Acute effects of NIV on peripheral muscle function and aerobic performance in patients with chronic obstructive pulmonary disease: a pilot study.

BACKGROUND: Non-invasive ventilation (NIV) reduces respiratory load and demands on peripheral muscles. METHODS: This study aims to evaluate the acute effects of bi-level NIV on peripheral muscle function during isokinetic exercise and aerobic performance in chronic obstructive pulmonary disease (COPD) patients. This is a pilot crossover study performed with a non-probabilistic sample of 14 moderate to very severe COPD patients. Procedures carried out in two days. Dyspnea, quality of life, lung function, respiratory muscle strength, functional capacity (6-min walk test-6MWT), and isokinetic assessment of the quadriceps were assessed. Blood samples (lactate, lactate dehydrogenase, and creatine kinase concentration) were also collected. Right after, NIV was performed for 30 min (bi-level or placebo, according to randomization) followed by new blood sample collection, 6MWT, and isokinetic dynamometer tests. Before and after evaluations, the subjective perception of dyspnea and fatigue in the lower limbs was quantified. After a wash-out period of seven days, participants returned, and all assessments were performed again. RESULTS: NIV showed improvements in perceived exertion and dyspnea after isokinetic exercise (p < 0.02 and p < 0.05, respectively). CONCLUSIONS: NIV improves the perception of dyspnea and fatigue during the isokinetic exercise.

Cyanotoxins and water quality parameters as risk assessment indicators for aquatic life in reservoirs.

We assessed the extent of pollution in an essential public water supply reservoir (southeastern Brazil). An environmental monitoring study was performed at the Billings Reservoir (at the water catchment site) to assess the water quality in 2017, 2018, and 2019. Physicochemical parameters were analyzed, quantifying the total cyanobacteria and the cyanotoxins microcystins (MCs) and saxitoxins (SXTs), as well as their possible ecological risk to the aquatic environment. We also determined metals and metalloids (As, Ba, Cd, Pb, Cu, Cr, Fe, Mn, Ni, Zn, and Sb) and fecal bacteria (Escherichia coli). Monthly samplings were performed for 2017, 2018, and 2019 (totaling 36 sampling campaigns). Metals, metalloids, and E. coli values were below the maximum limit allowed by the Brazilian legislation. High concentrations of total cyanobacteria (3.07 × 104 - 3.23 × 105 cells/mL), microcystin variants MC-LR (0.67-23.63 µg/L), MC-LA (0.03-8.66 µg/L), MC-RR (0.56-7.92 µg/L), and MC-YR (0.04-1.24 µg/L), as well as the saxitoxins GTX2 (0.18-5.37 µg/L), GTX3 (0.13-4.40 µg/L), and STX (0.12-2.92 µg/L) were detected. From an ecotoxicological point of view, the estimated values for the risk quotient (RQ) for microcystins and saxitoxins were largely greater than 1, indicating a high risk to aquatic life. Therefore, further efforts need to be made to delay the eutrophication of the reservoir.

Interaction Between Near-Infrared Radiation and Temozolomide in a Glioblastoma Multiform Cell Line: A Treatment Strategy?

Photodynamic therapy (PDT) is a potential therapeutic modality against cancer, resulting from the interaction of a photosensitizer (PS) and radiation that generates damage to tumor cells. The use of near-infrared radiation (IR-A) is relevant because presents recognized biological effects, such as antioxidant, neuroprotective and antitumor effects. Glioblastoma is the most aggressive central nervous system (CNS) neoplasm with high proliferation and tissue invasion capacity and is resistant to radio and chemotherapy. Here, we evaluated in vitro the possible interaction of temozolomide (TMZ) with IR-A in a glioblastoma cell line (C6) and in a human keratinocyte cell line (HaCat) how non-tumor cell model, in an attempt to search for a new treatment strategy. The effects of TMZ, IR-A and the interaction between TMZ and IR-A was evaluated by viability exclusion with trypan blue. To perform the interaction experiments, we have chosen 10 µM TMZ and 4.5 J/cm2 of IR-A. From this, we evaluated cytotoxicity, cell proliferation, intracellular reactive oxygen species levels (ROS), as well as the process of cell migration and the P-gp and MRP-1 activity. Cell death mainly due to apoptosis, followed by necrosis, decreased cell proliferation, increased ROS levels, decreased cell migration and decreased P-gp and MRP1 activity were observed only when there was interaction between TMZ and IR-A in the C6 cell line. The interaction between TMZ and IR-A was not able to affect cell proliferation in the HaCat non-tumor cell line. Our results suggest that this interaction could be a promising approach and that in the future may serve as an antitumor strategy for PDT application.

Determinants of access to the SARS-CoV-2 vaccine: a preliminary approach.

BACKGROUND: The determinants of access to immunizers are still poorly understood, leading to questions about which criteria were considered in this distribution. Given the above, the present study aimed to analyze the determinants of access to the SARS-CoV-2 vaccine by different countries. METHODS: The study covered 189 countries using data from different public databases, and collected until February 19, 2021. We used eight explanatory variables: gross domestic product (GDP), extreme poverty, human development index (HDI), life expectancy, median age, coronavirus disease 2019 (COVID-19) cases, COVID-19 tests, and COVID-19 deaths. The endogenous variables were total vaccine doses, vaccine doses per thousand, and days of vaccination. The structural equation modeling (SEM) technique was applied to establish the causal relationship between the country's COVID-19 impact, socioeconomic variables, and vaccine access. To support SEM, we used confirmatory factor analysis, t-test, and Pearson's correlation. RESULTS: We collected the sample on February 19, and to date, 80 countries (42.1%) had already received a batch of immunizers against COVID-19. The countries with first access to the vaccine (e.g., number of days elapsed since they took the first dose) were the United Kingdom (68), China (68), Russia (66), and Israel (62). The countries receiving the highest doses were the United States, China, India, and Israel. The countries with extreme poverty had lower access to vaccines and the richer countries gained priority access. Countries most affected by COVID (deaths and cases) also received immunizers earlier and in greater volumes. Unfortunately, similar to other vaccines, indicators, such as income, poverty, and human development, influence vaccines' access. Thus affecting the population of vulnerable and less protected countries. Therefore, global initiatives for the equitable distribution of COVID need to be discussed and encouraged. CONCLUSIONS: Determinants of vaccine distribution consider the impact of the disease in the country and are also affected by favorable socioeconomic indicators. The COVID-19 vaccines need to be accessible to all affected countries, regardless of their social hands.

Happier and further by going together: The importance of software team behaviour during the COVID-19 pandemic.

The COVID-19 pandemic, and the associated move to remote work and the resulting changes to the normal work routine, have introduced a plethora of new difficulties and challenges for software developers. Recent research has focused on the impact of the COVID-19 pandemic on the developer's wellness, productivity, team collaboration, job satisfaction, and work-life balance. However, research exploring the association between these feelings and team behaviour during such a crisis period has not been previously developed. Moreover, previous research has indicated that organisations are still struggling to understand the pandemic and its relationship with both team behaviour and developer feelings. To address this gap, we analysed how COVID-19 influences a developer's happiness and their feelings of (un)happiness associated with the team's behaviour during the COVID-19 pandemic. A state-of-the-art analysis helped to design a scale that we used in a cross-sectional study of 102 software developers. To test the proposed hypotheses, we conducted exploratory factor analysis and principal component analysis. Our results highlight that happiness positively influences a team's behaviour and that unhappiness negatively affects their work results and productivity. These findings provide software companies and organisations with a better understanding of the importance of team behaviour on individual happiness during crises. These results provide information that managers and companies can use to mitigate potentially negative effects.

Direct Effects of Temperature on Growth of Different Tropical Phytoplankton Species.

Temperature increase may influence competition among phytoplankton species, potentially intensifying cyanobacteria blooms that can be favored by direct and indirect effects of temperature. In this study, we aimed to clarify how cyanobacteria can be favored by the direct effects of increased temperature compared to diatoms and chlorophytes. Strains of the most representative species of a eutrophic coastal lagoon (Microcystis aeruginosa, Planktothrix agardhii, Desmodesmus communis, and Cyclotella meneghiniana) were used to test the hypothesis that cyanobacteria would be favored by the direct effect of temperature increase. First, we evaluated the effect of temperature increase on growth in monocultures (batch and chemostats) at 25 and 30 °C and after in mixed cultures (chemostats). In batch monocultures, the cyanobacteria showed higher growth rates in 30 °C than in 25 °C. However, in continuous culture experiments (chemostats), growth rates of M. aeruginosa and P. agardhii were not affected by temperature, but the strains showed higher biovolume in steady-state with the temperature increase. In continuous mixed cultures, M. aeruginosa was always dominant and C. meneghiniana was excluded, regardless of temperature tested. D. communis was able to coexist with lower biomass. This study shows that rising temperatures can be detrimental to diatoms, even for a tropical strain. Although some studies indicate that the dominance of cyanobacteria in warmer climates may be due to the indirect effect of warming that will promote physical conditions in the environment more favorable to cyanobacteria, the outcomes of mixed cultures demonstrate that the direct effect of temperature can also favor the dominance of cyanobacteria.

Quantitative gingival crevicular fluid proteome in type 2 diabetes mellitus and chronic periodontitis.

OBJECTIVE: The aim of this study was to investigate the proteome of the gingival crevicular fluid comparing the relative abundance of proteins from type 2 diabetes mellitus (2DM) individuals and chronic periodontitis (CP) affected sites, subjects affected by both conditions and healthy individuals. MATERIAL AND METHODS: Twenty individuals were equally allocated in four groups, 2DM with CP, 2DM periodontally healthy, CP without 2DM, and periodontally healthy without 2DM. The relative quantification of proteins was accessed with iTRAQ labeling and mass spectrometry. RESULTS AND CONCLUSION: A total of 104 proteins showed significant differences in abundance in pairwise comparisons. Some presented different levels in all diseased groups as compared to control, either increasing (rap guanine nucleotide exchange factor, S100A8, S100A9, and immunoglobulins) or decreasing (actins, myristoylated alanine-rich C-kinase substrate, and glutathione S-transferase). Other differences were specific for a given condition: Titin, neutrophil elastase, and myeloperoxidase levels were higher in the DP group, cathelicidin antimicrobial peptide decreased in CP, and annexin decreased in DH. These differences in the proteome can provide clues for further studies that will validate the variation in their levels and their role in both diseases.

In Vitro Anti/Pro-oxidant Activities of R. ferruginea Extract and Its Effect on Glioma Cell Viability: Correlation with Phenolic Compound Content and Effects on Membrane Dynamics.

Rapanea ferruginea antioxidant and antitumoral properties were not explored before in literature. This study aimed to investigate these biological activities for the R. ferruginea leaf extract and correlate them with its phenolic content and influence in biological membrane dynamics. Thus, in this study, anti/pro-oxidative properties of R. ferruginea leaf extract by in vitro DPPH and TBARS assays, with respect to the free radical reducing potential and to its activity regarding membrane free radical-induced peroxidation, respectively. Furthermore, preliminary tests related to the extract effect on in vitro glioma cell viability were also performed. In parallel, the phenolic content was detected by HPLC-DAD and included syringic and trans-cinnamic acids, quercetrin, catechin, quercetin, and gallic acid. In an attempt to correlate the biological activity of R. ferruginea extract and its effect on membrane dynamics, the molecular interaction between the extract and a liposomal model with natural-sourced phospholipids was investigated. Location and changes in vibrational, rotational, and translational lipid motions, as well as in the phase state of liposomes, induced by R. ferruginea extract, were monitored by Fourier-transform infrared spectroscopy, nuclear magnetic resonance, differential scanning calorimetry, and UV-visible spectroscopy. In its free form, the extract showed promising in vitro antioxidant properties. Free-form extract (at 1000µ g/mL) exposure reduced glioma cell in vitro viability in 40%, as evidenced by MTT tests. Pro-oxidant behavior was observed when the extract was loaded into liposomes. A 70.8% cell viability reduction was achieved with 500 µg/mL of liposome-loaded extract. The compounds of R. ferruginea extract ordered liposome interface and disorder edits a polar region. Phenolic content, as well as membrane interaction and modulation may have an important role in the oxidative and antitumoral activities of the R. ferruginea leaf extract.

Assessment of the Effects of Light Availability on Growth and Competition Between Strains of Planktothrix agardhii and Microcystis aeruginosa.

In this study, we tested the hypothesis that Planktothrix agardhii strains isolated from a tropical water body were better competitors for light than Microcystis aeruginosa strains. These cyanobacteria are common in eutrophic systems, where light is one of the main drivers of phytoplankton, and Planktothrix is considered more shade-adapted and Microcystis more high-light tolerant. First, the effect of light intensities on growth was studied in batch cultures. Next, the minimum requirement of light (I*) and the effect of light limitation on the outcome of competition was investigated in chemostats. All strains showed similar growth at 10 µmol photons m(-2) s(-1), demonstrating the ability of the two species to grow in low light. The optimum light intensity was lower for P. agardhii, but at the highest light intensity, Microcystis strains reached higher biovolume, confirming that P. agardhii has higher sensitivity to high light. Nonetheless, P. agardhii grew in light intensities considered high (500 µmol photons m(-2) s(-1)) for this species. M. aeruginosa showed a higher carrying capacity in light-limited condition, but I* was similar between all the strains. Under light competition, Microcystis strains displaced P. agardhii and dominated. In two cases, there was competitive exclusion and in the other two P. agardhii managed to remain in the system with a low biovolume (≈15%). Our findings not only show that strains of P. agardhii can grow under higher light intensities than generally assumed but also that strains of M. aeruginosa are better competitors for light than supposed. These results help to understand the co-occurrence of these species in tropical environments and the dominance of M. aeruginosa even in low-light conditions.

Effects of quercetin in preclinical models of Parkinson's disease: A systematic review.

Parkinson's disease (PD) is a neurodegenerative disease that affects dopaminergic neurons, thus impairing dopaminergic signalling. Quercetin (QUE) has antioxidant and neuroprotective properties that are promising for the treatment of PD. This systematic review aimed to investigate the therapeutic effects of QUE against PD in preclinical models. The systematic search was performed in PubMed, Scopus and Web of Science. At the final screening stage, 26 articles were selected according to pre-established criteria. Selected studies used different methods for PD induction, as well as animal models. Most studies used rats (73.08%) and mice (23.08%), with 6-OHDA as the main strategy for PD induction (38.6%), followed by rotenone (30.8%). QUE was tested immersed in oil, nanosystems or in free formulations, in varied routes of administration and doses, ranging from 10 to 400 mg/kg and from 5 to 200 mg/kg in oral and intraperitoneal administrations, respectively. Overall, evidence from published data suggests a potential use of QUE as a treatment for PD, mainly through the inhibition of oxidative stress, neuroinflammatory response and apoptotic pathways.

Cyanopeptides occurrence and diversity in a Brazilian tropical reservoir: Exploring relationships with water quality.

Microcystins (MCs) are a class of toxic secondary metabolites produced by some cyanobacteria strains that endanger aquatic and terrestrial organisms in various freshwater systems. Although patterns in MC occurrence are being recognized, divergences in the global data still hamper our ability to predict the toxicity of cyanobacterial blooms. This study aimed (i) to determine the dynamics of MCs and other cyanopeptides in a tropical reservoir, (ii) to investigate the correlation between peptides and potential cyanotoxin producers (iii) identifying the possible abiotic factors that influence the peptides. We analyzed, monthly, eight MC variants (MC-RR, -LA, -LF, -LR, -LW, -YR, [D-Asp3]-RR and [D-Asp3]-LR) and other peptides in 47 water samples collected monthly, all season long, from two sampling sites in a tropical eutrophic freshwater reservoir, in southeastern Brazil. The cyanopeptides were assessed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The biomass of potential cyanobacterial producers and water quality variables were measured. MCs were detected in both sampling sites year-round; the total MC concentration varied from 0.21 to 4.04 µg L-1, and three MC variants were identified and quantified (MC-RR, [D-Asp3]-RR, -LR). Additionally, we identified 28 compounds belonging to three other cyanopeptide classes: aeruginosin, microginin, and cyanopeptolin. As potential MC producers, Microcystis spp. and Dolichospermum circinalis were dominant during the study, representing up to 75% of the total phytoplankton. Correlational and redundancy analysis suggested positive effects of dissolved oxygen, nitrate, and total phosphorus on MC and microginins concentration, while water temperature appeared to favor aeruginosins. A comparison between our results and historical data showed a reduction in total phosphorus and cyanobacteria, suggesting increased water quality in the reservoir. However, the current MC concentrations indicate a rise in cyanobacterial toxicity over the last eight years. Moreover, our study underscores the pressing need to explore cyanopeptides other than MCs in tropical aquatic systems.

Light and phosphate competition between Cylindrospermopsis raciborskii and Microcystis aeruginosa is strain dependent.

The hypothesis that outcomes of phosphorus and light competition between Cylindrospermopsis raciborskii and Microcystis aeruginosa are strain dependent was tested experimentally. Critical requirements of phosphorus (P*) and of light (I*) of two strains of each species were determined through monoculture experiments, which indicated a trade-off between species and also between Microcystis strains. Competition experiments between species were performed using the weakest predicted competitors (with the highest values of P* and of I*) and with the strongest predicted competitors (with the lowest values of P* and of I*). Under light limitation, competition between the weakest competitors led C. raciborskii to dominate. Between the strongest competitors, the opposite was observed, M. aeruginosa displaced C. raciborskii, but both strains co-existed in equilibrium. Under phosphate limitation, competition between the weakest competitors led C. raciborskii to exclude M. aeruginosa, and between the strongest competitors, the opposite was observed, M. aeruginosa displaced C. raciborskii, but the system did not reach an equilibrium and both strains were washed out. Hence, outcomes of the competition depended on the pair of competing strains and not only on species or on type of limitation. We concluded that existence of different trade-offs among strains and between species underlie our results showing that C. raciborskii can either dominate or be displaced by M. aeruginosa when exposed to different conditions of light or phosphate limitation.

Switching from cetrorelix to dydrogesterone in an IVF cycle - a new strategy for unexpected freeze-all cycles.

Preventing a luteinizing hormone (LH) surge is a major concern in controlled ovarian stimulation (COS). Several strategies have been developed over the years, including protocols with Gonadotrophin Releasing Hormone agonists and antagonists. More recently Progestin Primmed Ovarian Stimulation (PPOS) has shown to be equally effective in pituitary suppression, with comparable clinical and laboratorial outcomes. This is the case of a 34 year old female, with a previous diagnosis of primary infertility due to tubal factor and high ovarian reserve markers. The initial plan was to perform IVF/ICSI. followed by fresh blastocyst transfer. The chosen COS strategy was to use Alfacorifolitropin 150mg (Elonva®) and Cetrorelix acetate 0,25mg (Cetrotide®) in a flexible pituitary suppression protocol. However, because of elevated risk for Ovarian Hyper-stimulation Syndrome (OHSS) detected during ultrasound and hormonal monitoring, in order to diminish financial burden and to have a more patient friendly protocol, we switched cetrorelix acetate to oral dydrogesterone. COS was successful and resulted in 24 retrieved oocytes (16 metaphase 2 oocytes) without any premature LH peak. No OHSS symptoms occurred. Our main goal with this case report is to reinforce the feasibility and efficacy of this innovative approach, especially in patients aiming for a fresh embryo transfer, who present alert sings of OHSS during the stimulation. Developing friendlier and cheaper protocols in assisted reproduction makes the treatment more accessible and affordable.

Toward a Platform for the Treatment of Burns: An Assessment of Nanoemulsions vs. Nanostructured Lipid Carriers Loaded with Curcumin.

Curcumin is a highly promising substance for treating burns, owing to its anti-inflammatory, antioxidant, antimicrobial, and wound-healing properties. However, its therapeutic use is restricted due to its hydrophobic nature and low bioavailability. This study was conducted to address these limitations; it developed and tested two types of lipid nanocarriers, namely nanoemulsions (NE-CUR) and nanostructured lipid carriers (NLC-CUR) loaded with curcumin, and aimed to identify the most suitable nanocarrier for skin burn treatment. The study evaluated various parameters, including physicochemical characteristics, stability, encapsulation efficiency, release, skin permeation, retention, cell viability, and antimicrobial activity. The results showed that both nanocarriers showed adequate size (~200 nm), polydispersity index (~0.25), and zeta potential (~>-20 mV). They also showed good encapsulation efficiency (>90%) and remained stable for 120 days at different temperatures. In the release test, NE-CUR and NCL-CUR released 57.14% and 51.64% of curcumin, respectively, in 72 h. NE-CUR demonstrated better cutaneous permeation/retention in intact or scalded skin epidermis and dermis than NLC-CUR. The cell viability test showed no toxicity after treatment with NE-CUR and NLC-CUR up to 125 µg/mL. Regarding microbial activity assays, free curcumin has activity against P. aeruginosa, reducing bacterial growth by 75% in 3 h. NE-CUR inhibited bacterial growth by 65% after 24 h, and the association with gentamicin had favorable results, while NLC-CUR showed a lower inhibition. The results demonstrated that NE-CUR is probably the most promising nanocarrier for treating burns.

Combination of Curcumin and Photodynamic Therapy Based on the Use of Red Light or Near-Infrared Radiation in Cancer: A Systematic Review.

BACKGROUND: Photodynamic therapy (PDT) is a therapeutic intervention that can be applied to cancer treatment. The interaction between a photosensitizer (PS), ideal wavelength radiation, and tissue molecular oxygen triggers a series of photochemical reactions responsible for producing reactive oxygen species. These highly reactive species can decrease proliferation and induce tumor cell death. The search for PS of natural origin extracted from plants becomes relevant, as they have photoactivation capacity, preferentially targeting tumor cells and because they do not present any or little toxicity to healthy cells. OBJECTIVE: Our work aimed to carry out a qualitative systematic review to investigate the effects of curcumin (CUR), a molecule considered as PS of natural origin, on PDT, using red light or near-infrared radiation in tumor models. METHODS: A systematic search was performed in three databases (PubMed, Scopus, and Web of Science) using the PICOT method, retrieving a total of 1,373 occurrences. At the end of the peer screening, 25 eligible articles were included in this systematic review using inclusion, exclusion, and eligibility criteria. RESULTS: CUR, whether in its free state, associated with metal complexes or other PS and in a nanocarrier system, was considered a relevant PS for PDT using red light or near-infrared against tumoral models in vitro and in vivo, acting by increasing cytotoxicity, inhibiting proliferation, inducing cell death mainly by apoptosis, and changing oxidative parameters. CONCLUSION: The results found in this systematic review suggest the potential use of CUR as a PS of natural origin to be applied in PDT against many neoplasms, encouraging further search in PDT against cancer and serving as an investigative basis for upcoming pre-clinical and clinical applications.

Temporal and spatial variation in the efficiency of a Floc & Sink technique for controlling cyanobacterial blooms in a tropical reservoir.

One of the main symptoms of eutrophication is the proliferation of phytoplankton biomass, including nuisance cyanobacteria. Reduction of the external nutrient load is essential to control eutrophication, and in-lake interventions are suggested for mitigating cyanobacterial blooms to accelerate ecosystem recovery. Floc & Sink (F&S) is one such intervention technique that consists of applying a low dose of coagulants in combination with ballasts for removing cyanobacteria biomass. It is especially suitable for deep lakes with an external nutrient load that is higher than the internal load and suffers from perennial cyanobacterial bloom events. Studies showing the efficacy of the F&S technique have been published, but those testing its variation in efficacy with changes in the environmental conditions are still scarce. Therefore, we evaluated the efficiency of the F&S technique to remove cyanobacteria from water samples collected monthly from two different sites in a deep tropical reservoir (Funil Reservoir, Brazil) in the laboratory. We tested the efficacy of two coagulants, chitosan (CHI) and poly-aluminum chloride (PAC), alone and in combination with lanthanum-modified bentonite (LMB) in settling phytoplankton biomass. We hypothesized that: ⅰ) the combined treatments are more effective in removing the algal biomass and ⅱ) the efficiency of F&S treatments varies spatially and monthly due to changes in environmental conditions. The combined treatments (PAC + LMB or CHI + LMB) removed up to seven times more biomass than single treatments (PAC, CHI, or LMB). Only the treatments CHI and LMB + CHI differed in efficiency between the sites, although all treatments showed significant variation in efficiency over the months at both the sampling sites. The combined treatments exhibited lower removal efficacy during the warm-rainy months (October-March) than during the mild-cold dry months (April-September). At high pH (pH > 10), the efficiency of the CHI and LMB + CHI treatments decreased. CHI had lower removal efficiency when single-cell cyanobacteria were abundant, while the combined treatments were equally efficient regardless of the morphology of the cyanobacteria. Hence, the combination of PAC as a coagulant with a ballast LMB is the most effective technique to precipitate cyanobacteria under the conditions that are encountered around the year in this tropical reservoir.

Increasing Temperature Counteracts the Negative Effect of UV Radiation on Growth and Photosynthetic Efficiency of Microcystis aeruginosa and Raphidiopsis raciborskii.

High temperature can promote cyanobacterial blooms, whereas ultraviolet radiation (UVR) can potentially depress cyanobacterial growth by damaging their photosynthetic apparatus. Although the damaging effect of UVR has been well documented, reports on the interactive effects of UV radiation exposure and warming on cyanobacteria remain scarce. To better understand the combined effects of temperature and UVR on cyanobacteria, two strains of nuisance species, Microcystis aeruginosa (MIRF) and Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii, CYRF), were grown at 24°C and 28°C and were daily exposed to UVA + UVB (PAR + UVA+UVB) or only UVA (PAR + UVA) radiation. MIRF and CYRF growth rates were most affected by PAR + UVA+UVB treatment and to a lesser extent by the PAR + UVA treatment. Negative UVR effects on growth, Photosystem II (PSII) efficiency and photosynthesis were pronounced at 24°C when compared to that at 28°C. Our results showed a cumulative negative effect on PSII efficiency in MIRF, but not in CYRF. Hence, although higher temperature ameliorates UVR damage, interspecific differences may lead to deviating impacts on different species, and combined elevated temperature and UVR stress could influence species competition.

SARS-COV-2 Vaccines: What Indicators are Associated with the Worldwide Distribution of the First Doses.

The present study aimed to identify the factors associated with the distribution of the first doses of the COVID-19 vaccine. In this study, we used 9 variables: human development index (HDI), gross domestic product (GDP per capita), Gini index, population density, extreme poverty, life expectancy, COVID cases, COVID deaths, and reproduction rate. The time period was until February 1, 2021. The variable of interest was the sum of the days after the vaccine arrived in the countries. Pearson's correlation coefficients were calculated, and t-test was performed between the groups that received and did not receive the immunizer, and finally, a stepwise linear regression model was used. 58 (30.4%) of the 191 countries received the SARS-CoV-2 vaccine. The countries that received the most doses were the United States, China, the United Kingdom, and Israel. Vaccine access in days showed a positive Pearson correlation HDI, GDP, life expectancy, COVID-19 cases, deaths, and reproduction rate. Human development level, COVID-19 deaths, GDP per capita, and population density are able to explain almost 50% of the speed of access to immunizers. Countries with higher HDI and per capita income obtained priority access.

'Floc and Sink' Technique Removes Cyanobacteria and Microcystins from Tropical Reservoir Water.

Combining coagulants with ballast (natural soil or modified clay) to remove cyanobacteria from the water column is a promising tool to mitigate nuisance blooms. Nevertheless, the possible effects of this technique on different toxin-producing cyanobacteria species have not been thoroughly investigated. This laboratory study evaluated the potential effects of the "Floc and Sink" technique on releasing microcystins (MC) from the precipitated biomass. A combined treatment of polyaluminium chloride (PAC) with lanthanum modified bentonite (LMB) and/or local red soil (LRS) was applied to the bloom material (mainly Dolichospermum circinalis and Microcystis aeruginosa) of a tropical reservoir. Intra and extracellular MC and biomass removal were evaluated. PAC alone was not efficient to remove the biomass, while PAC + LMB + LRS was the most efficient and removed 4.3-7.5 times more biomass than other treatments. Intracellular MC concentrations ranged between 12 and 2.180 µg L-1 independent from the biomass. PAC treatment increased extracellular MC concentrations from 3.5 to 6 times. However, when combined with ballast, extracellular MC was up to 4.2 times lower in the top of the test tubes. Nevertheless, PAC + LRS and PAC + LMB + LRS treatments showed extracellular MC concentration eight times higher than controls in the bottom. Our results showed that Floc and Sink appears to be more promising in removing cyanobacteria and extracellular MC from the water column than a sole coagulant (PAC).

The impact of social distancing on COVID-19 infections and deaths.

BACKGROUND: To assess the impact of the social isolation index on the number of infections and deaths by COVID-19 in the state of São Paulo (Brazil). METHODS: Daily isolation data, obtained through geolocation information by mobile phone, were evaluated together with the number of daily infections and deaths by COVID-19 in the state of São Paulo. The study was conducted from February 26 to May 19, 2020. The data were modeled through the vector autoregression (VAR) model. RESULTS: The isolation index has an effect of approximately 5% in variation in the number of infections, and 7% in the number of deaths. The impulse response function (IRF) caused a drop of 0.15% in the number of new cases/day, and 0.17% in the number of deaths/day following a shock in the isolation index. For both cases, this effect occurred 1 day after the shock and stabilized after 10 periods. An increase of 1% in the isolation index led to a reduction of 6.91% in new cases and 6.90% in the number of deaths. The 30 cumulative day reduction reached 22.72% in terms of transmission and 35.39% for deaths. CONCLUSIONS: The social isolation index is related to deaths and infections from SARS-CoV-2. Although distancing measures are accompanied with impacts on the economy and the emergence of other morbidities, the benefits caused by the reduction in the speed of contagion are significant. The adoption of distancing measures has a substantial impact on the number of infected individuals and deaths by COVID-19.