Load-induced transitions in the lubricity of adsorbed poly(L-lysine)-g-dextran as a function of polysaccharide chain density

Chain-density gradients of poly(l-lysine)-graft-dextran (PLL-g-dex), a synthetic comblike copolymer with a poly(l-lysine) backbone grafted with dextran side chains, were fabricated on an oxidized silicon substrate. The influence of the changing dextran chain density along the gradient on the local coefficient of friction was investigated via colloidal-probe lateral force microscopy. Both in composition and structure, PLL-g-dex shares many similarities with bottlebrush biomolecules present in natural lubricating systems, while having the advantage of being well-characterized in terms of both architecture and adsorption behavior on negatively charged oxide surfaces. The results indicate that the transition of the dextran chain density from the mushroom into the brush regime coincides with a sharp reduction in friction at low loads. Above a critical load, the friction increases by more than an order of magnitude, likely signaling a pressure-induced change in the brush conformation at the contact area and a corresponding change in the mechanism of sliding. The onset of this higher-friction regime is moved to higher loads as the chain density of the film is increased. While in the low-load (and low-friction) regime, increased chain density leads to lower friction, in the high-load (high-friction) regime, increased chain density was found to lead to higher friction.     

Photoelectrochemical Investigation of Fullerenes

Fullerene solar cells are demonstrated. Illuminated, C₆₀ drives oxidation of redox couples in solution. a photoelectrochemical solid/liquid, rather than a solid state, junction, improves photocurrent, and a C₆₀ single crystal, and not polycrystalline film, decreases dark current, and thereby light driven charge transfer dominates.     

Quetiapine, an atypical antipsychotic

The discovery of antipsychotic agents in the 1950s revolutionized the treatment of schizophrenia. A large body of evidence supports the dopamine D2 receptor antagonist's efficacy in the treatment of psychotic symptoms. However, the advent of newer agents seems to point to a more complex interaction of neurotransmission in the pathophysiology of schizophrenia. In fact, a defining characteristic of atypical agents is a higher ratio of serotonin (5HT2) receptor blockade to D2 receptor blockade. Clozapine was the first atypical agent to be introduced; it was followed by risperidone, olanzapine, and now quetiapine, which is a dibenzothiazepine derivative structurally related to clozapine and olanzapine.     

Classification and modeling for in-plant milk-run distribution systems

Material handling is one of the most important issues that should be taken into account for eliminating waste and reducing the cost. It is one of the seven wastes defined in the concept of lean manufacturing. In this study, for a lean material handling system under the lean manufacturing conditions such as pull-based and repetitive manufacturing, a system consisting of periodically moving vehicles in certain routes is taken into consideration. This system is also called milk-run distribution system. Application of milk-run distribution systems in plants standardizes the material handling system and eliminates the waste. Although there are huge numbers of studies related with inbound and outbound logistics, there are few studies especially related with milk-run applications in the manufacturing area. Within this study, based on the observations in real manufacturing environment and limited literature, the milk-run distribution problem in the plants is categorized and explained. For one of the main categories, modeling is performed. The objective of the developed models is to minimize the number of vehicles and the distance traversed. A numerical example inspired by real applications is presented for showing the applicability of the developed models.     

HIP processing of materials for offshore (energy) applications

Abstract

The Particulate Engineering Committee (PEC) of IOM3 held its long anticipated workshop on hot isostatic pressing (HIP) of materials for offshore (energy) applications on 16 April in Aberdeen, UK. Hosted by TWI and supported by EPMA, the one day meeting attracted about 30 delegates that filled comfortably the premises to its capacity. It was an opportunity for end users from the oil and gas sector and those involved in powders, consumables, engineering services and other end user communities to come together to capture the latest developments in the field of PM-HIP for offshore and energy applications.     

The effect of excessive steam curing on Portland composite cement concrete

Steam curing at atmospheric pressure is an important technique for obtaining high early strength values in precast concrete production. Cement type, as well as curing period and temperature, is an important parameter in the steam-curing process. PC42.5 is the type of cement that is most commonly used in Turkish precast concrete plants. Its behavior is well known. Nowadays, the production of composite cements is becoming more popular every other day due to its advantages. The object of this study was to determine the properties of this relatively new binder comparatively with conventional PC42.5 under steam curing. For this purpose, 15-cm concrete cubes were prepared with a water/cement ratio (W/C) of 0.44 and were subjected to steam curing for five different curing periods of 4, 8, 16, 24 and 36 h under curing temperatures of 65 and 85 °C. Cement dosage was kept constant (400 kg/m³) for all specimens. The variation of compressive strength values and maturity for each condition has been presented comparatively within this study. Test results indicated that Portland composite cement (PKC/A42.5) can be used in place of PC42.5 for steam curing at atmospheric pressure in precast concrete production. However, in case of early high strength demand for early demolding purposes, curing temperature should be increased to 85 °C for PKC/A42.5 cement concretes.     

Outpatient management with oral corticosteroid therapy for obstructive conditions in chronic granulomatous disease

We report the outpatient management of three patients with X-linked chronic granulomatous disease, two of whom had episodes of gastric outlet obstruction and another, urinary bladder obstruction. These obstructive conditions were successfully treated with 2-week courses of orally administered corticosteroids with or without the addition of orally administered clindamycin. There were no infectious or other adverse reactions.     

Indentation of a cantilever beam or plate

In this paper the general plane problem for a semi-infinite strip fixed at its short end, containing a crack perpendicular to its voundaries is considered. The strip is under the effect of a stamp. By extending the crack to the surfaces, one can reduce the problem to that of c cantilever beam or plate. Integral transform technique is used to provide an exact formulation of this problem, in terms of a system of four singular integral equations one of them being second kind. Stress singularities at the corners of the fixed-end, at the crack tips and at the end points of the contact region undermeath the stamp are obtained from the singular integral equations which are then solved numerically.     

Seeding approach to noble metal decorated conducting polymer nanofiber network

Metal displacement reactions between conducting polymers-"synthetic metals"-and noble metals (Pt, Au and Ag) have been demonstrated using a seeding polymerization technique, to produce a synthetic metal nanofiber network decorated with noble metal nanoparticles, in one-step.