Search

Three-dimensional bioprinting offers a novel strategy to create large-scale complex tissue models. Nowadays, layer by layer fabrication is used to create patient specific tissue substitutes. However, commercially available bioprinters cannot be widely used especially in small research facilities due to their high cost, and may not be suitable for bioprinting of complex tissue models. Besides, most of the systems are not capable of providing the required working conditions. The aim of this study is to design and assemble of a low-cost H-Bot based bioprinter that allows multimicro-extrusion to form complex tissue models in a closed cabin and sterile conditions. In this study, a micro-extrusion based bioprinter, Bio-Logic, with three different print heads, namely, Universal Micro-Extrusion Module (UMM), Multi-Micro-Extrusion Module (MMM), and Ergonomic Multi-Extrusion Module (EMM) were developed. The print heads were tested and scaffold models were bioprinted and analyzed. Bio-Logic was compared in price with the commercially available bioprinters. Scaffold fabrication was successfully performed with Bio-Logic. The average pore size of the scaffold was determined as 0.37±0.04 mm (n = 20). Total cost of Bio-Logic was considerably less than any other commercially available bioprinters. A new system is developed for bioprinting of complex tissue models. The cost of the system is appropriate for research and features of the device may be upgraded according to the needs. Bio-Logic is the first H-Bot kinematics based bioprinter and has ability to measure atmospheric conditions in a closed cabin.

The therapeutic efficacy of various concentrations and combinations of thymol, Artemisia absinthium oil and nanoparticle ozone against Nosemosis caused by Nosema ceranae in honey bees was studied. Two-hundred colonies were examined for N. ceranae positivity and negativity under light microscopy; 119 colonies were positive and 81 colonies were negative for Nosemosis. The study evaluated the therapeutic efficacy of 17 different combinations against N. ceranae. Nine of the 17 combinations were applied by spray to frames and eight were applied orally (combinations added to the sugar syrup reservoir) to the hives. Each of the 17 combinations was prepared in 1,000 ml from (2%, 3% and 5%) of thymol and (2% and 3%) A. absinthium oil, and 1,000, 2,000, 4,000, and 8,000 ppm concentrations of nanoparticle ozone. N. ceranae spore counts before and after the treatment were counted on Neubauer thoma slides by the digestion method, and the efficacy of the combinations was determined by the percent reduction test. In spray form, 200 ml 2,000 ppm nanoparticle ozone + 100 ml 3% thymol + 700 ml sugar syrup (efficacy-89.47%) (Group 5) and in oral form, 250 ml 2% thymol + 200 ml 2% A. absinthium oil + 500 ml sugar syrup (efficacy-85.95%) (Group 16), were found to be more effective. In conclusion, the combination of thymol and nanoparticle ozone in spray form was more effective than other combinations in this study.

The present study aims to design stacking sequences of dimensionally stable symmetric balanced laminated carbon/epoxy composites, with different numbers of layers, with a low coefficient of thermal expansion and high elastic moduli. To avoid excessive interlaminar stresses in the composites, the contiguity constraint for plies is also taken into consideration. In the design process, both single- and multiobjective optimization approaches, including genetic algorithms, are utilized. Results showed that stacking sequences ensuring lower thermal expansion coefficients and higher elastic moduli than those of traditional laminate designs can be obtained.

Ticks (Acari: Ixodidae) transmit pathogens causing some diseases like Crimean–Congo Hemorrhagic Fever, Lyme disease and Q fever. The most common method for tick control is the use of chemical acaricides, which harmful to animals, humans and the environment. The intense use of these products has also led to acaricide resistance in many tick species. Although there have been many resistance studies, there is no research about the resistance of ticks to acaricides in Turkey. In this research, it was aimed to determine the resistance status of Rhipicephalus sanguineus sensu lato Latreille populations to permethrin, fipronil and chlorpyriphos-methyl. The results obtained from the Larval packet test (LPT) show that lethal dose 50 (LD50) values are in the range of 0.0006 to 0.0316 gr ai/m2 for permethrin, 0.0021 to 0.033 gr ai/m2 for fipronil and 0.0016 to 0.0414 gr ai/m2 for chlorpyriphos-methyl. The resistance ratios (RR) of 13 populations varied from 2.52 to 52.09 for permethrin, 1.23 to 15.87 for fipronil and 1.29 to 26.6 for chlorpyriphos-methyl. This is the first study to determine the resistance levels of ticks against various acaricides in Turkey.

Objective: to monitor changes in cervical parameters before and after laminoplasty surgery. Cervical parameters and health-related quality-of-life (HRQOL) values that may be affected after laminoplasty were examined before and after surgery. The clinical and radiological course of these values was monitored, and their interaction with all spinal radiological parameters was revealed. Materials and methods: nineteen patients who underwent clinical and radiological evaluation for 2 years were followed in this study. Neck disability index, visual analog scale, and short form 36 scores were determined to evaluate HRQOL. For radiological parameters, the C0-C2 angle, C2-C7 angle, cervical sagittal vertical axis, T1 slope angle, neck tilt (NT) and thoracic inlet angle were used. The results of the 4-month, 1 year and 2-year follow-ups were statistically evaluated. Results: both the HRQOL and cervical radiological parameters deteriorated in the first 4 months and returned to normal in the 2ndyear. Statistically, all parameters were meaningful (P < 0.05), except for NT. Conclusion: cervical parameters and HRQOL values, which deteriorated in the early period, recovered in the late period in the long-term follow-up of patients undergoing laminoplasty. The important point is that preoperative cervical parameters suitable for laminoplasty should be present, and spinopelvic parameters should be normal., NA

Nowadays cardiovascular diseases (CVDs), mostly coronary artery diseases become a leading cause of death. Flow dynamics of a vessel is important to diagnose a CVD in advance. However, hemodynamic parameters may not be measured directly. Hence, computational methods are increasingly being used in the fields of neurosurgery and cardiovascular surgery to obtain realistic physiological simulations. In this study, a patient specific thoracic artery model is first segmented based on the MRI images and then a thoracic aneurysm disease model is simulated to assess blood flow changes under the predefined conditions.

In this study, a new design strategy with a systematic optimization process is proposed for the preparation of magnetite cross-linked tyrosinase aggregates (MCLTA) by using the concentration of magnetite nanoparticle, glutaraldehyde and tyrosinase enzyme as design variables. A comprehensive study on multiple non-linear neuro-regression analysis has been performed as a compelling alternative to the insufficient approaches on modeling-design-optimization of MCLTA. For this aim, the experimental process has been modeled with 13 candidate functional structures by using a hybrid method to test the accuracy of their predictions. R2training, R2testing values, and boundedness of the functions have been checked to reveal the realistic ones. Then four different design approaches in terms of three distinct scenarios have been used to optimize the process. The results show that, all models define the process well, depending on R2training. However, only five and nine models are appropriate based on R2testing for the first use activity and residual activity, respectively. On the other hand, depending on to be a realistic value, model TON best describes the "first use activity," while the best one is FONT for residual activity. It is also concluded that the scenario types and selection of constraints for design variables affect the optimization results.

Nosemosis is one of the most dangerous infectious diseases of honeybees in Azerbaijan and the World. Nosema ceranae is the dominant species detected in Azerbaijan, and this study aimed to detect the prevalence of the infection in the country. For this purpose, an average of 100 honeybee samples were collected from 64 hives, 24 from three regions in the north and 40 from five areas in the south. In the lab, the abdomens of 50 bees from each group were dissected and crushed in a container, adding 50 ml of distilled water. According to obtained data after microscopic examination, the N. ceranae spores were found to have a high-level prevalence in northern regions (45.8% average) than in the southern areas (22.5% average) of Azerbaijan. Molecular diagnoses of Nosema-positive samples have already been made with PCR and N. ceranae has been detected from all regions. Data show us that the Nosemosis is common in Azerbaijan and is a significant thread in the beekeeping industry.

BACKGROUND: Laminectomy may cause kyphotic postoperative deformity in the cervical region leading to segmental instability over time. Laminoplasty may be an alternative procedure to laminectomy, as it protects the spine against post-laminectomy kyphosis; however, similar to laminectomy, laminoplasty may cause sagittal plane deformities by destructing or weakening the dorsal tension band. OBJECTIVE: Using finite element analysis (FE), we attempted to determine whether a posterior motion preservation system (PEEK posterior rod system concept) could overcome the postoperative complications of laminectomy and laminoplasty and eliminate the side effects of rigid posterior stabilization in the cervical region. METHODS: We compared PEEK rods in four different diameters with a titanium rod for posterior cervical fixation. The present study may lead to motion preservation systems of the cervical vertebra. RESULTS: When PEEK rod is compared with titanium rod, considerable increase in range of motion is observed. CONCLUSIONS: PEEK rod-lateral mass screw instrumentation systems may be useful in motion preservation surgery of the posterior cervical region.

Bu çalışmada, Arion İlaç Ar-Ge Merkezi ve Bavet İlaç San. ve Tic. A.Ş. tarafından geliştirilen esansiyel yağ karışımı ile vitamin bileşiklerinin (Noseba®), Nosema ceranae ile doğal enfekte balarısı kolonilerinde etkinliğinin araştırılması amaçlanmıştır. Çalışma süresince kullanılan kolonilerde sadece N. ceranae bulunduğu, PCR ile daha önceki bir çalışmada saptanmıştır. Bursa yöresi İkizce köyünde Mayıs 2019’da 10’ar çerçeveli kolonilerden digestion yönteminde pozitiflik/negatiflik kontrolü için kovan başı en dış çerçeveden 25’er arı muayene edilip, pozitif çıkan kolonilerden Neubauer lamına alınarak ışık mikroskobunda 40x10 büyütmede sayılıp Shimanuki-Knox formülü ile arı başına düşen spor sayısı tespit edilmiştir. Pozitif kovanlar spor sayıları dikkate alınarak 7’şerli 4 gruba ayrılmış, toplam 28 kovan çalışmada kullanılmıştır. Üç ayrı deneme grubunda 1 lt 1:1’lik şeker şurubuna sırasıyla 20, 40 ve 80 cc Noseba® karıştırılmış, Nosema-pozitif bir adet kontrol grubu ise deneme sonuna kadar tedavi edilmeden bırakılmıştır. Nosema sayımını takiben 2 gün üst üste 0,5 lt Noseba® karışımları tedavi gruplarındaki kolonilere oral yolla verilmiştir. Tedavi sonrası +1, +5, +10 ve +15. günlerde tekrar spor sayımı yapılmış, kontrol grubu ile istatistiki olarak karşılaştırılmıştır. Sonuç olarak kontrol grubu ile karşılaştırıldığında sırası ile 1. tedavi grubu %34,2; 2. tedavi grubu %67,2 ve 3. tedavi grubu % 99,9 etkili bulunmuş, kontrol grubu çalışma sonunda 3. tedavi grubu (80 cc) ile tedavi edilmiş ve %99,9’luk etkinlik saptanmıştır. Çalışma süresince Noseba®’dan kaynaklı hiçbir yan etki ve koloni kaybı görülmemiştir.

Human beings face unprecedented Covid-19 pandemic outbreak since the beginning of 2020. This disease started to change economic, social, and individual conventional behaviors. Several economic activities have sharply declined, and demand for commodities is decreasing, such as oil. This commodity has also suffered from disagreement among Organization of Petroleum Exporting Countries (OPEC)+ members to deal with the amount of cutting oil production. This situation adds a supply-side problem into declining demand due to Covid-19. Turkey, as an emerging economy, highly depends on imported oil and suffers from this pandemic disease. This study aims to analyze the compensating role of falling oil prices for impacts of Covid-19 on non-recoverable sectors in Turkey, e.g. tourism, travel, and transportation. The main argument in the study, that is falling prices in oil can contribute to compensation for losing revenue from tourism, travel, and transport. Throughout the study, ORANI-G as a multisectoral computable general equilibrium model is employed. Three scenarios, namely Scenario-1, 2A, and 2B, are set to analyze the effects of falling oil prices as compensation for Covid-19 in the selected sectors. Results show that Covid-19 decreases gross domestic product by 1.16 but falling oil prices as 25 and 50% compensate for this decrease by 0.72 and 1.56% gross domestic product increases, respectively. It is concluded that through the falling oil prices, Turkey’s dependence on crude oil imports might provide a new reparation to overcome non-recoverable impacts. This study is scoped with selected sectors and falling oil prices. Other economic and social sectors need to be investigated in terms of challenges of Covid-19 and opportunities for declining crude oil prices. Besides, competitiveness based on the scale of firms and the ability to access business finance should be analyzed within the changing business model in the post-coronavirus period.

Post-traumatic hydrocephalus (PTH) is one of the primary complications during the course of traumatic brain injury (TBI). The aim of this study was to define factors associated with the development of PTH in patients who underwent unilateral decompressive craniectomy (DC) for TBI. A total of 126 patients, who met the inclusion criteria of the study, were divided into two groups: patients with PTH (n = 25) and patients without PTH (n = 101). Their demographic, clinical, radiological, operative, and postoperative factors, which may be associated with the development of PTH, were compared. Multivariate logistic regression analysis revealed that cranioplasty performed later than 2 months following DC was significantly associated with the requirement for ventriculoperitoneal shunting due to PTH (p

A novel design optimization strategy is proposed to enhance the analytical performance of a biosensor by taking into consideration the constructional and experimental parameters as design variables. A detailed study on multiple nonlinear neuro-regression analysis has been performed methodically in order to overcome the insufficient approaches on modeling-design-optimization of a biosensor. For this aim, the data were selected from a literature study. A hybrid method is used to test the accuracy of the predictions of 12 candidate functional structures that were proposed for modeling the data. The boundedness of the candidate models is checked after the calculation of R2 training and R2 testing values to reveal whether the model is realistic or not. Then appropriate models were optimized by using the four different optimization algorithms in terms of three different optimization scenarios. The results show that all the models express the process well regarding R2 training. However, only four models are appropriate based on R2 testing, and two of them were selected as the objective function depending on to be a realistic value. This novel optimization approach is also feasible for another modeling-design-optimization problem in analytical applications. © 2020, © 2020 Taylor & Francis Group, LLC.

This study aimed to investigate the effect of using high-quality colostrum in addition to paromomycin on the treatment outcomes and serum proteomes of calves naturally affected by cryptosporidiosis. Thirty Holstein calves infected with only Cryptosporidium spp. were divided into three equal groups. Calves in the PC group received paromomycin orally at a dose of 100 mg/kg once daily for 5 days. Calves in PCOL and PBCOL groups received 250 ml colostrum 3 h after feeding twice a day for 3 days. The PBCOL group was also given 6 g of sodium bicarbonate 15 min before colostrum administration. While the fecal scores of all calves were evaluated daily for 10 days from the initiation of the treatment, fecal oocyst counts were determined on the 0, 1, 2, 3, 5, 7, and 10th days. Brix%, total protein (TP), immunoglobulin G (IgG), gamma-glutamyltransferase (GGT) levels, and proteomic analyses were performed on the 0 and 3rd days' sera. Considering pretreatment values, fecal scores (8th, 2nd, and 2nd day), and fecal oocyst counts (10th, 3rd, and 2nd day) improved in a significantly (p 0.05) shorter time in the colostrum groups than in the control group. By serum proteomic analysis, 99, 93, and 83 proteomes were detected in PC, PCOL, and PBCOL groups, respectively. Although the significant changes in any protein in Group PC were absent, significant changes were observed in Alpha-1B-glycoprotein (A1BG), Zinc transporterZIP11 (S39AB), Cathelicidin-1 (CTHL1), Actin_ cytoplasmic-1 (ACTB), and Apolipoprotein A-IV (APOA4) proteins in Group PCOL and Alpha-1-antiproteinase (A1AT), Serum amyloid A protein (SAA), Actin-cytoplasmic-2 (ACTG), Protein HP-20 homolog (HP20) proteins in Group PBCOL with colostral treatment, which indicated that the use of colostrum had an effect on calf serum proteomes. The more pronounced healing and shorter clinical improvement time in the colostrum groups especially colostrum with sodium bicarbonate revealed that these proteomes have positive effects in the treatment with their systemic and local effects in the intestines.

Simultaneous analysis of buckling resistance and first ply failure behavior for synthetic and vegetable fiber-reinforced composites have been evaluated. The Modified Nelder-Mead Algorithm has been used to find the optimum buckling loads, and the failure criteria are selected to find the failure loads. The highlighted point in the present study is the probability of the first ply failure before the buckling. This may occur especially on vegetable fiber-reinforced composites. The study results show that first ply failure occurred before buckling for various loading cases of the structure.

Redundancy resolution techniques have been widely used for the control of kinematically redundant robots. In this work, one of the redundancy resolution techniques is employed in the mechanical design optimization of a robot arm. Although the robot arm is non-redundant, the proposed method modifies robot arm kinematics by adding virtual joints to make the robot arm kinematically redundant. In the proposed method, a suitable objective function is selected to optimize the robot arm’s kinematic parameters by enhancing one or more performance indices. Then the robot arm’s end-effector is fixed at critical positions while the redundancy resolution algorithm moves its joints including the virtual joints because of the self-motion of a redundant robot. Hence, the optimum values of the virtual joints are determined, and the design of the robot arm is modified accordingly. An advantage of this method is the visualization of the changes in the manipulator’s structure during the optimization process. In this work, as a case study, a passive robotic arm that is used in a surgical robot system is considered and the task is defined as the determination of the optimum base location and the first link’s length. The results indicate the effectiveness of the proposed method.

Turkey is the second largest honey producer in the world. However, the beekeeping sector, especially the export of honey and honey products, is not supported by income compatible with this asset. The main reasons for this discrepancy are the presence of honey bee diseases (predators) and their residues in honey. Due to the observation of Aethina tumida (small hive beetle; SHB) in Europe (Italy) and Tropilealaps spp. Iran’s border regions close to Turkey, the Ministry of Agriculture and Forestry of the Republic of Turkey has raised its alert level for these two notifiable diseases. Aethina tumida is a fruit insect originally from South Africa and it has later adapted to bee colonies. In the early 2000s, the agent came to North America with imported fruits and caused serious bee losses. SHB, which has spread to 12 countries so far, caused serious economic losses in the countries it entered and could not be eliminated. Tropilaelaps spp. is an ectoparasite that cannot survive for long without honey bee brood it feeds on and needs to survive. Tropilaelaps mite even suppresses Varroa when found in a colony and extinguishes the colony in a short time. It is a fact that these two pests may spread rapidly in Turkey due to the practice of migratory beekeeping and they can cause serious damage to our beekeeping.

Aim: to evaluate the role of posterior dynamic stabilization (PDS) with kyphoplasty (KP) in the surgical treatment of unstable osteoporotic compression fractures, which are common in the elderly population. Material and methods: this study included 25 patients with osteoporotic compression fractures. KP with PDS was performed on all patients. Radiological evaluation was performed with magnetic resonance imaging, computed tomography, and plain radiographs. The vertebral kyphosis angle (VKA), local kyphosis angle (LKA), and percentage of collapse were calculated. Clinical evaluation was performed with the visual analog scale and the Oswestry Disability Index (ODI). The preoperative and postoperative clinical and radiological data were compared. Results: the clinical and radiological parameters showed significant improvement following surgical treatment. The mean preoperative visual analog scale score of 7.78 decreased to 0.94 after 12 months. The mean preoperative ODI score of 70.33 decreased to 15.65 after 12 months. The mean preoperative VKA of 17.89° decreased to 9.22° after 12 months. The mean preoperative LKA of 9.61° decreased to 5.50° after 12 months. The mean preoperative percentage of collapse of 32.56% decreased to 19.00% after 12 months. There were no major complications. Conclusion: KP with the PDS method offered satisfactory outcomes in the surgical treatment of unstable osteoporotic compression fractures., NA

Objective Adjacent segment disease is a controversial process after spine stabilization. The two important factors discussed are natural aging and hypermobility in incidental segmental fusion anomalies; patients have two or more fused vertebrae from birth, which are the results of spinal movement restriction due to the fusion of some spinal units. This article's main purpose is to determine the degree of relationship of hypermobility and the aging process in the deterioration of the disks adjacent to fusion. Methods In this study, the degenerative process developed by hypermobility in the adjacent segment due to incidental segmental fusion was evaluated. The MRI images of 52 adjacent and nonadjacent disks of 45 patients in total were analyzed according to the Pfirrmann grading systems. The average Pfirrmann rating of the disks just above and below the fused segment and the distant first, second, and third non-neighboring levels were evaluated and calculated, respectively. Results The highest rate of incidental fusion is determined on the cervical area with 51.9%, followed by the thoracal area with 32.7%, and the lumbar area with 15.4%. Damage to the adjacent segment disks in cases with incidental fusion can still be seen at any age, with fusion, indicating that the hypermobility effect plays a more prominent role. The evidence of hypermobility without aging is that the segments adjacent to fusion undergo more degeneration than the distant disks. Conclusion Adjacent segment disease is under the influence of many factors. Our findings suggest that its incidence is increasing with the pathological processes initiated by hypermobility. It seems that, at least, it carries equal importance as compared to age. Fusion surgeries damage the adjacent segments under the influence of the passage of time beyond the physiological aging of the patient.

TiO2 is one of the most common materials for photocatalytic applications due to its stability, affordability, and photoactive efficiency. However, it has some drawbacks, such as limited solar radiation response and quick recombination of excitons. Using graphene could be one of the methods to enhance the photocatalytic properties of TiO2. This study intends to optimize the photocatalytic performance of TiO2/Graphene (TiO2/G) nanocomposite by using neuro-regression analysis. In the analysis, the effect of some hydrothermal synthesis parameters, namely, amount of graphene oxide, ethanol/water ratio, and hydrothermal reaction time on the photocatalytic activity of TiO2/G nanocomposite, have been investigated. The parameters were determined from a literature study focused on overcoming the drawbacks of TiO2 by combining it with graphene oxide. Nelder-Mead, Simulated Annealing, Differential Evolution, and Random Search algorithms are used to obtain the optimum synthesis parameters for maximum photocatalytic activity in the optimization process. The results are indicated that all algorithms give the realizable value for design variables and photodegradation rate.

Otomotiv, havacilik ve denizcilik endustrilerindeki ekolojik yaklasim, dogal liflerin (ozellikle keten) yuksek dogal frekans, dusuk maliyet ve agirlik performanslari nedeniyle cam elyaflara alternatif takviye malzemeleri olarak kullanilabilecegini gostermistir. Bu baglamda, bu calisma, keten lif kullaniminin inter-ply hibrit kompozit yapilarda dogal frekans, maliyet ve agirlik uzerindeki etkisini arastirmaktadir. Tabakali kompozitlerin optimum aci dizilimlerinin tespiti Gelistirilmis Benzetilmis Tavlama Algoritmasi kullanilarak yapilmistir. Mevcut calismada cok amacli optimizasyon yaklasimi ile maksimum dogal frekansa sahip, hafif ve dusuk maliyetli bir tasarim elde edebilmek icin gerekli olan yuksek rijitlige sahip dusuk maliyetli tabakalarin sayisi bulunmustur. Bu calisma, dogal bir fiber olan keten’e ait dogal frekans-fiyat ve dogal frekans-agirlik optimizasyon problemlerini tabakali kompozit plakalar acisindan inceleyen literaturdeki ilk calisma olma ozelligini tasimaktadir. Sonuclar, simetrik-balans hibrit grafit-keten/epoksi kompozit malzemenin spesifik rijitlik oranindan taviz vermeden istenen frekans, fiyat ve agirlik optimizasyonunu saglayarak grafit/epoksi yerine kullanilmasinin uygun oldugunu gostermistir

Object: To investigate the effect of anxiety and hopelessness on the quality of life of healthcare workers.Methods: This cross-sectional, online questionnaire-based study was conducted between August 31 - September 30, 2020, with 729 healthcare workers in Turkey. The Sociodemographic Information Form, the Turkish version of the Shorter Version of the World Health Organization Quality of Life Instrument (WHOQOL-BREF-TR), the State-Trait Anxiety Inventory (STAI-I) and the Beck Hopelessness Scale (BHS) were used for data collection.Results: The study showed that hopelessness, the weekly working time, fatigue, and the workload experienced by healthcare workers negatively affected their quality of life, and those who needed knowledge on various issues to improve their skills had lower quality of life and higher anxiety and hopelessness levels. Conclusion: Protective measures should be taken for the health of healthcare workers against the adverse effects of the intense anxiety, hopelessness, and workload during the pandemic period. To achieve sustainable success in the provision of health services, healthcare workers must be psychologically healthy. Therefore, taking protective measures to improve the resilience of healthcare workers in all health-related areas should be a priority.

Background In this article, clinical satisfaction and radiological results are discussed in a series of patients where the iliac wings participate in dynamic stabilization. Dynamic stabilization is an effective alternative surgical treatment method, especially in clinical pictures that go with pain due to minor instabilities. Practically the unique surgical instrument used in multilevel instabilities is the Dynesys system. The most important drawback of the Dynesys system is that the S1 screws become loose in time. In this article, our aim is to find solution to S1 insufficiency by extension of the system to the iliac wings. Methods Nineteen patients (eight females, 11 males) with a mean age of 54.16 were included in the study. Patients had multilevel (level 2 and above) instability, iliac wings were included in the stabilized segments, and Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) were used for patient follow-up. Results First year results showed a significant improvement in VAS and ODI. Regarding the complications, infection developed in one patient, loosening in the proximal iliac wing in one patient, and both S1 and iliac proximals in one patient, but no clinical findings were encountered. Conclusion When more than two levels of dynamic systems are used in chronic instability, especially in the elderly patients, S1 screws are loosened. In these patients, if the iliac bones are also included in stabilization, this problem is solved successfully. However unfortunately, Dynesys system does not have a screw suitable for the iliac bones.

In this study, it is intended to optimize a high-velocity impact case of a composite plate. The case selected from literature focused on the failure response of advanced carbon–carbon (C/C) composites under high-velocity impacts. Based on the stochastic optimization method, three unique models are introduced within the present study's scope as dimensionless damage areas of front and back sides and the composite impact energy response. The difference between the equations found in the present study and the base study is the number of variables. Obtained prediction models consist of only the tests' input variables; thus, these models can be considered the essential prediction functions of high-velocity impact response of C/C composites under high temperatures. Multiple nonlinear regression method is used for objective functions of the optimization problem. Since the determination coefficient values have been found quite similar to the ones in the literature, the presented models can be considered successful in predicting the results. By utilizing the novel regression functions presented in this study, the damaged areas are minimized. Without the necessity of experimental research, further predictions can be made by operating the models found in the present study.

The objective of the study was to analyze the complications of neurosurgical operations during the COVID-19 pandemic by comparing them with the complications observed in the pre-pandemic period.Two groups were formed: (1) Patients who were operated in the 5-month period of the pandemic (March-July 2020) and (2) those who were operated the same operations in the same period 1 year before (March-July 2019). Demographics, characteristics, medical follow-up data, complications, and outcome compared between the groups.Similar demographics were observed between the groups. The number of all neurosurgical cases and neurotrauma cases decreased by 79% and 68% in pandemic period, respectively. The rate of emergency surgeries was significantly higher in pandemic group (p0.001). The operation time was significantly longer in pandemic group (p=0.014). Total complication rate was significantly higher in pandemic group (p=0.002). Specifically, the rate of pulmonary complications was significantly higher during pandemic period (p0.001). The infection rate (p0.001), antibiotic use (p0.001), and intensive care unit stay (p=0.023) were significantly higher in pandemic group.During pandemic period complication rates increased and a higher risk than expected was encountered. Treatment should be performed by taking the precautions and informing the patients about additional risks.

This paper presents a comparative study on the burst pressure performance of aluminum (Al) liner for type-III composite overwrapped pressure vessels (COPVs). In the analysis, the vessels were loaded with increasing internal pressure up to the burst pressure level. In the analytical part of the study, the burst pressure of the cylindrical part was predicted based on the modified von Mises, Tresca, and average shear stress criterion (ASSC). In the numerical analysis, a finite element (FE) model was established in order to predict the behavior of the vessel as a function of increasing internal pressure and determine the final burst. The Al pressure vessels made of Al-6061-T6 alloy with a capacity of 5 L were designed. The manufacturing of the metallic vessels was purchased from a metal forming company. The experimental study was conducted by pressurizing the Al vessels until the burst failure occurred. The radial and axial strain behaviors were monitored at various locations on the vessels during loading. The results obtained through analytical, numerical, and experimental work were compared. The average experimental burst pressure of the vessels was found to be 279 bar. The experimental strain data were compared with the results of the FE analysis. The results indicated that the FE analysis and ASSC-based elastoplastic analytical approaches yielded the best predictions which are within 2.2% of the experimental burst failure values. It was also found that the elastic analysis underestimated the burst failure results; however, it was effective for determining the critical regions over the vessel structure. The strain behavior of the vessels obtained through experimental investigations was well correlated with those predicted through FE analysis.

INTRODUCTION: Carpal tunnel syndrome (CTS) is estimated to be the most frequently seen mononeuropathy, needing surgical intervention. Its prevalence is known to range between 1, and 3 percent. The components contained in this tunnel are the median nerve, four deep digital flexor tendons, as well as four superficial flexors and the tendon of flexor pollicis longus. Between the tendons and bursae an anatomical structure is present called subsynovial connective tissue (SSCT). SSCT absorbs and transmits stress between tendons and the median nerve and it functions as a scaffold for vascular elements. To find out the role of compression or pathologic proliferation of SSCT in the pathogenesis of CTS, we aimed to conduct a study about the surgical technique of this pathology and compared the long- term results of patients operated with or without SSCT excision in our neurosurgery clinic. METHODS: Between 2003 and 2019 we operated 1279 patients at our neurosurgery clinic. Among them 250 patients who had SSCT excision (syn+) were chosen and they were compared with other 250 patients operated without SSCT excision (Syn-). RESULTS: All patients were evaluated preoperatively and 12 months postoperatively based on the results of Boston Carpal Tunnel Syndrome Questionnaire. When pre-, and post-operative results were compared, we didn’t observe a statistically significant intergroup difference. DISCUSSION AND CONCLUSION: Although our primary goal in patients in whom we performed excision of tenosynovium is to relieve the median nerve by increasing decompression, we observed that there was no difference between the two groups in this large-scale study. We think that only liberation of the transverse carpal ligament during surgery will be sufficient.

In this chapter, Vegetable―Synthetic Hybrid Fiber Laminated Composites problems will be designed optimally in terms of high buckling resistance and low weight. Optimization problems will be solved with mixed-integer programming approach. In order to achieve this challenge, the performance of (i) non-hybrid vegetable (ii) non-hybrid synthetic (iii) inter-ply hybrid vegetable-synthetic fiber-reinforced composites was evaluated in terms of critical buckling load based on single-objective optimization approach and in terms of weight-buckling resistance simultaneously based on multi-objective optimization approach for different aspect ratios, number of plies. Three different optimization problems, each with different scenarios, are defined and solved by performing Modified Differential Evolution (DE) Algorithm. In all cases, the use of fibers with an angle increase of 15° and the layers being symmetric and balanced were considered as constraints. Results revealed that the glass/epoxy-sitka spruce hybrid laminated composite structure is to be more preferable in multi-objective critical buckling factor-weight problems than the other hybrid structures if multi-layered composites are required for use.