The importance of being alkaline

The earliest forms of "protolife" on Earth must have been able to reproduce and replicate; it is likely that they were also cellular. How might such systems have formed? In his Perspective, Russell highlights the report by Hanczyc et al., who show that clay particles can catalyze the formation of lipid vesicles. These particles also adsorb RNA. If the vesicles are forced to divide, RNA is distributed among the daughter vesicles. Similar conditions to those used in the experiments may have existed at mounds created by alkaline, hydrothermal seepages on the ancient ocean floor. However, instead of lipids, polypeptides formed from amino acids may have formed the first organic membranes

Intracerebral Haemorrhage Following Carotid Endarterectomy

AbstractObjectives. To determine risk factors for the development of hyperperfusion and intra-cerebral haemorrhage following carotid endarterectomy and formulate potential protocols for prevention.Methods. MEDLINE database search of the English language literature (1966–2002) was performed using the words ‘cerebral haemorrhage’, ‘intracranial haemorrhage’ and ‘carotid endarterectomy’. Other articles were cross-referenced by hand.Results. There are no data from randomised trials confirming the significance of any single risk factor. The evidence suggests that the following may have a role: pre-operative hypertension, recent ipsilateral non-haemorrhagic stroke, previous ischaemic cerebral infarction, surgery for a >90% ipsilateral internal carotid artery (ICA) stenosis, impaired cerebrovascular reserve, intra-operative haemodynamic or embolic ischaemia, post-operative hypertension, an ipsilateral increase of ≥175% in peak middle cerebral artery velocity (MCAV) and/or a ≥100% increase in pulsatility index.Conclusions. A critical ICA stenosis with impaired cerebrovascular reserve resulting in maximal intracerebral vasodilatation and post-operative hyperperfusion (impaired autoregulation) appear to be central to the development of ICH. Appropriate pre-operative screening and post-operative monitoring in high risk patients might identify those who would benefit from manipulation of the haemodynamic events that appear to promote ICH

Physical aspects of soil fertility - the response of roots to mechanical impedance.

Penetrability of soil by roots is reviewed. Roots of barley did not decrease in diameter in order to penetrate small pores. Where substrates were selected with pores smaller than the diameter of root axes but larger than that of laterals, axes were impeded but lateral roots proliferated, indicating that an appreciable reduction in root extension caused by mechanical stress would not necessarily reduce crop yield. Where barley root axes were forced to bend, lateral root initials typically developed on the convex side. (Abstract retrieved from CAB Abstracts by CABI’s permission

Attenuation of skeletal muscle atrophy in cancer cachexia by d-myo-inositol 1,2,6-triphosphate

PURPOSE: To determine the effectiveness of the polyanionic, metal binding agent D-myo-inositol-1,2,6-triphosphate (alpha trinositol, AT), and its hexanoyl ester (HAT), in tissue wasting in cancer cachexia. METHODS: The anti-cachexic effect was evaluated in the MAC16 tumour model. RESULTS: Both AT and HAT attenuated the loss of body weight through an increase in the nonfat carcass mass due to an increase in protein synthesis and a decrease in protein degradation in skeletal muscle. The decrease in protein degradation was associated with a decrease in activity of the ubiquitin-proteasome proteolytic pathway and caspase-3 and -8. Protein synthesis was increased due to attenuation of the elevated autophosphorylation of double-stranded RNA-dependent protein kinase, and of eukaryotic initiation factor 2alpha together with hyperphosphorylation of eIF4E-binding protein 1 and decreased phosphorylation of eukaryotic elongation factor 2. In vitro, AT completely attenuated the protein degradation in murine myotubes induced by both proteolysis-inducing factor and angiotensin II. CONCLUSION: These results show that AT is a novel therapeutic agent with the potential to alleviate muscle wasting in cancer patients

The floor in the interplanetary magnetic field: Estimation on the basis of relative duration of ICME observations in solar wind during 1976-2000

To measure the floor in interplanetary magnetic field and estimate the time- invariant open magnetic flux of Sun, it is necessary to know a part of magnetic field of Sun carried away by CMEs. In contrast with previous papers, we did not use global solar parameters: we identified different large-scale types of solar wind for 1976-2000 interval, obtained a fraction of interplanetary CMEs (ICMEs) and calculated magnitude of interplanetary magnetic field B averaged over 2 Carrington rotations. The floor of magnetic field is estimated as B value at solar cycle minimum when the ICMEs were not observed and it was calculated to be 4,65 \pm 6,0 nT. Obtained value is in a good agreement with previous results.Comment: 10 pages, 2 figures, submitted in GR

Dislocation Density-Dependent Quality Factors in InGaN Quantum Dot Containing Microdisks

Microdisks incorporating InGaN quantum dots were fabricated using SiO2 microspheres as a hard mask in conjunction with a photoelectrochemical etch step from a structure containing a sacrificial InGaN/InGaN superlattice. Formation of microdisks from two near-identical structures with differing dislocation densities was carried out and investigated using microphotoluminescence. This confirmed the existence of quantum dots through the presence of resolution limited spectral lines and showed a clear correlation between the resulting modes quality factors and the dislocation densities within the disks. The disks with higher dislocation densities showed up to 80% lower quality factors than the low dislocation density disks.Engineering and Applied Science