can cause irreversible damage to Conilon coffee quality, possibly increasing the overall number of defects, causing losses to crop yield and changing the organoleptic properties of the product. The objective of this study was to quantify the changes caused by permanence time of the Conilon coffee in the plantation after harvest over the mass and classification of the product. The experiment followed a completely random design, with 8 treatments and 4 repetitions, using standardized bags of mature fruits of Coffea canephora Pierre ex Froehner that were kept in the plantation field for periods of 0, 1, 2, 3, 4, 6, 8 or 10 days after manual harvest of the grains. After these periods, the coffee was dried, processed and weighted to quantify losses. The samples from each parcel were used to classify the resulting coffee regarding grain size in standardized classification sieves (sieves 12, 11 and 10 for round grains; sieves 17, 15 and 13 for flat grains), grain defects (brocaded, sour, black, defective percentage and total number of defects) and yield losses (dried coffee weight and processing ratio). The results showed that keeping the harvested fruits in the plantation causes losses over mass and over the overall product classification, affecting grain size and increasing the number and type of defects. This reinforces the recommendation to transport the harvested coffee for drying as soon as possible after harvesting. &nbsp; Key words: Coffea canephora, harvest, grain defects, quality, physical classification.

Can a Repeated Opt-Out Reminder mitigate hypothetical bias in discrete choice experiments? An application to consumer valuation of novel food products

Can a Repeated Opt-Out Reminder mitigate hypothetical bias in discrete choice experiments? An application to consumer valuation of novel food products

Weight of Backpacks and Musculoskeletal Pain among Iranian Elementary School Students

The study aims to investigate the relationship between the weight of backpacks and musculoskeletal pain among Iranian elementary school students. In addition, this study also aims to identify the common pain areas reported among Iranian elementary school students as the result of carrying heavy backpacks. The subjects of the study consisted of 1118 females and 5474 males’ students from elementary school at all different grades. They represented 36 schools which were selected based on stratified random sampling out of all elementary schools in Quchan, Iran. Students as well as their bags and backpacks were separately weighed using a calibrated weight scale. The mean weights of students and their bags and backpacks were also calculated for each grade. Musculoskeletal questionnaire was administered to 23% of female and 9% of male students through an interview procedure to find the difference between males and females musculoskeletal pain. The results showed that the male first and third-graders carried backpacks which were respectively 9.9% and 9.0% of their body weight. While the female first and third-graders’ backpacks and second-graders’ were reported to be heavier with the backpacks weight of 10.2% and 10.4% of their body weights, respectively. It was concluded that elementary students considering their average weight, carry heavy bags to school (higher than the standard bag weight, i.e., 3-5% of body weight). In addition, the findings showed the existence of different musculoskeletal problems among female and male students. The commonest pain areas among males were neck (24.9%) and backbone (24.6%) and among females were knees (51.9%) and shoulders (34.5%).