Geochemical assessment of metal transfer from rock and soil to water in serpentine areas of Sabah (Malaysia)

The mobility of metals in ultramafic rock–soil systems and metal contamination in serpentine soils were investigated from the Ranau area in Sabah, East Malaysia. Metal concentrations were analysed after division into seven operationally defined fractions by selective sequential extraction (SSE). Geochemical studies showed that the soils are exceptionally high in Cr (95%) residing in refractory residual fractions. Metal speciation studies will shed further light on toxicities in the Malaysian ultramafic tropical environment, reconciled against elemental metal tenure, adopted by common standards

Environmental impact of heavy metals (Fe, Ni, Cr, Co) in soils waters and plants of triada in Euboea from ultrabasic rocks and nickeliferous mineralisation

Soil, water and vegetation samples were collected from the Triada area of Central Euboea and analysed for heavy metals in order to evaluate their environmental impact. The geology of the are studied includes ultrabasic rocks that are overlaid by Upper Cretaceous limestones whereas Fe-Ni mineralisation is intercalated between either the ultrabasic parent rocks or the karstified Jurassic/Triassic carbonates and the transgressive Upper Cretaceous limestones. All the samples were analysed for heavy metals by using atomic absorption spectroscopy. The heavy metal ranges (in μg g-1) for soils samples are: Ni 480-4000, Cr 240-2720, Co 40-208, Fe 24,000-380,000, Mn 46-1680, Pb 16-56, Zn 40-144, Cu 2-82. The values of soil samples of the Triada area are much higher than the values found for Ni, Cr, Co and Fe, in normal soils of the world. The heavy metal ranges (in μg L-1) for water samples are: Ni 19-24, Cr 19-476, Co <5, Fe <100, Mn <100, Mg 5.7-220.5, As 30-69, Cd <2, Pd <10, Zn 5-11, Cu 2-7. The water samples of the Triada area have Cr and Mg concentrations higher than the permittable values. The heavy metal ranges (in μg g-1) for vegetation samples are: Ni 1-135, Cr 0-24, Co 1-21.5, Fe 20-680, Mn 10-206, Cd 0-10, Pb 0-14, Zn 14-70, Cu 0-10.5. The vegetation samples of the Triada area have so high values of Ni, Cr and Co that are considered toxic. The intercorrelated elements Fe, Ni, Cr, Co of the Triada soils, waters and vegetation reflect their association with the ultrabasic rocks and with the Fe-Ni mineralisation

Subwavelength terahertz imaging of graphene photoconductivity

Using a spatially structured, optical pump pulse with a terahertz (THz) probe pulse, we are able to determine spatial variations of the ultrafast THz photoconductivity with subwavelength resolution (75 μm ≈ λ/5 at 0.8 THz) in a planar graphene sample. We compare our results to Raman spectroscopy and correlate the existence of the spatial inhomogeneities between the two measurements. We find a strong correlation with inhomogeneity in electron density. This demonstrates the importance of eliminating inhomogeneities in doping density during CVD growth and fabrication for photoconductive devices

Multiphoton imaging and Raman spectroscopy of the bovine vertebral endplate

The interface between the intervertebral disc and the vertebral body is important to the discs’ biomechanics and physiology, and is widely implicated in its pathology. This study aimed to explore biochemically and structurally the bony endplate, cartilage endplate and intervertebral disc, below the nucleus and below the annulus in healthy bovine tails. Multiphoton imaging and spontaneous Raman spectroscopy were employed. Raman spectroscopy provided relative quantification of mineral and matrix components across the vertebral endplate and its adjacent areas with microscopic spatial resolution. Microscopy utilising second-harmonic generation (SHG) and two-photon fluorescence (TPF) allowed for the structural identification of distinct endplate regions. The cartilage endplate was revealed as structurally distinct from both the bone and disc, supporting its biomechanical function as a transition zone between the soft and hard tissue components. The collagen fibres were continuous across the tidemark which defines the interface between the mineralised and non-mineralised regions of the endplate. Raman spectroscopy revealed gradients in phosphate and carbonate content through the depth of the endplate and also differences beneath the nucleus and annulus consistent with a higher rate of remodelling under the annulus

Biopsy-proven resolution of renal light-chain deposition disease after autologous stem cell transplantation

Light-chain deposition disease (LCDD) is caused by an underlying clonal plasma cell dyscrasia in which monoclonal immunoglobulin light chains (LCs) are deposited in tissues, resulting in varying degrees of organ dysfunction. Autologous stem cell transplantation (ASCT) has been reported to stabilize renal function in patients with LCDD, but currently, no evidence of histopathologic resolution of LC deposition after ASCT exists. We present a patient, with severe renal dysfunction due to LCDD, who was treated with high-dose melphalan and ASCT that resulted in a significant and extended period of improved renal function. Four years after the initial improvement, the patient developed nephrotic range proteinuria, without any evidence of relapse of the plasma cell dyscrasia. At that time, a repeat renal biopsy showed complete resolution of LC depositions and development of extensive glomerulosclerosis, thus explaining proteinuria. To the best of our knowledge, this is the first report of a biopsy-proven resolution of renal LCDD following ASCT. A timely application of ASCT should be considered in LCDD to prevent deterioration of renal function in the long run. © 2010 The Author