46 research outputs found

    Crystal-to-crystal transition of ultrasoft colloids under shear

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    Ultrasoft colloids typically do not spontaneously crystallize, but rather vitrify, at high concentrations. Combining in-situ rheo-SANS experiments and numerical simulations we show that shear facilitates crystallization of colloidal star polymers in the vicinity of their glass transition. With increasing shear rate well beyond rheological yielding, a transition is found from an initial bcc-dominated structure to an fcc-dominated one. This crystal-to-crystal transition is not accompanied by intermediate melting but occurs via a sudden reorganization of the crystal structure. Our results provide a new avenue to tailor colloidal crystallization and crystal-to-crystal transition at molecular level by coupling softness and shear

    Laparoscopic Cholecystectomy for Severe Acute Cholecystitis in a Patient with Situs Inversus Totalis and Posterior Cystic Artery

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    Situs inversus totalis is an inherited condition characterized by a mirror-image transposition of thoracic and abdominal organs. It often coexists with other anatomical variations. Transposition of the organs imposes special demands on the diagnostic and surgical skills of the surgeon. We report a case of a 34-year-old female patient presented with left upper quadrant pain, signs of acute abdomen, and unknown situs inversus totalis. Severe acute cholecystitis was diagnosed, and an uneventful laparoscopic cholecystectomy was performed. A posterior cystic artery was identified and ligated. Laparoscopic cholecystectomy is feasible in patients with severe acute calculus cholecystitis and situs inversus totalis; however, the surgeon should be alert of possible anatomic variations

    POROUS STRUCTURES AS ACTIVE MICROFLUIDIC COMPONENTS

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    Active control of droplet mobility through low cost tools is highly desirable in applications entailing microfluidics, Lab-on-Chip devices and pertinent technologies. Here, we present the design concepts of a versatile, low cost tool for dynamic droplet mobility manipulation, employing a scheme with backpressure application. Initially sticky open- or closed- channel fluidics with hydrophobic, porous walls are rendered slippery with the application of backpressure through the porous walls. Deliberate control of backpressure directs the wetting phenomena to the desired state. Operation parameters, and control system considerations are presented. Ultra-low backpressure values, are needed for channels with small cross-sections, which in turn are compatible with ultra-low energy demands

    Deterministic and controllable photonic scattering media via direct laser writing

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    Photonic scattering materials, such as biological tissue and white paper, are made of randomly positioned nanoscale inhomogeneities in refractive index that lead to multiple scattering of light. Typically these materials, both naturally-occurring or man-made, are formed through self assembly of the scattering inhomogeneities, which imposes challenges in tailoring the disorder and hence the optical properties. Here, We report on the nanofabrication of photonic scattering media using direct laser writing with deterministic design. These deterministic scattering media consist of submicron thick polymer nanorods that are randomly oriented within a cubic volume. We study the total transmission of light as a function of the number density of rods and of the sample thickness to extract the scattering and transport mean free paths using radiative transfer theory. Such photonic scattering media with deterministic and controllable properties are model systems for fundamental light scattering in particular with strong anisotropy and offer new applications in solid-state lighting and photovoltaics.Comment: 18 pages, 9 figure

    Pertinence of salt-related knowledge and reported behaviour on salt intake in adults : a cross-sectional study

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    The association between salt-related knowledge, attitude, behaviour (KAB) and actual salt consumption in Greek adults is uncertain. This study investigates the correlation between salt intake, gauged by 24-h urinary sodium excretion, with salt-related KAB. It further explores how socio-demographic factors influence these behaviors. Salt consumption was evaluated using a 24-h urinary sodium test, and compared to self-reported KAB data. Knowledge and behavior scores related to salt were computed. An overall cohort-adjusted model examined the relationship between daily salt consumption, knowledge and behavior scores, and certain covariates. Through the stratification by the cohort random effect, two models were established (Cohort I Adults; Cohort II Students) examining the same relationships of the overall cohort model. 463 Greek adults participated. The average salt intake was 9.54 g/day, nearly double the WHO recommendation. Significant differences in knowledge scores were noted based on sex, age, education, and BMI. A trend suggesting lower discretionary salt use with increased salt intake was observed (p = 0.06). However, comprehensive analysis revealed no direct correlation between salt intake and either knowledge (p = 0.562) or behavior scores (p = 0.210). The results emphasize the need for food product reforms by industry stakeholders and accelerated efforts towards reducing salt intake

    Isolated complete avulsion of the gallbladder (near traumatic cholecystectomy): a case report and review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>Injury of the gallbladder after blunt abdominal trauma is an unusual finding; the reported incidence is less than 2%. Three groups of injuries are described: simple contusion, laceration, and avulsion, the last of which can be partial, complete, or total traumatic cholecystectomy.</p> <p>Case presentation</p> <p>A case of isolated complete avulsion of the gallbladder (near traumatic cholecystectomy) from its hepatic bed in a 46-year-old Caucasian man without any other sign of injury is presented. The avulsion was due to blunt abdominal trauma after a car accident. The rarity of this injury and the stable condition of our patient at the initial presentation warrant a description. The diagnosis was made incidentally after a computed tomography scan, and our patient was treated successfully with ligation of the cystic duct and artery, removal of the gallbladder, coagulation of the bleeding points, and placement of a drain.</p> <p>Conclusions</p> <p>Early diagnosis of such injuries is quite difficult because abdominal signs are poor, non-specific, or even absent. Therefore, a computed tomography scan should be performed when the mechanism of injury is indicated.</p

    Kinematics of the Southern Rhodope Core Complex (North Greece)

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    The Southern Rhodope Core Complex is a wide metamorphic dome exhumed in the northern Aegean as a result of large-scale extension from mid-Eocene to mid-Miocene times. Its roughly triangular shape is bordered on the SW by the Jurassic and Cretaceous metamorphic units of the Serbo-Macedonian in the Chalkidiki peninsula and on the N by the eclogite bearing gneisses of the Sideroneron massif. The main foliation of metamorphic rocks is flat lying up to 100 km core complex width. Most rocks display a stretching lineation trending NEâ SW. The Kerdylion detachment zone located at the SW controlled the exhumation of the core complex from middle Eocene to mid-Oligocene. From late Oligocene to mid-Miocene exhumation is located inside the dome and is accompanied by the emplacement of the synkinematic plutons of Vrondou and Symvolon. Since late Miocene times, extensional basin sediments are deposited on top of the exhumed metamorphic and plutonic rocks and controlled by steep normal faults and flat-ramp-type structures. Evidence from Thassos Island is used to illustrate the sequence of deformation from stacking by thrusting of the metamorphic pile to ductile extension and finally to development of extensional Plio-Pleistocene sedimentary basin. Paleomagnetic data indicate that the core complex exhumation is controlled by a 30� dextral rotation of the Chalkidiki block. Extensional displacements are restored using a pole of rotation deduced from the curvature of stretching lineation trends at core complex scale. It is argued that the Rhodope Core Complex has recorded at least 120 km of extension in the North Aegean, since the last 40 My
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