Determining animal drug combinations based on efficacy and safety

A procedure for deriving drug combinations for animal health is used to derive an optimal combination of 200 mg of novobiocin and 650,000 IU of penicillin for nonlactating cow mastitis treatment. The procedure starts with an estimated second order polynomial response surface equation. That surface is translated into a probability surface with contours called isoprobs. The isoprobs show drug amounts that have equal probability to produce maximal efficacy. Safety factors are incorporated into the probability surface via a noncentrality parameter that causes the isoprobs to expand as safety decreases, resulting in lower amounts of drug being used.     

Principal Factors of Contact Charging of Minerals for a Successful Triboelectrostatic Separation Process – a Review

Triboelectrostatic separation is a promising method used to separate non-conductive minerals. However, the knowledge about the underlying triboelectrification mechanisms is still very limited. Thus, predicting the separation results and finding proper separation parameters are challenging tasks.     

Charged point defects in semiconductors

Native point defects control many aspects of semiconductor behavior. Such defects can be electrically charged, both in the bulk and on the surface. This charging can affect numerous defect properties such as structure, thermal diffusion rates, trapping and recombination rates for electrons and holes, and luminescence quenching rates. Charging also introduces new phenomena such as nonthermally photostimulated diffusion, thereby offering distinctive mechanisms for defect engineering. The present work incorporates the first comprehensive account of semiconductor defect charging, identifying correspondences and contrasts between surfaces and the bulk as well as among semiconductor classes (group IV, groups III–V, and metal oxides). For example, small lattice parameters, close-packed unit cells, and basis atoms with large atomic radii all inhibit the formation of ionized interstitials and antisites. The charged defects that exist in III–V and oxide semiconductors can be predicted with surprising accuracy from the chemical potential and oxygen partial pressure of the ambient. The symmetry-lowering relaxations, formation energies, and diffusion mechanisms of bulk and surface defect structures often depend strongly on charge state with similar qualitative behavior, although for a given material surface defects do not typically take on the same configurations or range of stable charge states as their counterparts in the bulk.     

A Social Network Perspective of Lead Users and Creativity: An Empirical Study among Children

Generating ideas at the ‘fuzzy front end’ of new product development is risky and has serious consequences for all preceding development stages. One of the currently most prominent techniques in supporting this idea‐generation stage is the lead user approach. Involving lead users in idea generation closely correlates to individual creativity, and both, in turn, to the provision of information in social networks. This study, guided by lead user theory, creativity research and network theory, investigates 16 school‐groups of children examining the relationship between the children's social networks and their resulting creativity and lead userness. In addition, the interplay between lead userness and creativity is discussed and empirically tested. The main result of this study is that children who are positioned as bridging links between different groups in social networks reveal both a high degree of lead userness and a high level of creativity.     

Catalytic role of gold nanoparticle in GaAs nanowire growth: a density functional theory study

The energetics of Ga, As, and GaAs species on the Au(111) surface (employed as a model for Au nanoparticles) is investigated by means of density functional calculations. Apart from formation of the compound Au(7)Ga(2), Ga is found to form a surface alloy with gold with comparable ΔH ~ -0.5 eV for both processes. Dissociative adsorption of As(2) is found to be exothermic by more than 2 eV on both clean Au(111) and AuGa surface alloys. The As-Ga species formed by reaction of As with the surface alloy is sufficiently stable to cover the surface of an Au particle in vacuo in contact with a GaAs substrate. The results of the calculations are interpreted in the context of Au-catalyzed growth of GaAs nanowires. We argue that arsenic is supplied to the growth zone of the nanowire mainly by impingement of molecules on the gold particle and identify a regime of temperatures and As(2) partial pressures suitable for Au-catalyzed nanowire growth in molecular beam epitaxy.     

Effect of dietary ascorbic acid on iron utilization in the growing chick

Day-old male broiler chicks were fed for three weeks a purified casein diet with the addition of different levels of iron and ascorbic acid. Dietary ascorbic acid fed at 0.4% increased the hemoglobin concentration and total body iron retention when the diets fed were low in iron (23 p.p.m.). At 0.1% level in the diet, ascorbic acid caused an increase in total body iron retention in chicks fed diets marginal in iron (40 p.p.m.) and did not affect either parameter in chicks fed diets adequate in iron (100 p.p.m.).     

Solitary versus multiple gallstones: the importance of total biliary protein concentration and other factors

BACKGROUND: Nucleating and antinucleating factors play an important role in the pathogenesis of cholesterol crystal nucleation. PATIENTS AND METHODS: In 88 gallstone patients (59 female, 29 male) bile was examined for total biliary protein and glycoprotein concentration, nucleation time and cholesterol saturation index. Gallstone density was measured by in vivo computed tomography. RESULTS: Total biliary protein concentration was positively correlated with the number of gallstones (r = 0.84, p < 0.01) and higher in radiologically detectable isodense gallstones as compared to non-isodense stones (p < 0.01). A negative correlation between total biliary protein concentration, glycoprotein concentration and nucleation time was observed (r = -0.45, p < 0.01 and r = -0.49, p < 0.05). Nucleation time was significantly shorter in the case of multiple versus solitary stones (2.6 +/- 1.3 versus 8.5 +/- 3.0 days, p < 0.01). Cholesterol saturation index and biliary cholesterol concentration were similar in both cases, however a negative correlation between cholesterol saturation index and stone density (r = -0.79, p < 0.01) was found. No correlation was found between cholesterol saturation index and nucleation time (r = -0.04, p > 0.1), independent of gallstone number. None of the examined parameters was related to sex, age, weight or gallbladder function. CONCLUSIONS: Multiple gallbladder stones seem to be associated with shorter nucleation time and higher biliary concentrations of total protein and glycoprotein than solitary stones.     

Praxisnahe Prüfung korrosions- und erosionsbeständiger Pumpenwerkstoffe

Corrosion- and Erosion-Resistant Pump Material-Investigations Under Flow Conditions Close to Practice The major goals of these investigations can be described as follows:

• design, construction and test of laboratory appraratus to study the resistance of pump impellers under corrosive and erosive attack in various aggressive media,
• simulation of flow conditions characteristics for pumps as close to practice as possible to study the non-uniform attack in corrosive media of various type, concentration and temperature.

The following materials were used in these studies:

• a ferritic-austenitic cast stainless steel of type 0,03% C – 24% Ni – 20% Cr – 6% Ni – 2,5% Mo – 3% Cu – 0,15% N (German designation: G-X3 CrNiMoCuN24 6)
• a purely austenitic cast stainless steel of type 0,07% C – 25% Ni – 20% Cr – 3% Mo – 2% Cu – 0,25% Nb (German designation: G-X 7 NiCrMoCuNb 25 20, Werkstoff-No. 1.4500).

The investigations were concentrated on the corrosion and erosioncorrosion behaviour of these steels in static and flowing sulfuric acid of various concentrations and temperatures. The effect of flow conditions of the acid was studied by evaluating the weight losses of the materials in three different apparaturs: the rotating disc, the once-through tube and the impeller with tube-shaped flow canals. The main result of these studis was the well exposed effect of flow conditions of the acid on the corrosion and erosion-corrosion behaviour of the materials. A detailed analysis shows that:

• 1 there is the well-known decrease of the corrosion resistance of both materials under flow in the rotating disc apparatus.
• 2 there is, however, an increase of the corrosion resistance in the tube and model impeller apparatus compared to static solutions.
• 3 there is a strong increase of the corrosion rate in the region of active corrosion itself under any flow condition of the acid.
• 4 there are three types of corrosive attack occuring on the duplex stainless steel independent of the flow of the sulfuric acid:
  • uniform corrosion,
  • selective corrosion of the femte,
  • selective corrosion of the austenite.
• 5 there is a region of undefined corrosion behaviour separating the range of corrosion resistance from that of active corrosion for the duplex as well as for the austenitic stainless steel.

     

How the Network Position of R&D Team Managers and Members Affects their Evaluations of Creative Performance

Monitoring the creative performance of R&D teams as the nucleus of creating new knowledge is inherently difficult. In most cases, only the team managers and team members can be tapped as reliable sources of information. However, there are indications that neither team managers nor team members provide a sufficient introspection to evaluate the R&D team's creative performance. This contradiction was investigated in 51 R&D teams by examining the team managers' and members' network position and their resulting performance evaluations. The central findings of the study are that team managers and members evaluate the creative performance of their R&D teams more negatively when the amount and variety of information they are supplied are insufficient and that there are no relevant differences between team managers' and team members' evaluations or network positions.