Metal Oxide Gas Sensors by Nanostructures

Recently, metal oxide gas sensors by nanostructures have stirred interest and have found their way in many applications due to their high sensitivity, material design compliance and high safety properties. Gas performance tests of n-type ZnO, Al-doped ZnO and ZnO/MWCNT structures toward different type gases from our previous studies have been reported. It is indicated that nanoparticle formations on the film surfaces, grain sizes, gas types and operating temperatures have a severe effect on the chemisorption/physisorption process. Low concentration detection, determination of grain size limit values and reducing operating temperature to room temperature are already obstacles on long-life sensitivity and long-term stability characters. Doping is an effective way to increase gas sensitivity with atomic surface arrangement and active gas adsorption sites, which are generated by doping atoms. However, C-based material/MO nanostructures are preferred than doped MO films with their working even at room temperature. Up to now, a lot of methods to improve the gas sensitivity has been proposed. With the help of the development of surface modification methods such as different types of doping and MO-C composite, sensitivity, which is the most important parameter of sensor performance, can also be stable as well as increasing later on

Investigation of potassium doping effect on the structural properties of Ag:ZnO films

Bu çalışmada, Ag:ZnO ve Ag-K:ZnO filmleri basit ve efektif bir üretim tekniği olan kimyasal banyolama tekniği ile ZnO gövde tabakalar üzerine sentezlenmiştir. Filmlerin yapısal özelliklerinin detaylı şekilde incelenmesinin yanı sıra yüzey pürüzlülük değerleri hesaplanmış ve örneklerin Raman spektrumu incelenmiştir. Tüm filmler hekzagonal würtzite ZnO kristal yapısına sahiptir. Ag katkılaması ile tane büyüklüğü µm mertebesinden 36 nm’ye azalmış ve ZnO kristalleşmesi iyileşmiştir. Buna karşın, K+ iyonlarının yapıya girmesiyle tane büyüklüğü nispeten azalmasına karşın (32 nm) ZnO kristalleşmesi ciddi biçimde bozunmuştur. Yüzeyde nanoparçacıkların oluşumuna ve yüzey pürüzlülük değerlerinde azalmaya potasyum katkılamanın etkisi olduğu gözlenmiştir. Numunelerde gözlenen farklı şiddette tüm zirveler, ZnO würtzite yapısının Raman modlarından bazıları ile eşleşme göstermiştir. Elde edilen sonuçlardan, gerek tekil (Ag) gerek ise ikili (Ag-K) katkılamayla beraber, ZnO yapısındaki kusur yoğunluklarının artması ve değişmesi nedeniyle, kristal yapı ve yüzey dağılımında bozulma meydana geldiği düşünülmektedir. Ancak potasyum atomlarının Ag:ZnO yapısına girmesi ile fiziksel ve kimyasal özellikler üzerinde iyileştirici etkisi saptanmıştır.In this study, Ag:ZnO and Ag-K:ZnO films were synthesized on ZnO body layers by chemical bath technique, which can be defined as a simple and effective production method. In addition to investigation of the structural properties of the films in detail, the surface roughness values were also calculated and the Raman spectrum of the samples was determined. All films had a hexagonal würtzite ZnO crystal structure. The grain size decreased from one µm to 36 nm by adding Ag ions. ZnO crystallization was also improved. However, the crystallization of ZnO was severely impaired due to the adding K+ ions into the structure which reduced the grain size to 32 nm. It has been observed that potassium doping has an effect on the formation of nanoparticles on the surface and the decrease in surface roughness values. In the samples, different peaks were observed and some of the Raman modes were matched in the ZnO würtzite structure. It can be concluded that the crystal structure and surface distribution deteriorated due to the the changes in the ZnO structure, together with both single (Ag) and double (Ag-K) doping technique. However, it was determined that the potassium atoms had a healing effect on the physical and chemical properties in the Ag:ZnO structure

Sciatica leading to the discovery of a renal cell carcinoma

Metastatic renal cell cancer is not exceptional in kidney cancer (30% of patients with kidneyl cancer). Its prognosis is particularly severe. However, sciatic neuralgia (sciatica) remains an exceptional revealing clinical sign of this disease. The authors report the case of a patient admitted with right sciatica as chief complain, leading to the discovery of a renal cell carcinoma. Although uncommon, renal cell carcinoma spine metastasis should be included in the differential diagnosis of back pain and sciatica

Combined vesicovaginal and rectovaginal fistulas associated with a vaginal foreign body

Long-duration intravaginal foreign bodies are a rare entity, but may cause serious complications to the bladder or rectum. We describe a 22-year-old woman who presented with a calcified pelvic mass caused by a long-duration intravaginal foreign body complicated by perforation into the bladder and rectum. The vesicovaginal and rectovaginal fistulas were simultaneously repaired by suprapubic approach after retrieval of the foreign body during the same procedure.Key Words: Vesicovaginal fistula, rectovaginal fistula, vagina, foreign bod

Mule Bite to the Male Genitalia with Complete Penile and Anterior Urethra Amputation: Unusual Case and Review of the Literature

Animal bite is rare with few cases reported in the literature. The morbidity of animal bites is directly related to the severity of the initial wound. Most victims are boys, and dog bites are the most common injury. Infectious complications are unusual, since treatment is sought early (Wein 2007). Thus, urologists are not usually familiar with management and principles for treating this condition. The authors report the case of a 38-year-old male with a severe mule bite injury to the genitalia causing complete penile and anterior urethra amputation and scrotal wound with no involvement of its contents. To our knowledge, no such case had ever been reported in the medical literature. This kind of emergencies is challenging for urologists

Organisation et fonctionnement d’un écosystème côtier du Maroc : la lagune de Khnifiss

La lagune de Khnifiss, située au sud du Maroc, est une réserve biologique d’intérêt mondial pour l’avifaune. Des études pluridisciplinaires portant sur la physico-chimie des eaux, la biologie, la sédimentologie et les courants ont été réalisées par l’INRH dans la lagune en septembre 1998 et février 2001. Les résultats du courant obtenus montrent que la circulation des eaux à l’intérieur de la lagune est gérée par un courant alternatif et bidirectionnel : les courants du jusant sont plus importants que ceux du flot et varient également en fonction du rythme de la marée vive-eau/morte-eau. Ce mode de circulation des eaux attribue à la lagune une richesse en éléments azotés et phosphatés, surtout en période de vive-eau. La biomasse chlorophyllienne, assez importante dans la lagune, est causée par la richesse du milieu en éléments nutritifs et le phénomène d’upwelling qui se manifeste en été et au printemps dans la zone sud du Maroc. Ces études ont montré que la lagune de Khnifiss est un milieu propice à la conchyliculture. Néanmoins, l’installation de tout projet aquacole dans le site devra tenir compte de sa capacité trophique et de son équilibre écologique.The Moroccan coastal marine area has several zones that are targets for exploitation but must simultaneously be protected. Lagoons are considered to be among the most productive natural systems in the world, but they are also vulnerable systems due to natural and human constraints. Lagoons can also be a target of economic expansion. This is why an understanding about the state of these ecosystems is important in order to proceed with rational use of the resource. The Khnifiss lagoon, situated on the South Atlantic coast of Morocco, is a potential site for aquaculture and tourism if planned with an ecological awareness. The large surface area and high biological production for the avifauna qualify it to be among the four protected sites by the RAMSAR convention for humid zone conservation (lagoons of Khnifiss and Moulay Bousselham, lakes of Sidi Boughaba and Afennourir). The objective of this work was to complete previous studies and to estimate the nutritive richness of the Khnifiss lagoon. To understand the spatio-temporal variability in the water currents, and the physico-chemical and biological and characteristics of this lagoon, two surveys were organized in September 1998 and February 2001.The Khnifiss lagoon (20 km long and 65 km2 surface area) is situated between Tantan and Tarfaya (28°02'54'' N, 12°13'66'' W). It opens up into the Atlantic ocean by a narrow inlet called ''Foum Agouitir'', about 100 m wide. The lagoon continues upstream beyond a salt marsh, called "Sebkha Tazra". Physical, chemical and biological variables were monitored: temperature and salinity; dissolved oxygen, nitrates and phosphates; chlorophyll a. The current (direction and intensity) and the sediment were also studied. Samples were collected four times from the surface and bottom waters during spring tide (ST), neap tide (NT), low tide (LT) and high tide (HT) during two seasons (September 1998 and February 2001). Seven hydrological stations were sampled, representing the lagoon system and one reference station in a neighbouring zone (Hréf), which represents the marine zone of the lagoon. Temperature and salinity were measured with a multi-sensor probe. The chemical analyses were carried out according to methods suggested by AMINOT & CHAUSSEPIED (1983). Thirty (30) sediment samples were also collected. Currents were measured at two fixed points by two current-meters.Based on the hydrological characteristics of the lagoon, especially temperature, salinity, water circulation and the nature of sediment, three zones were identified :1. Zone I (downstream from the lagoon) was dominated by the ocean’s influence and included the Hréf, H1 and H2 stations. Maximum depths varied from 2.5 to 6.6 m, depending on the tide and location. The concentrations of the different hydrological parameters were controlled by the plug effect of the oceanic environment. The most important current in the lagoon was recorded in this zone in the spring tide (ST: 110 cm.s-1). The sediment was coarse and important water - sediment exchange was caused by the strong current recorded in this zone.2. Zone II (middle of the lagoon) was a transition zone with an intermediate oceanic influence. It was situated between the H3 and H5 stations. The size of the inlet and the important exchanges governed by currents caused by strong tides resulted in concentrations of the various parameters being similar to those in Zone I. Depths varied from 2.64 to 8.7 m. Waters were more saline during the LT and NT periods (36-41 practical salinity unit, or psu). The current decreased relative to that is zone I (56 cm.s-1 in September 1998 and 78 cm.s-1 in February 2001). In this zone the current moved preferentially towards the right strand at high tide and toward the left strand at low tide.3. Zone III (upstream in the lagoon) covered a different biotope compared to the first two zones. The waters were less deep (2.64 to 5.3 m) and included the stations H6, H7 and the upper part of the lagoon. This zone was characterized by a very low oceanic influence. Water temperature and salinity were higher, 24-26°C and 41-44 psu respectively, during the LT and NT periods.On the basis of the hydrological zonation, the conjunction of the climate descriptors (moderate wind, rare precipitation, absence of storms, moderate air temperature) of the lagoon and the strong hydrodynamic influence in the lagoon suggest that the Knifiss lagoon is a relatively unconfined ecosystem. The hydrodynamics of this lagoon permit a fast water renewal rate and insure a good environmental quality. In addition, studies carried out on the healthiness of this lagoon demonstrated not only a healthy environment, but also healthy shellfish. This diagnosis seemed to be related to the geographical location and important rates of water exchange. However, the absence of continental freshwater sources leads to an important increase in salinity and temperature at the level of the upstream zone (zone III). Zone III therefore cannot be considered for shellfish breeding.On the basis of the biological zones: With respect to the bathymetry of the lagoon (depths varied from 2.5 to 8.7 m), shellfish, in contrast to fish, require less water depth. Therefore, it is sufficient to search for a less turbulent zone, which offers sufficient planktonic food for the shellfish growth. In the Khnifiss lagoon, the taxonomy of the phytoplankton has not been yet studied. However, BENNOUNA (1999) demonstrated that the phytoplankton community was dominated by dinoflagellates and diatoms in the Oualidia and Sidi Moussa lagoons. RHARBI (2000) found that picophytoplankton were the principal breeding food source of oysters and clams in Oualidia lagoon. The source of shellfish for breeding is located in the neighbouring upwelling marine waters. Development projects planned for the lagoon must include an awareness programme for fishermen about the role that moderate and responsible shellfish breeding programs can play in the preservation and reconstitution of the marine resource as well as in the improvement of their incomes

ПРИМЕНЕНИЕ СИНТЕТИЧЕСКИХ ОБРАЗОВ ДЛЯ РЕШЕНИЯ ЗАДАЧИ КЛАССИФИКАЦИИ НА ПРИМЕРЕ ДИАГНОСТИКИ РАКА ЛЕГКОГО

Background: From a mathematical point of view, the problems of medical diagnostics are the tasks of data classification. It is important to understand how significant distortions can contribute to the result of classification errors in the collection of primary diagnostic information, in particular, the results of biochemical tests.Aims: Determination of the dependence of the prediction result on the variability of the primary diagnostic information on the example of the model classifier.Materials and methods: The case-control study enrolled patients who were divided into 2 groups: the main (diagnosed with lung cancer, n=200) and the control group (conditionally healthy, n=500). Questioning and biochemical saliva study was performed in all participants. Patients of the main group and the comparison group were hospitalized for surgical treatment, after which carried out the histological verification of the diagnosis. The biochemical composition of saliva is determined spectrophotometrically. Based on the data obtained, a model classifier for the diagnosis of lung cancer (a random forest) has been constructed. In each parameter underlying the classifier, deviations were made in the specified range (±1–5%, ±5–10%, ±10–15%), creating synthetic images. Then, the results of the classification were evaluated by the cross-validation method.Results: The basic diagnostic characteristics of the model classifier are determined (sensitivity ― 72.5%, specificity ― 86.0%). As the deviations of synthetic images from the baseline increase, diagnostic characteristics deteriorate with the general classification. However, the result of a confident classification, on the contrary, gives higher values (sensitivity ― 81.8%, specificity ― 93.1%). In case of a confident classification, similar images that fall into different classes according to the classification results are deleted, whereas in the case of a general classification, they are taken into account. The difference between methods of classification is associated with the presence of images on which the classifier gives the result of belonging to the class in the range of 0.45–0.55. Therefore, it is necessary to introduce a third class into the classifier, the so-called gray zone (0.4–0.6), since the probability of making an erroneous diagnosis in this area is significantly increased.Conclusions: The obtained results allow to conclude that the measurement error in the range (±1–15%) does not significantly affect the quality of the classification.Обоснование. С математической точки зрения задачи медицинской диагностики представляют собой задачи классификации данных. При этом важно понимать, насколько существенные искажения могут внести в результат классификации погрешности сбора первичной диагностической информации, в частности результатов биохимических тестов.Цель исследования ― установление зависимости результата классификации от вариативности первичной диагностической информации на примере модельного классификатора.Методы. В исследовании случай-контроль приняли участие пациенты, которые были разделены на 2 группы ― основную (с диагнозом рака легкого, n=200) и контрольную (условно здоровые, n=500). Всем участникам было проведено биохимическое исследование слюны, а также последующая гистологическая верификация диагноза. Биохимический состав слюны определен спектрофотометрически. На основе полученных данных построен модельный классификатор для диагностики рака легкого (случайный лес). В каждый параметр, лежащий в основе классификатора, вносили отклонения в заданном диапазоне (±1–5%, ±5–10%, ±10–15%), создавая синтетические образы. Затем методом кросс-валидации проведена оценка результатов классификации.Результаты. Определены базовые диагностические характеристики модельного классификатора (чувствительность ― 72,5%; специфичность ― 86,0%). При увеличении отклонений синтетических образов от базового значения диагностические характеристики при общей классификации ухудшаются. Однако результат уверенной классификации, напротив, дает более высокие значения (чувствительность ― 81,8%, специфичность ― 93,1%). В случае уверенной классификации близкие образы, которые по результатам классификации попадают в разные классы, удаляются, тогда как в случае общей ― учитываются. Разница между методами классификации связана с наличием образов, на которых классификатор дает результат принадлежности к классу в диапазоне 0,45–0,55. Поэтому необходимо введение третьего класса в классификатор, так называемой серой зоны (0,4–0,6), т.к. вероятность постановки ошибочного диагноза в данной области существенно повышается.Заключение. Полученные результаты позволяют сделать вывод, что измерительная погрешность в диапазоне (±1–15%) не оказывает существенного влияния на качество классификации

Change, stress and sustainability: aquatic ecosystem resilience in North Africa

Summary report of a workshop held at the Institute Scientifique, University Mohammed V, Rabat, Morocco, 2-5th December 1998. Cassarina report no. 4

Position paper on ethical, legal and social challenges linked to audio- and video-based AAL solutions

This publication is based upon work from COST Action GoodBrother – Network on Privacy-Aware Audio- and VideoBased Applications for Active and Assisted Living, supported by COST (European Cooperation in Science and Technology).In this position paper, we have used Alan Cooper’s persona technique to illustrate the utility of audio- and video-based AAL technologies. Therefore, two primary examples of potential audio- and video-based AAL users, Anna and Irakli, serve as reference points for describing salient ethical, legal and social challenges related to use of AAL. These challenges are presented on three levels: individual, societal, and regulatory. For each challenge, a set of policy recommendations is suggested.publishedVersio