Properties, performance and associated hazards of state-of-the-art durable water repellent (DWR) chemistry for textile finishing.

Following the phase-out of long-chain per- and polyfluoroalkyl substances (PFASs), the textile industry had to find alternatives for side-chain fluorinated polymer based durable water repellent (DWR) chemistries that incorporated long perfluoroalkyl side chains. This phase-out and subsequent substitution with alternatives has resulted in a market where both fluorinated and non-fluorinated DWRs are available. These DWR alternatives can be divided into four broad groups that reflect their basic chemistry: side-chain fluorinated polymers, silicones, hydrocarbons and other chemistries (includes dendrimer and inorganic nanoparticle chemistries). In this critical review, the alternative DWRs are assessed with regards to their structural properties and connected performance, loss and degradation processes resulting in diffuse environmental emissions, and hazard profiles for selected emitted substances. Our review shows that there are large differences in performance between the alternative DWRs, most importantly the lack of oil repellence of non-fluorinated alternatives. It also shows that for all alternatives, impurities and/or degradation products of the DWR chemistries are diffusively emitted to the environment. Our hazard ranking suggests that hydrocarbon based DWR is the most environmentally benign, followed by silicone and side-chain fluorinated polymer-based DWR chemistries. Industrial commitments to reduce the levels of impurities in silicone based and side-chain fluorinated polymer based DWR formulations will lower the actual risks. There is a lack of information on the hazards associated with DWRs, in particular for the dendrimer and inorganic nanoparticle chemistries, and these data gaps must be filled. Until environmentally safe alternatives, which provide the required performance, are available our recommendation is to choose DWR chemistry on a case-by-case basis, always weighing the benefits connected to increased performance against the risks to the environment and human health.

Chemical contaminants in feedlot wastes: concentrations, effects and attenuation.

Commercial feedlots for beef cattle finishing are potential sources of a range of trace chemicals which have human health or environmental significance. To ensure adequate protection of human and environmental health from exposure to these chemicals, the application of effective manure and effluent management practices is warranted. The Australian meat and livestock industry has adopted a proactive approach to the identification of best management practices. Accordingly, this review was undertaken to identify key chemical species that may require consideration in the development of guidelines for feedlot manure and effluent management practices in Australia. Important classes of trace chemicals identified include steroidal hormones, antibiotics, ectoparasiticides, mycotoxins, heavy metals and dioxins. These are described in terms of their likely sources, expected concentrations and public health or environmental significance based on international data and research. Androgenic hormones such as testosterone and trenbolone are significantly active in feedlot wastes, but they are poorly understood in terms of fate and environmental implications. The careful management of residues of antibiotics including virginiamycin, tylosin and oxytetracycline appears prudent in terms of minimising the risk of potential public health impacts from resistant strains of bacteria. Good management of ectoparasiticides including synthetic pyrethroids, macrocyclic lactones, fluazuron, and amitraz is important for the prevention of potential ecological implications, particularly towards dung beetles. Very few of these individual chemical contaminants have been thoroughly investigated in terms of concentrations, effects and attenuation in Australian feedlot wastes.

An assessment of the variability of early scalp-components of the somatosensory evoked response in uncomplicated, unshunted carotid endarterectomy.

Although many publications deal with the usefulness of the SER in CEAs, the criteria of calling a SER abnormal during a CEA are largely arbitrary. One way to define the limits of normalcy for SERs during the CEA will be to analyze the SER tracings obtained during unshunted and uncomplicated (intra- and postoperative) CEAs. In 23 such CEAs (10 right, 13 left; clamptime 10-23 mins.), data analysis at the ipsilateral parietal electrode, on stimulation of the contralateral median nerve (square pulse -5.1/sec, 10-30 V, 200 microseconds; bandpass-30-3000 Hz trials-500 stimuli), revealed that (1) latency fluctuations of the N20 (21.4 msec) were narrowest, being less than 1.5 msec different during and after clamping compared to the preclamp latency in all 23 CEAs, whereas those of P25 (27.4 msec) and N35 (38.5 msec) were greater than 2.0 msec different from the preclamp latency in 3 and 8 CEAs respectively, and (2) the amplitudes of N20, P25 and N35 measured from the preceding peak of opposite polarity, fell to less than 75% of the preclamp value on 3, 4 and 7 CEAs respectively. It is concluded that N20 was the most stable of the first three short-latency components in the SER and should perhaps be most relied upon to predict abnormality of the SER during CEAs.

Ototoxicity associated with cis-platinum in three chemotherapy multi-drug regimens.

Hearing threshold differences postcis-platinum, relative to precis-platinum levels, were studied in 21 men from a Veterans Administration Medical Center. These patients had previously untreated advanced epidermoid cancers of the head and neck. Each patient received one of three drug combinations: (1) cis-platinum, Oncovin, and bleomycin (n = 9); (2) cis-platinum and 5-fluorouracil (n = 7); or (3) cis-platinum and bleomycin (n = 5). Wide variations in prechemotherapy hearing thresholds prevented analysis among various drug combinations. Therefore, the three groups were pooled to compare the thresholds by frequency. The frequencies tested and analyzed were: 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz. Significant differences were found at 2000 Hz (P less than 0.01) and 8000 Hz (P less than 0.05). Any existing ototoxic effects of cis-platinum may have been overridden by already high prechemotherapy hearing thresholds at 4000 Hz. Since 2000 Hz was most sensitive to the ototoxic effects of cis-platinum it is suggested that this frequency be monitored routinely as a part of standard chemotherapy assessment.

High-frequency Bekesy audiometry: III. Reliability and validity revisited.

Normal-hearing young adults (N: 30) produced 3 fixed-frequency monaural audiograms by Bekesy tracking on a Grason-Stadler E-800 audiometer (modified for high frequencies) for pulsed pure tones in 2-kc/s steps progressively from 7-19 kc/s. The earphone was not moved between one pair of audiograms but was removed and replaced between another pair. After 1 mo, 16 Ss returned for retest on the HF E-800 audiometer and on a similar audiometer using the conventional Method of Limits. Maximum group mean retest HTL differences approximated 5 db. Statistical analysis indicated that the arrays of HTLs within and across sessions were equivalent. Reliability and validity coefficients were high and significantly different from zero. It was concluded that the HF E-800 could with such Ss be used with some confidence to assess high-frequency sensitivity.