Purification and characterization of a thermostable glucoamylase produced by Aspergillus flavus HBF34

Glucoamylase (GA) from Aspergillus flavus HBF34 strain was partially purified 120 folds using starch affinity chromatography. Two isoenzymes (GA1 and GA2) were identified by polyacrylamide gel electrophoresis (PAGE) zymography. Sodium dodecyl sulfate (SDS)-PAGE analysis revealed that one of the enzymes consist of one subunit and the other, two subunits. The optimum pH of the purified GA was 6.0 and the optimum temperature was 60°C. GA was found to be stable at temperatures up to 50°C and at a pH range between 3.0 and 9.0. Km and Vmax values of the enzymes were determined using soluble potato starch, glycogen, amylopectin and amylose as substrates and calculated to be 0.046,0.075, 0.1 and 0.125 mg/ml and 769, 1250, 3333 and 2500 U/mg protein, respectively. While GA was activated by Mn2+, Ca2+, Co2+ and Ba2+, it was inhibited by Hg2+, Fe3+, Al3+, Zn2+ and Cu2+. The activity ofGA was found to be tolerant up to 5 M NaCl concentration.  N-bromosuccinimide (NBS) and phenylmethanesulfonylfluoride (PMSF) inhibited the enzyme, suggesting the involvement of tryptophan and serine residues in the catalytic process. Raw corn starch adsorption of GA was found to be 93%. Thin-layer chromatography (TLC) results showed that amylase was in fact a glucoamylase

Coordinated movement of multiple mobile sinks in a wireless sensor network for improved lifetime

Sink mobility is one of the most effective solutions for improving lifetime and has been widely investigated for the last decade. Algorithms for single-sink mobility are not directly applied to the multiple-sink case due to the latter’s specific challenges. Most of the approaches proposed in the literature use mathematical programming techniques to solve the multiple-sink mobility problem. However, doing so leads to higher complexities when traffic flow information for any possible sink-site combinations is included in the model. In this paper, we propose two algorithms that do not consider all possible sink-site combinations to determine migration points. We first present a centralized movement algorithm that uses an energy-cost matrix for a user-defined threshold number of combinations to coordinate multiple-sink movement. We also give a distributed algorithm that does not use any prior network information and has a low message exchange overhead. Our simulations show that the centralized algorithm gives better network lifetime performance compared to previously proposed MinDiff-RE, random movement, and static-sink algorithms. Our distributed algorithm has a lower network lifetime than centralized algorithms; sinks travel significantly less than in all the other schemes. © 2015, Koç and Korpeoglu

Algorithms for sink mobility in wireless sensor networks to improve network lifetime

Ankara : The Department of Computer Engineering and the Institute of Engineering and Science of Bilkent University, 2008.Thesis (Master's) -- Bilkent University, 2008.Includes bibliographical references leaves 60-65.A wireless sensor network (WSN) consists of hundreds or thousands of sensor nodes organized in an ad-hoc manner to achieve a predefined goal. Although WSNs have limitations in terms of memory and processor, the main constraint that makes WSNs different from traditional networks is the battery problem. Since sensor nodes are generally deployed to areas with harsh environmental conditions, replacing the exhausted batteries become practically impossible. This requires to use the energy very carefully in both node and network level. Different approaches are proposed in the literature for improving network lifetime, including data aggregation, energy efficient routing schemes and MAC protocols, etc. Main motivation for these approaches is to prolong the network lifetime without sacrificing service quality. Sink (data collection node) mobility is also one of the effective solutions in the literature for network lifetime improvement. In this thesis, we focus on the controlled sink mobility and present a set of algorithms for different parts of the problem, like sink sites determination, and movement decision parameters. Moreover, a load balanced topology construction algorithm is given as another component of network lifetime improvement. Experiment results are presented which compare the performance of different components of the mobility scheme with other approaches in the literature, and the whole sink mobility scheme with random movement and static sink cases. As a result, it is observed that our algorithms perform better than random movement and static cases for different scenarios.Koç, MetinM.S

Purification and characterization of a thermostable glucoamylase produced by Aspergillus flavus HBF34

Glucoamylase (GA) from Aspergillus flavus HBF34 strain was partially purified 120 folds using starch affinity chromatography. Two isoenzymes (GA1 and GA2) were identified by polyacrylamide gel electrophoresis (PAGE) zymography. Sodium dodecyl sulfate (SDS)-PAGE analysis revealed that one of the enzymes consist of one subunit and the other, two subunits. The optimum pH of the purified GA was 6.0 and the optimum temperature was 60° C. GA was found to be stable at temperatures up to 50° C and at a pH range between 3.0 and 9.0. Km and Vmax values of the enzymes were determined using soluble potato starch, glycogen, amylopectin and amylose as substrates and calculated to be 0.046, 0.075, 0.1 and 0.125 mg/ml and 769, 1250, 3333 and 2500 U/mg protein, respectively. While GA was activated by Mn 2+ , Ca 2+ , Co 2+ and Ba 2+ , it was inhibited by Hg 2+ , Fe 3+ , Al 3+ , Zn 2+ and Cu 2+ . The activity of GA was found to be tolerant up to 5 M NaCl concentration. N-bromosuccinimide (NBS) and phenylmethanesulfonylfluoride (PMSF) inhibited the enzyme, suggesting the involvement of tryptophan and serine residues in the catalytic process. Raw corn starch adsorption of GA was found to be 93%. Thin-layer chromatography (TLC) results showed that amylase was in fact a glucoamylase.This work was supported by Adnan Menderes University, Research Foundation (FEF 05010)

HAPS-Enabled Sustainability Provision in Cellular Networks through Cell-Switching

There is a consensus in the literature that cell-switching is a viable solution to tackle the draconian increase in the energy consumption of cellular networks. Although the literature is full of works addressing the energy consumption problem via cell-switching, where small cells with low or no load are turned off and the traffic is offloaded to either adjacent base stations or macro cells, in terrestrial communication networks, they may not be feasible when there is either a lack of infrastructure or insufficient capacity due to high demand. The integration of non-terrestrial networks (NTN) into the cell-switching process can be considered as a visionary approach to handle this problem. In this regard, high altitude platform station (HAPS) draws considerable attention with its massive footprint, high capacity, and ubiquitous connectivity. The aim of this study is to show the potential benefits of using HAPS in cell-switching methods by being a bountiful host for offloaded users from cell-switching operations. More specifically, HAPS is included in the network so that it can increase the switching off opportunities by providing extra coverage and capacity. The simulation results demonstrate that a significant amount of reduction in energy consumption (as high as 16%) is obtained while ensuring quality-of-service (QoS) requirements

Şiddet Yaşantıları Ölçeği - Gözden Geçirilmiş Formunun Türkçeye Uyarlanması: Geçerlik ve Güvenirlik Çalışması

DergiPark: 614768tredKing ve Russell (2017)tarafından geliştirilen Şiddet Yaşantıları Ölçeği- Gözden Geçirilmiş Formukatılımcıların 5-8 yaş, 9-12 yaş ve 13-16 yaş aralığındaki aile düşmanlığı,kardeş düşmanlığı, ev içindeki düşmanlığı ve akran düşmanlığına ilişkin şiddetyaşantılarını ölçen, 36 maddeden, 12 endeksten ve dört faktörden oluşan birölçektir. Ölçeğin dört faktörlü yapısına ek olarak çocukluk, erinlik veergenlik dönemlerini kapsayan dönemsel şiddet yaşantıları daincelenebilmektedir. Ölçeğin hem farklı kişilerden maruz kalınan şiddetyaşantılarını hem de yaş dönemine göre maruz kalınma durumunu ortaya çıkarmasınedeniyle Türk kültürü için de geçerlilik ve güvenirliğinin yapılmasının önemliolduğu öne çıkmaktadır. Bu çalışmanın amacı Şiddet Yaşantıları Ölçeği GözdenGeçirilmiş Formunun Türkçeye uyarlanması ve psikometrik özelliklerininincelenmesidir. Bu amaçla İstanbul’daki üniversitelerde öğrenim gören 460katılımcıya ölçek uygulanmıştır. Doğrulayıcı faktör analizi sonucunda ölçeğin dörtboyutlu yapısının doğrulandığı ve iç güvenirliğinin yüksek olduğu görülmüştür

Relationship between apnea-hypopnea index and oxygen desaturation in REM-sleep period and morning headache in patients with obstructive sleep apnea syndrome

Introduction: In patients with morning headache, REM sleep period decreases though little is known about its physiopathology. We evaluate the polysomnographic records of obstructive sleep apnea syndrome (OSAS) patients with the hypothesis that oxygen desaturations may be a better determinant in patients with morning headache, especially those in REM sleep periods. Methods: Patient group (group 1) with a total of 361 patients with OSAS and the controls (group 2) with 107 healthy individuals were evaluated. The presence of morning headache was compared between the groups, and sleep parameters were correlated with morning headache. Results: In group 1, patients with OSAS and morning headache, apneahypopnea index in the REM sleep period (26.7/hour, min-max: 0-108.4/hour) was higher than those in patients without morning headache (17.8/hour, min-max: 0-107.8/hour). The minimum oxygen saturation in REM sleep period and total sleep time (TST) was lower in patients with morning headache (REM sleep period: 82%, min-max: 50-94%; TST: 79%, min-max: 50-97%) in compared to patients without morning headache (REM sleep period: 84%, min-max: 50-93%; TST: 81%, min-max: 50-90%). Conclusion: Here we demonstrated that higher apnea-hypopnea index and lower oxygen saturation in REM sleep period were associated with morning headache in patients with obstructive sleep apnea syndrome

UAV-based Maritime Communications: Relaying to Enhance the Link Quality

Providing a stable connectivity in maritime communications is of utmost importance to unleash the full potential of smart ports. Nonetheless, due to the crowded nature of harbor environments, it is likely that some ships are shadowed by others, resulting in reduced received power that subsequently diminishes their data rates-even threatens basic connectivity requirements. Given that UAVs have been regarded as an integral part of future generations of wireless communication networks, they can be employed in maritime communications as well. In this paper, we investigate the use of UAV-mounted relays in order to help mitigate the reduced data rates of blocked links in maritime communications. Various communication architectures are considered based on the positioning mechanism of the UAV; in this regard, fixed, k-means algorithm-based, and landing spot-based positioning approaches are examined. On the other hand, since UAVs are predominantly battery-operated, the energy consumption performances of these approaches are also measured. Results reveal that the landing spot-based UAV relay positioning approach finds the best trade-off between the data rate and energy consumption

DR-70: A promising biomarker for the detection of lung cancer

Objective: Lung cancer (LC) is characterized by an aggressive phenotype with a high mortality rate, early metastasis, and proliferation rate. Treatment options and prognosis differ significantly at each stage. Despite the availability of multiple imaging studies and invasive procedures, the disorder is diagnosed at an advanced stage. Therefore, it is essential to find biomarkers for the early detection of LC. Patients and Methods: Between 2018 and 2020, 73 LC and 71 control with the same demographic characteristics were included in our study. DR-70 level was measured by a photometric method in serum samples taken from all subjects. Results: A total of 144 subjects (110 male, 34 female) was included in the study. DR-70 levels in the LC group (2.53 +/- 2.64 mu g/mL) were found to be statistically significantly higher than the control group (0.56 +/- 1.23 mu g/mL). Clinical sensitivity and specificity of DR-70 for LC were found to be 87.67% and 88.73%. Conclusions: The high sensitivity and specificity of DR-70 can be used as a biomarker for rapid diagnosis in patients with LC. Compared with other tumor biomarkers, DR-70 seems to have a better sensitivity and specificity in the diagnosis of LC

Conversion in Turkish : an overview

This paper presents an overview of possible cases of conversion in Turkish. I argue that apparent cases of conversion between nouns and adjectives are cases of syntactic transposition, and apparent cases of conversion between nouns/adjectives and verbs are end products of phonological changes in the history of the language, which resulted in pairs of lexemes that are formally identical synchronically, but not historically. This does not mean that no cases of morphological conversion can be traced in the language. I will present two cases of secondary word-class conversion from derived, inflected and uninflected words to toponyms which might be taken as instances of morphological conversion or derivation by zero-affixation