Hydrogen can be easily produced from the catalytic hydrolysis of sodium borohydride (NaBH 4 ), with sodium metaborate (NaBO 2 ) being the co-product. If NaBO 2 can be economically recycled in the process, NaBH 4 could be considered as a promising hydrogen carrier in fuel cells because of its high hydrogen content. In this paper, we report our investigation into the synthesis of NaBH 4 from NaBO 2 via ball milling. The starting materials for the synthesis were NaBO 2 and magnesium hydride (MgH 2 ). After ball milling at ambient temperature in inert gas, NaBH 4 and magnesium oxide (MgO) were produced. The synthesized NaBH 4 was extracted from the admixture by isopropylamine. Our results indicated that the yield of NaBH 4 from this process was 71 wt % when the MgH 2 /NaBO 2 mole ratio, ball/powder ratio (BPR), inert gas (argon) pressure, and milling time were 2.07:1, 50:1, 200 kPa, and 2 h, respectively. The mole ratio of the reactants (MgH 2 and NaBO 2 ), ball-milling time, BPR, and milling atmosphere were found to have significant influence over NaBH 4 synthesis. We present the results and discuss the effects of these key parameters in this paper.

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BackgroundTo evaluate the effects of proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors on major adverse cardiovascular events (MACE).MethodsOur systematic review included randomised controlled trials if they studied PCSK9 inhibitors in patients for primary and/or secondary prevention of cardiovascular diseases or with hypercholesterolaemia/hyperlipidaemia. Dichotomous variables from individual studies were pooled by relative risks (RR) and their 95% CIs using the random-effect model. Risk difference (RD) in the 10-year frame was also estimated using the pooled RR and the estimated baseline risk using the control group. Grading of Recommendation Assessment, Development and Evaluation was used to assess the quality of evidence.ResultsWe included 54 trials with 97 910 patients in the analysis. Compared with controls, PCSK9 inhibitors significantly reduced the risk of MACE by 16% (RR, 0.84; 95% CI 0.79 to 0.89; RD: 47 fewer per 1000 vs 286 as the baseline risk; 95% CI 32 to 59 fewer), non-fatal myocardial infarction (MI) by 17% (RR, 0.83; 95% CI 0.74 to 0.93; RD, 35 fewer per 1000 vs 207 as the baseline; 95% CI 13 to 53 fewer) and any stroke by 25% (RR, 0.75; 95% CI 0.65 to 0.85; RD, 16 fewer per 1000 vs 61 as the baseline; 95% CI 9 to 21 fewer) with moderate quality evidence. No significant differences were found between PCSK9 inhibitors and control groups in all-cause mortality, cardiovascular death, heart failure or unstable angina with low-quality evidence.ConclusionsThis study demonstrated that PCSK9 inhibitors could significantly reduce the risk of MACE, non-fatal MI and stroke.Trial registrationPROSPERO; CRD42017073904.

ObjectiveTo determine the harms of proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors in people who need lipid-lowering therapy.MethodsThis systematic review included randomised controlled trials that compared PCSK9 inhibitors with placebo, standard care or active lipid-lowering comparators in people who need lipid-lowering therapy with the follow-up duration of at least 24 weeks. We summarised the relative effects for potential harms from PCSK9 inhibitors using random-effect pairwise meta-analyses and assessed the certainty of evidence using GRADE (Grading of Recommendation Assessment, Development and Evaluation) for each outcome.ResultsWe included 32 trials with 65 861 participants (with the median follow-up duration of 40 weeks, ranging from 24 to 146 weeks). The meta-analysis showed an incidence of injection-site reaction leading to discontinuation (absolute incidence of 15 events (95% CI 11 to 20) per 1000 persons in a 5-year time frame, high certainty evidence). PCSK9 inhibitors do not increase the risk of new-onset diabetes mellitus, neurocognitive events, cataracts or gastrointestinal haemorrhage with high certainty evidence. PCSK9 inhibitors probably do not increase the risks of myalgia or muscular pain leading to discontinuation or any adverse events leading to discontinuation with moderate evidence certainty. Given very limited evidence, PCSK9 inhibitors might not increase influenza-like symptoms leading to discontinuation (risk ratio 1.5; 95% CI 0.06 to 36.58). We did not identify credible subgroup analyses results, including shorter versus longer follow-up duration of trials.ConclusionsPCSK9 inhibitors slightly increase the risk of severe injection-site reaction but not cataracts, gastrointestinal haemorrhage, neurocognitive events, new-onset diabetes or severe myalgia or muscular pain.