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Introduction Varicocele, which is defined as varicose veins in the scrotum, is associated with different complications, in particular infertility. However, the definite etiologies have not determined yet. Our objective was to investigate the association between left lumbar, renal, and gonadal veins diameters and varicocele occurrence and grading in kidney donors underwent left-sided nephrectomy. Also, the frequency of varicocele were evaluated three months after the surgery. Methods In this observational study, male kidney donors aged 18 to 65, who underwent open nephrectomy were included between 2022 and 2023. Baseline data on age, body mass index (BMI), and the presence or grade of varicocele were collected through medical records and physical examinations. During the procedure, the diameter of the left lumbar, renal, and gonadal veins was measured using a graded ruler on the back Table. Three months after the nephrectomy, the patients were re-evaluated for varicocele recurrence. Results We included 30 kidney donor with a mean age of 38.2 years and BMI of 23.5 kg/m2. The renal vein diameter decreased with higher grading (P-Value=0.05) and the gonadal vein diameter increased with higher grading (P-Value=0.04). However, there was no significant association between varicocele grading and left lumbar vein diameter. Following three months of nephrectomy, the frequency of varicocele increased from 33.4% to 50.0%. Conclusions The diameter of the left lumbar vein was almost unchanged in varicocele, while the size of the left renal vein decreased, and the size of the left gonadal vein increased. Furthermore, occurrence of varicocele increased after three months of left-sided nephrectomy. Therefore, people undergoing nephrectomy are at a higher risk of developing varicocele which should be considered in follow-up visits. [ABSTRACT FROM AUTHOR]

Culture and worldview form the foundations of a society's existence and knowledge, which are transformed by various external and internal factors. One of the platforms that embodies these infrastructures in every culture is folklore narratives, the analysis of which can be used to recover sources that are less visible in historical documents. According to historical evidence, matriarchy culture in Zagros was the dominant social phenomenon before the widespread presence of Aryan peoples in the Iranian Plateau. Such phenomena bring with them certain subcultures and social customs that are represented at different social and literary levels. Exogamy is one of the characteristics of matriarchal culture, which can be found in the oral literature of Kurdistan. While examining the data on exogamy based on the worldview of matriarchy by using its data, the present study analyzes the content of three popular Kurdish oral narratives in an analytical-descriptive manner and shows that action and conflict in these narratives are the result of the clash of two cultures of exogamy (ex-marriage) and endogamy (in-marriage). [ABSTRACT FROM AUTHOR]

Key Clinical Message: Giant cell tumor of bone (GCT) is a rare neoplasm which often presents as a lytic lesion in the epiphyseal region of long bones and which are usually accompanied by pain, swelling, and restricted movement. Giant cell tumor of bone (GCT) is a rare neoplasm that affects individuals in their third and fourth decades of life. Clinically, it often presents as a lytic lesion in the epiphyseal region of bones, notably the distal femur and proximal tibia. Radiologically, GCT appears as a distinct lytic lesion in the epiphyseal region. Histopathologically, GCTs are composed of mononuclear cells, macrophages, and multinuclear giant cells, indicative of osteoclastogenic stromal tumors. A 37‐year‐old man presented with left wrist pain, swelling, and restricted movement persisting for a year, worsening over the last 7 months. Radiographic assessments revealed a distal radius bone mass involving the radiocarpal joint. Biopsy confirmed a GCT with extension into peripheral muscle. PET/CT scan showed localized pathology without metastasis. Histopathologically, GCT exhibited multinucleated giant cells, spindle cells, and aneurysmal bone cyst‐like regions with coagulation necrosis. Surgical resection involved en‐bloc removal and reconstruction with a non‐vascularized radius bone graft. Postoperatively, the patient showed no complications at the one‐year follow‐up, suggesting successful intervention. [ABSTRACT FROM AUTHOR]

This paper deals with the control and performance improvement of parallel-operated voltage-source inverters (VSIs) controlled as virtual synchronous generators (VSGs). In publications regarding the parallel-operated VSGs, transmission lines are considered to be mainly inductive. However, less analytical works have been done regarding the control of paralleled VSGs in low-voltage grids with dominant resistive impedances. Once VSIs are controlled as VSGs in a microgrid with more resistive transmission lines, swing equation and system representation for the power-angle synchronization will change leading to a new control structure. Therefore, this paper deals with the control of parallel-operated converter-based VSGs in low-voltage grids with dominant resistive line impedances. In this way, the VSG representation, comprising the swing equation and V-P droop characteristic, for applications in highly resistive microgrids is presented, in which the swing equation and VSG frequency are related to reactive power. Then, the V-P droop characteristic is modified and an enhanced P-V droop characteristic for proper sharing of active power between the VSGs in highly resistive microgrids is proposed. Next, the VSG control is modified so that the R/X ratio at the VSG output increases and thus the decoupled control of active/reactive powers in relatively inductive cases is realized as well. [ABSTRACT FROM AUTHOR]

This paper assesses the dynamic performance of permanent magnet synchronous generator‐based wind turbine (WT) regarding the blade in‐plane fatigue loads once the WT is controlled in power control mode. Blade in‐plane oscillations, associated with the poorly blade in‐plane modes, can be excited by turbulent winds or grid disturbances that may lead to damage of the blades and reduce the drive‐train reliability. To overcome this drawback, at first, a model with three degrees of freedom is extracted for the drive‐train system, and then, an active mitigation approach is proposed to mitigate the blade in‐plane oscillations. The proposed method can effectively suppress the blade in‐plane vibrations by adding a supplementary term into the power control loop that is proportional to the speed difference between the blade and generator. The speed difference between the blade and generator is obtained by estimation of the blade‐hub and hub‐generator shaft torsional torques. Next, the performance of the proposed active mitigation approach is examined by the modal and frequency response analyses and time‐domain simulations. Finally, it is shown that the proposed approach has superior performance over the conventional approaches based on the simplified drive‐train model and crossing the measured generator speed through a band‐pass filter. [ABSTRACT FROM AUTHOR]

Key Clinical Message: The modified nail folding approach, a new surgical technique, has been shown to be safe and effective for the treatment of subungual glomus tumors, providing clinicians with a new treatment option for patients with this condition. Glomus tumors (GTs) are rare benign tumors that originate from the glomus body in the skin of the fingertips, toes, and nail beds. GTs are more prevalent in women than in men and can occur sporadically or as part of an inherited condition known as multiple GTs. The exact cause of GTs is unknown, but it is believed that mutations in the cells of the glomus body contribute to their development. In this study, we present the efficacy of a novel surgical technique called the modified nail folding approach for treating subungual GTs. We report a case series involving 17 patients who underwent the nail folding approach for surgical removal of subungual GTs. The primary objective of this article is to provide evidence supporting the safety and effectiveness of this technique. Additionally, we aim to introduce clinicians to a new, secure, and efficient treatment option for patients with subungual GTs. [ABSTRACT FROM AUTHOR]

This paper deals with the stability analysis and enhancement in the AC‐microgrid system comprising parallel‐operated voltage‐source inverters (VSIs) supplying an active‐load. The active‐load behaves such as a constant power load from the AC‐side. In the paper, two models for the active‐load modeling in the AC microgrid are considered: (i) simple model in which the active‐load is modeled as an ideal current source, (ii) detailed model in which all dynamics of the active‐load converter and related controllers are taken into account. The main findings and contribution of this paper are as follows. (a) All linearized state equations of the study system are extracted and transferred into a unified common dq‐reference frame, and then, small‐signal stability of the study system is carried out in the common reference frame by using the simple and detailed models of the active‐load. (b) It is shown that the simple model of the active‐load, as a current source, leads to more pessimistic results in comparison to the active‐load detailed model. (c) Impacts of the active‐load power and bandwidth of the active‐load voltage control loop on the system stability are examined. (d) Control of the generation‐side VSIs is modified and a stabilizing approach, called generation‐side virtual capacitor, is proposed for stabilizing the system under high active‐load penetration. Next, modal analysis and time‐domain simulations are used to investigate the study system responses with and without the proposed stabilizing approach. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Osteochondromas (OCs) are developmental anomalies that originate from the periosteum and typically form during enchondral ossification near the joints. Retro‐patellar OC caused by exostosis forms in various intracapsular, intra‐tendon, and joint‐adjacent positions within the knee joint. In this case, a 19‐year‐old male presented with swelling and a mass in his left knee, which raised suspicion of bone tumors. After evaluating x‐ray images and conducting histopathological examinations, the diagnosis was confirmed as retro‐patellar OC. [ABSTRACT FROM AUTHOR]

Background: Early graft loss (EGL) is one of the rare complications of kidney transplantation. Several factors play a role in the occurrence of EGL in kidney transplant recipients, which must be identified and limited. Objectives: This ten-year retrospective study was conducted in a single center on 32 kidney transplant recipients with EGL to determine the reasons for and risk factors of kidney transplant rejection in Iran. Methods: This descriptive-analytical study's population included 605 kidney transplant recipients receiving kidneys during the last ten years in our center. The diagnosis of EGL was based on renal allograft biopsy examination and primary clinical complications, including a rapid increase in serum creatinine. The age, gender, blood group, and rhesus (Rh) of both donors and recipients, as well as the kinship between the donor and recipient (relative and non-relative), right/left-sided living donor/recipient kidneys, primary kidney disease, the presence of underlying disease in the recipient, dialysis duration, the year of kidney transplantation, transplant survival time, patient survival time, and complications (surgery and others) were gathered. The data were analyzed using SPSS version 18. Results: In this study, 32 out of 605 kidney transplant recipients (5.28%) experienced EGL (53.1% male and 46.9% female, average age of 41.12 years). The duration of kidney function after transplantation was 5.56 ± 0.13 days. The transplanted kidneys were functional between 72 hours and one week after transplantation in 34.4% of the patients. The causes of EGL were found to be tissue rejection in 31.3% of the patients and vascular thrombosis and hyperacute rejection in 21.8%. Nephrectomy occurred in 41% of the patients, and 43.75% died because of a heart attack. Conclusions: Our findings supported previous studies' results, suggesting that EGL is associated with receiving an incompatible kidney transplant and surgery-related complications, including bleeding and thrombosis. [ABSTRACT FROM AUTHOR]

Inverter‐based virtual synchronous generators (VSGs) by introducing the virtual inertia enhance the microgrid frequency stability. The subject of this paper is regarding the stability analysis and enhancement of the study system comprising parallel‐operated VSGs feeding an active load. The active load with tightly closed‐loop control behaves such as constant power load resulting in stability issue. In the article, impacts of the dc‐side voltage control bandwidth of the active load and power level of active load on the system stability are examined. Then, an approach based on feedback linearising technique implemented on VSGs is presented for stabilising the system at higher levels of active load power. By employing the presented approach, the VSGs show reduced output impedance at the low and middle‐frequency ranges, and this in turn stabilises the system even at the rated level of the active load power and at higher control bandwidths of the active load dc‐side voltage control loop. Next, the linearised state‐space equations of converters and related controllers are transferred from local dq‐reference frames to a common dq‐reference frame, and then stability of the whole study system is analytically examined. At the end, time‐domain simulations and hardware‐in‐the‐loop experiments are given to verify the analytical results. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that occurs mainly in skeletal muscles which can be removed through surgery after diagnosis. Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that typically occurs in skeletal muscles. Its diagnosis is based on magnetic resonance imaging (MRI) and histopathologic evaluation of the lesion. In our report, we describe the case of a 60‐year‐old female with an IMM in the supinator muscle of the right forearm, which was confirmed by MRI and histopathologic examination. Following surgery to remove the mass, a follow‐up confirmed the patient's recovery and the absence of movement limitations in the elbow joint. [ABSTRACT FROM AUTHOR]

This paper deals with the integration and control of the doubly fed induction generator‐based wind turbine (DFIG‐WT) in a DC grid. In this way, the stator of the DFIG‐WT is integrated with the DC grid via an uncontrolled diode‐bridge rectifier as well as a buck converter to provide a flexible connection path. In addition, the rotor of the DFIG‐WT exchanges power with the DC grid through a rotor‐side converter (RSC). By considering the DFIG‐WT system topology, three control strategies based on the stator flux‐oriented vector control are developed for the RSC and buck converter. The control schemes consist of the outer and the inner control loops with the proportional–integral (PI) controllers. Additionally, the stability of control strategies and their dependence on the generator parameters are evaluated and compared using modal analysis and numerical simulations in the MATLAB/SIMULINK environment. Finally, a real‐time hardware‐in‐the‐loop emulation‐based OPAL‐RT 5600 is accomplished to assess the performance of the superior control method from a practical perspective. [ABSTRACT FROM AUTHOR]

Background: A temporary loop ileostomy is one of the most common methods for the prevention of anastomotic leakage in rectal cancer patients who underwent low anterior resection. However, the optimal timing of loop ileostomy reversal remains unknown. The main objective of this study was to evaluate the debilitating complications caused by early closure of ileostomy in comparison with late closure in rectal cancer patients. Design: A randomized, controlled, unblinded, and monocentric trial. Methods: A total of 104 rectal cancer patients were randomly assigned to the case group of early closure of ileostomy (n = 50) and the control group of late closure of ileostomy (n = 54). This trial was undertaken in a single colorectal institution, a university-affiliated teaching hospital in Tehran, Iran. Randomization and allocation to the trial group were conducted by using variable block randomization based on quadruple numbers. The primary endpoint of this trial was determined by the complications of early ileostomy closure versus those of late closure in rectal cancer patients who had undergone low anterior resection. In early closure, loop ileostomy is reversed 2–3 weeks after the first two courses of adjuvant chemotherapy, while in late closure, the ileostomy is reversed 2–3 weeks after the last course of adjuvant chemotherapy. Results: Follow-up of 1 year demonstrated a reduction in the risk of complications and an improved quality of life in patients with rectal cancer following low anterior resection and chemotherapy (neoadjuvant and adjuvant) in the case group but did not reach a significant difference (p = 0.555). In addition, there was no significant difference in perioperative outcomes, such as blood loss, operative time, readmission, and reoperation; also, no statistically significant differences were reported between the groups in patients’ quality of life or LARS score. Conclusion: In summary, it seems that early closure of ileostomy is not better than late closure in improving patients’ quality of life with rectal cancer following low anterior resection and chemotherapy (neoadjuvant and adjuvant); no statistical difference was observed for reduction of risk of ostomy complications. Thus, neither of these methods (early closure versus late closure) is superior to the other, and controversy still exists. Trial registration number and date of registration: IRCT20201113049373N1 [ABSTRACT FROM AUTHOR]

Due to the negative impedance potential of constant power loads (CPLs), the stability of power electronic converters-based electrical distribution networks is prone to instability. This brief proposes a robust control technique based on deep reinforcement learning to stabilize a DC microgrid (MG) with parallel boost converters when feeding CPLs. For this purpose, a model-free sliding mode controller (MFSMC) has been applied to the DC MG. The MFSMC controller does not need any identification of converters in the DC MG system while ensuring the efficiency and the stability of the control synthesis. The key control coefficients are designed by Proximal Policy Optimization (PPO) Reinforcement Learning (RL). The PPO is made from two deep neural networks (NNs) (actor NN and critic NN) which are trained to adjust the coefficients of the MFSMC controller. The MFSMC controller designed by the PPO with actor-critic architecture is applied to the DC MG system feeding CPL in an OPAL-RT setup to verify the efficiency of the proposed controller through Hardware-in-the-Loop (HiL) simulations. [ABSTRACT FROM AUTHOR]

Integration of doubly‐fed induction generator (DFIG) based wind turbines (WTs), in series‐compensated power grids, may result in a phenomenon known as sub‐synchronous control interaction (SSCI). Indeed, SSCI, created due to interaction between WTs controllers and series‐compensated power grid, may worsen damping of sub‐synchronous resonance (SSR) oscillations. This paper deals with the analytical assessment and mitigation of SSCI phenomenon in series compensated grids comprising of DFIG‐based WTs. In this way, first, theoretical and mathematical expressions and equivalent circuits regarding the SSCI phenomenon and the impacts of the RSC and GSC controls on the SSR oscillations damping are given and then a comprehensive impedance model for the DFIG‐WT at the sub‐synchronous frequency is extracted. Next, the rotor current control is modified, and an efficient approach based on the feedback linearizing technique (FLT), different from approaches presented in the related literature, is presented to mitigate the negative role of the DFIG in SSR frequencies. By mathematical analyses and developing related formula, it is shown that the proposed approach changes the impedance of the rotor circuit to infinity at the SSR frequency. This in turn results in suppression of the SSR oscillations initiated as a result of induction generator effect and SSCI phenomenon. [ABSTRACT FROM AUTHOR]

Commonly, a simple topology consisting of a single diode‐rectifier and pulse‐width‐modulation (PWM) converter is used for the connection of the doubly‐fed induction generator‐based wind turbines (DFIG‐WTs) to the DC grid, in which the rotor‐side converter (RSC) and the stator diode‐rectifier are linked to the common DC bus. But, this topology suffers from less flexibility due to the requirement of matching the stator nominal voltage with the DC grid. Hence, in this paper, a buck converter is added to the DFIG‐WT topology and two methods are proposed to control the power converters, where in the first one, the RSC regulates the active power and stator flux linkage, and in the second one, the RSC regulates the DC bus voltage and stator flux linkage. Then, the small‐signal stability and the performance of the DFIG‐WT system with the mentioned control strategies are compared analytically and through the off‐line simulations. At last, a real‐time hardware‐in‐the‐loop (HIL) emulation‐based OPAL‐RT is carried out to investigate the performance of the proposed control methods from a practical perspective. [ABSTRACT FROM AUTHOR]

Purpose: Echinococcosis is one of the most important parasitic zoonotic diseases around the world. Echinococcus granulosus is the most widespread species of the genus Echinococcus that can develop cysts in different parts of the body. We tried to present a case of pulmonary cystic echinococcosis. Methods: Here, we report a rare case of two ruptured and intact cysts in a 54-year-old woman with weakness, lethargy, body pain, stomachache, dizziness, and vision problems. Results: According to the patient's manifestations and imaging findings, besides the COVID-19 pandemic, she was suspected of having COVID-19 and tuberculosis. However, when the aspirated sample was stained, hooklets of E. granulosus were observed. Surgical removal and chemotherapy were used for treatment. Conclusion: Treatment of pulmonary cystic echinococcosis is based on surgery, but, along with it, the chemotherapy makes a better prognosis. [ABSTRACT FROM AUTHOR]

Infertility is defined as the failure to achieve a successful pregnancy after 12 months' sexual activity that affects 15%–17% of couples in the world and about 50% of them are related to female infertility factors. In this study, using the PRISMA checklist and MeSH keywords, 128 articles were extracted from various databases (PubMed, Cochrane library, WHO, Iranmedex, Science Direct, SID, and Google Scholar search engine) without language and time restrictions, and 128 articles were selected after eliminating duplicate studies. In this review, we present some solid evidence for role of herbal medicine in the treatment of female infertility. The results of this study showed that different parts of some plants are rich in polyphenolic compounds (isoflavones and flavonoids) and other compounds which are beneficial to in reproductive health in women. The compounds in these plants, along with regulating the female endocrine pathways, and improving symptoms of menopause, treat female reproductive disorders such as polycystic ovary syndrome (PCOS), premature ovarian failure (POF), endometriosis, hyperprolactinemia, and hypothalamic dysfunction; moreover, because of their anticancer, antioxidant, and antidepressant properties, they can be used in traditional medicine or in the pharmaceutical industry as safe compounds in women's health. [ABSTRACT FROM AUTHOR]

Remdesivir initially was intravenously administrated to treat the Ebola disease however right now it has been administered to treat COVID-19 in some countries. However it is necessary to find the exact effect of remdesivir in patients with COVID-19. Remdesivir solution is administered with a cyclodextrin carrier that filters solely by the glomeruli; thereby patients with abnormal renal function cannot eliminate it quickly; therefore, remdesivir can lead to renal failure or liver dysfunction during therapeutic process of COVID-19. Assessment of renal function in patients with COVID-19 who have acute kidney injury (AKI) or end-stage renal disease is fundamental. [ABSTRACT FROM AUTHOR]

Summary: Wind‐farms are usually placed in remote areas, and thus high‐voltage AC‐based transmission systems with series capacitive compensation may be cost‐effective approaches for connection of wind‐farms to the grid over long transmission lines. However, the risk of subsynchronous resonance (SSR) is the main issue raised in series compensated transmission systems. This article first analytically investigates the effect of SSR phenomenon on the doubly fed induction generator (DFIG) dynamic behavior in a series compensated grid, and then proposes a proficient damping approach for complete suppression of SSR oscillations. The proposed damping approach is created by partial/full compensation of rotor back‐emf voltages by modifying the rotor‐side converter control. It is shown that under full compensation of rotor back‐emf voltages: (a) the rotor, stator, and grid currents become independent of SSR and (b) the DFIG and rotor circuit do not contribute to the induction generator effect, and subsynchronous oscillations have vanished quickly. In this article by the modal analysis and simulation results, it is shown that the proposed approach has a satisfactory response under different values of short circuit ratio and different series compensation levels. Next, it is shown that the proposed approach has superior performance compared to the rotor virtual resistance emulation approach. [ABSTRACT FROM AUTHOR]

Summary: The study system in this paper is a grid‐connected DC microgrid system comprising PV and wind generation sources, resistive and constant power loads (CPLs), and grid‐connected VSC. The VSC keeps the DC link voltage constant, and the wind and PV sources operate in maximum power point tracking (MPPT) mode, and thus, the DC–DC converters related to these sources act such as controlled current sources behaving similar to negative CPLs. The study system suffers from the stability under high CPL penetration and weak AC grid conditions. Hence, this paper investigates and enhances the system stability under both high CPL penetration and weak AC grid conditions. To do this, modal and small‐signal stability analysis of the system is carried out, and then, as the main findings, impacts of the wind and PV sources output powers, CPL power, and AC grid short‐circuit power on the system stability are studied. Next, as the main contribution, VSC control structure is modified by adding stabilizing signals to enhance the system stability under high CPL penetration, reduced output powers of the wind and PV sources, and weak AC grid conditions. At the end, several simulation results verify the theoretical results at different conditions. [ABSTRACT FROM AUTHOR]

Recently, variable speed wind turbines (WTs) employing dual stator‐winding induction generators (DSWIGs) have gained interest in related kinds of literature. A DSWIG has two sets of stator windings known as power‐winding (PW) and control‐winding (CW), where CW is connected to a pulse‐width modulation converter called semiconductor excitation controller (SEC). This study, first, presents a topology for connection of DSWIG‐based WT to the grid, in which unlike most of the related kinds of literature, both the PW and CW contribute in transmission of active power to the grid. In the study system, PW is connected to the diode rectifier‐boost converter and CW to the SEC, and thus PW and CW active powers are controlled by the related boost converter and SEC, respectively. Hence, this study extends theoretical expression and presents a new relation for the generator torque as a function of the CW and boost converter currents, and then develops control structures for the study system. Next, mathematical expressions are presented for the selection of excitation capacitor at the PW terminals. Besides, the presented control strategy of the system is modified to enhance the WT‐low voltage ride‐through capability. In the end, simulation results are presented for examining the system performance and verifying the theoretical analyses. [ABSTRACT FROM AUTHOR]

Osteoporosis is defined as a reduction in bone density up to 2.5 standard deviations less than the maximum mean bone density in humans. It is estimated that 50% to 80% of the differences in the bone mass of the individuals are related to their genetic and heredity. The prevalence of osteoporosis is 6% in Iran, in which it is more than Japanese and less than in the United States. In this cross-sectional descriptive-analytical study, patients with a history of recurrent kidney stones (those who had referred to the stone clinic more than one time) undergoing bone density measurement using the DEXA method to determine the presence or absence of osteoporosis (Reduction of bone density up to 2.5 standard deviations less than the maximum mean bone density) were enrolled. Exclusion criteria were patients with metabolic diseases, corticosteroid intake, renal failure, hyperparathyroidism, and age >60 years. According to the results of this study, there were 61 patients with a history of recurrent kidney stones, which 34 of them (55.74%) were male and 27 (44.26%) were female; the mean age was 42.41±9.8 years (ranging from 18 to 60 years). Evaluation of frequency distribution of patients showed that 18% of patients had osteoporosis. In this study, 52.5% of patients were without osteoporosis and osteopenia. It should be noted that 29.5% of patients had only osteopenia. The frequency distribution of osteoporosis in patients with a history of recurrent kidney stones by gender showed that four males (36.4%) and seven females (63.6%) had osteoporosis. There was no significant relationship between gender and osteoporosis in patients with a history of recurrent kidney stones (P=0.153). There was also no significant relationship between gender and osteopenia in these patients (P=0.380). There was no significant relationship between age and osteoporosis in patients with a history of recurrent kidney stones (P=0.203). There was no significant relationship between BMI and osteoporosis in patients with a history of recurrent kidney stones (P=0.344). There was no significant relationship between osteoporosis with age and BMI in patients with a history of recurrent kidney stones, and the highest percentage of osteoporosis was in the spine region, which consisted of 8.2% of all patients. There was no significant relationship between osteopenia with gender and BMI in patients with a history of recurrent kidney stones, but there was a significant relationship between age and osteopenia in patients with recurrent kidney stones. [ABSTRACT FROM AUTHOR]

Objective(s): Rapid healing of cutaneous leishmaniasis as one of the most important parasitic diseases leads to the decrease of scars and prevention of a great threat to the looks of the affected people. Today, the use of nano-scaffolds is rapidly increasing in tissue engineering and regenerative medicine with structures similar to the target tissue. Chitosan (CS) is a bioactive polymer with antimicrobial and accelerating features of healing wounds, which is commonly used in biomedicine. This study aimed to investigate the effects of CS/polyethylene oxide (PEO)/berberine (BBR) nanofibers on the experimental ulcers of Leishmania major in BALB/c mice. Materials and Methods: CS/PEO/BBR nanofibers were prepared by the electrospinning method, and their morphology was examined by SEM, TEM, and AFM. Then, water absorption, stability, biocompatibility, porosity, and drug release from nano-scaffolds were explored. Afterward, 28 BALB/c mice infected with the parasite were randomly divided into control and experimental groups, and their wounds were dressed with the produced nano-scaffolds. Finally, the effect of nanobandage on the animals was investigated by macroscopic, histopathologic, and in vivo imaging examinations. Results: The prepared nanofibers were completely uniform, cylindrical, bead-free, and biocompatible with an average diameter of 94±12 nm and had appropriate drug release. In addition, the reduced skin ulcer diameter (P=0.000), parasite burden (P=0.003), changes in the epidermis (P=0.023), and dermis (P=0.032) indicated significantly strong effectiveness of the produced nano-scaffolds against leishmania ulcers. Conclusion: Studies showed that CS/PEO/BBR nanofibers have a positive effect on the rapid healing of leishmania ulcers. Future studies should focus on other chronic ulcers treatment. [ABSTRACT FROM AUTHOR]

Introduction: Benign prostate hyperplasia, pathophysiology contributes to bladder outlet obstruction due to functional obstruction caused by gland size enlargement resulting in the lower urinary tract symptoms (LUTS). Objectives: To determine the correlation of the prostate volume with surgical outcomes and postoperative LUTS in patients with benign prostatic hyperplasia (BPH) undergoing transurethral resection of the prostate (TURP). Patients and Methods: Patients with BPH who were refractory for medical treatment enrolled in the study. Patients divided into three groups with attention to their prostate volume conducted by transabdominal ultrasonography. To evaluate patients' LUTS, the International Prostate Symptom Score (IPSS) questionnaire was filled for all patients preoperatively and during the first and third months follow up sessions. Results: In the current study, mean age of the patients was 66.92 ± 1.08 years. Of 111 patients, eight patients (7.2%) had prostate volume less than 30 cc, 59 patients (53.2%) had prostate volume between 30-60 cc, and 44 patients (39.6%) had prostate volume more than 60 cc. During first month postoperative, mean decrease in IPSS scores in patients with prostate volume less than 30 cc, prostate volume between 30--60 cc and prostate volume more than 30 cc were 27.72 ± 3.53, 27.32 ± 3.37 and 27.45 ± 2.87, respectively. The ANOVA test showed no significant difference between the groups (P= 0.93). Mean decrease in IPSS score during third month postoperative, had no significant difference between the three groups, too (P=0.71). Symptoms alleviation observed in 94.6% and 95.5% of the patients, during first and third months follow-up, respectively. Conclusion: There was no correlation between the IPSS scores decrease and patients' symptoms recovery and preoperative prostate volume in patients with BPH who underwent TRUP. [ABSTRACT FROM AUTHOR]

Introduction: Sirolimus is a macrolide and a type of immunosuppressant drug to prevent rejection of transplanted organs. This drug inhibits the activation of T and B lymphocytes and reduces the production of interleukin-2 (IL-2). Objectives: This study aimed to review the effect of sirolimus in kidney transplantation in patients with diabetes mellitus as a systematic review. Materials and Methods: International databases including PubMed, Web of Science and Scopus were considered for search of English articles by 29 June 2019. Twenty-one published articles were finally entered into the study. Keywords were sirolimus, rapamune, rapamycin, diabetes mellitus and kidney transplantation or a combination of them in the title/abstracts. Treatment using a combination of sirolimus and tacrolimus were excluded. Results: There were more than 3244 subjects reviewed in this systematic review including 21 published articles (Total population of 21 articles: 3244 people). Conclusion: According to the results, sirolimus-based immunosuppression for preventing kidney transplantation is effective and has a low-risk in diabetic patients resulting in suitable glucose control. [ABSTRACT FROM AUTHOR]

Objective(s): Design and construction of biocompatible and biodegradable scaffolds are among the main goals of tissue engineering. Recently, use of nano-hydroxyapatite as a bioactive bioceramic agent with high similarity to the mineral phase of the human bone tissue, in combination with biodegradable polymers and implant coatings has attracted the attention of researchers in the field of biomaterial sciences. The present study aimed to assess the differentiation of bone marrow stromal cells (BMSCs) in osteoblast-like cells on the chitosan/polyethylene oxide (PEO)/nano-hydroxyapatite scaffold in mature rats. Materials and Methods: Chitosan and PEO solution with the weight ratio of 80:20 and 70:30 were prepared, and 2% weight of nano-hydroxyapatite was added. Nanofibers were prepared using the electrospinning method, and the morphology was studied using scanning electron microscopy (SEM). Afterwards, the BMSCs of mature rats were cultured on nanofibers and differentiated by adding a differentiation medium. The survival of the differentiated cells was evaluated at the end of the first, second, and third week using acridine orange staining, and the morphology of the differentiated cells exposed to nanofibers was assessed using SEM. Results: The mean diameter of the nanofibers with the ratio of 80:20 was 150±17 nanometers. The differentiation of BMSCs into the osteoblast-like cells on nanofibers was confirmed using Alizarin red staining. The results indicated a significant decrease in the survival of the differentiated cells in the nanofiber groups by the end of the third week of differentiation compared to the control samples. Conclusion: According to the results, BMSCs could be differentiated into osteoblast-like cells in the presence of the chitosan/PEO nanofibers containing nano-hydroxyapatite. [ABSTRACT FROM AUTHOR]

A microgrid is a well known solution to increase the technical and economical capability of distributed generations. Recently, DC microgrids, as small‐scale DC networks, have attracted more attention due to lower losses and simple control structure. Stability of DC microgrids can be an important issue under high penetration of constant power loads (CPLs). In this study, stability analysis of the DC microgrid system including hybrid wind/battery and CPLs is studied, and then three different types of stabilising compensators are presented in two groups to increase the stability margin and to stabilise the system under high penetration of CPLs. The proposed stabilising compensators modify the voltage reference, current reference and duty cycle by adding active damping signals in the external, middle and internal parts of the interfaced converter control loops. These active damping signals are obtained by the feedback of the output voltage and current and modify the DC microgrid control structure. To evaluate the system stability under different stabilising compensators, small signal and frequency response analyses are done with and without active damping signals. Simulation results based on a detailed DC microgrid model are given to verify the effectiveness of the proposed compensators. [ABSTRACT FROM AUTHOR]

Background: Effective malaria control strategies require an accurate understanding of the epidemiology of locally transmitted Plasmodium species. Emerging evidence indicates that migrants from malaria endemic regions are at risk of delayed presentation of Plasmodium spp. and malaria infection. Cases Report: We reported a case of P. vivax malaria occurring after arrival in Iran. Patient was originally from Iraq. A 48-year-old male patient who was hospitalized with fever attacks, chills, and headache after arriving from Iraq to Tehran. Conclusion: In this patient, new prevention and screening strategies should be studied and blood safety policies adapted. Thus, ultimate elimination of malaria in Iran will require national malaria control program to adopt policy and practice aimed at all human species of malaria since neighbor country are still face to problem to control of malaria. [ABSTRACT FROM AUTHOR]

Objective (s): Several methods have been proposed for repairing defects and damages, one of which is cell therapy. Bone marrow stromal cells seem to be suitable for this purpose. On the other hand, many biometric materials are used to improve and correct the defects in the body. Nanofibers are widely used in the medical industry, especially in tissue engineering, as scaffolds in wound healing and wound dressing. Chitosan/ polyethylene oxide nanofibers can be a suitable replacement for routine wound coverages. Hence, this study was conducted to present a combination of these methods. Materials and Methods: Chitosan/polyethylene oxide nanofibers and thin films of chitosan were produced and optimized by electron microscopy, on which the bone marrow stromal cells were then cultivated. Interactions between the cells and these biomaterials were investigated through viability, morphology, immunocytochemistry and electron microscopy of cells after 6 days. All data were analyzed using Student's t-test and one-way ANOVA tests in SPSS version 16. P<0.05 was considered significant. Results: It seems that the high viscosity of chitosan prevents the formation of nanofibers, while chitosan/polyethylene oxide solutions with 80/20 and 90/10 ratios produce perfect, regular, bead free and non-toxic nanofibers with average diameter of 240±10 and 220±10 nm, respectively. The results of immunocytochemistry and viability showed that the cells had relatively high proliferation on the thin chitosan membranes, while the results of the electron microscopy showed that the morphology of cells was better on the nanofibers than on the thin membrane of chitosan. Conclusion: Since bone marrow stromal cells were grown well on chitosan-nanofibers, each of them alone was used in the therapeutic methods. It is better to consider a combination of two methods as the treatment method, especially in tissue engineering and cell therapy. [ABSTRACT FROM AUTHOR]

Fault ride through (FRT) capability creates a challenging condition for wind turbines (WTs) with a doubly fed induction generator (DFIG). In order to fulfill the FRT requirement for WTs with DFIG, the over-current in rotor circuit and theDC-link over-voltage during fault conditions must be addressed. This paper proposes an application of the model predictive control (MPC) system to power converters and uses Takagi-Sugeno-Kang type fuzzy logic control for improving the FRT capability of WTs with DFIG. The effectiveness of the proposed MPC method is compared with conventional proportional-plus-integral controllers with pulse-width modulation. The real-time simulation results illustrate the improved performance offered by the proposed control scheme for maintaining the rotor current and the DC-link voltage within permissible ranges when power grid faults occur. [ABSTRACT FROM AUTHOR]

Background: Intestinal parasitic infections are major causative agents of wildlife health complications among different parts of the world. This study aimed to investigate the gastro-intestinal parasites in feces of the zoo animals based on parasitological and morphometric criteria. Methods: One hundred fresh fecal samples were collected from 35 species of animal lived in Eram park zoo, Tehran, Central Iran during Oct 2015 to Jun 2015. All collected samples were examined by microscopic observation following direct wet mount preparation (normal saline and Lugol's iodine), formalin-ether concentration, and permanent staining. The morphometric aspects of the recovered eggs were surveyed with the aid of Camera Lucida (×400). Results: 65.7% (23/35) of zoo animal species were infected with intestinal parasites. The superfamily Trichostrongyloidea (6/16) and Strongylus sp. (16/4) were the most prevalent helminthic infections, while Blastocystis sp. (6/14), Entamoeba cyst (3/14) and Eimeria sp. (3/14) were the common protozoan parasites. For the first time, Bivitellobilharzia nairi egg was identified an elephant at Iran. Intestinal parasitic infections were apparently circulating among animals of the Eram park zoo. Conclusion: Identified parasitic infections can consider as a threatening source to visitors and workers' health that have contact with animals or their feces. Therefore, the effectual preventive strategies should be addressed to determine the risk factors, mechanisms of cross-transmission of parasite, the importance of applying the hygienic practices and well adjusting deworming programs for the animals, zoo workers and visitors. [ABSTRACT FROM AUTHOR]

Introduction: Varicocele is a common problem with a high prevalence in population with primary and secondary infertilities. The adverse effects of varicocele on spermatogenesis and fertility are known, but the association between clinical varicocele and testosterone is not clear. Hence, we decided to evaluate the serum levels of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in patients with varicocele after varicocelectomy.Methods: In this study, 100 patients with varicocele were divided into two groups: hypogonadal patients with testosterone level <280 ng/dL and eugonadal patients with testosterone level >280 ng/dL. The serum levels of testosterone, FSH, and LH were measured before surgery and 3 months after surgery, and the results were analyzed using the SPSS software. P-value <0.05 was considered statistically significant.Results: Patients with varicocele after puberty till 50 years were divided into two groups: hypogonadal (testosterone <280 ng/dL) and eugonadal (testosterone >280 ng/dL) patients who required varicocelectomy. The mean testosterone level before surgery in hypogonadal patients was 215.22±83.31 ng/dL, which reached 326.95±35.125 ng/dL after surgery (P<0.0001), which was significant. There was no significant decrease in the mean FSH level, but there was a significant decrease in the mean LH level after varicocelectomy. In eugonadal group, testosterone level before surgery was 471.90±145.71 ng/dL, which reached 469.57±145.61 ng/dL after surgery, which was not significant.Conclusion: In our study, patients who underwent varicocelectomy had improved testosterone levels, so that this increase was more significant in hypogonadal patients than in eugonadal patients. Decrease in LH and FSH levels in all patients was seen after varicocelectomy, which can be due to increase in testosterone levels. [ABSTRACT FROM AUTHOR]

Summary: This paper first deals with the dynamic performance evaluation and stability analysis of permanent magnet synchronous generator‐based wind turbine. Then, the permanent magnet synchronous generator speed control system is modified, and an efficient control approach is proposed for suppression of electromechanical oscillations in drive train system. Generator speed feedback‐based active compensation techniques employing high pass, band pass, or notch filters have been widely used to actively damp the torsional electromechanical oscillations in variable speed wind turbines. However, usefulness of these approaches is highly dependent on the filter parameters, and thus, their performance may be failed when existing uncertainty in shaft stiffness changes the drive train resonance frequency. To overcome this issue, a new active method is proposed for damping improvement of drive train torsional oscillations. The proposed method increases the effective damping of the drive train system by adding a damping torque component that is proportional to the speed difference between the turbine and generator. The speed difference between the turbine and generator is provided by estimation of shaft torsional torque. It is shown that the proposed active damping method has superior efficacy in damping of torsional electromechanical oscillations with and without considering the model uncertainty. [ABSTRACT FROM AUTHOR]

This paper deals with the detailed mathematical modeling, in-depth stability analysis, and control of PMSG-based wind turbine (WT), when PMSG works with an alternative control structure. In the alternative control structure, machine-side converter (MSC) is used for control of the dc-link voltage and grid-side converter (GSC) for control of the output power. In this way, full linearized dynamics of the dc-link model is achieved by using the equivalent current based model of the MSC and GSC. Based on the system detailed linearized representation, it is shown that the dc-link dynamics is non-minimum phase with a right half plane (RHP) zero, where the RHP zero depends on operating point and changes under wind speed variation. Hence, due to stability issue, careful considerations are considered for selection of the dc-link controller parameters, and necessary conditions are proposed to guarantee the closed-loop system stability at all operating conditions. Then, the dc-link control system is modified by introducing an auxiliary compensation block which virtually adds a positive damping resistor in parallel with the dc-link capacitor. Next design considerations for selection of the auxiliary compensation term are proposed, and finally response of the system is examined by the several time domain simulations. [ABSTRACT FROM AUTHOR]

Background: Toxoplasmosis is one of the world's most common infections in human and other warm-blooded vertebrates and has the most extensive universal spread. The purpose of this study is determining the seroprevalence of human Toxoplasma gondii infection, in the military personnel and their families referred to Baqiyatallah hospital, 2011-2015. Materials and Methods: In this cross-sectional study, the serum of 3370 person contain 770 men and 2600 women attending the laboratories were selected and after completing the questionnaires and also by implementing Chemiluminescence method, these serums were examined for the presence of IgM and IgG immunoglobulins of the Toxoplasma gondii. Results: The results were analyzed using the chi-square test. They showed that there were no statistical relationships between the prevalence of IgG and gender in 2011, 2013, (P>0.05) but there were significant relationships between them in 2012, 2014 and 2015 (P<0.05), also there were no statistical relationships between the prevalence of IgM and gender in all years (P>0.05). The results showed that there were statistical relationships among IgG and age (P<0.01) but there was no statistical relationships between IgM and age in all cases (P>0.05). Conclusion: The results showed high prevalence of Toxoplasmosis in the military personnel and their families in Baqiyatallah hospital. The prevalence of IgG was somehow in the range and positive IgG titer was somewhat higher than what was reported in other studies in the North-West of the country; this could be partly due to the sensitivity and specificity of Chemiluminescence method compared to other methods of serology in diagnosis of Toxoplasmosis. [ABSTRACT FROM AUTHOR]

Blade passing effects (BPEs) including tower shadow and wind shear cause 3P oscillations on mechanical and electrical active power profiles in a grid-connected doubly fed induction generator (DFIG) wind turbine. The basic aim of this paper was to present an effective method to mitigate the destructive problems caused by BPEs and to smooth the active power profile in DFIG, in addition to mitigate 3P oscillations on the voltage profile of the weak connected grid. The proposed approach was based on design and application of a band pass filter (BPF) to the external loop of DFIG active power control in the rotor side converter to remove 3P oscillations of the rotor reference current at mean wind speeds of 9-16 m/s. At high wind speeds, the proposed BPF is simultaneously used in the pitch angle control loop of DFIG to reduce 3p pulsations in the pitch angle profile. The simulation process is carried out at multiple wind speeds considering the new model of BPEs, which was derived to model these phenomena with a simple equation. The proposed model could be effective to analyze the DFIG performance, suitably via considering the adverse effects of tower shadow and wind shear, and to study the grid power quality problems. Simulation results are obtained for DFIG active power and grid RMS voltage profiles. These results validated the usefulness of the proposed method to improve the DFIG performance by smoothing the produced active power profile. Moreover, the periodic pulsations of the grid voltage profile are mitigated to enhance the grid power quality. [ABSTRACT FROM AUTHOR]

The patient was a 51-year-old lady with left flank colicky pain accompanied with nausea and vomiting for a month. Transurethral lithotripsy and ureteral stent placement was considered for the patient. The patient had a narrow ureteral lumen and while bringing the ureteroscope out, ureteral avulsion occurred at a distance approximately 4 cm from ureteropelvic junction. After bringing the uretroscope out, the avulsed ureter was observed hanging at the tip of the ureteroscope. Anastomosis of the ureter to the bladder was accomplished with Lich-Gregoir technique. A drainage tube was inserted at the site of incision and the surgical wound closed. The patient was discharged with acceptable general condition after 3 days and the drainage tube removed. The ureteral stent was removed 4 weeks later by cystoscopy. An ultrasound imaging study of the genitourinary system 8 months into the patients follow up showed normal size, echo and cortical thickness in the operated kidney after renal autotransplantation. [ABSTRACT FROM AUTHOR]

Objective(s): Various methods for repairing bone defects are presented. Cell therapy is one of these methods. Bone marrow stromal cells (BMSCs) seem to be suitable for this purpose. On the other hand, lots of biomaterials are used to improve and repair the defect in the body, so in this study we tried to produce a similar structure to the bone by the chitosan and hydroxyapatite. Materials and Methods: In this study, the solution of chitosan-nanohydroxyapatite-polyethylene oxide (PEO) Nanofibers was produced by electrospinning method, and then the BMSCs were cultured on this solution. A piece of chitosan-nanohydroxyapatite Nanofibers with BMSCs was placed in a hole with the diameter of 1 mm at the distal epiphysis of the rat femur. Then the biomechanical and radiographic studies were performed. Results: Biomechanical testing results showed that bone strength was significantly higher in the Nanofiber/BMSCs group in comparison with control group. Also the bone strength in nanofiber/BMSCs group was significant, but in nanofiber group was nearly significant. Radiographic studies also showed that the average amount of callus formation (radio opacity) in nanofiber and control group was not significantly different. The callus formation in nanofiber/BMSCs group was increased compared to the control group, and it was not significant in the nanofiber group. Conclusion: Since chitosan-nanohydroxyapatite nanofibers with BMSCs increases the rate of bone repair, the obtained cell-nanoscaffold shell can be used in tissue engineering and cell therapy, especially for bone defects. [ABSTRACT FROM AUTHOR]

The removal of methylene blue by activated carbon of corn husk by ZnCl2 activation (CHACZ) was investigated in the present study. Adsorption studies were performed by batch experiments. The effect of pH, initial dye concentration, adsorbent dose, the particle size of CHACZ, agitation speed, temperature, and contact time was explored. The equilibrium adsorption data were analyzed using two widely applied isotherms: Langmuir, Freundlich. Best fits were found to be Freundlich isotherm. Langmuir adsorption capacity (Qm) in 298, 308, and 318K is 462.96, 546.45, and 662.25 mgg-1. The amount of RL indicates that CHACZ has a favorable adsorption. Maximum MB removal was observed at pH 4.0. The results indicate that CHACZ is an efficient adsorbent for removing dye from wastewater. [ABSTRACT FROM AUTHOR]

Rheology and morphology of cyclic olefin copolymer (COC) / ethylene vinyl acetate copolymer (EVA) immiscible blends with droplet and co-continuous morphologies were experimentally examined and theoretically analyzed using emulsion and micromechanical models. The blends showed an asymmetric phase diagram in which the EVA-rich blends had smaller dispersed size domains as compared to the COC-rich blends. This could be explained based on the higher melt elasticity and viscosity of COC as compared to EVA determined by the rheological investigations. The rheological tools were used to investigate the miscibility of the blends. From the melt viscosity data it is found that the COC/EVA blends show a positive deviation behavior at all compositions which is a hint for strong interaction between the COC and EVA. Analysis of Cole-Cole and Han diagrams revealed that COC/EVA blends, at high EVA contents, were more compatible than COC-rich blends. For the droplet morphology, Palierne model was more successful but, by increasing the dispersed phase content some deviation was observed. In the co-continuous region, the Coran model was in good correspondence with the experimental data as compared to the Veenstra's model. The storage and loss modulus of EVA-rich blends had a better correspondence with the Palierne model than the COC-rich blends which further confirmed the morphological findings. Interfacial tension calculated for the COC/EVA blends using the Palierne model, were about 1.2 and 15 mN/m for EVA-rich (10/90) and COC-rich blends (90/10), respectively. In both EVA-rich and COC-rich systems the interfacial tension increased with increasing the dispersed phase content. [ABSTRACT FROM AUTHOR]

This paper deals with the coordinated control of rotor- and grid-side converters in wind turbines with doubly fed induction generators (DFIGs) to improve the low-voltage ride-through capability. The rotor-side converter control and additional equipment, called stator damping resistor, are used to limit the rotor inrush current and to reduce the oscillations and settling time of DFIG transient response during the voltage dip. Also, the grid-side converter is controlled to limit the dc-link overvoltage during the voltage drop. It is found that the dynamics of the grid-side converter and dc-link voltage exhibit nonminimum phase behavior, and thus there is an inherent limitation on the achievable dynamic response during the fault. Since the dc-link dynamics is nonlinear, the linear control scheme cannot properly limit the dc-link voltage under large voltage dips. Thus, a nonlinear control scheme applied to the grid-side converter is proposed, which stabilizes the internal dynamics and limits the dc-link voltage fluctuations during the fault. The proposed ride-through approaches limit the peak values of rotor current and dc-link voltage at the instants of occurring and clearing the fault. They also limit the oscillations of electromagnetic torque, and consequently, improve the DFIG voltage dip behavior. [ABSTRACT FROM PUBLISHER]

This paper first discusses dynamic characteristics of wind turbines with doubly fed induction generator (DFIG). Rotor back electromotive force (EMF) voltages in DFIG reflect the effects of stator dynamics on rotor current dynamics, and have an important role on rotor inrush current during the generator voltage dip. Compensation of these voltages can improve DFIG ride-through capability and limit the rotor current transients. It is found that the electrical dynamics of the DFIG are in nonminimum phase for certain operating conditions. Also, it is shown that the dynamics of DFIG, under compensation of rotor back EMF and grid voltages, behave as a partially linearizable system containing internal and external dynamics. The internal and external dynamics of DFIG include stator and rotor dynamics, respectively. It is found that under certain operating conditions, the internal dynamics, and thus, the entire DFIG system becomes unstable. This phenomenon deteriorates the DFIG postfault behavior. Since the DFIG electrical dynamics are nonlinear; the linear control scheme cannot properly work under large voltage dips. We address this problem by means of a nonlinear controller. The proposed approach stabilizes the internal dynamics through rotor voltage control, and improves the dynamic behavior of the DFIG after clearing the fault. [ABSTRACT FROM AUTHOR]

The mm-long carbon nanotube (CNT) arrays were grown in a floating catalyst reactor, using xylene-ferrocene and a small amount of acetic acid as the feed. The CNT arrays deposited on a quartz substrate at several positions along the reactor were extensively characterized using Raman spectroscopy, scanning electron microscopy, X-ray diffraction, high-resolution transmission electron microscopy, and optical microscopy. Various characterization methods consistently reveal that the acetic acid additive to the feed alleviates deposition of amorphous carbon layer, which gradually thickens CNTs along the reactor. The acetic acid also resulted in a higher growth rate along the so-called growth window, where CNT arrays are deposited on the quartz substrate. High-performance liquid chromatography of extracted byproducts (PAHs) confirmed the presence of some polycyclic aromatic hydrocarbons. The solid weight of PAHs decreased upon addition of ferrocene as the catalyst precursor, as well as of acetic acid to xylene feed. The results suggest that primary light products of xylene pyrolysis can be competitive reactants for both catalytic and subsequent pyrolytic reactions. They may also be more efficient feeds for CNT growth than xylene itself. [ABSTRACT FROM AUTHOR]

Expansive cement mortar can be used in conjunction with a Type I cement mortar to develop a composite beam, which after curing will have residual ·compressive stresses on the tensile surface which can result in significantly increased flexural strength. The magnitude of the increased flexural strength, for a particular beam geometry and a given expansive cement, depends on the relative thicknesses of the layers of the two mortars. [ABSTRACT FROM AUTHOR]