Immobilization of Enzymes on Hierarchically-Structured Supports

In the last decades, the energy consumption of the world has been dramatically enlarged, owing to increased globalization and the economic growth. Thus, new renewable energy sources have been developed to overcome this drawback. In recent years, biomass, which is one of the most widespread renewable energy sources, promises to satisfy this demand. Biomass is also utilized as a sustainable resource to be situated for some valuable chemicals as well as biofuels and biopolymer intermediates. Conversion of biomass can be accomplished by catalytic processes in which enzymes play a key role as biocatalysts. Contrary to the side effects of many physical and chemical processes in industry, biocatalysis has been preferred due to their inhibition of the environmental pollution. Contrary to chemical catalysts, enzymes are used under mild conditions due to their proverbial sensibility and limited operational stability. These features of enzymes cause some challenges in recovery and reusability for a given industrial application. In order to enhance stability of enzymes-based catalysts, immobilization techniques were improved. Besides, many scientists investigate with a great interest the most effective way to obtain maximized exposure of enzyme’s active site in the biocatalytic reaction mixture, with an obvious impact in the catalyst activity. A suitable strategy for the above described issue is usually to be benefit from a porous support, which should provide suitable binding sites for enzymes in active conformation, and/or allow encapsulation of enzymes, whilst minimizing enzyme leakage and deactivation. Additionally, the characteristics of a carrier utilized in immobilization of enzyme have to be well-considered including its permeability, surface area, hydrophilic character, insolubility, mechanical and thermal stability. While keeping in mind of the above-described properties, it is not a surprise that inorganic porous materials are commonly preferred due to their cage-like configurations, which allow the constructions of suitable microenvironments for enzymes. Inorganic porous materials present very interesting features, such as tunable pore size and shape, high specific surface area, high chemical and structural stability, and a variety of chemical functionalities, which can be used as anchoring sites for hosted enzymes. They also possess many advantages, such as increasing enzyme stability, protecting enzymes from harsh reaction conditions, having ability of tailored-cages construction for different enzyme sizes, etc. In this thesis, several different inorganic porous supports were used for enzyme immobilization. These are gradient macroporous stainless steel discs (GMSDs), gradient nanoporous ceramic discs (GNCDs), microporous zeolites, metal organic frameworks (MOFs), and silica-based nanoparticles (SiO2). In addition to that, several chemical catalysts were employed in biomass conversion. Hierarchical nanosheet zeolites, zeolitic imidazolate frameworks (ZIFs) as well as zinc oxide (ZnO) were tested in isomerization of monosaccharides. From the point of biomass type, starch became prominent in this thesis since it is a kind of primary biomass which appears abundantly in nature. This polysaccharide is constructed from glucose units linked with each other via glycosidic bonds and highly exploited in numerous applications in industry. There are several enzymes available for converting starch molecules. Here, we used α-amylase (and thermostable α-amylase) and ß-amylase to hydrolyze the starch to glucose. Additionally, α-glucosidase to hydrolyze maltose to glucose, invertase to hydrolyze sucrose to glucose and fructose and glucose oxidase to oxidase β-D-glucose to D-glucono-δ-lactone were employed. Alongside of the carbohydrate enzymes, lipases are also commonly used in many industrial applications. In this thesis, lipase from Thermomyces lanuginosus to perform transesterification of vinyl propionate (VP) with 1butanol as well as lipase from Aspergillus niger to hydrolase p-nitrophenyl palmitate to p-nitrophenol were tested. The specificity of an enzyme, the versatile activation of a chemical catalyst and the utility of inorganic porous materials in immobilization of enzymes allow several different designs for process engineering. Consequently, combining of biocatalysts and inorganic porous materials in order to achieve much more efficient reaction mechanisms is mainly focused on in this thesis

Contexts used for real life connections in mathematics textbook for 6th graders

The aim of this study is to examine the real life connections in the mathematics textbook for 6th graders and to identify how the contexts used in these connections are handled depending on learning areas. Document analysis of qualitative research methods was used in the study. The results of the study revealed that almost half of the activities (46.6%) in the textbook was connected with real life. The contexts used in these real life connections were analyzed by categorizing them under two different context types: weak and rich context. It can be concluded from the results of this research that the weak contexts were mostly utilized (68.4 %) in real life connections. When these contexts were analyzed on the basis of the learning area itself, it was revealed that weak contexts are frequently employed in the learning area of algebra, while rich contexts are most commonly used in the learning area of data processing

Design and development of a multi-functional laparoscopic device

This study presents a design of a multifunctional laparoscopic appendectomy device that includes three surgical instruments commonly used in laparoscopic appendicitis surgeries: endoloop, endobag and scissors. It collects these three independent surgical tools in a single laparoscopic appendectomy device. These days there is a trend of moving to multi-functional surgery devices during minimally invasive surgery. The main reasons behind the minimal invasive surgery are to avoid changing the devices several times during the operation, to reduce the time spent in operation, to increase the efficiency of the operation, to facilitate the follow-up of the camera and devices, and to leave trocars to be used for other surgical instruments. The multi-functional appendectomy device that, we present here, provides these benefits. The standard trocar entries are appropriate for its usage. The presented multifunctional laparoscopic appendectomy device offers more practical use in comparison to individual devices. On the other hand, development of these multi-functional surgery devices can be directly enhanced to the robotic surgery devices

Impact of T Wave Amplitude in Lead Avr on Predicting Appropriate Therapies in Hypertrophic Cardiomyopathy Patients With An Implantable Cardioverter Defibrillator

DergiPark: 420837tmsjAims: Although implantable cardioverter defibrillator reduces mortality in hypertrophic cardiomyopathy patients,inappropriate implantable cardioverter defibrillator shocks are related to increased mortality. The aim of this studyis to investigate whether a new electrocardiographic marker of T wave amplitude in lead aVR can be used to predictappropriate therapy of implantable cardioverter defibrillator (shock or anti-tachycardia pacing) in hypertrophic cardiomyopathypatients.Methods: Thirty-six hypertrophic cardiomyopathy patients, who were admitted to the outpatient clinic for pacemakercontrol, with implantable cardioverter defibrillator were retrospectively examined (mean age: 51 ± 10.2 years,72.2% male). The primary endpoint was appropriate implantable cardioverter defibrillator therapy. All hematological,biochemical and electrocardiogram parameters were measured before implantable cardioverter defibrillator wasimplanted.Results: Over a median follow-up period of 33 months, 9 (25%) patients experienced appropriate implantablecardioverter defibrillator therapy. Heart rate and QRS interval were similar between groups. QT and QTc valueswere higher in patients that received appropriate shocks. Patients who have T wave inversion were higher in therapypositive group. T wave amplitude in lead aVR values were significantly associated with appropriate therapy.Conclusion: Using simple ECG parameters, we may predict arrhythmic episodes before ICD implantation and animprovement of the medical antiarrhythmic therapy might be protective for HCM patients with ICD

Editorial: Nutrition at the Crossroads: Food at the Intersection of Environmental, Economic, and Social Sustainability

Kurt A. Rosentrater, Laetitia Palmade, and Elif Kongar's editorial about food and environmental, economic, and social sustainability

Evaluation of sleep quality in patients with carpal tunnel syndrome

AMAÇ: Karpal tünel sendromu (KTS) median sinirin el bileği düzeyindeki tuzak nöropatisidir. Geceleri şiddetlenen ağrı ve dizesteziler hastalığın tipik bulgusudur. Çalışmamızın amacı KTS hastalarında uyku kalitesinin araştırılması, mevcut uyku bozukluklarının semptom şiddeti ve fonksiyonel bozuklukla ilişkisinin saptanmasıdır. GEREÇ VE YÖNTEMLER: Elektrodiagnostik olarak KTS tanısı alan 29 kişi ve kontrol grubu olarak hastane personelinden 25 sağlıklı kişi çalışmaya alındı. Tüm katılımcıların bilgilendirilmiş onamı alındı. Hastaların semptom şiddeti ve fonksiyonel bozukluklarını değerlendirmek üzere Boston sorgulaması kullanıldı. Çalışmaya katılan hastaların ve sağlıklı kontrol grubunun uyku kalitesi Pittsburgh Uyku Kalitesi İndeksi ile değerlendirildi. BULGULAR: Karpal tünel sendromlu hastaların genel uyku kalitesinin kontrol grubuna kıyasla anlamlı olarak daha kötü olduğu saptandı (p=0,046). Pittsburgh skoru bileşenleri ayrıntılı olarak değerlendirildiğinde alışılmış uyku etkinliğinin karpal tünel sendromlu hastalarda anlamlı düzeyde bozulmuş olduğu saptandı (p=0.001). SONUÇ: Uyku kalitesi KTS’li hastalarda anlamlı düzeyde bozulmaktadır ve gece uykuda geçirdikleri toplam süre azalmaktadır.OBJECTIVE: Carpal tunnel syndrome (CTS) is defined as entrapment neuropathy of the median nerve at the wrist. Pain and disestesia that worsen at night are characteristic features of the disease. The aim of this study was to determine sleep quality of patients with CTS and also defining the association between symptom severity, functional impairment with existing sleep disturbance. MATERIALS AND METHODS: Twenty-nine patients with CTS according to electrodiagnostic evaluation and 25 healthy volunteers recruited from hospital staff were included into the study. Informed consent was obtained from all participants. Boston Questionnaire was used to evaluate symptom severity and functional impairment. Sleep quality of the participants was assessed with Pittsburgh Sleep Quality Index. RESULTS: Overall sleep quality of the CTS patients was significantly worse than control group (p=0.046). Detailed analysis of Pittsburgh Sleep Quality index components revealed that habitual sleep efficiency was significantly impaired in patients with CTS (p=0.001). CONCLUSION: Sleep quality was significantly disturbed in patients with CTS, and also the total time that patients were asleep was shortened

Measurement of cognitive dynamics during video watching through event-related potentials (ERPs) and oscillations (EROs)

Event-related potentials (ERPs) and oscillations (EROs) are reliable measures of cognition, but they require time-locked electroencephalographic (EEG) data to repetitive triggers that are not available in continuous sensory input streams. However, such real-life-like stimulation by videos or virtual-reality environments may serve as powerful means of creating specific cognitive or affective states and help to investigate dysfunctions in psychiatric and neurological disorders more efficiently. This study aims to develop a method to generate ERPs and EROs during watching videos. Repeated luminance changes were introduced on short video segments, while EEGs of 10 subjects were recorded. The ERP/EROs time-locked to these distortions were analyzed in time and time-frequency domains and tested for their cognitive significance through a long term memory test that included frames from the watched videos. For each subject, ERPs and EROs corresponding to video segments of recalled images with 25% shortest and 25% longest reaction times were compared. ERPs produced by transient luminance changes displayed statistically significant fluctuations both in time and time-frequency domains. Statistical analyses showed that a positivity around 450 ms, a negativity around 500 ms and delta and theta EROs correlated with memory performance. Few studies mixed video streams with simultaneous ERP/ERO experiments with discrete task-relevant or passively presented auditory or somatosensory stimuli, while the present study, by obtaining ERPs and EROs to task-irrelevant events in the same sensory modality as that of the continuous sensory input, produces minimal interference with the main focus of attention on the video stream