Influence of the quasi-biennial oscillation on the extratropical winter stratosphere in an atmospheric general circulation model and in reanalysis data

The interannual variability of the stratospheric polar vortex during winter in both hemispheres is observed to correlate strongly with the phase of the quasi-biennial oscillation (QBO) in tropical stratospheric winds. It follows that the lack of a spontaneously generated QBO in most atmospheric general circulation models (AGCMs) adversely affects the nature of polar variability in such models. This study examines QBO–vortex coupling in an AGCM in which a QBO is spontaneously induced by resolved and parameterized waves. The QBO–vortex coupling in the AGCM compares favorably to that seen in reanalysis data [from the 40-yr ECMWF Re-Analysis (ERA-40)], provided that careful attention is given to the definition of QBO phase. A phase angle representation of the QBO is employed that is based on the two leading empirical orthogonal functions of equatorial zonal wind vertical profiles. This yields a QBO phase that serves as a proxy for the vertical structure of equatorial winds over the whole depth of the stratosphere and thus provides a means of subsampling the data to select QBO phases with similar vertical profiles of equatorial zonal wind. Using this subsampling, it is found that the QBO phase that induces the strongest polar vortex response in early winter differs from that which induces the strongest late-winter vortex response. This is true in both hemispheres and for both the AGCM and ERA-40. It follows that the strength and timing of QBO influence on the vortex may be affected by the partial seasonal synchronization of QBO phase transitions that occurs both in observations and in the model. This provides a mechanism by which changes in the strength of QBO–vortex correlations may exhibit variability on decadal time scales. In the model, such behavior occurs in the absence of external forcings or interannual variations in sea surface temperatures

An unexpected disruption of the atmospheric quasi-biennial oscillation

One of the most repeatable phenomena seen in the atmosphere, the quasi-biennial oscillation (QBO) between prevailing eastward and westward wind jets in the equatorial stratosphere (approximately 16 to 50 kilometers altitude), was unexpectedly disrupted in February 2016. An unprecedented westward jet formed within the eastward phase in the lower stratosphere and cannot be accounted for by the standard QBO paradigm based on vertical momentum transport. Instead, the primary cause was waves transporting momentum from the Northern Hemisphere. Seasonal forecasts did not predict the disruption, but analogous QBO disruptions are seen very occasionally in some climate simulations. A return to more typical QBO behavior within the next year is forecast, although the possibility of more frequent occurrences of similar disruptions is projected for a warming climate

Estudo do Pré-Tratamento Ácido e Hidrólise Enzimática da Borra de Café Visando a Produção de Bioetanol

O presente trabalho tem como objetivo avaliar a possibilidade de produzir um biocombustível, o bioetanol, valorizando resíduos de baixo valor, nomeadamente as borras de café. Temos cada vez mais assistido a uma evolução tecnológica em larga escala e a um aumento populacional, que se traduz numa vertente positiva no primeiro caso, mas devido ao crescente consumo de energia pela sociedade atual e alteração de padrões de consumo, origina uma grande dependência de utilização de combustíveis fósseis, o que levará a um previsível esgotamento das suas reservas naturais. No que respeita ao aumento populacional, este provoca um aumento da produção de resíduos. Assim, cada vez mais se torna necessário procurar recursos energéticos alternativos, de natureza renovável, designadamente através da produção de biocombustíveis a partir de resíduos de baixo valor comercial. Esta utilização de resíduos como matéria-prima para a produção de biocombustíveis traduz-se em duas vantagens: i) por um lado diminui-se a acumulação dos resíduos gerados, e ii) por outro, podem estes ser aproveitados de uma forma eficiente. O trabalho foi realizado em duas etapas fundamentais: a caraterização físico-química da borra de café e a quantificação dos açúcares formados, após aplicação do pré-tratamento ácido e hidrólise enzimática, por três métodos: DNS (ácido 3,5-dinitrosalicílico), refratometria e cromatografia líquida de alta eficiência (HPLC). Para a caraterização físico-química da borra de café analisaram-se vários parâmetros, dos quais se salientam, o poder calorífico (5082,82 kcal/kg), o teor de cinzas (1,83%), o teor de proteínas (13,74 g / 100gcafé), o teor de celulose (16,17%) e o teor de lenhina (29,04%). No pré-tratamento ácido utilizou-se concentrações (v/v) de 1% a 5% dos ácidos H2SO4, HCI, HNO3, CH3COOH e de 7% para o CH3COOH, a uma temperatura de 85 ºC, com tempo de reação de 270 min e agitação de 50 rpm. A hidrólise enzimática foi concretizada num banho a 50 ºC, durante 120 minutos, mantendo a mesma velocidade de agitação do pré-tratamento e recorrendo à enzima Viscozyme L, na proporção de 100 L enzima/g amostra. A eficiência do pré-tratamento e hidrólise enzimática foi avaliada através da quantificação dos açúcares formados. Na quantificação pelo método DNS, o ácido sulfúrico e nítrico a 3% foram os que apresentaram rendimentos superiores de açúcares redutores totais, com 43,1% e 43,2%, respetivamente, seguido do ácido nítrico a 5%, cujo rendimento igualou os 41,4%. Na determinação dos açúcares totais, realizada por refratometria, confirmou-se que o ácido sulfúrico a 5% foi aquele que apresentou um rendimento mais alto - 78,9% - seguido da concentração de 3% com 65,3%. Finalmente, no método de HPLC, o ácido sulfúrico a 5% proporcionou rendimentos mais elevados de xilose, arabinose e glucose, que tomaram os valores de 6,1%, 9,3% e 11,0%, respetivamente.The present work aims to evaluate the possibility of producing a biofuel, bioethanol, by valuing low value residues, namely coffee grounds. We have been increasingly witnessing a large-scale technological evolution and a population increase, which translates into a positive aspect in the first case, but, due to the increasing consumption of energy by the current society and changes in consumption patterns, causes a great dependence on the use of fossil fuels, which will lead to a predictable depletion of their natural reserves. As regards population growth, this causes an increase in waste production. Thus, it is increasingly necessary to look for alternative energy resources of a renewable nature, namely through the production of biofuels from low commercial value waste. This use of waste as a raw material for the production of biofuels has two advantages: (i) on the one hand, the accumulation of generated waste is reduced, and (ii) on the other, it can be used efficiently. This work was carried out in two fundamental stages: the physical-chemical characterization of coffee grounds and the quantification of the sugars formed, after application of acid pretreatment and enzymatic hydrolysis, by three methods: DNS (3,5-Dinitrosalicylic acid), refractometry and high performance liquid chromatography (HPLC). In the chemical characterization of coffee grounds, several parameters were used, such as calorific value (5082,82 cal/g), ash content (1,83%), protein (13,74 g/100gcoffee), cellulose (16,17%) and lignin (29,04%). In acid pre-treatment, 1% to 5% concentrations of H2SO4, HCl, HNO3, CH3COOH acids and 7% of CH3COOH were used (v/v) at a temperature of 85°C with a reaction time of 270 min and stirring at 50 rpm. The enzymatic hydrolysis was carried out in a bath at 50°C for 120 minutes, maintaining the same stirring speed of the pretreatment and using the enzyme Viscozyme L in the proportion of 100 μl enzyme/g sample. The efficiency of pretreatment and enzymatic hydrolysis was evaluated by quantifying the sugars formed. In the DNS method, 3% sulfuric and nitric acid were those that presented higher yields of total reducing sugars, with 43,1% and 43,2%, respectively, followed by 5% nitric acid, whose yield was equal to 41,4%. In the determination of total sugars, performed by refractometry, 5% sulfuric acid was the one that presented a higher yield – 78,9% - followed by the concentration of 3% with 65,3%. Finally, in the HPLC method, 5% sulfuric acid provided higher yields of xylose, arabinose and glucose, which took the values of 6,1%, 9,3% and 11%, respectively

Liver Function Test Abnormalities in Experimental and Clinical Plasmodium vivax Infection

Liver transaminase elevations after treatment in malaria volunteer infection studies (VISs) have raised safety concerns. We investigated transaminase elevations from two human Plasmodium vivax VISs where subjects were treated with chloroquine (n = 24) or artefenomel (n = 8) and compared them with studies in Thailand (n = 41) and Malaysia (n = 76). In the VISs, alanine transaminase (ALT) increased to ≥ 2.5 × upper limit of normal (ULN) in 11/32 (34%) volunteers, peaking 5–8 days posttreatment. Transaminase elevations were asymptomatic, were not associated with elevated bilirubin, and resolved by day 42. The risk of an ALT ≥ 2.5 × ULN increased more than 4-fold (odds ratio [OR] 4.28; 95% CI: 1.26–14.59; P = 0.02) for every log10 increase in the parasite clearance burden (PCB), defined as the log-fold reduction in parasitemia 24 hours post-treatment. Although an elevated ALT ≥ 2.5 × ULN was more common after artefenomel than after chloroquine (5/8 [63%] versus 6/24 [25%]; OR 5.0; 95% CI: 0.91–27.47; P = 0.06), this risk disappeared when corrected for parasite clearance burden (PCB). Peak ALT also correlated with peak C-reactive protein (R = 0.44; P = 0.012). Elevations in ALT (≥ 2.5 × ULN) were less common in malaria-endemic settings, occurring in 1/41 (2.5%) Thai patients treated with artefenomel, and in none of 76 Malaysians treated with chloroquine or artemisinin combination therapy. Post-treatment transaminase elevations are common in experimental P. vivax infection but do not appear to impact on participant safety. Although the mechanism of these changes remains uncertain, host inflammatory response to parasite clearance may be contributory

Transcriptional profiling and immunophenotyping show sustained activation of blood monocyte in subpatent Plasmodium falciparum infection

Objectives Malaria, caused by Plasmodium infection, remains a major global health problem. Monocytes are integral to the immune response, yet their transcriptional and functional responses in primary Plasmodium falciparum infection and in clinical malaria are poorly understood. Methods The transcriptional and functional profiles of monocytes were examined in controlled human malaria infection with P. falciparum blood stages and in children and adults with acute malaria. Monocyte gene expression and functional phenotypes were examined by RNA sequencing and flow cytometry at peak infection and compared to pre‐infection or at convalescence in acute malaria. Results In subpatent primary infection, the monocyte transcriptional profile was dominated by an interferon (IFN) molecular signature. Pathways enriched included type I IFN signalling, innate immune response and cytokine‐mediated signalling. Monocytes increased TNF and IL‐12 production upon in vitro toll‐like receptor stimulation and increased IL‐10 production upon in vitro parasite restimulation. Longitudinal phenotypic analyses revealed sustained significant changes in the composition of monocytes following infection, with increased CD14+CD16− and decreased CD14−CD16+ subsets. In acute malaria, monocyte CD64/FcγRI expression was significantly increased in children and adults, while HLA‐DR remained stable. Although children and adults showed a similar pattern of differentially expressed genes, the number and magnitude of gene expression change were greater in children. Conclusions Monocyte activation during subpatent malaria is driven by an IFN molecular signature with robust activation of genes enriched in pathogen detection, phagocytosis, antimicrobial activity and antigen presentation. The greater magnitude of transcriptional changes in children with acute malaria suggests monocyte phenotypes may change with age or exposure

Variability in Serum Sodium Concentration and Prognostic Significance in Severe Traumatic Brain Injury: A Multicenter Observational Study.

BACKGROUND/OBJECTIVE: Dysnatremia is common in severe traumatic brain injury (TBI) patients and may contribute to mortality. However, serum sodium variability has not been studied in TBI patients. We hypothesized that such variability would be independently associated with mortality. METHODS: We collected 6-hourly serum sodium levels for the first 7 days of ICU admission from 240 severe TBI patients in 14 neurotrauma ICUs in Europe and Australia. We evaluated the association between daily serum sodium standard deviation (dNaSD), an index of variability, and 28-day mortality. RESULTS: Patients were 46 ± 19 years of age with a median initial GCS of 6 [4-8]. Overall hospital mortality was 28%. Hypernatremia and hyponatremia occurred in 64% and 24% of patients, respectively. Over the first 7 days in ICU, serum sodium standard deviation was 2.8 [2.0-3.9] mmol/L. Maximum daily serum sodium standard deviation (dNaSD) occurred at a median of 2 [1-4] days after admission. There was a significant progressive decrease in dNaSD over the first 7 days (coefficient - 0.15 95% CI [- 0.18 to - 0.12], p < 0.001). After adjusting for baseline TBI severity, diabetes insipidus, the use of osmotherapy, the occurrence of hypernatremia, and hyponatremia and center, dNaSD was significantly independently associated with 28-day mortality (HR 1.27 95% CI (1.01-1.61), p = 0.048). CONCLUSIONS: Our study demonstrates that daily serum sodium variability is an independent predictor of 28-day mortality in severe TBI patients. Further prospective investigations are necessary to confirm the significance of sodium variability in larger cohorts of TBI patients and test whether attenuating such variability confers outcome benefits to such patients

Plasmacytoid dendritic cells appear inactive during sub-microscopic Plasmodium falciparum blood-stage infection, yet retain their ability to respond to TLR stimulation

Plasmacytoid dendritic cells (pDC) are activators of innate and adaptive immune responses that express HLA-DR, toll-like receptor (TLR) 7, TLR9 and produce type I interferons. The role of human pDC in malaria remains poorly characterised. pDC activation and cytokine production were assessed in 59 malaria-naive volunteers during experimental infection with 150 or 1,800 P. falciparum-parasitized red blood cells. Using RNA sequencing, longitudinal changes in pDC gene expression were examined in five adults before and at peak-infection. pDC responsiveness to TLR7 and TLR9 stimulation was assessed in-vitro. Circulating pDC remained transcriptionally stable with gene expression altered for 8 genes (FDR < 0.07). There was no upregulation of co-stimulatory molecules CD86, CD80, CD40, and reduced surface expression of HLA-DR and CD123 (IL-3R-α). pDC loss from the circulation was associated with active caspase-3, suggesting pDC apoptosis during primary infection. pDC remained responsive to TLR stimulation, producing IFN-α and upregulating HLA-DR, CD86, CD123 at peak-infection. In clinical malaria, pDC retained HLA-DR but reduced CD123 expression compared to convalescence. These data demonstrate pDC retain function during a first blood-stage P. falciparum exposure despite sub-microscopic parasitaemia downregulating HLA-DR. The lack of evident pDC activation in both early infection and malaria suggests little response of circulating pDC to infection

Early Osmotherapy in Severe Traumatic Brain Injury : An International Multicenter Study

The optimal osmotic agent to treat intracranial hypertension in patients with severe traumatic brain injury (TBI) remains uncertain. We aimed to test whether the choice of mannitol or hypertonic saline (HTS) as early (first 96 h) osmotherapy in these patients might be associated with a difference in mortality. We retrospectively analyzed data from 2015 from 14 tertiary intensive care units (ICUs) in Australia, UK, and Europe treating severe TBI patients with intracranial pressure (ICP) monitoring and compared mortality in those who received mannitol only versus HTS only. We performed multi-variable analysis adjusting for site and illness severity (Injury Severity Score, extended IMPACT score, and mean ICP over the first 96 h) using Cox proportional hazards regression. We collected data on 262 patients and compared patients who received early osmotherapy with mannitol alone (n = 46) with those who received HTS alone (n = 46). Mannitol patients were older (median age, 49.2 (19.2) vs. 40.5 (16.8) years; p = 0.02), with higher Injury Severity Scores (42 (15.9) vs. 32.1 [11.3]; p = 0.001), and IMPACT-TBI predicted 6-month mortality (34.5% [23-46] vs. 25% [13-38]; p = 0.02), but had similar APACHE-II scores, and mean and maximum ICPs over the first 96 h. The unadjusted hazard ratio for in-hospital mortality in patients receiving only mannitol was 3.35 (95% confidence interval [CI], 1.60-7.03; p = 0.001). After adjustment for key mortality predictors, the hazard ratio for in-hospital mortality in patients receiving only mannitol was 2.64 (95% CI, 0.96-7.30; p = 0.06). The choice of early osmotherapy in severe TBI patients may affect survival, or simply reflect clinician beliefs about their different roles, and warrants controlled investigation.Peer reviewe

Sensitive Detection of Plasmodium vivax Using a High-Throughput, Colourimetric Loop Mediated Isothermal Amplification (HtLAMP) Platform: A Potential Novel Tool for Malaria Elimination.

INTRODUCTION: Plasmodium vivax malaria has a wide geographic distribution and poses challenges to malaria elimination that are likely to be greater than those of P. falciparum. Diagnostic tools for P. vivax infection in non-reference laboratory settings are limited to microscopy and rapid diagnostic tests but these are unreliable at low parasitemia. The development and validation of a high-throughput and sensitive assay for P. vivax is a priority. METHODS: A high-throughput LAMP assay targeting a P. vivax mitochondrial gene and deploying colorimetric detection in a 96-well plate format was developed and evaluated in the laboratory. Diagnostic accuracy was compared against microscopy, antigen detection tests and PCR and validated in samples from malaria patients and community controls in a district hospital setting in Sabah, Malaysia. RESULTS: The high throughput LAMP-P. vivax assay (HtLAMP-Pv) performed with an estimated limit of detection of 1.4 parasites/ μL. Assay primers demonstrated cross-reactivity with P. knowlesi but not with other Plasmodium spp. Field testing of HtLAMP-Pv was conducted using 149 samples from symptomatic malaria patients (64 P. vivax, 17 P. falciparum, 56 P. knowlesi, 7 P. malariae, 1 mixed P. knowlesi/P. vivax, with 4 excluded). When compared against multiplex PCR, HtLAMP-Pv demonstrated a sensitivity for P. vivax of 95% (95% CI 87-99%); 61/64), and specificity of 100% (95% CI 86-100%); 25/25) when P. knowlesi samples were excluded. HtLAMP-Pv testing of 112 samples from asymptomatic community controls, 7 of which had submicroscopic P. vivax infections by PCR, showed a sensitivity of 71% (95% CI 29-96%; 5/7) and specificity of 93% (95% CI87-97%; 98/105). CONCLUSION: This novel HtLAMP-P. vivax assay has the potential to be a useful field applicable molecular diagnostic test for P. vivax infection in elimination settings

Effects of brain tissue oxygen (PbtO2) guided management on patient outcomes following severe traumatic brain injury: A systematic review and meta-analysis.

Monitoring and optimisation of brain tissue oxygen tension (PbtO2) has been associated with improved neurological outcome and survival in observational studies of severe traumatic brain injury (TBI). We carried out a systematic review of randomized controlled trials to determine if PbtO2-guided management is associated with differential neurological outcomes, survival, and adverse events. Searches were carried out to 10 February 2022 in Medline (OvidSP), 11 February in EMBASE (OvidSP) and 8 February in Cochrane library. Randomized controlled trials comparing PbtO2 and ICP-guided management to ICP-guided management alone were included. The primary outcome was survival with favourable neurological outcome at 6-months post injury. Data were extracted by two independent authors and GRADE certainty of evidence assessed. There was no difference in the proportion of patients with favourable neurological outcomes with PbtO2-guided management (relative risk [RR] 1.42, 95% CI 0.97 to 2.08; p = 0.07; I2 = 0%, very low certainty evidence) but PbtO2-guided management was associated with reduced mortality (RR 0.54, 95% CI 0.31 to 0.93; p = 0.03; I2 = 42%; very low certainty evidence) and ICP (mean difference (MD) - 4.62, 95% CI - 8.27 to - 0.98; p = 0.01; I2 = 63%; very low certainty evidence). There was no significant difference in the risk of adverse respiratory or cardiovascular events. PbtO2-guided management in addition to ICP-based care was not significantly associated with increased favourable neurological outcomes, but was associated with increased survival and reduced ICP, with no difference in respiratory or cardiovascular adverse events. However, based on GRADE criteria, the certainty of evidence provided by this meta-analysis was consistently very low. MESH: Brain Ischemia; Intensive Care; Glasgow Outcome Scale; Randomized Controlled Trial; Craniocerebral Trauma