Variation in the properties of biochars produced by mixing agricultural residues and mineral soils for agricultural application.

The research and application of biochars enriched with minerals have increased in recent years; however, the mineral fraction used consists of specific minerals, such as clay minerals and synthesized compounds. In this work, the effects of adding two specific soil types (sandy and clayey) to rice and coffee husks in order to generate biochars via pyrolysis was investigated. Chemical, physical-chemical, thermal, spectroscopic and crystallographic analyses were conducted on the produced biochars. The study confirmed that the presence of mineral soils during the pyrolysis process increases the yield, C retention ratio, and specific surface area. It also decreases the pH, cation exchange capacity (CEC), nutrient content, and carbon-to-nitrogen ratio of biochars. However, the biochars produced by mixing coffee husks and mineral soils still demonstrate a capacity to increase the pH and the CEC of tropical soils. In addition, increased C retention demonstrates an environmental benefit of this biochar production method. Biomass pyrolysis combined with clayey soil results in a biochar with a higher degree of aromaticity and higher thermal stability when compared to biomass pyrolysis alone. These characteristics give the biochar a recalcitrant character, without the necessity for steps related to the synthesis of specific mineral compounds, which reduces the economic and energy cost of the process.

Soil mineralogy-controlled phosphorus availability in soils mixed with phosphate fertiliser and biochar.

The biochar amendment to soil proved to be beneficial to improve soil quality and provide nutrients. However, the effect of biochar on the availability of P is still controversial. We aim to study the effect of adding phosphate fertiliser and biochar on the P bioavailability in soils of different mineralogies. Eight biochars derived from biomass (rice husk and coffee husk), soil (sandy and clayey), and phosphate fertiliser (triple superphosphate) were produced. The biochar enrichment process with superphosphate was carried out before and after pyrolysis. Thus, we tested two biochar groups: (1) enriched biochars prior to pyrolysis; (2) enriched biochars after pyrolysis. These biochars were tested as P sources in soils of three mineralogies (kaolinite/oxide, kaolinite, and smectite). Batch sorption-desorption experiments were conducted. The sorbed P was fractionated to examine the factors controlling the retention of applied P. In the three soil mineralogies the use of enriched biochars prior to pyrolysis results in lower availability of P. In contrast, the enriched biochars after pyrolysis increase the bioavailability of P. The coffee husk biochar is more suitable than rice husk biochar to protect P from soil retention reactions. The use of sandy soil rather than clayey soil in enriched biochars compositions results in higher P content availability when applied to soils. The factor that controls the retention of P is the reaction between P, organic compounds, and Fe and Al compounds. The greater the relationship between biochar and soluble P in the fertiliser, the higher the increase of P retention.

Antimicrobial use and aetiology of bloodstream infections in critically ill patients during early stages of SARS-CoV-2 pandemic.

Background: During early stages of COVID-19 pandemic, antimicrobials were commonly prescribed. Aim: To describe clinical, microbiological and antimicrobial use changes in bloodstream infections (BSI) of ICU patients during the first wave of COVID-19 pandemic compared to pre-COVID-19 era. Methods: Observational cohort study of patients admitted to ICU of Bellvitge University Hospital was conducted during the COVID-19 pandemic (March-June 2020) and before COVID-19 pandemic (March-June 2019). Differences in clinical characteristics, antimicrobial consumption and incidence and aetiology of BSI were measured. Findings: COVID-19 patients had significantly less comorbidities with obesity the only risk factor that increased in frequency. COVID-19 patients more frequently required invasive supportive care measures, had longer median ICU stay and higher mortality rates. The incidence of BSIs was higher in COVID-19 period (RR 3.2 [95%CI 2.2-4.7]), occurred in patients who showed prolonged median ICU stay (21days) and was associated with high mortality rate (47%). The highest increases in the aetiological agents were observed for AmpC-producing bacteria (RR 11.1 [95%CI 2.6-47.9]) and non-fermenting rods (RR 7.0 [95%CI 1.5-31.4]). The emergence of bacteraemia caused by Gram-negative rods resistant to amoxicillin-clavulanate, which was used as empirical therapy during early stages of the pandemic, led to an escalation towards broader-spectrum antimicrobials such as meropenem and colistin which was also associated with the emergence of resistant isolates. Conclusions: The epidemiological shift towards resistant phenotypes in critically ill COVID-19 patients was associated with the selective use of antimicrobials. Our study provides evidence of the impact of empirical therapy on the selection of bacteria and their consequences on BSI over the subsequent months.

Effectiveness of treatments for severe sepsis: a prospective, multicenter, observational study.

RATIONALE: Several Surviving Sepsis Campaign Guidelines recommendations are reevaluated. OBJECTIVES: To analyze the effectiveness of treatments recommended in the sepsis guidelines. METHODS: In a prospective observational study, we studied all adult patients with severe sepsis from 77 intensive care units. We recorded compliance with four therapeutic goals (central venous pressure 8 mm Hg or greater for persistent hypotension despite fluid resuscitation and/or lactate greater than 36 mg/dl, central venous oxygen saturation 70% or greater for persistent hypotension despite fluid resuscitation and/or lactate greater than 36 mg/dl, blood glucose greater than or equal to the lower limit of normal but less than 150 mg/dl, and inspiratory plateau pressure less than 30 cm H(2)O for mechanically ventilated patients) and four treatments (early broad-spectrum antibiotics, fluid challenge in the event of hypotension and/or lactate greater than 36 mg/dl, low-dose steroids for septic shock, drotrecogin alfa [activated] for multiorgan failure). The primary outcome measure was hospital mortality. The effectiveness of each treatment was estimated using propensity scores. MEASUREMENTS AND MAIN RESULTS: Of 2,796 patients, 41.6% died before hospital discharge. Treatments associated with lower hospital mortality were early broad-spectrum antibiotic treatment (treatment within 1 hour vs. no treatment within first 6 hours of diagnosis; odds ratio, 0.67; 95% confidence interval, 0.50-0.90; P = 0.008) and drotrecogin alfa (activated) (odds ratio, 0.59; 95% confidence interval, 0.41-0.84; P = 0.004). Fluid challenge and low-dose steroids showed no benefits. CONCLUSIONS: In severe sepsis, early administration of broad-spectrum antibiotics in all patients and administration of drotrecogin alfa (activated) in the most severe patients reduce mortality.

Critical Care Updates for the Nephrologist, 2016.

With improvements in supportive care, mortality from sepsis and the acute respiratory distress syndrome has declined over the past 20 years. However, mortality associated with these conditions is still high. We will review the latest clinical trial findings in these fields, along with implications for the nephrologist. Very recently, there have been significant changes with regard to the management of anterior ischemic strokes; given the high rate of cerebrovascular disease in patients with CKD or ESRD, we will review those studies here. Finally, we will comment on best care practices in the intensive care unit, which are relevant to the nephrologist.

Management of Acute Kidney Injury and Acid-Base Balance in the Septic Patient.

Acute kidney injury (AKI) is an abrupt decrease in kidney function that takes place over hours to days. Sepsis is the leading cause of AKI and portends a particularly high morbidity and mortality, although the severity may vary from a transient rise in serum creatinine to end-stage renal disease. With regard to acid-base management in septic AKI, caution should be used with hyperchloremic crystalloid solutions, and dialysis is often used in the setting of severe acidosis. In the future, biomarkers may help clinicians identify AKI earlier and allow for potential interventions before the development of severe AKI.

Synthesis of enriched biochar as a vehicle for phosphorus in tropical soils

Phosphorus (P) is one of the nutrients that most limits agricultural productivity, especially in tropical soils. Enriched biochar has been proposed to increase the bioavailability of P and other nutrients in the soil. Thus, the objective of this study was to evaluate the availability of P in phosphate biochar (composed of biomass and soil) as a function of the triple superphosphate mixture before and after the pyrolysis process. We produced eight types of enriched biochar via pyrolysis by combining sandy or clayey soil with rice or coffee husk, and by adding triple superphosphate before or after pyrolysis. The heating of the phosphate fertilizer during the pyrolysis process resulted in a higher crystallinity of the phosphates, lower content of labile fractions of P and lower content of available P in phosphate biochars than when the superphosphate was added after pyrolysis. (AU)

Short-term independent mortality risk factors in patients with cirrhosis undergoing cardiac surgery.

OBJECTIVES: Cirrhosis represents a serious risk in patients undergoing cardiac surgery. Several preoperative factors identify cirrhotic patients as high risk for cardiac surgery; however, a patient's preoperative status may be modified by surgical intervention and, as yet, no independent postoperative mortality risk factors have been identified in this setting. The objective of this study was to identify preoperative and postoperative mortality risk factors and the scores that are the best predictors of short-term risk. METHODS: Fifty-eight consecutive cirrhotic patients requiring cardiac surgery between January 2004 and January 2009 were prospectively studied at our institution. Forty-two (72%) patients were operated on for valve replacement, 9 (16%) for a CABG and 7 (12%) for both (CABG and valve replacement). Thirty-four (58%) patients were classified as Child-Turcotte-Pugh class A, 21 (36%) as class B and 3 (5%) as class C. We evaluated the variables that are usually measured on admission and during the first 24 h of the postoperative period together with potential operative predictors of outcome, such as cardiac surgery scores (Parsonnet, EuroSCORE), liver scores (Child-Turcotte-Pugh, model for end-stage liver disease, United Kingdom end-stage liver disease score) and ICU scores (acute physiology and chronic health evaluation II and III, simplified acute physiology score II and III, sequential organ failure assessment). RESULTS: Seven patients (12%) died in-hospital, of whom 5 were Child-Turcotte-Pugh class B and 2 class C. Comparing survivors vs non-survivors, univariate analysis revealed that variables associated with short-term outcome were international normalized ratio (1.5 ± 0.24 vs 2.2 ± 0.11, P < 0.0001), presurgery platelet count (171 ± 87 vs 113 ± 52 l nl(-1), P = 0.031), presurgery haemoglobin count (11.8 ± 1.8 vs 10.2 ± 1.4 g dl(-1), P = 0.021), total need for erythrocyte concentrates (2 ± 3.4 vs 8.5 ± 8 units, P < 0.0001), PaO(2)/FiO(2) at 12 h after ICU admission (327 ± 84 vs 257 ± 78, P = 0.04), initial central venous pressure (11 ± 3 vs 16 ± 4 mmHg, P = 0.02) and arterial blood lactate concentration 24 h after admission (1.8 ± 0.5 vs 2.5 ± 1.3 mmol l(-1), P = 0.019). Multivariate analysis identified initial central venous pressure as the only independent factor associated with short-term outcome (P = 0.027). The receiver operating characteristic curve showed that the model for end-stage Liver disease score had a better predictive value for short-term outcome than other scores (AUC: 90.5 ± 4.4%; sensitivity: 85.7%; specificity: 83.7%), although simplified acute physiology score III was acceptable. CONCLUSIONS: We conclude that central venous pressure could be a valuable predictor of short-term outcome in patients with cirrhosis undergoing cardiac surgery. The model for end-stage liver disease score is the best predictor of cirrhotic patients who are at high risk for cardiac surgery. Sequential organ failure assessment and simplified acute physiology score III are also valuable predictors.

Higher requirements of dialysis in severe lithium intoxication.

Severe lithium poisoning is a frequent condition in the intoxicated intensive care unit population. Dialysis is the treatment of choice, but no clinical markers predicting higher requirement for dialysis have been identified to date. We analyze the characteristics of lithium overdose patients needing dialysis to improve lithium clearance, and identify the ones associated with higher dialysis requirement. This is an observational, retrospective study of 14 patients with lithium poisoning admitted from 2004 to 2009. Median age was 41.8 ± 16.1 years. Poisonings were acute in 7.1%, acute-on-chronic in 64.28%, and chronic in 28.5% of cases. Comparing clinical and biochemical data in patients requiring more than one dialysis session with those requiring only one session, the univariate analysis showed differences at admission in creatinine clearance (40.5 ± 23 vs. 73.3 ± 24.9 mL/min, P = 0.025), white blood cells (17,528 ± 3,530 vs. 11,580 ± 3360 cells/L, P = 0.007), and blood sodium concentration (134.8 ± 5.9 vs. 141.8 ± 8.4 mmol/L, P=0.035). We measured the degree of association between the number of sessions and the variables with partial correlations. High lithium levels (P = 0.006, r = 0.69), low creatinine clearance (P = 0.04, r = -0.55), and low blood sodium concentration (P = 0.024, r = -0.59) were associated with a greater number of dialysis sessions. The correlation remained significant for blood sodium concentration (P = 0.016, r = -0.67) after adjustment for creatinine clearance and initial lithium levels. Presence on admission of low creatinine clearance, low blood sodium concentration, and/or high lithium levels correlated with a higher number of dialysis sessions in severe lithium poisoning. These factors, especially low blood sodium concentration, are associated with higher dialysis requirements in severe lithium intoxication.

Bacteremia related with arterial catheter in critically ill patients.

OBJECTIVE: Catheter-related bloodstream infections (CR-BSI) are an increasing problem in the management of critically ill patients. Our objective was to analyze the incidence and epidemiology of CR-BSI in arterial catheters (AC) in a population of critically ill patients. METHODS: We conducted a two-year, prospective, non-randomized study of patients admitted for > 24 h in a 24-bed medical-surgical major teaching ICU. We analyzed the arterial catheters and differentiated between femoral and radial locations. Difference testing between groups was performed using the two-tailed t-test and chi-square test as appropriate. Multivariate logistic regression analyses were conducted to identify independent predictors of CR-BSI occurrence and type of micro-organism responsible. RESULTS: The study included 1456 patients requiring AC placement for ≥ 24 h. A total of 1543 AC were inserted for 14,437 catheter days. The incidence of AC-related bloodstream infections (ACR-BSI) was 3.53 episodes per 1000 catheter days. In the same period the incidence of central venous catheter (CVC)-related bloodstream infections was 4.98 episodes per 1000 catheter days. Logistic regression analysis showed that days of insertion (OR: 1.118 95% confidence interval (CI) 1.026-1.219) and length of ICU stay (OR: 1.052 95% CI: 1.025-1.079) were associated with a higher risk of ACR-BSI. Comparing 705 arterial catheters in femoral location with 838 in radial location, no significant differences in infection rates were found, although there was a trend toward a higher rate among femoral catheters (4.13 vs. 3.36 episodes per 1000 catheter days) (p = 0.72). Among patients with ACR-BSI, Gram-negative bacteria were isolated in 16 episodes (61.5%) in the femoral location and seven (28%) in radial location (OR: 2.586; 95% CI: 1.051-6.363). CONCLUSIONS: We concluded that as has been reported for venous catheters ACR-BSI plays an important role in critically ill patients. Days of insertion and length of ICU stay increase the risk of ACR-BSI. The femoral site increases the risk for Gram-negative infection.

Atributos de solos hidromórficos no Pantanal Norte Matogrossense / Attributes of the hydromorphic soils in the Pantanal of North Matogrosso

Os solos hidromórficos, comuns na Amazônia e no Pantanal, estão sujeitos à alternância natural de períodos de alagamento e secamento, que conduzem a uma formação e características diferenciadas. Estes solos guardam estreita relação com a natureza do material de origem e com os processos de deposição e sedimentação. O objetivo neste trabalho foi avaliar as características químicas, morfológicas e mineralógicas de três perfis de solos do Pantanal Norte Matogrossense (Planossolo, Plintossolo e Gleissolo), a fim de interpretar as relações entre suas propriedades e o ambiente em que foram formados. Os Planossolos e Gleissolos possuem maior fertilidade natural, evidenciada pelos valores expressivos de CTC (capacidade de troca de cátions) e saturação por bases. Os menores teores de Fe2O3 do Planossolo estão relacionados com a redução e remoção do Fe durante sua gênese A mineralogia da fração areia dos solos é constituída principalmente de quartzo, nódulos e concreções de Fe e de Mn, e em menor grau, biotita, muscovita e traços de turmalina, magnetita, ilmenita, epídoto, zircão e rutilo. Os solos apresentaram perfil mineralógico semelhante na fração argila, constituído por caulinita, esmectita, ilita e interestratificados do tipo ilita-esmectita. A mineralogia da fração argila dos solos foi compatível com as diferenças químicas constatadas entre eles, pois o Planossolo apresentou argila de maior atividade relativa às esmectitas e interestratificados ilita/esmectita, com maior soma de bases trocáveis e CTC, enquanto o Plintossolo e o Gleissolo, cujo mineral predominante foi a caulinita, apresentaram baixo teor de bases trocáveis e menor CTC.

The hydromorphic soils, common in the Amazon and the Pantanal, are subject to alternating periods of natural flooding and drying, leading to formation and differentiated characteristics. These soils are closely related to the nature of the sediments, a consequence of the source material and the processes of deposition and sedimentation. The objective of this study was to evaluate the chemical, mineralogical, and morphological profiles of three soils in the North Brazilian Pantanal North (Solonetz, Plinthosol and Gleysol) in order to interpret the relations between their properties and the environment in which they were formed. The Solonetz and Gleysol have higher fertility, as evidenced by the significant values of CEC (cation exchange rate) and base saturation. The lowest levels of Fe2O3 in the Solonetz are related to the reduction and removal of Fe during its genesis. The mineralogy of sand fraction consists mainly of quartz, nodules and concretions of Fe and Mn and to a lesser extent, biotite, muscovite and traces of tourmaline, magnetite, ilmenite, epidote, zircon and rutile. The soil profile was similar in clay mineralogy, consisting of kaolinite, smectite, illite and interstratified illite-smectite type. The clay mineralogy of soils was consistent with the observed chemical differences between them, as the clay Planossolo showed greater activity on smectite and interstratified illite / smectite, with greater total exchangeable bases and CEC, while the Plinthosol and Gleysol, whose predominant mineral was kaolinite, showed a low content of exchangeable bases and lower CEC.