A Fabrication Process for Microstrip-Coupled Superconducting Transition Edge Sensors Giving Highly Reproducible Device Characteristics

Astronomical instruments for measuring Cosmic Microwave Background polarisation, such as CLOVER, require large arrays of Superconducting Transition Edge Sensors (TESs). We report recent results from a processing route development aimed at high yield fabrication of microstrip-coupled TESs. The incoming signal is delivered onto a silicon nitride membrane by means of a superconducting microstrip transmission line. This transmission line is then terminated with a thin-film load resistor. The wafer-based fabrication route of the Mo/Cu TESs gives highly reproducible device characteristics in terms of superconducting transition temperature, electrical and thermal characteristics. An overall device yield of 65% has been achieved for a multi-wafer processing run.      

A CW CO2 laser with DC-discharge preionization

The application of the plasma-injection technique (involving DC-discharge preionization) to a CW CO₂ laser operating with recirculated gas is described. Measured characteristics of the discharges, the gain, and the output power are presented. An output of 110 W was obtained with a specific efficiency of 1.0 J/l^-1 of flowed gas at a pressure of 10 kPa. A simplified model to calculate a characteristic length of the main discharge, which is useful for design purposes, is developed. This type of laser may be scaled simply to higher output powers, requires a gas mixture with only 20% He, is compact and robust, and yet is simple in its electrical and mechanical requirements     

A signal-processing algorithm for the extraction of thinfreshwater-ice thickness from short pulse radar data

A radar data processing algorithm is presented which can estimate freshwater ice thicknesses both greater than and less than the normal minimum resolvable thickness. The basis for the algorithm is a model of the geophysical system and the resulting phase signature of the transfer function. The algorithm attempts to isolate this signature and estimate the relevant parameters. In principle, the method can be used to detect layering in other dielectric media. The algorithm was based on a simple model for scattering from a thin-ice layer and refined using radar returns taken over a range of thin-ice thicknesses in a laboratory environment. The method was also applied to data obtained with two different radar frequencies and over a wide range of thickness and surface roughness. The results were compared to thickness estimates from classical deconvolution methods     

Mapping protein-protein interactions by affinity-directed mass spectrometry

A precise and rapid method for identifying sites of interaction between proteins was demonstrated; the basis of the method is direct mass spectrometric readout from the complex to determine the specific components of the proteins that interact--a method termed affinity-directed mass spectrometry. The strategy was used to define the region of interaction of a protein growth factor with a monoclonal antibody. A combination of proteolytic digestion and affinity-directed mass spectrometry was used to rapidly determine the approximate location of a continuous binding epitope within the growth factor. The precise boundaries of the binding epitope were determined by affinity-directed mass spectrometric analysis of sets of synthetic peptide ladders that span the approximate binding region. In addition to the mapping of such linear epitopes, affinity-directed mass spectrometry can be applied to the mapping of other types of molecule-molecule contacts, including ligand-receptor and protein-oligonucleotide interactions.     

Mutation analysis of the MEN1 gene in multiple endocrine neoplasia type 1, familial acromegaly and familial isolated hyperparathyroidism

Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant disease characterized by neoplasia of the parathyroid glands, the endocrine pancreas, and the anterior pituitary gland. In addition, families with isolated endocrine neoplasia, notably familial isolated hyperparathyroidism (FIHP) and familial acromegaly, have also been reported. However, whether these families constitute MEN 1 variants or separate entities remains speculative as the genetic bases for these diseases are unclear. The gene for MEN 1 has recently been cloned and characterized. Using single strand conformation analysis (SSCA) and sequencing, we performed mutation analysis in: a) a total of 55 MEN 1 families from 7 countries, b) 13 isolated MEN 1 cases without family history of the disease, c) 8 acromegaly families, and d) 4 FIHP families. Mutations were identified in 27 MEN 1 families and 9 isolated cases. The 22 different mutations spread across most of the 9 translated exons and included frameshift (11), nonsense (6), splice (2), missense mutations (2), and in-frame deletions (1). Among the 19 Finnish MEN 1 probands, a 1466del12 mutation was identified in 6 families with identical 11q13 haplotypes and in 2 isolated cases indicating a common founder. One frameshift mutation caused by 359del4 (GTCT) was found in 1 isolated case and 4 kindreds of different origin and haplotypes; this mutation therefore represents a common "warm" spot in the MEN1 gene. By analyzing the DNA of the parents of an isolated case one mutation was confirmed to be de novo. No mutation was found in any of the acromegaly and small FIHP families, suggesting that genetic defects other than the MEN1 gene might be involved and that additional such families need to be analyzed.     

Comparison of two dust collection methods for reservoir indoor allergens and endotoxin on carpets and mattresses

Variable methods of dust collection may lead to uncertainty in the measurement of biomarkers. The purpose of this study was to examine the effect of two different dust collection devices on dust weight, Der p 1, Fel d 1, and endotoxin levels. We compared: (1) a nylon mesh sock inserted between the furniture attachment and the vacuum hose (the reference method) and (2) the ALK device. Duplicate dust samples were collected for 2 min from 2 m(2) of 37 living room floors and from each longitudinal half of 37 mattresses. Measurement of Der p 1 and Fel d 1 were by double monoclonal antibody enzyme-linked immunosorbent assay (ELISA) and endotoxin by a Limulus Amobocyte Lysate assay. Geometric mean ratios (95% confidence intervals) were calculated to show the differences between sampling devices for each measurement. Compared with the ALK device, the reference method collected significantly more dust from floors (sevenfold) and mattresses (threefold) and more total Der p 1, Fel d 1, and endotoxin in both sites. Floor, but not mattress, Der p 1 concentrations were also significantly higher (threefold) using our reference method. We recommend that, in order to minimize sampling device bias, allergen and endotoxin are expressed as a concentration, and that the bed is considered the major source of allergen exposure. Practical Implications Dust sampling equipment can influence the dust yield. In order to have confidence in comparisons of allergen and endotoxin reservoir levels between centers, standardization in the use of sampling equipment is important.     

Agreement and clinical utility of 2 techniques for measuring cardiac output in patients with low cardiac output

BACKGROUND: The reliability of cardiac output obtained with the bolus technique is a problem. OBJECTIVES: To compare measurements of cardiac output measured with bolus and continuous techniques in patients with low cardiac output and to determine if measurements obtained with the continuous technique increased the number of subsequent clinical decisions. METHODS: In 60 intensive care patients, a nurse recorded a single continuous cardiac output measurement and then obtained the mean of 3 consecutive bolus determinations. The medical records of these 60 patients (experimental group) for the next 48 hours and of 60 other patients with regular or mixed venous oximetry catheters (control group) were reviewed to assess the occurrence of cardiac output events and the frequency of clinical decisions based on the events. RESULTS: Mean cardiac output was 4.46 L/min by the continuous technique and 5.20 L/min by the bolus technique (P = .011) for the experimental group. Median bias between the 2 types of measurements was -0.10 L/min (P = .79). Twenty-three of the pairs (38%) had an absolute percent difference greater than 15%. Of these, 18 (78%) had a higher bolus reading. Treatment decisions per 48 hours were 9.9 for the experimental group and 8.6 for the control group (P = .014). Median length of stay was 2 days less in the experimental group (P = .02), and mean highest cardiac output was 0.81 L/min higher (P = .009). CONCLUSIONS: Measurements of cardiac output determined with the continuous technique may be more precise than measurements determined with the bolus technique. Continuous cardiac output information increases the number of treatment decisions and actions that may shorten hospital length of stay.     

The volitional unit: a functional concept in cortico-motoneuronal connections in humans

AIM: The effect of breathing 100% oxygen on retinal and optic nerve head capillary blood flow in smokers and non-smokers was investigated using scanning laser Doppler flowmetry (SLDF) as a new non-invasive method to visualise and quantify ocular blood flow. METHOD: 10 eyes of 10 young healthy non-smoking volunteers (mean age 26 (SD 3) years) and nine eyes of nine young healthy smoking volunteers (mean age 26 (4) years) were investigated. All participants were asked not to smoke or consume caffeine containing drinks for at least 4 hours before the measurements. Blood flow measurements were performed before and after 100% oxygen was applied to the subjects through a mask over a period of 5 minutes (6 litres per minute). Juxtapapillary retinal and optic nerve head blood flow were determined in arbitrary units using SLDF representing a combination of laser Doppler flowmetry and a scanning laser system allowing visualisation and quantification of the retinal and optic nerve head blood flow. Blood flow was determined in an area of 100 microns x 100 microns. The level of carboxyhaemoglobin was determined in all subjects. A Wilcoxon matched pairs signed ranks test (non-parametric) was used for statistical evaluation. RESULTS: In the non-smoking group, retinal 'flow' was reduced by 33% (p = 0.005), optic nerve head 'flow' by 37% (p = 0.005). In the smoking group retinal flow was reduced by 10% (p = 0.01), optic nerve head flow by 13% (p < 0.008). The difference in reactivity to oxygen breathing between smokers and non-smokers was highly significant (p < 0.00001). Increased carboxyhaemoglobin levels were not found in either of the groups. A significant reduction of the mean arterial blood pressure of 6% (5%) (p < 0.02) was observed in the non-smoking group after administration of oxygen. CONCLUSION: These results indicate that hyperoxia leads to a decrease in capillary blood flow of the retina and optic nerve head secondary to vasoconstriction, and that smokers do not respond to oxygen breathing as non-smokers do. The findings might be based on factors such as long term effects of nicotine on the sympathetic and parasympathetic nervous system.