Risk factors associated with intraoperative persistent hypotension in pancreaticoduodenectomy

BACKGROUND Intraoperative persistent hypotension(IPH)during pancreaticoduodenectomy(PD)is linked to adverse postoperative outcomes,yet its risk factors remain unclear.AIM To clarify the risk factors associated with IPH during PD,ensuring patient safety in the perioperative period.METHODS A retrospective analysis of patient records from January 2018 to December 2022 at the First Affiliated Hospital of Nanjing Medical University identified factors associated with IPH in PD.These factors included age,gender,body mass index,American Society of Anesthesiologists classification,comorbidities,medication history,operation duration,fluid balance,blood loss,urine output,and blood gas parameters.IPH was defined as sustained mean arterial pressure<65 mmHg,requiring prolonged deoxyepinephrine infusion for>30 min despite additional deoxyepinephrine and fluid treatments.RESULTS Among 1596 PD patients,661(41.42%)experienced IPH.Multivariate logistic regression identified key risk factors:increased age[odds ratio(OR):1.20 per decade,95%confidence interval(CI):1.08-1.33](P<0.001),longer surgery duration(OR:1.15 per additional hour,95%CI:1.05-1.26)(P<0.01),and greater blood loss(OR:1.18 per 250-mL increment,95%CI:1.06-1.32)(P<0.01).A novel finding was the association of arterial blood Ca^(2+)<1.05 mmol/L with IPH(OR:2.03,95%CI:1.65-2.50)(P<0.001).CONCLUSION IPH during PD is independently associated with older age,prolonged surgery,increased blood loss,and lower plasma Ca^(2+).

Process mineralogy characteristics of acid leaching residue produced in low-temperature roasting-acid leaching pretreatment process of refractory gold concentrates

To provide a theoretical basis for a suitable process to extract gold from refractory gold concentrates, process mineralogy on the acid leaching residue of gold calcine was studied by chemical composition, X-ray diffraction, scanning electron microscopy-energy spectrum, and mineral dissociation analysis. The results showed that the acid leaching residue contained Au 68.22 g/t, Ag 92.71 g/t, Fe 0.44%, As 0.10%, and S 0.55%. Gold and silver minerals existed as native gold, argentite, and proustite. Quartz, the main gangue mineral, accounted for 78.33 wt/%. The dissociation degree analysis showed that the proportions of monomer and exposed gold in acid leaching residue were 96.66 wt%. The cyanidation results showed that the cyanide gold leaching rate of acid leaching residues was close to 100 wt%. However, the maximum cyanide gold leaching rate of gold calcine was only 85.31 wt%. This suggests that acid leaching can increase the gold dissolution rate in the cyanide process.

Differences of cyanide leaching between calcine and dust from refractory gold concentrates

Differences of cyanide leaching between the calcine and the dust from a refractory gold concentrate were investigated by comparative method. Results showed that gold leaching efficiencies of the calcine and the dust were 85.31% and 54.30%, respectively, with direct cyanidation. Contents and existing forms of arsenic and carbon were the main reasons for those differences. The maximum gold leaching efficiencies of the calcine and the dust were 87.70% and 58.60%, respectively, with cyanidation after NaOH pre-leaching. Harmful elements removal, gold loss in NaOH pre-leaching and iron oxides hindrance codetermined gold leaching efficiencies of the calcine and the dust. After H2SO4 pre-leaching, the maximum gold leaching efficiencies of the calcine and the dust achieved 94.96% and 80.40%, respectively. The effect of carbonaceous matter was the main reason for differences for leaching efficiencies of the calcine and the dust. Based on those differences, two proper gold extraction processes were put forward, and gold leaching efficiencies for the calcine and the dust achieved 94.91% and 91.90%, respectively.

Graphene-based silicon modulators

Silicon photonics is a promising technology to address the demand for dense and integrated nextgeneration optical interconnections due to its complementary-metal-oxide-semiconductor(CMOS) compatibility.However, one of the key building blocks, the silicon modulator, suffers from several drawbacks, including a limited bandwidth, a relatively large footprint, and high power consumption. The graphene-based silicon modulator, which benefits from the excellent optical properties of the two-dimensional graphene material with its unique band structure,has significantly advanced the above critical figures of merit. In this work, we review the state-of-the-art graphenebased silicon modulators operating in various mechanisms, i.e., thermal-optical, electro-optical, and plasmonic. It is shown that graphene-based silicon modulators possess the potential to have satisfactory characteristics in intra-and inter-chip connections.