261 research outputs found
A versatile and reconfigurable microassembly workstation
In this paper, a versatile and reconfigurable
microassembly workstation designed and realized as a research
tool for investigation of the problems in microassembly and
micromanipulation processes and recent developments on
mechanical and control structure of the system with respect to
the previous workstation are presented. These developments
include: (i) addition of a manipulator system to realize more
complicated assembly and manipulation tasks, (ii) addition of
extra DOF for the vision system and sample holder stages in
order to make the system more versatile (iii) a new optical
microscope as the vision system in order to visualize the
microworld and determine the position and orientation of micro
components to be assembled or manipulated, (iv) a modular
control system hardware which allows handling more DOF. In
addition several experiments using the workstation are presented
in different modes of operation like tele-operated, semiautomated
and fully automated by means of visual based
schemes
Mikro montaj İş İstasyonu
Bu makalede, mikro boyuttaki komponentlerin verimli ve güvenilir montajı için açık-mimarili, tekrar yapılandırılabilir bir mikromontaj iş istasyonu sunulmaktadır. Bu iş istasyonu mikro dünyadaki problemlerin çözümlendirilmesine yardımcı olmak amacıyla bir araştırma aracı olarak tasarlanmıştır. Böyle
bir iş istasyonunun geliştirilmesi aşağıdaki alt sistemlerin tasarımını içermektedir: (i) montaj görevlerininin gerçekleştirilebilmesi için yeterli hareket menzilini ve hassasiyeti sağlayabilecek hareket platformlarından oluşan bir manipülatör sistemi, (ii) mikro dünyanın görselleştirilmesini
ve montajı yapılacak olan mikro parçaların konum ve yönelimlerini belirleyebilmek için bir görü sistemi, (iii) dayanıklı bir denetleme sistemi ve bunlara ek olarak manipülasyon araçlarının kolayca değişmesine olanak
sağlayan ve sistemin önceden belirlenmiş göreve hazır hale getirilmesine yardımcı olacak uç takımlar için gerekli fikstürler. Ayrıca sistemde kumandalı ve yarı otomatik montaj uygulamaları da gerçekleştirilmiştir. Tasarım mikro parça manipülasyonu içeren çeşitli uygulamalar yapılarak test edilmiştir. İş istasyonunun çok yönlülüğü ve yüksek doğrulukta konumlama yeteneği yapılan deneylerle gösterilmiştir
Seven years of postseismic deformation following the 2003 Mw = 6.8 Zemmouri earthquake (Algeria) from InSAR time series
International audience[1] We study the postseismic surface deformation of the Mw 6.8, 2003 Zemmouri earthquake (northern Algeria) using the Multi-Temporal Small Baseline InSAR technique. InSAR time series obtained from 31 Envisat ASAR images from 2003 to 2010 reveal sub-cm coastline ground movements between Cap Matifou and Dellys. Two regions display subsidence at a maximum rate of 2 mm/yr in Cap Djenet and 3.5 mm/yr in Boumerdes. These regions correlate well with areas of maximum coseismic uplifts, and their association with two rupture segments. Inverse modeling suggest that subsidence in the areas of high coseismic uplift can be explained by afterslip on shallow sections (<5 km) of the fault above the areas of coseismic slip, in agreement with previous GPS observations. The earthquake impact on soft sediments and the ground water table southwest of the earthquake area, characterizes ground deformation of non-tectonic origin. The cumulative postseismic moment due to 7 years afterslip is equivalent to an Mw 6.3 earthquake. Therefore, the postseismic deformation and stress buildup has significant implications on the earthquake cycle models and recurrence intervals of large earthquakes in the Algiers area
InSAR velocity field across the North Anatolian Fault (eastern Turkey): Implications for the loading and release of interseismic strain accumulation
International audienceWe use the Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) technique with the European Space Agency's Envisat and ERS SAR data acquired on three neighboring descending tracks (T350, T078, and T307) to map the interseismic strain accumulation along a ~225 km long, NW-SE trending section of the North Anatolian Fault that ruptured during the 1939, 1942, and 1943 earthquakes in eastern Turkey. We derive a line-of-sight velocity map of the region with a high spatial resolution and accuracy which, together with the maps of earthquake surface ruptures, shed light on the style of continental deformation and the relationships between the loading and release of interseismic strain along segmented continental strike-slip faults. In contrast with the geometric complexities at the ground surface that appear to control rupture propagation of the 1939 event, modeling of the high-resolution PS-InSAR velocity field reveals a fairly linear and narrow throughgoing shear zone with an overall 20 ± 3 mm/yr slip rate above an unexpectedly shallow 7 ± 2 km locking depth. Such a shallow locking depth may result from the postseismic effects following recent earthquakes or from a simplified model that assumes a uniform degree of locking with depth on the fault. A narrow throughgoing shear zone supports the thick lithosphere model in which continental strike-slip faults are thought to extend as discrete shear zones through the entire crust. Fault segmentation previously reported from coseismic surface ruptures is thus likely inherited from heterogeneities in the upper crust that either preexist and/or develop during coseismic rupture propagation. The geometrical complexities that apparently persist for long periods may guide the dynamic rupture propagation surviving thousands of earthquake cycles
Çok Yönlü ve Tekrar Yapılandırılabilir Mikro Montaj İş İstasyonu
Bu makalede, mikro montaj ve mikro manipülasyon
süreçlerindeki sorunların incelenmesi amacıyla bir araştırma
aracı olarak tasarlanan ve geliştirilen çok yönlü ve tekrar
yapılandırılabilir mikro montaj iş istasyonu ve yine aynı grup
tarafından geliştirilen bir önceki sistem üzerinde mekanik ve
denetim yapıları açısından yapılan geliştirmeler
sunulmaktadır. Bu geliştirmeler; (i) daha karmaşık montaj ve
manipülasyon işlemlerinin gerçekleştirilebilmesi için ek bir
manipülatör modülünün eklenmesi, (ii) sistemi daha yetenekli
kılabilmek için görü sistemi ve numune taşıyıcı platformlarına
ek hareket serbestlik derecesi eklenmesi (iii) mikro dünyanın
görüntülenmesi ve montajı yapılacak veya manipüle edilecek
parçaların konum ve yönelimlerinin belirlenebilmesi amacıyla
görü sistemi olarak yeni bir optik mikroskobun eklenmesi (iv)
daha fazla serbestlik derecesinin denetimini sağlayabilmek
amacıyla varolan sistemin daha modüler bir denetim sistemi
donanımı ile değiştirilmesi gibi unsurları içermektedir. Ayrıca
sistemde kumandalı, yarı otomatik ve görü bazlı yöntemler
aracılığı ile tamamen otomatik çalışma modlarında yapılan
deney sonuçları da sunulmaktadır
Advanced oxidation protein products and malondialdehyde — the new biological markers of oxidative stress — are elevated in postmenopausal women
Objectives: The aim of the study was to measure advanced oxidation protein products (AOPPs) as markers for oxidative stress to evaluate cardiovascular risk in pre- and postmenopausal women and to compare the results with malondialdehyde (MDA) levels.
Material and methods: Twenty premenopausal women and 84 naturally postmenopausal patients were enrolled in the study. AOPP and MDA plasma levels were measured. The postmenopausal group was further subdivided into two groups: postmenopausal age of 40–49 and of 50–59 years. AOPP and MDA levels were compared between premenopausal, 40–49 and 50–59 year old menopausal women.
Results: Plasma AOPP and MDA levels in postmenopausal women were increased when compared with their premenopausal peers (123.83 ± 55.51 μmol/L vs. 61.59 ± 16.42 μmol/L and 6.50 ± 1.05 μmol/L vs. 5.98 ± 0.77 μmol/L; respectively). Mean plasma AOPP levels in the two menopausal age groups were both significantly higher from the premenopausal group (118.64 ± 59.1 μmol/L vs. 61.59 ± 16.42 μmol/L and 132.31 ± 48.97 μmol/L vs. 61.59 ± 16.42 μmol/L; respectively). No significant difference was found in mean AOPP levels between postmenopausal subjects of 40–49 and 50–59 years age (118.64 ± 59.12 μmol/L vs. 132.31 ± 48.97 μmol/L). Mean plasma MDA levels of each of two postmenopausal age groups were both significantly higher from the premenopausal group (6.50 ± 1.04 μmol/L vs. 5.98 ± 0.77 μmol/L and 6.50 ± 1.10 μmol/L vs. 5.98 ± 0.77 μmol/L; respectively). However, no statistically significant difference between the two postmenopausal age groups (6.50 ± 1.04 μmol/L vs. 6.50 ± 1.10 μmol/L) was found.
Conclusions: AOPP and MDA levels are elevated in postmenopausal women as compared to their premenopausal peers, suggesting they can be used as markers for cardiovascular risk in postmenopausal women
Applicability of fetal renal artery Doppler values in determining pregnancy outcome and type of delivery in idiopathic oligohydramnios and polyhydramnios pregnancies
Aims: To investigate the relationship between fetal renal artery Doppler results and pregnancy outcomes in patients with idiopathic abnormal amniotic fluid indices. Material and method: A total of 110 patients without signs of fetal distress were included in the study: 31 idiopathic oligohydramnios and 29 idiopathic polyhydramnios pregnancies (study group) and 50 normal pregnancies (controls). Doppler investigation of the umbilical artery (UA), middle cerebral artery (MCA), fetal descendant thoracic aorta (DTA) and fetal renal artery (RA) was performed in all patients. Fetal RA resistive index (RI) and pulsatile index (PI) values were measured. Values pertaining to type of birth, newborn weight and APGAR scores were compared. Results: Average patient age, gravidity and week of pregnancy were 25±4, 1.6, and 37.4±1, respectively. There were no statistically significant differences between the groups as far as UA S/D, MCA S/D, DTA S/D, DTA RI, DTA PI, and RA S/D measurements were concerned. However, in the oligohydramnios group RA RI and RA PI values were significantly higher than the other two groups. Birth weight in the polyhydramnios group and cesarean section rate due to fetal distress in the oligohydramnios group were significantly higher. Conclusions: In the oligohydramnios group, without affecting fetal distress parameters, Doppler USG evaluation identified an increase in the RA resistance. Also in that group, cesarean rate due to fetal distress during labor was significantly higher than in the remaining two groups. Due to the predictive potential of values of fetal renal artery Doppler of fetal outcome further large sample-sized studies on the subject ought to be carried out
The Mitochondrion: A Promising Target for Kidney Disease
Acute kidney injury; Chronic kidney disease; Mitochondrial dysfunctionLesión renal aguda; Enfermedad renal crónica; Disfunción mitocondrialLesió renal aguda; Malaltia renal crònica; Disfunció mitocondrialMitochondrial dysfunction is important in the pathogenesis of various kidney diseases and the mitochondria potentially serve as therapeutic targets necessitating further investigation. Alterations in mitochondrial biogenesis, imbalance between fusion and fission processes leading to mitochondrial fragmentation, oxidative stress, release of cytochrome c and mitochondrial DNA resulting in apoptosis, mitophagy, and defects in energy metabolism are the key pathophysiological mechanisms underlying the role of mitochondrial dysfunction in kidney diseases. Currently, various strategies target the mitochondria to improve kidney function and kidney treatment. The agents used in these strategies can be classified as biogenesis activators, fission inhibitors, antioxidants, mPTP inhibitors, and agents which enhance mitophagy and cardiolipin-protective drugs. Several glucose-lowering drugs, such as glucagon-like peptide-1 receptor agonists (GLP-1-RA) and sodium glucose co-transporter-2 (SGLT-2) inhibitors are also known to have influences on these mechanisms. In this review, we delineate the role of mitochondrial dysfunction in kidney disease, the current mitochondria-targeting treatment options affecting the kidneys and the future role of mitochondria in kidney pathology
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