Inhibition of Orientia tsutsugamushi infection by a truncated recombinant 56-kDa outer membrane protein

AIMS

The objective of this study was to evaluate recombinant 56-kDa outer membrane protein as a potential inhibitor to infection from Orientia tsutsugamushi.

METHODS AND RESULTS

The 56-kDa protein was cloned and expressed in an Escherichia coli system, and the degree of target cell attachment to immobilized 56-kDa protein was measured in a cell adhesion assay. The results showed that the 56-kDa protein has an ability to attach HeLa cells. Furthermore, treatment of target cells with a truncated 56-kDa 1-418 (amino acid residues) protein inhibited target cell infection by O. tsutsugamushi, demonstrated with an indirect immunofluorescence antibody assay.

CONCLUSIONS

The truncated 56-kDa protein (a.a. 1-418) plays an important role in O. tsutsugamushi infection, and the 56-kDa protein could be useful and effective in the inhibition of O. tsutsugamushi attachment and infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

The attachment of the 56-kDa protein to target cells was directly determined by in vitro adherence test, and the invasion of target cells by O. tsutsugamushi was inhibited by treating the target cells with a truncated 56-kDa protein.

Urban and rural variation in walking patterns and pedestrian crashes

OBJECTIVE

To examine the urban and rural variation in walking patterns and pedestrian crashes.

DESIGN

The rates of pedestrians being struck by motor vehicles was estimated according to miles walked and resident years.

SETTING

New York State, USA during 2001 through 2002.

PARTICIPANTS

35 732 pedestrians struck by vehicles.

MAIN OUTCOME MEASURES

The adjusted rate ratio (aRR) of pedestrian-vehicle crash and pedestrian injury based on resident years and miles walked according to urban and rural areas.

RESULTS

Compared with rural areas, the aRR for a pedestrian-vehicle collision, based on resident years, was 2.0 (95% CI 1.7 to 2.3) in small urban areas, 1.8 (95% CI 1.5 to 2.3) in mid-size urban areas, and 4.2 (95% CI 3.6 to 4.8) in the large urban area. The aRR based on miles walked was 2.3 (95% CI 1.6 to 3.2) in small urban areas, 2.0 (95% CI 1.4 to 2.9) in mid-size urban areas, and 1.9 (95% CI 1.4 to 2.7) in the large area. The aRR for a fatal pedestrian injury, based on miles walked, was 2.1 (95% CI 1.3 to 3.6) in small urban areas, 1.9 (95% CI 1.3 to 2.9) in mid-size urban areas, and 0.9 (95% CI 0.6 to 1.3) in the large urban area.

CONCLUSIONS

The rate of pedestrian crashes and injuries in small and mid-size urban areas was twice that in rural areas, whether based on resident years or miles walked. The high rate of pedestrian crashes in the large urban area based on resident years could be partly explained by the fact that residents in such areas walk about twice as much as residents in rural areas. The rate of fatal pedestrian injury based on miles walked was similar in the large urban area and rural areas.

Isolation and characterization of alginate-degrading bacteria for disposal of seaweed wastes

AIMS

Isolation of novel alginate degrading bacteria for the disposal of seaweed waste in composting process.

METHODS AND RESULTS

Decomposition of alginate polymers was checked by the 3,5-dinitrosalicylic acid (DNS) method for reducing sugar, and absorbance at 235 nm for unsaturated sugar. A bacterium A7 was isolated from wakame compost and confirmed to belong to the genus Gracilibacillus by partial 16S rDNA analysis. The optimum condition for the growth of A7 in a medium containing 5 g l(-1) of sodium alginate is as follows: pH, 8.5-9.5; NaCl, 0.5 mol l(-1); temperature, 30 degrees C and polypeptone as nutrient content, 2-5 g l(-1). In a laboratory-scale composting experiment, the alginate content in wakame compost decreased to 14.3% after 72 h of composting from an initial value of 36%, indicating the effectiveness of alginate decomposition of A7 in wakame composting.

CONCLUSIONS

The bacterium A7 was found to be alginate lyase-producing in genus Gracilibacillus and effective in degrading alginate to oligosaccharides in wakame during composting process.

SIGNIFICANCE AND IMPACT OF THE STUDY

Development of new methods for the disposal of marine wastes and production of functional products.

Longitudinal changes in serum lipids among HIV-infected men on highly active antiretroviral therapy

OBJECTIVE

The aim of the study was to describe longitudinal changes in serum lipids among HIV-infected men receiving highly active antiretroviral therapy (HAART) with long-term follow-up.

METHODS

A total of 304 HIV-infected men who initiated HAART and who had serum lipid measurements prior to and for up to 7 years after HAART initiation were identified from the Multicenter AIDS Cohort Study (MACS). Mean levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were examined at biannual time-points.

RESULTS

Significant lipid changes were seen within 0.5 years of HAART initiation but increases in TC (+1.09 mmol/L), LDL-C (+0.57 mmol/L), HDL-C (+0.16 mmol/L) and non-HDL-C (+0.91 mmol/L) reached peak levels 2-3 years after HAART initiation. Declines in serum TC, LDL-C and non-HDL-C in subsequent years occurred concurrently with a substantial increase in use of lipid-lowering medications (from 1% usage pre-HAART to 43% 6-7 years after HAART initiation) but the proportion of men who either were treated with cholesterol-lowering medication or had elevated cholesterol levels (>5.18 mmol/L) did not change during the 2-7-year interval after HAART. Mean HDL-C also decreased after 2-3 years and was low (<1.04 mmol/L) in 55% of HIV-infected men 6-7 years after HAART initiation.

CONCLUSIONS

Atherogenic serum lipids increased early after the initiation of HAART, peaked at 2-3 years and remained high or required treatment thereafter. Low HDL-C levels persisted in the majority of men. The long-term effects of lipid abnormalities on cardiovascular risk and the effectiveness and toxicity of prolonged use of lipid-lowering medications in combination with HAART are not known.

A batch study on the bio-fixation of carbon dioxide in the absorbed solution from a chemical wet scrubber by hot spring and marine algae

Carbon dioxide mass transfer is a key factor in cultivating micro-algae except for the light limitation of photosynthesis. It is a novel idea to enhance mass transfer with the cyclic procedure of absorbing CO(2) with a high performance alkaline abosorber such as a packed tower and regenerating the alkaline solution with algal photosynthesis. Hence, the algae with high affinity for alkaline condition must be purified. In this study, a hot spring alga (HSA) was purified from an alkaline hot spring (pH 9.3, 62 degrees C) in Taiwan and grows well over pH 11.5 and 50 degrees C. For performance of HSA, CO(2) removal efficiencies in the packed tower increase about 5-fold in a suitable growth condition compared to that without adding any potassium hydroxide. But ammonia solution was not a good choice for this system with regard to carbon dioxide removal efficiency because of its toxicity on HSA. In addition, HSA also exhibits a high growth rate under the controlled pHs from 7 to 11. Besides, a well mass balance of carbon and nitrogen made sure that less other byproducts formed in the procedure of carboxylation. For analysis of some metals in HSA, such as Mg, Mn, Fe, Zn, related to the photosynthesis increased by a rising cultivated pH and revealed that those metals might be accumulated under alkaline conditions but the growth rate was still limited by the ratio of bicarbonate (useful carbon source) and carbonate. Meanwhile, Nannochlopsis oculta (NAO) was also tested under different additional carbon sources. The results revealed that solutions of sodium/potassium carbonate are better carbon sources than ammonia carbonate/bicarbonate for the growth of NAO. However, pH 9.6 of growth limitation based on sodium was lower than one of HSA. The integrated system is, therefore, more feasible to treat CO(2) in the flue gases using the algae with higher alkaline affinity such as HSA in small volume bioreactors.

Anomalous decrease in groundwater radon before the Taiwan M6.8 Chengkung earthquake

On December 10, 2003, an earthquake of magnitude (M) 6.8, the strongest since 1951, occurred near the Chengkung area in eastern Taiwan. Approximately 65 d prior to the 2003 Chengkung earthquake, precursory changes in the groundwater radon concentration were observed at the Antung radon-monitoring station located 20 km from the epicenter. The radon anomaly was a decrease from a background level of 28.9 BqL(-1) to a minimum of 12.2 BqL(-1). Observations at the Antung hot spring suggest that the groundwater radon, when observed under suitable geological conditions, can be a sensitive tracer for strain changes in the crust preceding an earthquake.

Characterization of southern Taiwan red soils as a regenerable sorbent for sorption of hydrogen sulfide from coal gas with spectroscopic techniques

The purpose of this research is to use red soils as a high-temperature regenerable sorbent for sorption of hydrogen sulfide from coal gas and collocates with a series of spectroscopic apparatuses in order to investigate the structure changes after multiple sorption/regeneration processes. Results indicate that red soils could be reused after 10 multiple sorption/regeneration cycles and maintain approximately 80% sorption efficiency. With EDS and EA analyses, residual sulfur species are detected in the 10th regenerated red soils and exist with values of 0.6 and 0.33%, respectively. Undesired sulfur species including sulfide, sulfate and elemental sulfur are further identified by XPS spectroscopy. With the best regression fitting results, sulfate species is the dominative sulfur species, which occupies approximately 71% of residual sulfur. It is believed that these residual sulfur species are the major cause to result in red soils' deterioration after regeneration and reduce the sorption efficiency. Appreciable amounts of regeneration gases CO, CO(2) and SO(2) are detected by on-line FTIR spectroscopy. Their formation mechanisms are attributed to the different gas-solid reaction, one is the reaction of carbon and oxygen, and the other is FeS and oxygen. From the analysis of solid-state nuclear magnetic resonance spectroscopy (SSNMR), a significant change for (27)Al and (29)Si and it is established that a portion of aluminum is reformed into pentacoordinated structure. Formation of aluminosilicate is maybe another reason to result in deterioration as a result of the loss of surface area.

Spectroscopic study on sorption of hydrogen sulfide by means of red soil

This paper reports the results of the characterization of red soils in relation to the sorption of H2S from coal gas at 500 degrees C by spectroscopic techniques in order to provide more information on red soils' structural change both before and after reaction. In addition, by-products analysis has also been studied using Fourier transform infrared (FTIR) spectroscopy. Before and after the experiments the red soils were characterized with X-ray powder diffraction (XRPD), energy dispersion spectrum (EDS), X-ray photoelectron spectroscopy (XPS) and FTIR spectroscopy. XRPD results indicate that iron oxide species disappear from the original to reacted red soil. EDS analysis shows that a significant amount of sulfur is present in the reacted red soil, which is in agreement with the results of the elemental analysis and the calculated value based on breakthrough curve. XPS regression fitting results further indicate that sulfur retention may be associated with the iron oxides. S 2p XPS fittings point out that the major sulfur species present in the reacted red soil are composed of S(-2), elemental sulfur, polysulfide, sulfite and sulfate. Additionally, the binding energy of iron shifts to a lower position for the reacted red soil, which indicates that iron oxides in the original red soil have been converted into iron sulfide. Appreciable amounts of the by-products CO2, SO2 and COS are detected by on-line FTIR spectroscopy during the initial and later stages of the sorption process. The formation of CO2 is related to the water-shift reaction, and SO2 is probably attributable to the reaction of organic matters and H2S. The concentration of COS is quantified by GC/FPD and found it to be about 350 ppm, which is close to the equilibrium concentration of the reaction of inlet CO and H2S at a temperature of 500 degrees C.

High temperature removal of hydrogen sulfide using an N-150 sorbent

In this study, an N-150 sorbent was used as a high temperature desulfurization sorbent for the removal of hydrogen sulfide from coal gas in a fixed bed reactor. The results indicate that the N-150 sorbent could be used for H(2)S removal in the tested temperature ranges. Regeneration test also reveals that utilization of the N-150 sorbent maintains up to 85% compared to the fresh sorbent. No significant degeneration occurs on the N-150 sorbent. In addition, various concentrations of H(2)S, H(2) and CO were also considered in the performance test of the N-150 sorbent. Except for H(2)S, H(2) and CO act the important roles in the high temperature desulfurization. By increasing the H(2) concentration, the sulfur capacity of the sorbent decreases and an adverse result is observed in the case of increasing CO concentration. This can be explained via water-shift reaction. On the basis of the instrument analysis, X-ray powder diffraction determination and SEM images with EDS spectrum characterization, residual sulfur is found in the regenerated N-150 sorbent and this sulfur species is sulfate which resulted by incomplete regeneration. The sulfate formation and sintering effect are major reasons to cause activity loss in the sulfidation/regeneration cycles.

One year comparison of costs of coronary surgery versus percutaneous coronary intervention in the stent or surgery trial

OBJECTIVES

To compare initial and one year costs of coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) in the stent or surgery trial.

DESIGN

Prospective, unblinded, randomised trial.

SETTING

Multicentre study.

PATIENTS

988 patients with multivessel disease.

INTERVENTIONS

CABG and stent assisted PCI.

MAIN OUTCOME MEASURES

Initial hospitalisation and one year follow up costs.

RESULTS

At one year mortality was 2.5% in the PCI arm and 0.8% in the CABG arm (p = 0.05). There was no difference in the composite of death or Q wave myocardial infarction (6.9% for PCI v 8.1% for CABG, p = 0.49). There were more repeat revascularisations with PCI (17.2% v 4.2% for CABG). There was no significant difference in utility between arms at six months or at one year. Quality adjusted life years were similar 0.6938 for PCI v 0.6954 for PCI, Delta = 0.00154, 95% confidence interval (CI) -0.0242 to 0.0273). Initial length of stay was longer with CABG (12.2 v 5.4 days with PCI, p < 0.0001) and initial hospitalisation costs were higher (7321 pounds sterling v 3884 pounds sterling for PCI, Delta = 3437 pounds sterling, 95% CI 3040 pounds sterling to 3848 pounds sterling). At one year the cost difference narrowed but costs remained higher for CABG (8905 pounds sterling v 6296 pounds sterling for PCI, Delta = 2609 pounds sterling, 95% CI 1769 pounds sterling to 3314 pounds sterling).

CONCLUSIONS

Over one year, CABG was more expensive and offered greater survival than PCI but little added benefit in terms of quality adjusted life years. The additional cost of CABG can be justified only if it offers continuing benefit at no further increase in cost relative to PCI over several years.

A feasibility study on the predictive emission monitoring system applied to the Hsinta power plant of Taiwan Power Company

The continuous emission monitoring system (CEMS) can monitor flue gas emissions continuously and instantaneously. However, it has the disadvantages of enormous cost, easily producing errors in sampling periods of bad weather, lagging response in variable ambient environments, and missing data in daily zero and span tests and maintenance. The concept of a predictive emission monitoring system (PEMS) is to use the operating parameters of combustion equipment through thermodynamic or statistical methods to construct a mathematic model that can predict emissions by a computer program. The goal of this study is to set up a PEMS in a gas-fired combined cycle power generation unit at the Hsinta station of Taiwan Power Co. The emissions to be monitored include nitrogen oxides (NOx) and oxygen (O2) in flue gas. The major variables of the predictive model were determined based on the combustion theory. The data of these variables then were analyzed to establish a regression model. From the regression results, the influences of these variables are discussed and the predicted values are compared with the CEMS data for accuracy. In addition, according to the cost information, the capital and operation and maintenance costs for a PEMS can be much lower than those for a CEMS.