Heavy metals in emergent trees and pioneers from tropical forest with special reference to forest fires and local pollution sources in Sarawak, Malaysia

Leaf samples of tropical trees, i.e. Dryobalanops lanceolata (Kapur paji), Dipterocarpaceae and Macaranga spp. (Mahang), Euphorbiaceae were analyzed for 21 chemical elements. The pioneer Macaranga spp. exhibited higher concentrations for the majority of elements compared to the emergent species of Dryobalanops lanceolata, which was attributed to the higher physiological activity of the fast growing pioneer species compared to emergent trees. Lead showed rather high concentrations in several samples from the Bakam re-forestation site. This is suggested to be caused by emissions through brick manufacturing and related activities in the vicinity. A comparison of Dryobalanops lanceolata samples collected in 1993, 1995 and 1997 in the Lambir Hills National Park revealed that certain heavy metals, i.e. Co, Cu, Mn, Ni, Pb and Ti showed higher values in 1997 compared to the previous years, which could indicate an atmospheric input from the haze caused by the extensive forest fires raging in Borneo and other parts of Southeast Asia.     

Demonstration of infectious bovine rhinotracheitis virus antigen by immunoperoxidase method in tissues of aborted bovine fetuses preserved for 25 years in paraffin blocks

Infectious bovine rhinotracheitis (IBR) virus antigen was demonstrated by the immunoperoxidase method in tissues of two aborted bovine fetuses, which had been stored for 25 years after fixing in formalin and embedding in paraffin. Necrotic foci were detected in the liver, kidney, adrenal gland, and thymus of the fetuses. Coincidenting with the distribution of the necrotic foci, IBR virus antigen was demonstrated by immunostaining. The present study proved the immunoperoxidase method in one of useful techniques to demonstrate IBR virus antigen in tissue sections from preserved paraffin blocks.     

Somatostatin-receptor-negative carcinoid tumour responsible for Cushing''s syndrome

A 64-year-old woman presented with cardiomegaly, Sweet's syndrome, and refractory anemia (RA), and died of sudden cardiac arrest. The autopsy revealed a perivascular and myocardial infiltration by neutrophils, which could be responsible for the cardiomegaly and probably had caused disturbances in the conduction system leading to sudden cardiac arrest. Myocardial infiltration by functionally defective neutrophils can develop in a patient with myelodysplastic syndrome (MDS) without peripheral neutrophilia or leukemic blood picture and needs a special diagnostic and therapeutic consideration.     

A pentamidine-treated acquired immunodeficiency syndrome patient associated with sudden onset diabetes mellitus and high tumor necrosis factor alpha level

Orbital implant infection is a rare cause of anophthalmic socket pain. Because of the potential danger of infection spreading to nearby structures, it is of paramount importance to diagnose the condition as soon as possible. Scintigraphy is a method for diagnosis of graft infections by radioisotopic imaging of inflammatory sites. We report on a patient with socket pain 3 months after implantation of an acrylic implant. The socket appearance was normal and there were no signs of infection other than culture-positive socket exudation. Three consecutive computed tomography scans revealed no abnormalities. 99mTc leukocyte scintigraphy revealed white blood cell accumulation at the implantation site. The implant was removed and cultured. This produced Staphylococcus epidermidis and R. equii. A parenteral antibiotic treatment was instituted with subsequent improvement of symptoms. Four months later, after negative scintigraphy, a hydroxyapatite implant was inserted, demonstrating full vascularization on a bone scan after 2 months. Two months later, the patient developed the previous symptoms, with all of the former findings, including positive scintigraphy. The implant was removed, revealing a microabscess on the anterior aspect, producing S. epidermidis on culture. We conclude that scintigraphy using 99mTc-labeled leukocytes is a useful technique in diagnosing low-grade orbital infection.     

The preparation of TiO2 nanometer photocatalyst film by a hydrothermal method and its sterilization performance for Giardia lamblia

The photocatalytic property of TiO(2) is utilized to sterilize the Giardia lamblia in an aqueous solution in this study. The TiO(2) colloidal solution used for the film was prepared by the modified hydrothermal method and it was directly coated on a UV-lamp, which was set up using a photoreactor manufactured in our laboratory. The TiO(2) film was very stably attached to the UV-lamp, and it was transparent until 5-time coating. The size of the TiO(2) particle in the film was distributed around 20-30 nm and the film thickness was about 200 nm per 1-time coating.The G. lamblia cell was just partially damaged under UV-irradiation without a TiO(2) photocatalyst, but the dead cell became very small and the dead body finally disappeared with an increase in the intensity of UV-irradiation after 2 h. In addition, under the TiO(2)/UV-irradiation system, the sterilized (dead) rate of G. lamblia was very fast. The sterilizing power increased at lower pH in the initial step, but it rather increased at a higher pH in the final step. And the sterilization of G. lamblia was very sensitive to the temperature, and resulted in an increase in the sterilized rate at higher temperatures. On the basis of these experimental observations, it can be concluded that TiO(2) photocatalyst under UV-irradiation could be adopted as one of the sterilization modalities for the G. lamblia.     

高压下N_2、Ar、CH_4、CO_2和N_2O气体在丝光沸石上的吸附平衡及关联

本文用定容型吸附量测定装置,在压力为3.04×10~3至1.43×10~7Pa范围内,温度为—196、0、25、50和75°C下测定了N_2、Ar、CH_4、CO_2和N_2O等气体在氢型丝光沸石上的吸附平衡数据.实验结果表明:N_2、Ar和CH_4的吸附量随压力增加而增加,直到在6.08×10~6Pa附近达到饱和;CO_2和N_2O的吸附等温线出现了极大值,且不同温度同一吸附质的吸附等温线出现了相互交叉的现象.用扩展了的吸附势理论进行关联,取得了满意的结果.     

Towards Tuneable Retaining Glycosidase‐Inhibiting Peptides by Mimicry of a Plant Flavonol Warhead

Retaining glycosidases are an important class of enzymes involved in glycan degradation. To study better the role of specific enzymes in deglycosylation processes, and thereby the importance of particular glycosylation patterns, a set of potent inhibitors, each specific to a particular glycosidase, would be an invaluable toolkit. Towards this goal, we detail here a more in‐depth study of a prototypical macrocyclic peptide inhibitor of the model retaining glycosidase human pancreatic α‐amylase (HPA). Notably, incorporation of l ‐DOPA into this peptide affords an inhibitor of HPA with potency that is tenfold higher (K_i=480 pm ) than that of the previously found consensus sequence. This represents a first successful step in converting a recently discovered natural‐product‐derived motif, already specific for the catalytic side‐chain arrangement conserved in the active sites of retaining glycosidases, into a tuneable retaining glycosidase inhibition warhead.     

Optimizing the dimensions of magnesium ammonium phosphate to maximize its ammonia uptake ability

Magnesium ammonium phosphate (MgNH₄PO₄·6H₂O:MAP) releases approximately 70% of its ammonia at a mild temperature of 378 K. The resultant material (magnesium hydrogen phosphate (MgHPO₄:MHP)-like material), which appears to be an amorphous phase, to remove ammonia from wastewater was investigated. Because the original size of MAP crystals was found to critically affect the kinetics of ammonia uptake by the corresponding MHP-like material, MAP with different sizes were synthesized by changing concentration, pH and temperature of the synthesis solution. The variation in the synthesis concentration was found to change the size of MAP as well as the aspect ratio of the long-axis to the short-axis. The rate of ammonia uptake depends primarily on the dimension of the short-axis of the corresponding MAP crystals. Furthermore, analysis of ammonia uptake using a method similar to the shrinking-core model shows approximately 0.5 μm from the surface is effectively used for ammonia uptake over a period of a realistic process time. Thus, the results suggest it is crucial to synthesize small MAP crystals with the size of short-axis less than 1 μm. Our results also show that small MAP crystals can be used at least four times repeatedly for ammonia uptake.