Plasma insulin and growth hormone concentrations in pregnant sheep II: post-absorptive levels in mid- and late pregnancy

1. The incorporation of L-[U-14C]leucine, L[U-14C]histidine and L-[U-14C]phenylalanine into casein secreted during perfusion of isolated guinea-pig mammary glands was demonstrated. 2. The extent of incorporation of label into casein residues was consistent with their being derived from free amino acids of the perfusate plasma. 3. The mean transit time of the amino acids from perfusate into secreted casein was approx. 100 min. 4. Whereas radioactive histidine and phenylalanine were incorporated solely into milk protein, radioactivity from [U-14C]valine was also transferred to CO2 and to an unidentified plasma component, and from [U-14C]leucine to plasma glutamic acid. 5. Evidence from experiments with [U-14C]phenylalanine suggests that, as in rats, but in contrast with ruminant species, guinea-pig mammary tissue does not possess phenyl alanine hydroxylase activity. 6. The results are discussed in relation to the possible role of essential amino acid catabolism in the control of milk-protein synthesis.     

Mirex in the Sediments of Lake Ontario

Analysis of sediment samples collected in Lake Ontario in 1968 revealed the occurrence of mirex in two anomalous zones related to input from the Niagara and Oswego Rivers. These anomalies were confirmed in a 1976 resampling program. A suspended solids sample taken in the Niagara River confirmed an upstream source (Hooker Chemical) of the compound. Bottom sediment samples in the Oswego River identified an industrial source (Armstrong Cork) 14 km upstream of the river mouth. Known use of mirex by this plant indicated a substantial loss some 15 years ago. This was confirmed by sediment coring in the open lake sediments indicating that mirex deposition commenced 7 to 14 years before present.     

Four logic states using two resonant tunnelling diodes

Using a series connection of two specially designed resonant tunnelling diodes, the authors observed three negative differential resistance regions, resulting in four possible logic states. This behaviour can be expanded, at least in theory, to n tunnelling diodes, resulting in 2/sup n/-1 times switching and 2/sup n/ logic states. These new devices can be used for analogue/digital conversion and multivalued logic or as multistate memory cells using only a minimum in device area.<>     

Modelling and simulation of hot-carriers degradation of high voltage floating lateral NDMOS transistors

This paper presents the Hot Carrier Endurance of a High Voltage (100V) self aligned Floating lateral nDMOS transistor. Based on experimental results, a Safe Operating Area is determined according to maximum 10% shift of electrical parameters within 25 years. Process/Device simulation has been done in order to understand the degradation phenomena based on bulk current. Two points of high Impact Ionization rates have been found : one close to the channel junction but in depth, and the second one in the drift region. This later explains the Hot Carrier Degradation of the R_on parameter observed experimentally.     

Surface restructuring as a mechanism for bond breaking and catalytic reactions at metal surfaces

Low energy electron diffraction-surface crystallography studies indicate that the more open crystal surfaces with higher Miller index restructure more readily when clean. These investigations also uncovered the predominance of adsorbate induced restructuring of surface atoms. It is suggested that one mechanism of chemical bond breaking for adsorbate molecules is surface restructuring induced bond scission and that catalytic processes on metals can be induced by the restructuring of surface atoms around the adsorbate species. While direct experimental evidence is lacking, many of the properties of the chemisorption bond and the catalytic activity on metal surfaces can be explained by the surface restructuring model. These are a) higher activity for bond breaking on more open surfaces, b) bond breaking in narrow temperature ranges and sequentially as the temperature is increased, c) the higher surface dissociation probability of molecules with higher incident kinetic energy, and d) the structure sensitivity and insensitivity of catalytic reactions.     

Development and validation of a behavioural video coding scheme for detecting mental workload in manual assembly

Abstract

Manual assembly in the future Industry 4.0 workplace will put high demands on operators’ cognitive processing. The development of mental workload (MWL) measures therefore looms large. Physiological gauges such as electroencephalography (EEG) show promising possibilities, but still lack sufficient reliability when applied in the field. This study presents an alternative measure with a substantial ecological validity. First, we developed a behavioural video coding scheme identifying 11 assembly behaviours potentially revealing MWL being too high. Subsequently, we explored its validity by analysing videos of 24 participants performing a high and a low complexity assembly. Results showed that five of the behaviours identified, such as freezing and the amount of part rotations, significantly differed in occurrence and/or duration between the two conditions. The study hereby proposes a novel and naturalistic method that could help practitioners to map and redesign critical assembly phases, and researchers to enrich validation of MWL-measures through measurement triangulation.

Practitioner summary: Current physiological mental workload (MWL) measures still lack sufficient reliability when applied in the field. Therefore, we identified several observable assembly behaviours that could reveal MWL being too high. The results propose a method to map MWL by observing specific assembly behaviours such as freezing and rotating parts.

Abbreviations: MWL: mental workload; EEG: electroencephalography; fNIRS: functional near infrared spectroscopy; AOI: area of interest; SMI: SensoMotoric Instruments, ETG: Eye-Tracking Glasses; FPS: frames per second; BORIS: Behavioral Observation Research Interactive Software; IRR: inter-rater reliability; SWAT: Subjective Workload Assessment Technique; NASA-TLX: National Aeronautics and Space Administration Task Load Index; EL: emotional load; DSSQ: Dundee Stress State Questionnaire; PHL: physical load; SBO: Strategisch Basis Onderzoek     

The role of risk in e-retailers’ adoption of payment methods: evidence for transition economies

We use logit analysis to exploit a self-collected dataset on the payment and delivery options offered by the vast majority of B2C websites in five Central Asian transition economies. Specifically, we conduct a supply-side test of (elements of) the Transaction Context Model, which highlights the role of perceived risk. Our results confirm that e-retailers in sectors with higher average transaction values are more likely to adopt ‘pay in advance’ instruments—such as debit cards—that have a lower payment risk for the seller. We also find that merchants who offer higher-risk delivery options are more prone to also adopt higher-risk payment instruments (such as credit cards). Our control variables also yield interesting results. In particular, in line with the network externalities theory, we find evidence that the offline penetration of a payment instrument positively affects online merchant adoption.     

GaN-based HEMTs tested under high temperature storage test

In this work, the impact of 1000 h thermal storage test at 325 °C on the performance of gallium nitride high electron mobility transistors grown on Si substrates (GaN-on-Si HEMTs) is investigated. The extensive DC- and pulse-characterization performed before, during and after the stress did not reveal degradation on the channel conduction properties as well as formation of additional trapping states. The failure investigation has shown that only the gate and drain leakage currents were strongly affected by the high temperature storage test. The physical failure analysis revealed a Au inter-diffusion phenomenon with Ni at the gate level, resulting in a worsening of the gate–AlGaN interface. It is speculated that this phenomenon is at the origin of the gate and drain leakage current increasing.     

Effect of oxide and W-CMP on the material properties and electromigration behaviour of layered aluminum metallisations

It has been found that chemical mechanical polishing increases the electromigration resistance of a Ti/AlCu/Ti/TiN metal stack. (111) X-ray diffraction polefigures indicate an increased (111) texture of AlCu deposited on a substrate that received at least one CMP step. This improved (111) texture can be attributed to a decreased roughness of the underlying oxide when chemical mechanical polishing is used.     

Feeding of palm oil fatty acids or rapeseed oil throughout lactation: Effects on energy status,body composition,and milk production in Norwegian dairy goats

The objective of this experiment was to examine how supplements of rapeseed oil or palm oil fatty acids would affect milk production and composition, body lipid stores, and energy balance in 30 multiparous goats of Norwegian dairy goat breed. The experiment lasted 230 d, with 1 to 120 d in milk (DIM) for indoor feeding (P1), 120 to 200 DIM for mountain grazing (P2), and 200 to 230 DIM for indoor feeding (P3). Grass silage was fed according to appetite during indoor feeding periods. After an adjustment period (1–60 DIM) when the control diet was given to the goats, the animals were subdivided into 3 groups of 10 goats. Treatments (60–230 DIM) were (1) basal concentrate (control; no added fat); (2) control concentrate with 8% (added on air-dry basis) hydrogenated palm oil enriched with palmitic acid (POFA); and (3) control concentrate with 8% (added on air-dry basis) rapeseed oil (RSO). Individual energy balances based on energy intake and milk production were estimated on 10, 30, 60, 90, 120, 200, and 230 DIM. At the same times, body weight (BW), body condition score (BCS), body mass index, and body tissue stores using computed tomography were monitored. Silage intake was depressed by POFA throughout the experimental period. Reduced BW and body mass index were observed in the POFA and RSO groups, whereas no effect on BCS or body composition was observed throughout lactation. Generally, a minor decrease in BW was observed from 10 to 120 DIM (only 0.6 kg on average) and the total amount of body lipid was reduced by 4.4 kg. During the mountain grazing period, a further reduction in body lipid stores (2.7 kg) was observed, and BW was reduced by 3.9 kg in the same period. The goats mobilized, on average, 72% of their fat reserves during the first 200 DIM. In this period, dietary fat supplementation did not reduce the mobilization of adipose tissue but resulted in greater milk fat yield (2 kg more, on average, compared with the control group). Milk yield was not affected by POFA or RSO supplementation. Milk fat content was higher in the POFA group than in the control and RSO groups. Milk protein and lactose contents were not affected by lipid supplements. In late lactation, a rapid accumulation of fat deposits followed the intense mobilization during the grazing period. Dietary lipid supplements had no effect on milk fat yield at this stage. Milk production depends heavily on the ability to mobilize body lipid stores, and neither POFA nor RSO supplements at rates used in our study affected this mobilization.