Elektronenmikroskopische Darstellung von strukturellen Einzelheiten in Nadelholz-Zellwänden anhand sehr dünner Ultramikrotomschnitte

An improvement of the embedding and staining method for the study of wood tissue in the transmission electron microscope enables a detailed representation of the lignin distribution in the various cell wall layers. Studies of very thin sections of spruce tracheids show that the strongly lignified “compound middle lamella” includes also the outer part of the secondary wall 1. In the secondary wall 2 of untreated wood a concentric lamellation was made visible. An irregularly lamellar lignin distribution in the S1 and the S2 of compression wood tracheids could also be found by the new method.     

“Integrated Water Resources Management: A Reassessment” by Asit K. Biswas

Abstract

A hydrogeological and microbiological study was carried out in Italy in order to verify the effectiveness of a DRASTIC-based method for groundwater vulnerability assessment in carbonate (fractured-karstified) aquifers. The research was developed: (a) by the monitoring of microbial contamination of two springs from January to July 2001 and from December 2002 to March 2003; and (b) by column tests in intact soil blocks, utilizing a collection strain of Enterococcus faecalis. The comparison of the vulnerability map with the results of the microbiological experiments demonstrated the effectiveness of the new DRASTIC-based method as a predictor of groundwater microbial contamination in carbonate aquifers. The effectiveness of the new proposed approach was verified and highlights the diversified role of the diffuse infiltration of precipitations through the fracture pattern and the more or less concentrated infiltration of surface water in karst areas.     

Interference from 24-GHz automotive radars to passive microwave earth remote sensing satellites

The automotive industry is currently considering the introduction of short-range radars (SRR) operating near 24 GHz for improving road traffic safety. SSRs are intended to observe the full azimuthal space cover around a vehicle using up to eight sensors. The sensors would operate in an ultrawideband (UWB) mode, occupying 3-5 GHz of bandwidth. Interference from SRR transmitters with passive microwave remote sensing satellites used for weather and climate monitoring could occur as the result of several coupling mechanisms, including direct coupling via the transmit antenna beam and scattering and diffraction of the transmitted signals from leading vehicles, buildings, and other nearby objects. In this study, we estimate the amount of coupling anticipated to occur from SRRs, including the direct and scattered contributions. The calculations are based on bistatic scattering measurements of a typical automobile and ray optical simulations of reflection and propagation in an urban environment. Using these calculations, the maximum allowable SRR transmitted power for interference levels acceptable for meteorological and climatological remote sensing applications are quantified. The study provides criteria for SRR operation with the Earth Exploration Satellite Service on a noninterference basis.     

Arsonic Acid Self‐Assembled Monolayers Protect Oxide Surfaces from Micronewton Nanomechanical Forces

The development of new surface coatings is critical for combating wear and increasing the device lifetime in microelectromechanical systems (MEMS). Here, a class of arsonic acid self‐assembled monolayers (SAMs) is reported that form readily on oxide substrates including silicon oxide, borosilicate glass, and titanium oxide. Monolayers are easily prepared using a straightforward soaking technique, which is amenable to large‐scale commercial applications. Monolayer formation on borosilicate glass and titanium oxide is characterized using infrared spectroscopy. Monolayers on borosilicate glass, native silicon oxide and titanium oxide are evaluated with contact angle measurements, as well as wear measurements using nanoscratching experiments. On titanium oxide and borosilicate glass, monolayers prepared from hexadecylarsonic acid provide significantly greater surface protection than surfaces reacted under similar conditions with hexadecylphosphonic acid, a common modifying agent for oxide substrates.     

Chlorinated phenols in human milk

The paper deals with the contamination of human milk with chlorinated phenols. The average and median concentrations of the chlorophenols investigated ranged from 0.75 to 9.74 g.kg^–1 and from being not detectable to 5.62 g.kg^–1, respectively, for the different compounds. The highest average and median levels were found for pentachlorophenol and 2,4,5-trichlorophenol. The concentrations determined were below the permissible levels.     

Photo-induced transformations in amorphous chalcogenide nano-multilayers

Photo-stimulated interdiffusion in a-Se/As₂S₃ amorphous chalcogenide nano-multilayers (ANML) is known as a useful method for amplitude-phase optical relief formation besides the known amorphous–amorphous or amorphous–crystalline photo-induced structural transformations (PST) in homogeneous chalcogenide layers, but it has a relatively narrow sensitivity spectral range and small amplitude modulation. Experimental evidences of improvement of optical recording processes were obtained in Te-, Bi-, Sb-containing nano-layered structures based on As₂S₃ matrix. The influence of nano-structuring and combination of components on the sensitivity, type of the recorded relief is discussed.     

Advances in space technology: the NSBRI Technology Development Team

As evidenced from Mir and other long-duration space missions, the space environment can cause significant alterations in the human physiology that could prove dangerous for astronauts. The NASA programme to develop countermeasures for these deleterious human health effects is being carried out by the National Space Biomedical Research Institute (NSBRI). The NSBRI has 12 research teams, ten of which are primarily physiology based, one addresses on-board medical care, and the twelfth focuses on technology development in support of the other research teams. This Technology Development (TD) Team initially supported four instrumentation developments: (1) an advanced, multiple projection, dual energy X ray absorptiometry (AMPDXA) scanning system: (2) a portable neutron spectrometer; (3) a miniature time-of-flight mass spectrometer: and (4) a cardiovascular identification system. Technical highlights of the original projects are presented along with an introduction to the five new TD Team projects being funded by the NSBRI.