Dynamic modeling of three-phase upflow fixed-bed reactor including pore diffusion

The dynamics of a three-phase upflow fixed-bed reactor are investigated using a non-isothermal heterogeneous model including gas–liquid and liquid–solid mass transfer and diffusion/reaction phenomena inside the catalyst. The partial differential and algebraic equations involving three integration variables (time and two space coordinates) are solved via discretization of the spatial coordinates coupled with the Gear method. For a multistep hydrogenation on a shell catalyst, the model exhibits significant effects of the external and above all internal resistance to hydrogen transfer but also non-trivial internal hydrocarbons concentration profiles. A simplified model is compared with the extended one and with experimental data in transient regime. In the investigated conditions—hydrocarbons in large excess—the diffusion of hydrocarbons appears to be actually not limiting, so that the simplest model predicts accurately the transient reactor behavior

Expression of the nociceptin precursor and nociceptin receptor is modulated in cancer and septic patients

Background A role of nociceptin and its receptor (NOP) in pain and immune function has been suggested. The hypothesis was that mRNA expression of NOP and the nociceptin precursor pre-pronociceptin (pN/OFQ) in peripheral blood cells differs in end-stage cancer patients suffering from chronic pain and septic intensive care unit (ICU) patients compared with healthy controls. Methods Blood samples were drawn from end-stage cancer patients and septic ICU patients. Additionally, postoperative patients representing individuals with surgical stress and healthy controls were enrolled as comparative groups. NOP and pN/OFQ mRNA expression, quantified by real-time polymerase chain reaction (RT-PCR), was compared between study groups, and associated to opioid medication, pain intensities, and the inflammatory markers procalcitonin (PCT) and interleukin-6. Results NOP expression was significantly higher in cancer patients [normalized ratio, median (inter-quartile range): 10.2 (7.4/17.8)], postoperative patients [8.0 (5.3/10.2)], and ICU patients [6.6 (4.2/9.5)] compared with healthy controls [4.4 (2.7/7.0); P<0.001]. Expression of pN/OFQ was lower in cancer patients [3.8 (1.9/5.9)] and ICU patients [1.9 (1.0/2.7)] but not in postoperative patients compared with healthy controls [7.2 (6.1/9.4); P<0.001]. Increased plasma PCT was associated with decreased pN/OFQ in all patient groups. In cancer patients, no association was seen with pain scores, opioid medication or duration of analgesia, and NOP or pN/OFQ mRNA. Conclusions NOP and pN/OFQ expression in peripheral blood cells was modulated in end-stage cancer and septic patients compared with healthy controls, whereas changes in postoperative patients were minor. The involvement of the NOP-pN/OFQ system in inflammation, impaired immune function, and pain has to be further elucidate

Heterogeneous microstructures tuned in a high throughput architecture

A new method applied to the sensor proposed by Zhang et al. in 2018 is demonstrated in this paper that combines the benefits of this design with the fast heating possible with nanocalorimetry. By applying a PID regulated pulse instead of a constant wattage, we unlock an accessible method to sense morphological changes occurring over short time periods that would be invisible to methods based only on heat capacity. In this study, multilayer Ni/Al thin films were linearly heated at 25, 50, 100, and 200 K/s to over 700°C, showing two distinct peaks in resistance change with activation energies of 554 and 747 kJ/mol, respectively. Through Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive X-ray Analysis (EDX) analysis on cross sections taken ex situ from samples quenched before and after the peaks of interest, we find strong evidence that peak 1 corresponds to Ni diffusing through Al grain boundaries forming intermetallic phases that essentially block the highly conductive Al pathway. This presents the potential to design and calibrate novel heterogeneous structures in a high throughput manner

The impact of pelvic venous pressure on blood loss during open radical cystectomy and urinary diversion: Results from a secondary analysis of a randomized clinical trial

PURPOSE Blood loss and blood substitution are associated with higher morbidity after major abdominal surgery. During major liver resection, low local venous pressure, has been shown to reduce blood loss. Ambiguity persists concerning the impact of local venous pressure on blood loss during open radical cystectomy. We aimed to determine the association between intraoperative blood loss and pelvic venous pressure (PVP) and determine factors affecting PVP. MATERIAL AND METHODS In the frame of a single-center, double-blind, randomized trial, PVP was measured in 82 patients from a norepinephrine/low-volume group and in 81 from a control group with liberal hydration. For this secondary analysis, patients from each arm were stratified into subgroups with PVP <5 mmHg or ≥5 mmHg measured after cystectomy (optimal cut-off value for discrimination of patients with relevant blood loss according to the Youden's index). RESULTS Median blood loss was 800 ml [range: 300-1600] in 55/163 patients (34%) with PVP <5 mmHg and 1200 ml [400-3000] in 108/163 patients (66%) with PVP ≥5 mmHg; (P<0.0001). A PVP <5 mmHg was measured in 42/82 patients (51%) in the norepinephrine/low-volume group and 13/81 (16%) in the control group (P<0.0001). PVP dropped significantly after removal of abdominal packing and abdominal lifting in both groups at all time points (at begin and end of pelvic lymph node dissection, end of cystectomy) (P<0.0001). No correlation between PVP and central venous pressure could be detected. CONCLUSIONS Blood loss was significantly reduced in patients with low PVP. Factors affecting PVP were fluid management and abdominal packing