Several Mousterian sites in France have yielded large numbers of small black blocs. The usual interpretation is that these 'manganese oxides' were collected for their colouring properties and used in body decoration, potentially for symbolic expression. Neanderthals habitually used fire and if they needed black material for decoration, soot and charcoal were readily available, whereas obtaining...

Thermal rearrangement of spirans (14) and (31) yields the xanthones (16,34) and diphenylrnethane (15, 32), respectively. The structure for xanthone (16), isolated from thermolysis, has been established by reduction to xanthene (20) followed by reoxidation to give xanthone (16). Alternatively, methylation of the diphenylmethane (15) followed by heating with selenium dioxide also yields xant...

the photocatalytic degradation of a common analgesic (acetaminophen) with titanium dioxide irradiated with low energy ultraviolet light (365 nm) was studied in order to determine the effect of several parameters such as catalyst’s weight, photochemical effect, and initial concentration. the results indicate that acetaminophen is degraded in the order of 4% by the photochemical effect. the pres...

the present research analyzes air quality in ahvaz, a city in the south of iran, paying special attention to sulfur dioxide (so2). in order to prepare the average data in the city, measurements have been carried out between 2009 and 2010 in two different locations. relations between sulfur dioxide and some meteorological parameters have been calculated statistically, using the daily average dat...

Pigment grade titanium dioxide is composed of sub-micron sized particles, including a nanofraction, and is widely utilized in food, cosmetic, pharmaceutical, and biomedical industries. Oral exposure to pigment grade titanium dioxide results in at least some material entering the circulation in humans, although subsequent interactions with blood immune cells are unknown. Pigment grade titanium d...

Background and Purpose: The response of cerebral blood flow to changes in the arterial carbon dioxide partial pressure (i.e., carbon dioxide reactivity) has been evaluated as a parameter of cerebral perfusion reserve in patients with cerebrovascular disease. In this study, variations in this reactivity in various ischemic cerebrovascular diseases were evaluated by a newly established method, a ...

Air embolization to the coronary arteries is a common cause of myocardial ischemia during open heart surgery. Carbon dioxide emboli may be absorbed faster than air emboli. In this randomized, double blind, placebo-controlled trial, we determined that flooding the surgical field with carbon dioxide is associated with improved myocardial function assessed by transesophageal echocardiography. Fort...

A method is described for the estimation of carbon dioxide output, oxygen uptake, and respiratory exchange ratio during nitrous oxide anaesthesia. The inspired and expired minute volumes are measured with a box-bag system, the carbon dioxide concentrations with a carbon dioxide sensitive electrode, and the oxygen concentrations with a polarograph. Carbon dioxide output can be measured with a co...

Using a rapid spectrographic method of carbon dioxide measurement previously described by McAlister (1937) further studies on the time course of photosynthesis in the higher plant, wheat, variety Marquis, are herein reported. Of major importance in this work is the discovery of a pick-up of carbon dioxide in darkness immediately following a high rate of photosynthesis (see Figs. 3 and 4). This ...