Mechanism of hardening for the surface phosphates under external high pressure

Mechanism by which Zn/Fe methaphosphate material is transformed to glassy meta-phosphate is partially understood. The two decades of intensive study demonstrates that Zn and Fe ions participate to cross-link network under friction, hardening the phosphate. In the present work we consider our (in progress) spectroscopy study of zinc and iron phosphates under the influence external high pressure to determine Zn ion change coordination from tetrahedral to octahedral (or hexahedral) structure. The standard equipment is the optical high pressure cell with diamond (DAC). The DAC is assembled and then vibrational or electronic spectra are collected by mounting the cell in an infrared, Raman, EXAFS or UV-visible spectrometer. Transition metal atoms with d orbital have flexible coordination numbers, for example zinc acts as a cross-linking agent increasing hardness, by changing coordination from tetrahedral to octahedral. Perhaps the external pressure effect on the [Zn–(O-P-)4 ] complex causes a transformation to an [Zn –(O-P-)6] grouping High pressure spectroscopy has been extensively applied for the investigation of 3d transition metal ions in solids. When studying pressure effects on coordination compounds structure, we can expect changes in ground electronic state (spin-crossovers), electronic spectra due to structural distortions (piezochromism), and changes in the ligand field causing shifts in the electronic transitions

Determination of oil and grease, total petroleum hydrocarbons and volatile aromatic compounds in soil and sediment samples

This paper describes a case study of petroleum‐contaminated soil/sediment samples which were analyzed using gas chromatography‐flame ionization detector (GC‐FID) for total petroleum hydrocarbons (TPH), volatile aromatic com‐pounds: benzene, toluene, ethylbenzene, and xylenes (BTEX) and naphthalene by GC‐MS, and oil and grease (O/G) con‐tent by sonication in hexane. The ratio of (TPH) / (O/G) shows that the hydrocarbon fraction is between 7% and 87%. The content of volatile organic fraction BTEX accounts for only a small proportion of total TPH, and the ratio of (BTEX) / (TPH) ranges from 0.1% to 0.6%. It should be stressed that the use of TPH methods as against gas chromatography must be done with care because the potential risk posed by BTEX compounds may not be adequately addressed. Santrauka Aprašomi nafta užterštu dirvožemio bei dumblo pavyzdžiai, kuriuose duju chromatografijos būdu GC‐FIDnustatytas bendrasis naftos angliavandeniliu kiekis (TPH), o GC‐MS – lakieji aromatiniai junginiai: benzenas, toluenas, etilbenzenas ir ksilenai (BTEX) bei naftalenas. Sonifikacijos n‐heksane būdu nustatytas alieju ir riebalu (O/G) kiekis. TPH ir O/G santykis rodo, kad angliavandeniliu frakcijos yra nuo 7% iki 87%. Lakioji organine frakcija (BTEX) sudaro palyginti maža bendrojo naftos angliavandeniliu kiekio (TPH) dali, o BTEX ir TPH santykis svyruoja nuo 0,1% iki 0,6%. Ypač vertetu atkreipti demesi i bendrojo naftos angliavandeniliu kiekio (TPH) nustatyma duju chromatografijos būdu, nes galimas lakiosios organines frakcijos (BTEX) pavojingumas gali būti nepakankamai ivertintas. Peзюме Описаны образцы почвы и седимента, в которых способом хроматографии газа GC-FID определено общее количество нефтяных углеводородов (TPH), при помощи GC-MS установлены летучие ароматические соединения: бензол, толуол, этилобензол, ксилолы (BTEX) и нафталин. Способом сонификации в н-гексане определено количество масел и жиров (O/G). Отношение (TPH) / (O/G) свидетельствует о том, что в них содержится от 7% до 87% фракции углеводородов. Летучие ароматические соединения составляют относительно небольшую часть cyммарных нефтяных углеводородов, а отношение (BTEX) / (TPH) колеблется в пределах 0,1–0,6%. Особое внимание следует обратить на определение общего количества нефтяных углеводородов (TPH) способом хроматографии газа в связи с тем, что может быть не полноcтью оценена возможная опасность летучих ароматических соединений (BTEX). First Publish Online: 10 Feb 2011 Reikšminiai žodžiai: dirvožemis ir dumblas, aliejai ir riebalai, bendrasis naftos angliavandenilių kiekis, lakieji aromatiniai junginiai. Ключевые слова: почвa/седимент, маслa и жиры, cyммарные нефтяныe yглеводороды, летучие ароматические соединени

Feet deformities are correlated with impaired balance and postural stability in seniors over 75

<div><p>Objective</p><p>Understanding the factors and mechanisms that determine balance in seniors appears vital in terms of their self-reliance and overall safety. The study aimed to determine the relationship between the features of feet structure and the indicators of postural stability in the elderly.</p><p>Methods</p><p>The study group comprised 80 seniors (41F, 39M; aged 75–85 years). CQ-ST podoscope and the CQ-Stab 2P two-platform posturograph were used as primary research tools. The data were analyzed based on Spearman’s rank correlation and forward stepwise regression.</p><p>Results</p><p>Analysis of forward stepwise regression identified the left foot length in females and Clarke’s angle of the left foot in men as significant and independent predictors of postural up to 30% of the variance of dependent variables.</p><p>Conclusions</p><p>Longer feet provide older women with better stability, whereas in men, the lowering of the longitudinal arch results in postural deterioration. In the elderly, the left lower limb shows greater activity in the stabilizing processes in the standing position than the right one. In gerontological rehabilitation special attention should be paid to the individually tailored, gender-specific treatment, with a view to enhancing overall safety and quality of seniors’ lives.</p></div

Procedure for determining the feet structure indices.

<p>(A) foot length, foot width and the Wejsflog index; (B) Clarke’s angle; (C) hallux valgus angle and the angle of the varus deformity of the fifth toe; mtt, metatarsale tibiale; mtf, metatarsale fibulare; D, foot length; S, foot width; C, point of the largest recess; α, hallux valgus angle, β, the angle of the varus deformity of the fifth toe.</p

Somatic parameters of the study subjects.

<p>Somatic parameters of the study subjects.</p

Example of the long path length for the COP.

<p>COP, Center of Foot Pressure; AP, anteroposterior direction; ML–mediolateral direction.</p

Example of the short path length for the COP.

<p>COP, Center of Foot Pressure; AP, anteroposterior direction; ML–mediolateral direction.</p