Spatial Contraction Based on Velocity Variation for Natural Walking in Virtual Reality.

Virtual Reality (VR) offers an immersive 3D digital environment, but enabling natural walking sensations without the constraints of physical space remains a technological challenge. Previous VR locomotion methods, including game controller, teleportation, treadmills, walking-in-place, and redirected walking (RDW), have made strides towards overcoming this challenge. However, these methods also face limitations such as possible unnaturalness, additional hardware requirements, or motion sickness risks. This paper introduces "Spatial Contraction (SC)", an innovative VR locomotion method inspired by the phenomenon of Lorentz contraction in Special Relativity. Similar to the Lorentz contraction, our SC contracts the virtual space along the user's velocity direction in response to velocity variation. The virtual space contracts more when the user's speed is high, whereas minimal or no contraction happens at low speeds. We provide a virtual space transformation method for spatial contraction and optimize the user experience in smoothness and stability. Through SC, VR users can effectively traverse a longer virtual distance with a shorter physical walking. Different from locomotion gains, the spatial contraction effect is observable by the user and aligns with their intentions, so there is no inconsistency between the user's proprioception and visual perception. SC is a general locomotion method that has no special requirements for VR scenes. The experimental results of our live user studies in various virtual scenarios demonstrate that SC has a significant effect in reducing both the number of resets and the physical walking distance users need to cover. Furthermore, experiments have also demonstrated that SC has the potential for integration with existing locomotion techniques such as RDW.

Antibacterial Activity and Mechanism of Polygonatum sibiricum Extract Against Bacillus cereus and Its Application in Pasteurized Milk.

The purpose of this study was to reveal the antibacterial activity and mechanism of Polygonatum sibiricum extract (PSE) against Bacillus cereus and further analyze the application of PSE in pasteurized milk (PM). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values and growth curve analysis were used to evaluate the antibacterial activity of PSE against B. cereus. The changes in contents of intracellular adenosine 5'-triphosphate (ATP) and reactive oxygen species (ROS), activities of ß-galactosidase, adenosine triphosphatase (ATPase) and alkaline phosphatase (AKP), cell membrane potential, protein and nucleic acid leakage, and cell morphology were used to reveal the antibacterial mechanism. The effects of PSE on viable count and sensory evaluation of PM during storage were analyzed. The results showed that the MIC and MBC values of PSE against B. cereus were 2 and 4 mg/mL, respectively. Growth curve analysis showed that PSE with a concentration of 2 MIC could completely inhibit the growth of B. cereus. After treatments with PSE, the levels of intracellular ATP and ROS, and activities of ß-galactosidase, ATPase and AKP of B. cereus were significantly reduced (p < 0.05). Cell membrane was depolarized, amounts of protein and nucleic acid leakage were significantly increased (p < 0.05), and cell morphology was destroyed. Furthermore, PSE significantly reduced the viable count of B. cereus in PM and improved the sensory quality of PM during storage (p < 0.05). Together, our findings suggested that PSE had the desired effect as a natural preservative applied in PM.

Negative pressure wound management in perineal wound status post abdominoperineal resection and extralevator abdominoperineal excision: a meta-analysis and trial sequential analysis.

PURPOSE: Recent evidence-based publications disclosed that negative pressure wound therapy (NPWT) may reduce the incidence rate of surgical site infection (SSI) and length of stay (LOS) compared with conventional drainage in patient status post abdominoperineal resection (APR) and extralevator abdominoperineal excision (ELAPE). METHODS: Data sources: Eligible randomized controlled trials and retrospective and prospective studies published before January 2023 were retrieved from databases (Cochrane Library, PubMed, and Embase). STUDY SELECTION: (a) The study involved patients undergoing ELAPE or APR with postoperative NPWT; (b) the study compared NWPT with conventional drainage and reported at least one outcome of interest (i.e., SSI); and (c) the study provided adequate information to calculate the effect estimated for meta-analysis. INTERVENTIONS: We calculated the odds ratio (ORs) and mean differences (MDs) with 95% confidence intervals (CIs). MAIN OUTCOME MEASURES: The measure outcomes included surgical site infection(SSI) and length of stay (LOS). RESULTS: Eight articles, involving 547 patients, met the selection criteria. Compared to conventional drainage, NPWT was associated with a significantly lower SSI rate (fixed effect, OR 0.29; 95% CI 0.18-0.45; I2 = 0%) in eight studies and 547 patients. Besides, NPWT was associated with a shorter LOS (fixed effect, MD - 2.00; CI - 2.60 to - 1.39; I2 = 0%) than conventional drainage in three studies and 305 patients. In a trial sequential analysis, the cumulative number of patients in the analyses of both outcomes exceeded the required information size and surpassed the significance boundary in favor of NPWT, suggesting conclusive results. CONCLUSION: NPWT is superior to conventional drainage in both SSI rate and LOS, and the statistical power of SSI and LOS are confirmed by trial sequential analysis.

Antibacterial Pattern of Rosa roxburghii Tratt Pomace Crude Extract Against Staphylococcus aureus and Its Application in Preservation of Cooked Beef.

Staphylococcus aureus is a common foodborne pathogen and spoilage bacterium in meat products. To develop a natural preservative for meat products, this study revealed the antibacterial activity and mechanism of Rosa roxburghii Tratt pomace crude extract (RRPCE) against S. aureus, and applied RRPCE to the preservation of cooked beef. The diameter of inhibition zone, minimum inhibitory concentration (MIC), and minimum bactericide concentration of RRPCE against S. aureus were 15.85 ± 0.35 to 16.21 ± 0.29 mm, 1.5 mg/mL, and 3 mg/mL, respectively. The growth curve of S. aureus was completely stalled by treatment with RRPCE at 2 MIC. RRPCE results in the decrease of intracellular adenosine 5'-triphosphate (ATP) content, depolarization of cell membrane, leakage of cell fluid including nucleic acid and protein, and destruction of cell membrane integrity and cell morphology. During storage, RRPCE significantly reduced S. aureus viable counts, pH, and total volatile basic nitrogen of cooked beef compared with untreated samples (p < 0.05). In addition, RRPCE could significantly increase the redness (a*) value, decrease lightness (L*) and yellowness (b*) values, and slow down the color change of cooked beef (p < 0.05). These findings suggest that RRPCE can effectively inhibit S. aureus, and has the potential as a natural preservative for the preservation of cooked beef.

Inferring Bacterial Community Interactions and Functionalities Associated with Osteopenia and Osteoporosis in Taiwanese Postmenopausal Women.

Growing evidence suggests that the gut microbiota and their metabolites are associated with bone homeostasis and fragility. However, this association is limited to microbial taxonomic differences. This study aimed to explore whether gut bacterial community associations, composition, and functions are associated with osteopenia and osteoporosis. We compared the gut bacterial community composition and interactions of healthy postmenopausal women with normal bone density (n = 8) with those of postmenopausal women with osteopenia (n = 18) and osteoporosis (n = 21) through 16S rRNA sequencing coupled with network biology and statistical analyses. The results of this study showed reduced alpha diversity in patients with osteoporosis, followed by that in patients with osteopenia, then in healthy controls. Taxonomic analysis revealed that significantly enriched bacterial genera with higher abundance was observed in patients with osteoporosis and osteopenia than in healthy subjects. Additionally, a co-occurrence network revealed that, compared to healthy controls, bacterial interactions were higher in patients with osteoporosis, followed by those with osteopenia. Further, NetShift analysis showed that a higher number of bacteria drove changes in the microbial community structure of patients with osteoporosis than osteopenia. Correlation analysis revealed that most of these driver bacteria had a significant positive relationship with several significant metabolic pathways. Further, ordination analysis revealed that height and T-score were the primary variables influencing the gut microbial community structure. Taken together, this study evaluated that microbial community interaction is more important than the taxonomic differences in knowing the critical role of gut microbiota in postmenopausal women associated with osteopenia and osteoporosis. Additionally, the significantly enriched bacteria and functional pathways might be potential biomarkers for the prognosis and treatment of postmenopausal women with osteopenia and osteoporosis.

Short-term microbial effects on n-alkane during the early phase degradation and consequential modification of biomarkers in a lowland subtropical rainforest in southern Taiwan: A litterbag experiment.

Accurate reconstructions of past environments are critical and urgent because they can help understand how modern environments might respond to current climatic and land-use changes. However, the effect of microbial degradation and consequential modification in plant-derived-biomarkers during the early degradation phase is not yet apparent, that might bias the paleoenvironmental investigation. In this regard, a litterbag experiment was conducted to reveal the microbial effects on n-alkane-associated biomarker changes associated with three habitats (ravine, windward, and leeward) in a lowland subtropical rainforest in southern Taiwan. Freshly collected leaves of plant species Iles rotunda, Ficus benjamina, and Castanopsis carlesii were distributed in the habitat leaf litterbag experiment for 15 and 75 days incubation, respectively. The results revealed that the average leaf decomposition rate was 19.4% ± 6.4% during the first 15 days and 39% ± 11% within 75 days incubation for all leaves. The overall leaf mass degradation of I. rotunda, F. benjamina and C. carlesii in the ravine after 75 days was 58%, 51% and 41%, respectively, which were higher than those in the windward (28%, 36% and 38%) and leeward habitats (35%, 26% and 42%, respectively) indicating higher decomposition rate in the ravine habitat than the others. The predominant n-alkanes in I. rotunda were C31 and C29, whereas in F. benjamina these were C31, C29, and C33, and in C. carlesii it was C31. After 75 days, the ravine habitat showed a 60% decrease in the total n-alkane concentration compared to windward and leeward habitats, suggesting the microbial community associated with the ravine habitat has a higher efficiency of degrading n-alkanes. However, the biomarkers such as carbon preference index (CPI), average carbon length (ACL) and the C31/C29 ratio did not show statistical difference in all habitats from 15 to 75 days incubation. The next-generation sequencing revealed that microbial communities changed significantly from 15 to 75 days in all habitats. The alkB gene-containing bacteria and their family lineages increased substantially during the first 15 days incubation in all habitats. Furthermore, several bacterial genera were exclusively present in the ravine habitat, whereas some were only in the leeward and windward habitats. Despite the heterogeneity of microbial proliferation, difference in biomass and n-alkane degradation among the three habitats, most of the n-alkane-associated biomarkers remained the same. Therefore, we concluded that the microbial effects on n-alkane degradation during the early phase in plant leaves had little influence on the results of most n-alkane biomarkers.

The Evaluation of Bacterial Abundance and Functional Potentials in the Three Major Watersheds, Located in the Hot Spring Zone of the Tatun Volcano Group Basin, Taiwan.

The Tatun Volcanic Group (TVG), located in northern Taiwan, is characterized by acidic hot springs where the outflow of the hot springs may affect the properties of the associated lotic water bodies. We investigated the bacterial diversity and functional profiles of the Peihuang (PHC), HuangGang (HGC), and Nanhuang Creeks (NHC) located in the TVG basin using 16S rRNA gene sequencing coupled with statistical analyses. Water samples were collected from various streams of the creeks for two months of the year. The NHC showed the highest diversity, richness, and a unique number of phyla, which was followed by the HGC. A reduced number of phyla and a lower diversity was noticed in the PHC. The NHC was found to be abundant in the genera Armatimonas, Prosthecobacter, Pirellula, and Bdellovibrio, whereas the HGC was rich in Thiomonas, Acidiphilium, Prevotella, Acidocella, Acidithiobacillus, and Metallibacterium. The PHC was abundant in Thiomonsa, Legionella, Acidocella, and Sulfuriferula. The samples did not show any strong seasonal variations with the bacterial diversity and abundance; however, the relative abundance of each sampling site varied within the sampling months. The iron transport protein- and the sulfur metabolism-related pathways were predicted to be the key functions in all the creeks, whereas the heavy metal-related functions, such as the cobalt/nickel transport protein and the cobalt-zinc-cadmium efflux system were found to be abundant in the HGC and PHC, respectively. The abundance of Bdellovibrio in the NHC, Diplorickettsia in the HGC, and Legionella in the PHC samples indicated a higher anthropogenic impact over the creek water quality. This study provides the data to understand the distinct bacterial community structure, as well as the functional potentials of the three major watersheds, and helps the knowledge of the impact of the physicochemical properties of the TVG hot springs upon the watersheds.

Assessment of Carbon Substrate Catabolism Pattern and Functional Metabolic Pathway for Microbiota of Limestone Caves.

Carbon utilization of bacterial communities is a key factor of the biomineralization process in limestone-rich curst areas. An efficient carbon catabolism of the microbial community is associated with the availability of carbon sources in such an ecological niche. As cave environments promote oligotrophic (carbon source stress) situations, the present study investigated the variations of different carbon substrate utilization patterns of soil and rock microbial communities between outside and inside cave environments in limestone-rich crust topography by Biolog EcoPlate™ assay and categorized their taxonomical structure and predicted functional metabolic pathways based on 16S rRNA amplicon sequencing. Community level physiological profiling (CLPP) analysis by Biolog EcoPlate™ assay revealed that microbes from outside of the cave were metabolically active and had higher carbon source utilization rate than the microbial community inside the cave. 16S rRNA amplicon sequence analysis demonstrated, among eight predominant bacterial phylum Planctomycetes, Proteobacteria, Cyanobacteria, and Nitrospirae were predominantly associated with outside-cave samples, whereas Acidobacteria, Actinobacteria, Chloroflexi, and Gemmatimonadetes were associated with inside-cave samples. Functional prediction showed bacterial communities both inside and outside of the cave were functionally involved in the metabolism of carbohydrates, amino acids, lipids, xenobiotic compounds, energy metabolism, and environmental information processing. However, the amino acid and carbohydrate metabolic pathways were predominantly linked to the outside-cave samples, while xenobiotic compounds, lipids, other amino acids, and energy metabolism were associated with inside-cave samples. Overall, a positive correlation was observed between Biolog EcoPlate™ assay carbon utilization and the abundance of functional metabolic pathways in this study.

Graphene Quantum Dot Reinforced Electrospun Carbon Nanofiber Fabrics with High Surface Area for Ultrahigh Rate Supercapacitors.

High surface area, good conductivity, and high mechanical strength are important for carbon nanofiber fabrics (CNFs) as high-performance supercapacitor electrodes. However, it remains a big challenge because of the trade-off between the strong and continuous conductive network and a well-developed porous structure. Herein, we report a simple strategy to integrate these properties into the electrospun CNFs by adding graphene quantum dots (GQDs). The uniformly embedded GQDs play a crucial bifunctional role in constructing an entire reinforcing phase and conductive network. Compared with the pure CNF, the GQD-reinforced activated CNF exhibits a greatly enlarged surface area from 140 to 2032 m2 g-1 as well as a significantly improved conductivity and strength of 5.5 and 2.5 times, respectively. The mechanism of the robust reinforcing effect is deeply investigated. As a freestanding supercapacitor electrode, the fabric performs a high capacitance of 335 F g-1 at 1 A g-1 and extremely high capacitance retentions of 77% at 100 A g-1 and 45% at 500 A g-1. Importantly, the symmetric device can be charged to 80% capacitance within only 2.2 s, showing great potential for high-power startup supplies.

Understanding the structural transformation of carbon black from solid spheres to hollow polyhedra during high temperature treatment.

Understanding the structural transformation of carbon black during high temperature treatment and the underlying mechanism are very important because of the correlation with nanocarbon species such as fullerenes and carbon onions. Herein, we find that carbon black nanoparticles exhibit a solid skin-core structure constructed from small graphene flakes. The skin shows a more ordered structure than the core. During heating treatment in an inert atmosphere, the small graphene flakes coalesce together to form large-area lamellae at 1600 °C. Then, the solid spherical nanoparticles completely transform to hollow polyhedra at 1800 °C with significantly improved crystallinity. What's more, the inner cores of carbon black can be removed through simple oxidation in air, demonstrating that the cores are more disordered and reactive than the skin. Accordingly, the structural transformation mechanism is ascribed to well-ordered graphitic shells being preferentially formed by coalescing ordered small graphene flakes in the skin region of carbon black nanoparticles. The multilocular hollow structure is subsequently formed by reconstruction of highly disordered and twisted inner cores in a confined space.

Empirical testing of modified Salmonella MLST in aquatic environmental samples by in silico analysis.

Multilocus sequence typing (MLST) is an approach for prediction of Salmonella servoar and eBRUST groups (eBGs) based on seven typing scheme of housekeeping genes. Up to date, >220.000 allelic profiles and 65,973 Salmonella strains have been established in the MLST database. Several studies have modified MLST method with fewer targeted housekeeping genes for the purpose of economy and efficiency. Nevertheless, no study has conducted systematically to evaluate the correlation between the numbers of housekeeping genes targeted and the accuracy of prediction rate. In this study, we aimed to tackle this problem by extracting data from the MLST database as a whole using the software RStudio. Our results indicated that as the numbers of genes in MLST scheme increased, the accuracy of the eBGs prediction rate increased and reached 100% when the gene numbers are greater than or equal to 5. To examine the applicability of the approach, 395 environmental water samples were subjected to this study. A set of 52 Salmonella enterica isolates was initially used to develop MLST targeting seven housekeeping genes. A total of 29 sequence types, including 11 new sequence types were found among the 52 sequenced isolates that differentiated into 19 serotypes. Moreover, two novel sequence types did not belong to current classification. Our results show that the outcome in the three-gene sequence typing (aroC, hisD, and purE) was as accurate as in the seven-gene sequence typing for prediction of environmental Salmonella isolates. Our data suggested that this five-gene and reduced gene-number sequence-typing scheme can serve as an alternative modified MLST when effectiveness and financial management were the concerns.

Seasonal difference of human adenoviruses in a subtropical river basin based on 1-year monthly survey.

In this study, the seasonal difference and the observable presence/absence of human adenovirus (HAdV) in the Puzih River basin in Taiwan was investigated. A total of 288 water samples were collected from 24 sites from March 2014 to February 2015. Human AdV analysis of sample was subjected to viral concentration using a GN-6 Metricel® filter, followed by DNA extraction, nested-PCR, and qPCR. Human AdV was detected in 34.3 % (99/288) of the entire river water sample. A higher percentage of HAdV (76.4 %) was obtained during the winter. The HAdV median concentration was relatively high in fall (1.4 × 10(3) copies/L) and winter (2.8 × 10(3) copies/L). Significant difference and correlation were found between the seasonal variation of HAdV and water quality parameters, including heterotrophic plate count, total coliform, water temperature, and turbidity. The most frequently identified HAdV (subgenus F) serotype was 41. Human AdV-41 is the main cause of gastroenteritis and should be considered for associated human health risk potential in the Puzih River basin.

Surveillance of parasitic Legionella in surface waters by using immunomagnetic separation and amoebae enrichment.

Free-living amoebae (FLA) are potential reservoirs of Legionella in aquatic environments. However, the parasitic relationship between various Legionella and amoebae remains unclear. In this study, surface water samples were gathered from two rivers for evaluating parasitic Legionella. Warmer water temperature is critical to the existence of Legionella. This result suggests that amoebae may be helpful in maintaining Legionella in natural environments because warmer temperatures could enhance parasitisation of Legionella in amoebae. We next used immunomagnetic separation (IMS) to identify extracellular Legionella and remove most free Legionella before detecting the parasitic ones in selectively enriched amoebae. Legionella pneumophila was detected in all the approaches, confirming that the pathogen is a facultative amoebae parasite. By contrast, two obligate amoebae parasites, Legionella-like amoebal pathogens (LLAPs) 8 and 9, were detected only in enriched amoebae. However, several uncultured Legionella were detected only in the extracellular samples. Because the presence of potential hosts, namely Vermamoeba vermiformis, Acanthamoeba spp. and Naegleria gruberi, was confirmed in the samples that contained intracellular Legionella, uncultured Legionella may survive independently of amoebae. Immunomagnetic separation and amoebae enrichment may have referential value for detecting parasitic Legionella in surface waters.

Assessment of Legionella pneumophila in recreational spring water with quantitative PCR (Taqman) assay.

Legionella spp. are common in various natural and man-made aquatic environments. Recreational hot spring is frequently reported as an infection hotspot because of various factors such as temperature and humidity. Although polymerase chain reaction (PCR) had been used for detecting Legionella, several inhibitors such as humic substances, calcium, and melanin in the recreational spring water may interfere with the reaction thus resulting in risk underestimation. The purpose of this study was to compare the efficiencies of conventional and Taqman quantitative PCR (qPCR) on detecting Legionella pneumophila in spring facilities and in receiving water. In the results, Taqman PCR had much better efficiency on specifying the pathogen in both river and spring samples. L. pneumophila was detected in all of the 27 river water samples and 45 of the 48 hot spring water samples. The estimated L. pneumophela concentrations ranged between 1.0 × 10(2) and 3.3 × 10(5) cells/l in river water and 72.1-5.7 × 10(6) cells/l in hot spring water. Total coliforms and turbidity were significantly correlated with concentrations of L. pneumophila in positive water samples. Significant difference was also found in water temperature between the presence/absence of L. pneumophila. Our results suggest that conventional PCR may be not enough for detecting L. pneumophila particularly in the aquatic environments full of reaction inhibitors.

Evaluation of diarrheagenic E. coli in riversheds by quantitative PCR in combination with enrichment.

Diarrheagenic Escherichia coli (DEC) is a group of the most common agents of diarrhea. Highly virulent DEC strains could cause illness with dozens of organisms. Waterborne DEC may be detected using polymerase chain reaction (PCR); however, environmental contaminants can interfere with PCR reaction, thus causing the prevalence of DEC to be underestimated. In this study, we propose an approach to efficiently quantify trace amounts of DEC. An enrichment procedure was performed to amplify total E. coli including DEC in the water samples. By normalizing the number of pathotype-specific genes to the amplification rate of a housekeeping gene in all E. coli, the quantity of DEC in original samples could be assessed. This method allows detection of trace amounts of DEC in receiving waters. The results showed that the presence of DEC in water samples was partially associated with riverside settlement. The DEC concentration was substantially higher at a few sampling sites, suggesting that evaluation of DEC along the river may help identify previously unknown pollution sources. Although the sustainability of DEC in the receiving waters may be low, the risk of DEC infection from the watershed warrants further examination.

Evaluation of immunomagnetic separation for the detection of Salmonella in surface waters by polymerase chain reaction.

Salmonella spp. is associated with fecal pollution and capable of surviving for long periods in aquatic environments. Instead of the traditional, time-consuming biochemical detection, polymerase chain reaction (PCR) allows rapid identification of Salmonella directly concentrated from water samples. However, prevalence of Salmonella may be underestimated because of the vulnerability of PCR to various environmental chemicals like humic acid, compounded by the fact that various DNA polymerases have different susceptibility to humic acid. Because immunomagnetic separation (IMS) theoretically could isolate Salmonella from other microbes and facilitate removal of aquatic PCR inhibitors of different sizes, this study aims to compare the efficiency of conventional PCR combined with immunomagnetic separation (IMS) for Salmonella detection within a moderately polluted watershed. In our study, the positive rate was increased from 17.6% to 47% with nearly ten-fold improvement in the detection limit. These results suggest the sensitivity of Salmonella detection could be enhanced by IMS, particularly in low quality surface waters. Due to its effects on clearance of aquatic pollutants, IMS may be suitable for most DNA polymerases for Salmonella detection.

Surveillance and evaluation of the infection risk of free-living amoebae and Legionella in different aquatic environments.

Free-living amoebae (FLA) are ubiquitous in various aquatic environments. Several amoebae species are pathogenic and host other pathogens such as Legionella, but the presence of FLA and its parasites as well as the related infection risk are not well known. In this study, the presence of pathogenic FLA and Legionella in various water bodies was investigated. Water samples were collected from a river, intake areas of drinking water treatment plants, and recreational hot spring complexes in central and southern Taiwan. A total of 140 water samples were tested for the presence of Acanthamoeba spp., Naegleria spp., Vermamoeba vermiformis, and Legionella. In addition, phylogenetic characteristics and water quality parameters were also assessed. The pathogenic genotypes of FLA included Acanthamoeba T4 and Naegleria australiensis, and both were abundant in the hot spring water. In contrast, Legionella pneumophila was detected in different aquatic environments. Among the FLA assessed, V. vermiformis was most likely to coexist with Legionella spp. The total bacteria level was associated with the presence of FLA and Legionella especially in hot spring water. Taken together, FLA contamination in recreational hot springs and drinking water source warrants more attention on potential legionellosis and amoebae infections.

Application of TaqMan qPCR for the detection and monitoring of Naegleria species in reservoirs used as a source for drinking water.

Naegleria spp. can be found in the natural aquatic environments. Naegleria fowleri can cause fatal infections in the central nervous system in humans and animals, and the most important source of infection is through direct water contact. In this study, PCR of 5.8S ribosomal RNA (rRNA) gene and internal transcribed spacer (ITS) region was performed in order to identify Naegleria isolates and quantify the Naegleria spp. by TaqMan real-time quantitative PCR in reservoir water samples. The occurrence of Naegleria spp. was investigated in 57 water samples from reservoirs with culture and PCR positive in 2 of them (3.5%), respectively. The total detection rate was 7.0% (4/ 57) for Naegleria spp. The identified species included Naegleria spp., Naegleria canariensis, and Naegleria clarki. N. fowleri was not found in Taiwan's reservoirs used for drinking purposes. The concentrations of Naegleria spp. in detected positive reservoir water samples were in the range of 599 and 3.1 × 10(3) cells/L. The presence or absence of Naegleria spp. within the reservoir water samples showed significant difference with the levels of water temperature. The presence of Naegleria spp. in reservoirs considered a potential public health threat if pathogenic species exist in reservoirs.

Evaluation of remediation process with soapberry derived saponin for removal of heavy metals from contaminated soils in Hai-Pu, Taiwan.

The use of a biodegradable natural plant-based surfactant extracted from soapberry is proposed for the remediation of Ni, Cr and Mn from industrial soil site in Hai-Pu, Taiwan. Batch experiments were performed under variation of fundamental factors (saponin concentration, pH, and incubation time) for metal remediation. Removal of Ni and Mn were increased with increasing saponin concentration (0.015-0.150 g/L), whereas the removal of Cr was increased upto 0.075 g/L saponin. The Ni, Cr and Mn were removed significantly (p < or = 0.05) at near to the neutral and slightly acidic (pH 5 to 8) conditions. Removal efficiency of Ni (99%) from the soil was found to be greater than that of Cr (73%) or Mn (25%) in the presence of saponin at a concentration of 0.150 g/L at pH 5. The removal percentage increased with incubation time where the removal of Ni was faster than that of Cr and Mn. The result indicates the feasibility of eco-friendly removal of heavy metal (Ni, Cr and Mn) from industrial soil by soil washing process in presence of plant derived saponin.