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Limited knowledge of fucoxanthin's changes during digestion necessitates comprehensive investigation to ensure its efficacy as a functional ingredient. This study assessed the effects of digestion on fucoxanthin's bioaccessibility, antioxidant activity, colour changes, and metabolite formation through in vitro gastrointestinal digestion. Results indicated the highest bioaccessibility during gastric digestion (0.03 ± 0.00 mg/mL), followed by intestinal and mouth with 0.012 ± 0.00 and 0.011 ± 0.13 mg/mL, respectively. Antioxidant activity was the highest at the gastric stage, with significant activity persisting post-digestion (P < 0.05). Colour changes were significant, with total colour differences (∆E*) of 2.40, 2.86, and 2.76 at the mouth, gastric, and intestinal stages, respectively. LC-MS/MS-based metabolomics analysis revealed 15 key metabolites, with carboxylic acids as major metabolites during gastric and intestinal stages. Pearson correlation analysis demonstrated a significant correlation between identified metabolites with bioaccessibility, antioxidant activity, and colour changes, underscoring fucoxanthin's potential as a promising functional food ingredient., Competing Interests: Declaration of competing interest The authors report no commercial or proprietary interest in any product or concept discussed in this article., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The present study evaluated the effects of temperature, pH, light and chemical oxidation on fucoxanthin changes in terms of colour, antioxidant activity and metabolomic profile. Additionally, the correlation between antioxidant activity and identified metabolites was analysed., Results: It was found that colour change was significantly reduced at elevated heat (100 °C, *∆E = 0.81 ± 0.05), reduced pH (pH 3, *∆E = 0.59 ± 0.04) and length of light exposure (*∆E = 3.16 ± 0.04). Antioxidant activity decreased under all treatments. Among the temperatures tested, fucoxanthin exhibited the highest activity at 60 °C, ranging from 0.92 to 3.04 mg Trolox equivalents (TE) g -1 . Significant activity reductions (P < 0.05) were observed as a result of pH changes in the 2,2-diphenyl-1-picrylhydrazyl and β-carotene bleaching assays. Exposure to light 2: warm white lamp for 120 h significantly reduced antioxidant activity (0.01 to 1.70 mg TE g -1 ). Chemical oxidation also led to reduced activity, ranging from 0.18 to 0.29 mg TE g -1 . Multivariate data analysis revealed distinct profiles for temperature, pH, light and chemical oxidation treatments. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolomics analysis identified 10 metabolites, and significant correlations (P < 0.05) indicate that these metabolites contributed to the samples' antioxidant activities., Conclusion: In conclusion, fucoxanthin tolerates well at 60 °C, within pH range 3-9, and within 8 h of light exposure, as indicated by its consistent antioxidant activity and minimal colour change. Each treatment resulted in distinct metabolite concentrations, as shown by LC-MS/MS-based metabolomics analysis. Further research into these metabolites could advance the understanding of their roles and aid in optimising processing conditions to favour beneficial metabolites. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Microalgae are photoautotrophic organisms in freshwater systems known to uptake and bioremediate arsenic, a heavy metal. In this study, we compared the growth and arsenic uptake of two microalgae strains, Nostoc and Chlorella , to determine their suitability for arsenic bioremediation. As compared to the control, our results showed that treatment with As (III) enhanced the Nostoc growth by approximately 15% when grown in the absence of phosphate. The highest bioconcentration factor of Nostoc at this treatment was 1463.6, whereas 0.10 mg L -1 As (V) treatment improved the Chlorella growth by 25%, in the presence of phosphate. However, arsenic uptake reduced from 175.7 to 32.3 throughout the cultivation period for Chlorella . This suggests that Nostoc has an upper advantage in the bioremediation of arsenic as compared to the Chlorella strain. To gain insights into the potential of Nostoc in arsenic bioremediation, we further conducted SEM analysis on the vegetative cell surface. The SEM results showed that As (III) disrupted the Nostoc vegetative cell surface and structure. Further to this, pathway analysis and polymerase chain reaction (PCR) were conducted to identify the potential arsenic pathway regulated by Nostoc . The primary As (III)-related pathways elucidated include the arsA transporter and arsD complex that require ATP and As (III) methylation to S -adenosylmethionine. The phosphate deficiency condition resulting in the inability to generate ATP caused As (III) could not be excreted from the Nostoc cells, potentially contributing to the high arsenic concentration accumulated under phosphate-depleted conditions. These insights contribute to understanding the efficacy of microalgae strains in freshwater arsenic bioremediation., Competing Interests: Declarations Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors report no commercial or proprietary interest in any product or concept discussed in this article., (© The Author(s) 2024.)

Microalgae's exceptional photosynthetic prowess, CO 2 adaptation, and high-value bioproduct accumulation make them prime candidates for microorganism-based biorefineries. However, most microalgae research emphasizes downstream processes and applications rather than fundamental biomass and biochemical balances and kinetic under the influence of greenhouse gases such as CO 2 . Therefore, three distinctly different microalgae species were cultivated under 0% to 20% CO 2 treatments to examine their biochemical responses, biomass production and metabolite accumulations. Using a machine learning approach, it was found that Chlorella sorokiniana showed a positive relationship between biomass and chl a, chl b, carotenoids, and carbohydrates under increasing CO 2 treatments, while Chlamydomonas angulosa too displayed positive relationships between biomass and all studied biochemical contents, with minimal trade-offs. Meanwhile, Nostoc sp. exhibited a negative correlation between biomass and lipid contents under increasing CO 2 treatment. The study showed the potential of Chlorella, Chlamydomonas and Nostoc for commercialization in biorefineries and carbon capture systems where their trade-offs were identified for different CO 2 treatments and could be prioritized based on commercial objectives. This study highlighted the importance of understanding trade-offs between biomass production and biochemical yields for informed decision-making in microalgae cultivation, in the direction of mass carbon capture for climate change mitigation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Cyanobacteria bioactive compounds are chemical treasure troves for product discovery and development. The wound healing effects and antioxidant capacities of water extracts from Nostoc NIES-2111&#95;MUM004 were evaluated via in vitro wound scratch assay and three antioxidant assays respectively. Results showed that the water extracts were protein-rich and exhibited good antioxidant properties in ABTS radical scavenging (11.27 ± 0.205 mg TAE g -1 extract), Ferric reducing antioxidant power (1652.71 ± 110.71 mg TAE g -1 extract) and β-carotene bleaching assay (354.90 ± 31.80 mg TAE g -1 extract). Also, extracts were non-cytotoxic in concentrations up to 250 µg/mL as reflected in cytotoxicity assay. Importantly, water extracts showed considerable proliferation and migration activity at 125 µg/mL with wound closure rate as high as 42.67%. Statistical correlation revealed no significant relationship ( p  > 0.05) between protein fraction and the wound healing properties, confirming that phycobiliproteins were not solely responsible for wound healing activities. Subsequent Q-TOF-LCMS analysis identified six protein families involved in enhancing the proliferation and migration of epithelial cells. These findings are antecedent in the uncovering of continuous supplies of bioactive compounds from new and sustainable sources. Ultimately, enriching the microalgae menu for applications in pharmaceutical, nutraceutical and cosmeceuticals., Competing Interests: Conflict of interestThe authors declare that they have no known competing financial interests or personal relationships and report no commercial or proprietary interest in any product or concept that could have appeared to influence the work reported in this paper., (© The Author(s) 2023.)

Marine carotenoids, particularly fucoxanthin, are emerging in the food value chain and gaining traction for their role in delivering health benefits. Unfortunately, the very feature of fucoxanthin which confers its bioactivities also renders it unstable. It is imperative to have a better understanding on the mechanisms involved to mitigate undesirable losses. This paper presented a review on fucoxanthin bioactivities, stability, and opportunities along the value chain specifically during processing, storage, and transportation conditions. For bioactivities, fucoxanthin demonstrated antioxidant, anti-inflammatory, anti-cancer, anti-obese, antidiabetic as well as skin protective activities. Conditions such as low pH (pH 2 to 4), high temperature (beyond 100 °C), presence of light (light intensity of 6.9 to 42 µmol/m 2 /s) and continuous air exposure caused fucoxanthin instability which lead to its degradation. This review acts as an antecedent by providing insights and enabling informed decisions for managing unaccounted risks within the carotenoid value chains to minimize losses., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Electropermeabilization-assisted liquid biphasic flotation (LBF) system is an emerging extraction system facilitated by the adsorptive bubble separation and the electroporation in an aqueous two-phase medium. This integrative extraction system is well suited for the direct recovery of intracellular biocompounds from cells without the needs of discrete steps of mid- or down-stream bioprocessing. The potential of electropermeabilization-assisted LBF system in bioseparation was demonstrated in this study by using the diatom Chaetoceros calcitrans (C. calcitrans) as the source of fucoxanthin, which is a promising antioxidant highly demanded by food and pharmaceutical industries. The extraction performances of LBF and electropermeabilization-assisted LBF system were comprehensively evaluated under the optimal operating conditions. Comparatively, the optimized LBF and electropermeabilization-assisted LBF systems achieved the satisfactory yields of fucoxanthin, i.e., 14.78 mg/g and 16.09 mg/g, respectively. The good recovery of fucoxanthin using electropermeabilization-assisted LBF system could be attributed to the higher release of fucoxanthin from the electrotreated C. calcitrans, allowing a higher partition of fucoxanthin to the top phase of LBF system (236.72 as compared to 152.15 from LBF system). In addition, the fucoxanthin extracted suing both methods exhibit satisfactory antioxidant activities. The application of electropermeabilization-assisted LBF system in the extraction of fucoxanthin is a greener and highly efficient bioprocessing route which can be prospectively extended to other biocompound extraction from microalgal sources., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objectives: This study profiled the prevalence of extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-EC) in the community and compared their resistome and genomic profiles with isolates from clinical patients through whole-genome sequencing., Methods: Fecal samples from 233 community dwellers from Segamat, a town in southern Malaysia, were obtained between May through August 2018. Putative ESBL strains were screened and tested using antibiotic susceptibility tests. Additionally, eight clinical ESBL-EC were obtained from a hospital in the same district between June through October 2020. Whole-genome sequencing was then conducted on selected ESBL-EC from both settings (n = 40) for pan-genome comparison, cluster analysis, and resistome profiling., Results: A mean ESBL-EC carriage rate of 17.82% (95% CI: 10.48%- 24.11%) was observed in the community and was consistent across demographic factors. Whole-genome sequences of the ESBL-EC (n = 40) enabled the detection of multiple plasmid replicon groups (n = 28), resistance genes (n = 34) and virulence factors (n = 335), with no significant difference in the number of genes carried between the community and clinical isolates (plasmid replicon groups, p = 0.13; resistance genes, p = 0.47; virulence factors, p = 0.94). Virulence gene marker analysis detected the presence of extraintestinal pathogenic E. coli (ExPEC), uropathogenic E. coli (UPEC), and enteroaggregative E. coli (EAEC) in both the community and clinical isolates. Multiple blaCTX-M variants were observed, dominated by blaCTX-M-27 (n = 12), blaCTX-M-65 (n = 10), and blaCTX-M-15 (n = 9). The clinical and community isolates did not cluster together based on the pan-genome comparison, suggesting isolates from the two settings were clonally unrelated. However, cluster analysis based on carried plasmids, resistance genes and phenotypic susceptibility profiles identified four distinct clusters, with similar patterns between the community and clinical isolates., Conclusion: ESBL-EC from the clinical and community settings shared similar resistome profiles, suggesting the frequent exchange of genetic materials through horizontal gene transfer., Competing Interests: The authors have declared that no competing interests exist.

Carbon capture and storage (CCS) via microalgae cultivations is getting renewed interest as climate change mitigation effort, owing to its excellent photosynthetic and CO 2 fixation capability. Microalgae growth is monitored based on their biomass, cell concentrations and cell sizes. The key parametric relationships on microalgae growth under CO 2 are absent in previous studies and this inadequacy hampers the design and scale-up of microalgae-based CCS. In this study, three representative microalgae species, Chlorella, Nostoc and Chlamydomonas, were investigated for establishing key correlations of cell concentrations and sizes towards their biomass fluctuations under CO 2 influences of 0% to 20% volume ratios (v/v). This revealed that Chlorella and Chlamydomonas cell concentrations significantly contributed towards increasing biomass concentration under CO 2 elevations. Chlorella and Nostoc cell sizes were enhanced at 20% (v/v). These findings provided new perspectives on growth responses under increasing CO 2 treatment, opening new avenues on CCS schemes engineering designs and biochemical production., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Understanding broadly neutralizing sarbecovirus antibody responses is key to developing countermeasures against SARS-CoV-2 variants and future zoonotic sarbecoviruses. We describe the isolation and characterization of a human monoclonal antibody, designated S2K146, that broadly neutralizes viruses belonging to SARS-CoV- and SARS-CoV-2-related sarbecovirus clades which use ACE2 as an entry receptor. Structural and functional studies show that most of the virus residues that directly bind S2K146 are also involved in binding to ACE2. This allows the antibody to potently inhibit receptor attachment. S2K146 protects against SARS-CoV-2 Beta challenge in hamsters and viral passaging experiments reveal a high barrier for emergence of escape mutants, making it a good candidate for clinical development. The conserved ACE2-binding residues present a site of vulnerability that might be leveraged for developing vaccines eliciting broad sarbecovirus immunity.

In this study, a series of 10 quinoline analogues was evaluated for their in vitro antiviral activity against a panel of alpha- and beta-coronaviruses, including the severe acute respiratory syndrome coronaviruses 1 and 2 (SARS-CoV-1 and SARS-CoV-2), as well as the human coronaviruses (HCoV) 229E and OC43. Chloroquine and hydroxychloroquine were the most potent with antiviral EC 50 values in the range of 0.12-12 μM. Chloroquine displayed the most favorable selectivity index (i.e. ratio cytotoxic versus antiviral concentration), being 165 for HCoV-OC43 in HEL cells. Potent anti-coronavirus activity was also observed with amodiaquine, ferroquine and mefloquine, although this was associated with substantial cytotoxicity for mefloquine. Primaquine, quinidine, quinine and tafenoquine only blocked coronavirus replication at higher concentrations, while piperaquine completely lacked antiviral and cytotoxic effects. A time-of-addition experiment in HCoV-229E-infected HEL cells revealed that chloroquine interferes with viral entry at a post-attachment stage. Using confocal microscopy, no viral RNA synthesis could be detected upon treatment of SARS-CoV-2-infected cells with chloroquine. The inhibition of SARS-CoV-2 replication by chloroquine and hydroxychloroquine coincided with an inhibitory effect on the autophagy pathway as visualized by a dose-dependent increase in LC3-positive puncta. The latter effect was less pronounced or even absent with the other quinolines. In summary, we showed that several quinoline analogues, including chloroquine, hydroxychloroquine, amodiaquine, ferroquine and mefloquine, exhibit broad anti-coronavirus activity in vitro., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The recent emergence of SARS-CoV-2 variants of concern 1-10 and the recurrent spillovers of coronaviruses 11,12 into the human population highlight the need for broadly neutralizing antibodies that are not affected by the ongoing antigenic drift and that can prevent or treat future zoonotic infections. Here we describe a human monoclonal antibody designated S2X259, which recognizes a highly conserved cryptic epitope of the receptor-binding domain and cross-reacts with spikes from all clades of sarbecovirus. S2X259 broadly neutralizes spike-mediated cell entry of SARS-CoV-2, including variants of concern (B.1.1.7, B.1.351, P.1, and B.1.427/B.1.429), as well as a wide spectrum of human and potentially zoonotic sarbecoviruses through inhibition of angiotensin-converting enzyme 2 (ACE2) binding to the receptor-binding domain. Furthermore, deep-mutational scanning and in vitro escape selection experiments demonstrate that S2X259 possesses an escape profile that is limited to a single substitution, G504D. We show that prophylactic and therapeutic administration of S2X259 protects Syrian hamsters (Mesocricetus auratus) against challenge with the prototypic SARS-CoV-2 and the B.1.351 variant of concern, which suggests that this monoclonal antibody is a promising candidate for the prevention and treatment of emergent variants and zoonotic infections. Our data reveal a key antigenic site that is targeted by broadly neutralizing antibodies and will guide the design of vaccines that are effective against all sarbecoviruses., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

An ideal therapeutic anti-SARS-CoV-2 antibody would resist viral escape 1-3 , have activity against diverse sarbecoviruses 4-7 , and be highly protective through viral neutralization 8-11 and effector functions 12,13 . Understanding how these properties relate to each other and vary across epitopes would aid the development of therapeutic antibodies and guide vaccine design. Here we comprehensively characterize escape, breadth and potency across a panel of SARS-CoV-2 antibodies targeting the receptor-binding domain (RBD). Despite a trade-off between in vitro neutralization potency and breadth of sarbecovirus binding, we identify neutralizing antibodies with exceptional sarbecovirus breadth and a corresponding resistance to SARS-CoV-2 escape. One of these antibodies, S2H97, binds with high affinity across all sarbecovirus clades to a cryptic epitope and prophylactically protects hamsters from viral challenge. Antibodies that target the angiotensin-converting enzyme 2 (ACE2) receptor-binding motif (RBM) typically have poor breadth and are readily escaped by mutations despite high neutralization potency. Nevertheless, we also characterize a potent RBM antibody (S2E12 8 ) with breadth across sarbecoviruses related to SARS-CoV-2 and a high barrier to viral escape. These data highlight principles underlying variation in escape, breadth and potency among antibodies that target the RBD, and identify epitopes and features to prioritize for therapeutic development against the current and potential future pandemics., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Ethnicity is consistently reported as a strong determinant of human gut microbiota. However, the bulk of these studies are from Western countries, where microbiota variations are mainly driven by relatively recent migration events. Malaysia is a multicultural society, but differences in gut microbiota persist across ethnicities. We hypothesized that migrant ethnic groups continue to share fundamental gut traits with the population in the country of origin due to shared cultural practices despite subsequent geographical separation. To test this hypothesis, the 16S rRNA gene amplicons from 16 studies comprising three major ethnic groups in Malaysia were analysed, covering 636 Chinese, 248 Indian and 123 Malay individuals from four countries (China, India, Indonesia and Malaysia). A confounder-adjusted permutational multivariate analysis of variance (PERMANOVA) detected a significant association between ethnicity and the gut microbiota (PERMANOVA R 2 =0.005, pseudo- F =2.643, P =0.001). A sparse partial least squares - discriminant analysis model trained using the gut microbiota of individuals from China, India and Indonesia (representation of Chinese, Indian and Malay ethnic group, respectively) showed a better-than-random performance in classifying Malaysian of Chinese descent, although the performance for Indian and Malay were modest (true prediction rate, Chinese=0.60, Indian=0.49, Malay=0.44). Separately, differential abundance analysis singled out Ligilactobacillus as being elevated in Indians. We postulate that despite the strong influence of geographical factors on the gut microbiota, cultural similarity due to a shared ethnic origin drives the presence of a shared gut microbiota composition. The interplay of these factors will likely depend on the circumstances of particular groups of migrants.

Antimicrobial resistance (AMR) in bacteria is a global health crisis due to the rapid emergence of multidrug-resistant bacteria and the lengthy development of new antimicrobials. In light of this, artificial intelligence in the form of machine learning has been viewed as a potential counter to delay the spread of AMR. With the aid of AI, there are possibilities to predict and identify AMR in bacteria efficiently. Furthermore, a combination of machine learning algorithms and lab testing can help to accelerate the process of discovering new antimicrobials. To date, many machine learning algorithms for antimicrobial-resistance discovery had been created and vigorously validated. Most of these algorithms produced accurate results and outperformed the traditional methods which relied on sequence comparison within a database. This mini-review will provide an updated overview of antimicrobial design workflow using the latest machine-learning antimicrobial discovery algorithms in the last 5 years. With this review, we hope to improve upon the current AMR identification and antimicrobial development techniques by introducing the use of AI into the mix, including how the algorithms could be made more effective.

The SARS-CoV-2 spike (S) glycoprotein contains an immunodominant receptor-binding domain (RBD) targeted by most neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite (designated site i) recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge, albeit selecting escape mutants in some animals. Indeed, several SARS-CoV-2 variants, including the B.1.1.7, B.1.351, and P.1 lineages, harbor frequent mutations within the NTD supersite, suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs for protective immunity and vaccine design., Competing Interests: Declaration of interests A.D.M., F.A.L., D.P., M.B., F.Z., J.d.I., M.M.-R., J.Z., L.E.R., S.B., B.G., C.S.F., F.B., E.C., G.S., A.T., H.W.V., D.C., and M.S.P. are employees of Vir Biotechnology Inc. and may hold shares in Vir Biotechnology Inc. D.C. is currently listed as an inventor on multiple patent applications, which disclose the subject matter described in this manuscript. The Neyts laboratories have received sponsored research agreements from Vir Biotechnology Inc. H.W.V. is a founder of PierianDx and Casma Therapeutics. Neither company provided funding for this work or is performing related work. D.V. is a consultant for Vir Biotechnology Inc. The Veesler laboratory has received a sponsored research agreement from Vir Biotechnology Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Ionic liquids (ILs) have emerged as an alternative solvent used in the bioprocessing of microalgae for recovery of valuable biomolecules. The aim of this work is to extract fucoxanthin from Chaetoceros calcitrants (C. calcitrans) by using the readily distillable CO 2 -based alkyl carbamate ILs. The degree of cell permeabilization was analysed by the quantification of extracted fucoxanthin and the analyses of cell surface morphology. Among the tested CO 2 -based alkyl carbamate ILs, diallylammonium diallylcarbamate (DACARB) extraction system gave the maximal yield of fucoxanthin at 17.51 mg/g under the optimal extraction conditions [90% (v/v), 3 min and 25 °C]. Moreover, the extracted fucoxanthin fraction exhibited the satisfactory antioxidant activities. The recyclability of DACARB was demonstrated in the multiple batches of fucoxanthin extraction. Hence, CO 2 -based alkyl carbamate ILs can prospectively substitute conventional organic solvents in the downstream processing of bioactive compounds from microalgae., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

No studies have investigated the influence of ethnicity in a multi-ethnic middle-income country with a long-standing history of co-habitation. Stool samples from 214 Malaysian community members (46 Malay, 65 Chinese, 49 Indian, and 54 Jakun) were collected. The gut microbiota of the participants was investigated using 16S amplicon sequencing. Ethnicity exhibited the largest effect size across participants (PERMANOVA Pseudo-F = 4.24, R 2  = 0.06, p = 0.001). Notably, the influence of ethnicity on the gut microbiota was retained even after controlling for all demographic, dietary factors and other covariates which were significantly associated with the gut microbiome (PERMANOVA Pseudo-F = 1.67, R 2  = 0.02, p = 0.002). Our result suggested that lifestyle, dietary, and uncharacterized differences collectively drive the gut microbiota variation across ethnicity, making ethnicity a reliable proxy for both identified and unidentified lifestyle and dietary variation across ethnic groups from the same community.

The ever-expanding human population puts tremendous pressure on global food security. With climate change threats lowering crop productivity and food nutritional quality, it is important to search for alternative and sustainable food sources. Microalgae are a promising carbon-neutral biomass with fast growth rate and do not compete with terrestrial crops for land use. More so, microalgae synthesize exclusive marine carotenoids shown to not only exert antioxidant activities but also anti-cancer properties. Unfortunately, the conventional method for fucoxanthin extraction is mainly based on solvent extraction, which is cheap but less environmentally friendly. With the emergence of greener extraction techniques, the extraction of fucoxanthin could adopt these strategies aligned to UN Sustainable Development Goals (SDGs). This is a timely review with a focus on existing fucoxanthin extraction processes, complemented with future outlook on the potential and limitations in alternative fucoxanthin extraction technologies. This review will serve as an important guide to the sustainable and environmentally friendly extraction of fucoxanthin and other carotenoids including but not limited to astaxanthin, lutein or zeaxanthin. This is aligned to the SDGs wherein it is envisaged that this review becomes an antecedent to further research work in extract standardization with the goal of meeting quality control and quality assurance benchmarks for future commercialization purposes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Foo, Khoo, Ooi, Show, Khong and Yusoff.)

Efficient therapeutic options are needed to control the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has caused more than 922,000 fatalities as of 13 September 2020. We report the isolation and characterization of two ultrapotent SARS-CoV-2 human neutralizing antibodies (S2E12 and S2M11) that protect hamsters against SARS-CoV-2 challenge. Cryo-electron microscopy structures show that S2E12 and S2M11 competitively block angiotensin-converting enzyme 2 (ACE2) attachment and that S2M11 also locks the spike in a closed conformation by recognition of a quaternary epitope spanning two adjacent receptor-binding domains. Antibody cocktails that include S2M11, S2E12, or the previously identified S309 antibody broadly neutralize a panel of circulating SARS-CoV-2 isolates and activate effector functions. Our results pave the way to implement antibody cocktails for prophylaxis or therapy, circumventing or limiting the emergence of viral escape mutants., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

The application of hydrogen peroxide (H 2 O 2 ) as a management tool to control Microcystis blooms has become increasingly popular due to its short lifetime and targeted action. H 2 O 2 increases intracellular reactive oxygen species resulting in oxidative stress and subsequently cell death. H 2 O 2 is naturally produced in freshwater bodies as a result of photocatalytic reactions between dissolved organic carbon and sunlight. Previously, some studies have suggested that this environmental source of H 2 O 2 selectively targets for toxigenic cyanobacteria strains in the genus Microcystis. Also, past studies only focused on the morphological and biochemical changes of H 2 O 2 -induced cell death in Microcystis with little information available on the effects of different H 2 O 2 concentrations on growth, esterase activity and membrane integrity. Therefore, this study investigated the effects of non-lethal (40-4000 nM) concentrations on percentage cell death; with a focus on sub-lethal (50 μM) and lethal (275 μM; 500 μM) doses of H 2 O 2 on growth, cells showing esterase activity and membrane integrity. The non-lethal dose experiment was part of a preliminary study. Results showed a dose- and time-dependent relationship in all three Microcystis strains post H 2 O 2 treatment. H 2 O 2 resulted in a significant increase in intracellular reactive oxygen species, decreased chlorophyll a content, decreased growth rate and esterase activity. Interestingly, at sub-lethal (50 μM H 2 O 2 treatment), percentage of dead cells in microcystin-producing strains was significantly higher (p < 0.05) than that in non-microcystin-producing strains at 72 h. These findings further cement our understanding of the influence of H 2 O 2 on different strains of Microcystis and its impact on membrane integrity and metabolic physiology: important to future toxic bloom control programmes.

Urbanization has caused an increase in favorable habitats for Aedes aegypti (Diptera: Culicidae), given their ability to reproduce in small and often non-degradable artificial water-containers. While much work has been done on Ae. aegypti biology and ecology in urban landscapes, the role of shading on immature stages as an independent factor from temperature, and any possible interactions between these factors, remains unexamined. We assessed how temperature and shading affected egg hatch-rate, larval/pupal mortality, and larval development to adult stage under different factorial temperature (28; 31; 34; 37; 40° C) and shade (0%, 3,100 lux; 40%, 1,860 lux; 75%, 775 lux; 100%, 0 lux) regimes. Hatch-rate was significantly lower at 37° C (57 %), and no eggs hatched at 40° C. There was no significant effect caused by shading on hatchability. Larval and pupal mortality at 37° C was significantly higher (35%) compared to lower temperature groups, while the effects of shading were emergent at low temperatures. Developmental times from hatching to adult emergence were significantly reduced with increasing temperatures and with greater light exposures. The eco-physiological response of Ae. aegypti larvae to temperature and light regimes suggest a photosensitivity previously unstudied in this species., (© 2019 The Society for Vector Ecology.)

In this study, anti-proliferative effects of C. calcitrans extract and its fucoxanthin rich fraction (FxRF) were assessed on human liver HepG2 cancer cell line. Efficacy from each extract was determined by cytotoxicity assay, morphological observation, and cell cycle analysis. Mechanisms of action observed were evaluated using multiplex gene expression analysis. Results showed that CME and FxRF induced cytotoxicity to HepG2 cells in a dose and time-dependent manner. FxRF (IC 50 : 18.89 μg.mL -1 ) was found to be significantly more potent than CME (IC 50 : 87.5 μg.mL -1 ) (p < 0.05). Gene expression studies revealed that anti-proliferative effects in treated cells by C. calcitrans extracts were mediated partly through the modulation of numerous genes involved in cell signaling ( AKT1 , ERK1/2 , JNK ), apoptosis ( BAX, BID, Bcl-2, APAF, CYCS ) and oxidative stress ( SOD1 , SOD2 , CAT ). Overall, C. calcitrans extracts demonstrated effective intervention against HepG2 cancer cells where enhanced apoptotic activities were observed with increased fucoxanthin content.

Natural antioxidants from sustainable sources are favoured to accommodate worldwide antioxidant demand. In addition to bioprospecting for natural and sustainable antioxidant sources, this study aimed to investigate the relationship between the bioactives (i.e. carotenoid and phenolic acids) and the antioxidant capacities in fucoxanthin-producing algae. Total carotenoid, phenolic acid, fucoxanthin contents and fatty acid profile of six species of algae (five microalgae and one macroalga) were quantified followed by bioactivity evaluation using four antioxidant assays. Chaetoceros calcitrans and Isochrysis galbana displayed the highest antioxidant activity, followed by Odontella sinensis and Skeletonema costatum which showed moderate bioactivities. Phaeodactylum tricornutum and Saccharina japonica exhibited the least antioxidant activities amongst the algae species examined. Pearson correlation and multiple linear regression showed that both carotenoids and phenolic acids were significantly correlated (p<0.05) with the antioxidant activities, indicating the influence of these bioactives on the algal antioxidant capacities., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Data in this article illustrate representative fucoxanthin chromatograms of a microalga, Chaetoceros calcitrans ; a macroalga, Saccharina japonica and; a pure fucoxanthin standard. High performance liquid chromatography (HPLC) eluted fucoxanthin at the 7.008±0.024th min. This data article refers to the research article ''Antioxidant capacities of fucoxanthin-producing algae as influenced by their carotenoid and phenolic contents'' Foo et al. [1]; where a more comprehensive data interpretation and analysis is explained.

Given the emotional nature of health care, patients and their families may express anger and mistreat their health care providers; in addition, those providers are expected to manage their own emotions when providing care--two interpersonal stressors that are linked to job burnout. Integrating conservation of resources (Hobfoll, 2002) and ego depletion (Muraven & Baumeister, 2000) theories, we propose that this creates a resource loss spiral that can be slowed by the presence of a "climate of authenticity" among one's coworkers. We describe this climate and how it differs from other work climates. We then propose that a work unit with a climate of authenticity should provide a self-regulatory break from emotional labor with patients, thus replenishing resources and buffering against strain from emotional labor. We tested this multilevel prediction by surveying 359 health care providers nested within 48 work units at a large, metropolitan hospital. We find that medical workers experiencing more mistreatment by patients are more likely to be managing emotions with patients, and this response further contributes to the employees' job-related burnout. As predicted, managing emotions with patients was unrelated to burnout for workers in a unit with a climate of authenticity.

Background: Previous studies have not found a consistent association between exposure to domestic cooking using gas appliances and exacerbation of asthma. We investigated the immediate airflow response to acute exposure from single episodes of gas cooking, and peak airflow variability from continued exposure to repeated episodes of gas cooking in a group of non-smoking asthmatic women., Methods: Sixteen adult non-smoking women with mild to severe persistent asthma were studied. The acute short term level of nitrogen dioxide (NO2) during gas cooking episodes and the mean exposure to NO2 from repeated gas cooking episodes were measured over a 2 week period, as well as proxy measures of frequency of cooking on each day and the length of time spent cooking each day. Their asthma status was monitored using peak expiratory flow rates (PEFR) before and after cooking, 2 week self-recorded serial readings of PEFR, respiratory symptom severity score, and use of rescue bronchodilators for acute asthma attacks., Results: Cooking was significantly associated with an immediate mean fall in PEFR of 3.4% (p=0.015, paired t test). The acute short term NO2 level during cooking was significantly correlated with the fall in PEFR (r=-0.579; p=0.019). The frequency of cooking over a 2 week period was positively correlated with the mean exposure to NO2 (r=0.529; p=0.042). Continued exposure to NO2 over a 2 week period was associated significantly with increased frequency of rescue bronchodilator usage for asthma attacks (r=0.597; p=0.031). However, it was negatively associated with PEFR variability (r=-0.512; p=0.051) and respiratory symptom severity score (r= -0.567; p=0.043), probably due to the masking effects of bronchodilator treatment., Conclusions: Acute short term exposure to NO2 from single episodes of gas cooking is associated with immediate airflow limitation. Continued exposure from repeated episodes of gas cooking in asthmatic women is associated with greater use of rescue bronchodilators.

Objectives: To assess the extent to which middle-aged women in Singapore engage in physical activity of a level which would result in long-term health benefits, and to determine the factors associated with this., Methods: We conducted a cross-sectional survey of women aged between 35 and 60 years residing in Marine Terrace. A standardised questionnaire incorporating a modified Seven-Day Recall Questionnaire was used to record the level and type of physical activity engaged in over the past week. Demographic information and factors promoting or discouraging sports and exercise were also elicited. The total energy expenditure for household, occupational and sports activities of moderate intensity and above was calculated using metabolic equivalents (METs) in kcal/kg/week., Results: Of the 341 respondents, 50.7% reported engaging in at least moderate activity for 30 minutes or more every day during the past week, thus fulfilling the WHO recommendations on physical activity. Housework contributed significantly to the energy expenditure on these activities among our target population. After adjusting for age, body mass index and educational level, we found that housewives without domestic help were most likely to fulfill the WHO recommendations. Housewives or working women with domestic help were the two groups at highest risk of low physical activity. A lack of time was the reason most commonly cited for not engaging in sports or exercise., Conclusion: Studies assessing physical activity in relation to disease risk among women should include domestic work in addition to the traditional leisure-time activities. There is a scope for further efforts to improve the level of activity in this population, which could be facilitated by the support of health professionals, employers and family members.

Metabolism of estradiol occurs via two mutually exclusive hydroxylative pathways, yielding metabolites of divergent biological properties. 2-hydroxyestrone (2OHE1) is anti-estrogenic while 16 alpha-hydroxyestrone (16 alpha OHE1) is a potent estrogen. The ratio of 2OHE1 to 16 alpha OHE1 (2/16 alpha-OHE1 ratio) represents the net in vivo estrogenic activity. In this study, we sought to determine if the urinary 2/16 alpha-OHE1 ratio could be a predictor of breast cancer risk and the factors which influence this ratio. Variables analysed included age at diagnosis, menopausal status, parity, use of oral contraceptives, body mass index, serum levels of insulin-like growth factor-I (IGF-I), IGF binding proteins (BPs) and the presence of breast cancer. Serum and urine were collected from 65 breast cancer patients and 36 controls after an overnight fast. Urinary estrogen metabolites were measured by enzyme immunoassays while serum levels of IGF-I, BP-1 and BP-3 were determined by immunoradiometric assays. 2OHE1 levels and 2/16 alpha-OHE1 ratios were significantly lower (P < 0.05) while 16 alpha OHE1 levels were higher (P < 0.01) in cancer patients. Multiple linear regression analysis showed that levels of urinary metabolites were influenced by parity and breast carcinoma. 2/16 alpha-OHE1 ratio correlated positively with serum BP-3 level (P = 0.03). By multiple logistic regression, 2/16 alpha-OHE1 ratio was the most significant factor predictive of breast cancer. The odds ratio for women with higher 2/16 alpha-OHE1 ratios was 0.10 (0.03-0.38, 95% confidence interval). In conclusion, the profile of urinary estradiol metabolites was distinctly altered in breast cancer patients. In addition, BP-3 may be a potential mechanism by which estradiol metabolites influence breast cancer progression. As 16 alpha OHE1 has been shown to initiate neoplastic transformation of mammary epithelial cells, the 2/16 alpha-OHE1 ratio may serve as a biomarker of increased risk of breast cancer.

Objectives: To investigate the occurrence of sick building syndrome in a tropical city, and its relation to indoor air quality and other factors., Methods: 2856 office workers in 56 randomly selected public and private sector buildings were surveyed. The study consisted of a self administered questionnaire assessing symptoms and perception of the physical and psychosocial environment, inspection of the building plans and premises, and measurement of temperature, relative humidity, respirable particles, chemicals, bioaerosols, and other variables., Results: Symptoms typical of the sick building syndrome were reported in 19.6% of the respondents. Multivariate modelling substantiated contributions associated with low thermal comfort, high work related stress, too much noise, a history of allergy or other medical conditions, poor lighting, young employees, and female sex. Measurements of indoor air quality or ventilation were not found to be reliable predictors of the symptoms., Conclusion: The survey confirmed the presence of sick building syndrome and its risk factors in the tropics. A biopsychosocial approach to the problem involving symptomatic treatment, environmental control, good ergonomic design, and stress management is recommended.

Mercury (Hg), lead (Pb), cadmium (Cd) and copper (Cu) in hair samples from Singapore island (85 samples) and two islands off Batam, Indonesia (68 samples) were analysed to assess the environmental uptake of elements. Hair samples were washed with 0.1% Triton X-100 solution for 20 min in an ultrasonic bath, rinsed five times with de-ionized water and air dried. Ten to 20 mg of hair samples were digested with 1 ml of ultra-pure concentrated nitric acid in Parr bombs at 120 degrees C for 2 h. Hair digests were analysed by atomic absorption spectrophotometry (AAS). Hg was determined by the cold vapour AAS method and Pb, Cd and Cu by the electro-thermal graphite furnace AAS method. For Singapore hair, the contents of Cd (in microgram/g) averaged 0.17 (range 0.02-1.81); Cu 13.2 (range 3.1-70.1); Hg 5.92 (range 1.14-35.52); and Pb 6.74 (range 0.06-107.8). For the islands off Batam, Cd was 0.32 (range 0.06-1.80); Cu 21.1 (range 3.8-143.6); Hg 5.59 (range 0.78-60.86); and Pb 15.1 (range 0.13-116.6). Statistically significant differences in Cd, Pb and Hg contents were observed between the hair samples from Singapore and those of the islands off Batam in cumulative logit analysis. Hair from Singapore contained more Hg, but less Cd and Pb compared to hair from the islands off Batam. For Pb in hair, significant differences were also observed between the two islands off Batam (island 1, 18.9; and island 2, 10.2). These differences in hair metal contents are due to differences in community lifestyle (dietary, environmental or occupational intake).

A simple and fast method was used to determine 1,1'-(2,2,2-trichloroethylene)-bis(4-chlorobenzene) (DDT) and 1,1'-(2,2-dichloroethylidene)-bis(4-chlorobenzene) (DDE) in blood serum. Serum samples pre-treated with formic acid were extracted with n-hexane and determined by gas chromatography (GC-ECD), using PTE-5 capillary column. Detection limits for DDT and DDE were 0.5 ppb. Recovery with a fortified pooled sample at 1 ppb level was 107.0% for DDT and 106.0% for DDE. At 10 ppb level, the recoveries for DDT and DDE were 96.1% and 92.7%, respectively. Eighty-nine random blood samples collected from volunteers were analyzed. The geometric mean (GM) serum level of DDT was 1.9 ppb (0.2-8.9 ppb) and that of DDE was 10.8 ppb (1.5-88.1 ppb). There was a positive correlation between DDE and DDT level (r = 0.33, P < 0.01). The serum DDE level was positively correlated with age (r = 0.49, P < 0.01) and DDT x Age (r = 0.62, P < 0.01). No correlation was observed between DDT and age. These results suggest that DDE, a metabolite of DDT, is cumulative in the body. Therefore blood DDE could be used as a cumulative exposure marker for DDT, whereas blood DDT may be used to reflect its recent exposure.

The neuropsychological functionings of workers (n = 29) occupationally exposed to low level of toluene (mean blood toluene level 1.25 ug/ml, standard deviation [SD] 0.37 ug/ml) were assessed by a test battery based on the recommendation of US National Institute of Occupational Safety and Health. The data revealed that the exposed workers performed poorer than a control group (mean blood toluene level 0.16 ug/ml, SD 0.06 ug/ml) in short-term memory, sustained attention and concentration, visual scanning, perceptual-motor speed, and finger dexterity. Results of the study confirmed that exposure to toluene may result in different degree of impairments of brain functions.

The objectives of this study were to determine the exposure levels among workers who handle 2-ethoxyethylacetate (EGEEA) in the liquid crystal display (LCD) manufacturing industry and to study the menstrual patterns among the exposed workers compared to a referent group of workers. A total of 52 female exposed workers and 55 referents was studied. Detailed menstrual histories were obtained by personal interview using a structured questionnaire. All the exposed had individual 8-hour personal monitoring for EGEEA in the environment and start-of-shift and end-of-shift urine analysis for EGEEA concentration. The geometric mean end-of-shift urine EGEEA concentration was 0.16 mg/g creatinine. End-of-shift urine EGEEA was well correlated with the air concentration; r = 0.81 [p < 0.0001]. No significant differences were observed between the exposed and referent groups for duration of each menstrual cycle (period), duration (days) of the menses, and the amount of flow, even after adjusting for possible confounders viz. age, years of education, use of oral contraceptive pills, age at menarche, gravidity, and race. The workers in the LCD manufacturing industry were exposed to a mean TWA of 0.51 ppm of EGEEA. At this concentration, the findings did not reveal any significant difference between the menstrual patterns of the exposed and referent subjects.

Postural stability was investigated by static posturography in 32 manganese exposed workers with exposure duration of 6.6 (range 1.1-15.7) years and 53 referent subjects. The mean current urine manganese concentration for the exposed was 6.0 micrograms/g creatinine (range 0.6 to 53.3). There was no significant differences between both groups for the postural sway parameters obtained during eyes open condition. However, significant differences were observed for L - length of sway path and Vel - mean velocity of the center of pressure along its path. The Romberg Ratios (the relationship between eyes closed/open conditions) for the exposed's Vel, L, and Ao were also significantly different from the referent. The study showed that manganese exposed workers had significantly poorer postural stability compared to a referent group. We postulate that this could be a subclinical effect of manganese on the basal ganglia (pallidus) resulting in the postural instability when the visual input is cut off. Based on the current urinary manganese levels, we were not able to obtain any significant association with the postural sway parameters.

Objective: To detect, with a computerised postural sway measurement system, any significant deviation of postural sway parameters among lead workers compared with a control group., Methods: Postural stability was investigated with a computerised postural sway measurement system in 60 workers exposed to lead with a duration of exposure of 84 (range 3-366) months and 60 controls. Sway parameter data were collected with an Advanced Mechanical Technology computerised biomechanics platform system., Results: The mean current blood lead concentration was 36.0 (range 6.4 to 64.5) micrograms/dl for the exposed workers and 6.3 (range 3.1 to 10.9) micrograms/dl for the 14 controls. There was no significant difference between the groups for the postural sway parameters obtained when the eyes were open. Significant differences were found for Xs, Ys (SDs of the coordinates of the centre of pressure); Xm, Ym (mean deviation of the coordinates of the centre of pressure); Rm (average displacement of Xi, Yi, from Xo, Yo); L (length of sway path); Vel (mean velocity of the centre of pressure along its path); Ao (area included within the path of the centre of pressure); Ae (95% confidence elliptical area). The Romberg ratios (the relation between eyes closed and open) for the Vel, L, Ao and Ae of the exposed workers were also significantly different from the controls., Conclusion: The study showed that workers exposed to lead had significantly poorer postural stability than the controls. Lead may affect certain parts of the whole sensory neural axis resulting in postural instability when the visual input is cut off. Based on current blood lead concentrations, we were not able to obtain any significant association with the postural sway parameters.

Twenty male naval volunteers, aged 18 to 20 years, with 12 to 14 years of education, underwent a total sleep deprivation experiment on board a Republic of Singapore Navy landing ship in the South China Sea for a period of 42-102 hours. The sleep group comprised eight volunteers who dropped out at the 44th-46th h of the experiment and were randomly assigned to a 2 or 4 h sleep regime. The rest served as sleep-deprived controls. Neurobehavioural performance tests, profile of mood state and the Stanford Sleepiness Scale were applied 6 hourly starting from 6.00 am on the first experimental day. No thresholds were observed in the performance of tests related to manual tasks and subjective feeling, including naval tasks, mood and sleepiness scale during the sleep deprivation experiment. However, thresholds were observed in the performance of tests requiring cognitive and perceptive skills, including the grooved peg board, trail making, sea-shore rhythm, addition, digit span, digit symbol, flicker fusion and dynamometer tests. Performances in these tests were observed to deteriorate only after approximately 30 h of sleep deprivation. The Z score for the non-threshold tests (Z-N) deteriorated from -0.01 at the start of the experiment to 1.25 at the 42nd h of the experiment just before the imposed sleep and improved to 0.81 at the 48th h of the experiment just after the imposed sleep; and the Z score for the threshold tests (Z-T) varied from -0.07 at the start to 0.49 just before sleep (at the 42nd h) and to continuously deteriorate to 0.83 just after sleep (at the 48th h).(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty-one male paint formulators with an average age of 41.3 years (range 27-53), educational level of 7.4 years (range 5-10) and exposure level of 0.09 times Threshold Limit Value (TLV) index of solvent mixture (range 0.003-0.24 times TLV-index) for 20.2 years (range 7-39) were studied with a battery of neurobehavioural performance tests including digit span, digit symbol, Benton visual retention, finger tapping, grooved peg board, and aiming test. A group of 21 male workers matched for age (mean 40.8 years, range 25-53) and education (mean 6.9 years, range 5-12), and with no history of exposure to neurotoxic agents were selected as controls. In all the neurobehavioural tests, the exposed workers' performances were observed to be poorer than the controls'. Statistically significant differences were observed in digit span, grooved peg board, and the Z score after adjusting for age, level of education and ethnicity. The least square means for digit span were 11.7 (standard error [SE] 0.77) and 9.2 (SE 0.79); for grooved peg board were 60.5 (SE 2.1) and 69.7 (SE 2.1); and for neurobehavioural Z score were 0.02 (SE 0.11) and 0.50 (SE 0.11) in the controls and exposed workers respectively. The exposed group also performed significantly poorer in aiming test error score and digit span when compared to the controls after adjusted for age, education and ethnicity. The least square means for aiming test error score were 6.5 (SE 2.7) and 12.8 (SE 2.8) for the controls and exposed workers respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Sleep deprivation leads to impairment in performance, loss of efficiency and deterioration in mood states such as tension, depression, aggression, fatigue, confusion and vigour. These can be detrimental to combat readiness and could contribute to "battle stress". In the present study, a homogeneous group of 20 seamen under total sleep deprivation was rated 6 hourly with the Stanford Sleepiness Scale (SSS), Profile of Mood States (POMS) and a battery of performance tests including the trail making, grooved peg board, digit span, digit symbol, sea-shore rhythm, flicker fusion, dynamometer and naval tasks. With the exception of the trail making test and naval tasks, the test performance was observed to correlate significantly (P < 0.05) with the SSS. A higher sleepiness score was associated with a poorer performance in test scores. On the time trends of sleep deprivation on the performance tests measured, a dip in performance was observed in all the tests at 42 hours of sleep deprivation and continuous deterioration of performance was observed after 72 hours of sleep deprivation. The cognitive, vigilance, mood and sleepiness tests were substantially affected by sleep deprivation. Greater effect was observed in tests that involved cognition, speed and precision and smaller effect was observed in routine tasks that involved gross manual movement. The decrease in performance observed at 42 hours of sleep deprivation was 5.9 standard deviation from initial values for SSS; 3.9 for sea-shore rhythm, 3.0 for grooved peg board; 2.6 for dynamometer; 2.4 for mood; 1.8 for digit span; 1.6 for trail making and digit symbol; 1.0 for naval tasks and addition; and 0.9 for flicker fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

1. Computerized postural sway measurement systems have been used recently in human physiology and pharmacology for determining postural stability, but their applicability for the assessment of the effects of exposure to neurotoxic agents is lacking. 2. We have examined the feasibility of using a computerized postural sway measurement system to assess the postural sway parameters of manganese exposed workers compared with a control group. 3. Sway parameter data were collected using a KISLTER multicomponent measuring platform (Type 9281B) connected to VICON motion analysis system for 13 exposed and 16 control subjects. 4. Significant differences in several of the sway parameters (Px, Py--mean distance (mm), from the centre of the platform along the X-axis [anterior-posterior movement] and Y-axis [lateral movement], respectively) between the exposed and control groups were observed even after adjustment for possible confounders. Computerized postural sway measurement system may be a useful method of assessing workers exposed to neurotoxic agents affecting posture.

Concentrations of lead, cadmium, methylmercury and total mercury were measured in maternal and umbilical cord blood using graphite atomic absorption spectrometry. Two essential metals, copper and zinc, were also determined using ion chromatography. Lead, copper and zinc were found to be lower in the cord blood whereas methylmercury and total mercury were higher in cord blood than in maternal blood. Little differences were noted for cadmium in maternal and cord blood. Significant positive correlations were observed between the concentrations in maternal and cord blood with regard to lead (correlation coefficient, r = 0.44), copper (r = 0.34), zinc (r = 0.29), methylmercury (r = 0.44) and total mercury (r = 0.58). These results suggest that, like essential metals, most heavy metals can move rather freely across the human placenta. The potential health effects of heavy metal transfer from mothers to young infants cannot be discounted.

Neurobehavioral effects in 30 female workers (aged 18-41, mean 25.6) exposed to an average of 341 mg/m3 (SD 100) toluene for an average of 5.7 years (SD 3.3) compared with 30 matched controls (aged 18-48, mean 25.1), 24 male workers (aged 18-32, mean 24.7) exposed to 268 mg/m3 (SD 185) toluene equivalent of mixed solvent (82.2% toluene, 12.3% ethyl acetate, and 5.5% methyl ethyl ketone) for 2.3 years (SD 3.0) compared with 24 matched controls (aged 17-31, mean 24.3), and 94 dentists (aged 24-49, mean 31.7) exposed to 0.017 mg/m3 (SD 0.009) of elemental mercury for 7.4 years (SD 5.3) compared with 54 referents (aged 23-50, mean 33.6) were studied. The Z score (made up of Digit Span, Symbols Digit, and Grooved Peg Board) for the workers exposed to toluene was 0.79, for workers exposed to mixed solvents was 0.38, and for the dentists exposed to mercury was 0.42. The Z score for each group of exposed subjects was statistically poorer than that for its controls. Neurobehavioral performance was statistically related to exposure intensity for the toluene-exposed workers and to years of exposure or dose (exposure intensity x years of exposure) for mixed solvent- and mercury-exposed subjects. The type of chemical species and pattern of exposure appear to influence whether the adverse effects will be cumulative.

Hair samples from three groups of occupationally exposed subjects were analyzed for their lead (Pb), manganese (Mn) and mercury (Hg) contents. For lead (number of subjects, n = 209), the hair Pb ranged from 0.93 to 3527 micrograms/g (geometric mean, GM = 641) and blood Pb from 33.3 to 774 micrograms/l (GM = 341); for manganese (n = 38), the hair Mn ranged from 0.20 to 52.97 micrograms/g (GM = 2.66) and urine Mn ranged from 1.70 to 17.9 micrograms/l (GM = 5.56); and for mercury (n = 85), the hair Hg from 1.79 to 12.8 micrograms/g (GM = 5.09) and the blood Hg from 0.63 to 57.3 micrograms/l (GM = 10.9). The hair Pb was significantly (P < 0.0001) correlated to blood Pb (r = 0.85); the hair Mn to urinary Mn (r = 0.45); and the hair Hg to blood Hg (r = 0.53). The average metal content at the distal end was not significantly (P > 0.05) different from that of proximal end. The GM levels for the distal end were 223 micrograms/g (95% CI 152-347) and 2.26 (95% CI 0.97-5.29); and those for the proximal end were 186 (95% CI 97-261) and 1.18 (95% CI 0.54-2.58) for Pb and Mn respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Rates of menstrual disorders were studied in 231 female production workers with high exposure to toluene (mean 88 (range 50-150 ppm) in a factory manufacturing audio speakers and compared with a control group of 58 female production workers in other departments in the same factory who had little or no exposure to toluene (0-25 ppm). An external community control group of 187 working class women under routine care at public maternal and child health centres were also studied. Detailed menstrual and reproductive histories were obtained by personal interview using a structured questionnaire. The rates for dysfunctional uterine bleeding (cycle irregularity and prolonged or heavy menstrual bleeding) were similar in all groups. Dysmenorrhoea seemed to occur more often in the women highly exposed to toluene compared with women at maternal and child health centres, but not compared with factory controls with low exposure to toluene. There was no evidence that dysfunctional uterine bleeding was likely to result from exposure to toluene. It is uncertain whether dysmenorrhoea was associated specifically with exposure to toluene, as other behavioural and work related factors may also result in dysmenorrhoea.