Electrolyte depletion syndrome (EDS) is characterized by a consciousness disorder and electrolyte imbalance due to frequent diarrhea associated with villous tumors of the rectum. We report a very ...rare case of EDS with acute renal failure and hyperammonemia that was successfully treated with continuous hemodiafiltration (CHDF) and laparoscopic surgery. A 68-year-old woman presenting a history of liver cirrhosis was presented to our hospital with the chief complaint of a consciousness disorder. Blood examination showed hyperammonemia, decreased renal function, and electrolyte imbalance, which were resolved by hemodialysis within a few days. A huge villous tumor measuring 160 mm × 150 mm was detected using abdominal computed tomography and colonoscopy. Histological examination using biopsy revealed villous adenoma. Hypokalemia is frequently observed, even after CHDF. We performed a laparoscopic Hartmann's operation after the treatment of hypokalemia. The pathological diagnosis revealed well-differentiated tubular adenocarcinoma in the villous adenoma. The postoperative course was uneventful, with no symptoms of EDS. She recovered, within a follow-up period of 24 months. EDS should be considered when frequent diarrhea or consciousness disorder accompanies rectal villous tumors, and appropriate examination and treatment are essential.
Quantification of the anode degradation with charge/discharge cycling is a primary requirement to develop lithium metal batteries (LMBs) with improved battery lifetime. Although the physical ...characterization such as scanning electron imaging, gas chromatography, and nuclear magnetic resonance, etc., can provide valuable insights into the anode degradation, these invasive techniques are not convenient for real-time degradation diagnostics during the cycling measurements. Here we show that the degradation diagnostics for LMBs can be greatly facilitated with non-invasive electrochemical voltage (EVS) spectroscopy. Though widely explored for conventional lithium-ion batteries, EVS techniques such as incremental capacity (IC), i.e., the derivative (<inline-formula><tex-math notation="LaTeX">dQ/dV</tex-math></inline-formula>) of the capacity vs. voltage response are not well understood for anode degradation in LMBs. We quantify the signatures of anode degradation in IC features as a function of cell design variations including anode thickness, electrolytes, E/C ratio, and C-rate and relate these with capacity loss and physical characterization results. We show that the polarization effects due to dead (inactive) lithium and depleted electrolyte which are not visible in the capacity loss during early cycles can reveal a prominent signature in the IC features including the peak height and its location. The evolution of these features shows consistent trends for different experimental datasets comprising a variety of electrolytes and cell design parameters. These findings suggest that IC can be a powerful approach for health diagnostics and lifetime prediction for LMB which can aid the ongoing research on further optimization of the anode and the electrolyte materials for enhancing the battery lifetime.
Refeeding syndrome Culkin, Alison; White, Rhys
Medicine (Abingdon. 1995, UK ed.),
July 2023, 2023-07-00, Letnik:
51, Številka:
7
Journal Article
Recenzirano
Refeeding syndrome is a group of biochemical shifts resulting in clinical symptoms that can occur in malnourished or starved individuals when reintroducing nutrition. The lack of an agreed definition ...makes the incidence difficult to determine. Risk factors proposed by NICE in 2006 lack specificity and sensitivity but act as a framework to identify individuals potentially at risk. During starvation, there is a reduction in insulin secretion and an increase in glucagon to promote glycogenesis. The introduction of carbohydrate results in insulin secretion, stimulating the sodium–potassium pump that drives electrolytes into cells. Severely low electrolyte concentrations or thiamine deficiency can affect respiratory, cardiac and neuromuscular function. NICE guidelines have been criticized for being overcautious and underfeeding individuals. Recent guidelines recommend starting energy provision at 10–20 kcal/kg, although higher energy intakes are appropriate in some specialized units. Generous amounts of electrolytes and thiamine should be provided from the onset of feeding, although there is a lack of evidence to recommend specific doses. Careful attention to fluid provision is required to reduce the risk of fluid overload and pulmonary oedema. Treatment of individuals at risk should be provided by health care professionals with training in nutrition support.
A 72-year-old man visited our hospital with anorexia and chronic diarrhea. Laboratory evaluation showed severe dehydration with renal dysfunction and electrolyte imbalance. Abdominal computed ...tomography revealed a giant wrinkled tumor in the pelvic cavity. Colonoscopy revealed a mucus-secreting giant villous tumor, and histopathological evaluation showed a moderately differentiated tubular adenocarcinoma. Laparoscopic abdominoperineal resection was performed for the villous tumor that was accompanied by electrolyte depletion syndrome. We manually applied pressure over the lower abdomen at the commencement of surgery to enable inversion of the tumor out of the anus, which ensured better visualization of the surgical field for safe rectal resection. The tumor measured 21 × 25 cm in size, and histopathological evaluation of the resected specimen confirmed diagnosis of adenocarcinoma with villous tubular adenoma (pT1a, pN0, cM0, Stage I). The patient was discharged 14 days postoperatively without electrolyte imbalance, and no recurrence has been observed. Endoscopic or surgical resection is feasible for treatment of villous tumors associated with electrolyte depletion syndrome.
A variety of electrolyte additives were comprehensively evaluated to understand their relative capability in stabilizing lithium metal anode. Although the Li||Cu test is an effective test to rule out ...ineffective additives, a reliable assessment of individual additives cannot be obtained just by a single evaluation method. Therefore, various methods must be combined to truly assess the stabilization of a lithium anode. Moreover, it was also discovered that a significant depletion of electrolytes occurred during the end-of-life of the lithium batteries, which partially contributed to the sudden failure of the lithium batteries during cycling. However, the main culprit of the sudden failure was identified as the significant increase in the resistance of the lithium metal anode. When used as an additive, cyclic fluorinated carbonates are the most effective in stabilizing the lithium anode and improving the cycling performance of lithium batteries among all the common additives. Despite its cost-effectiveness, the additive in the conventional electrolyte approach provides insufficient protection for lithium metal due to the complete consumption of the additive materials, which is necessary to repair the solid-electrolyte interphase (SEI). Therefore, it is suggested that a larger ratio (>15 wt %) of the SEI former should be employed to achieve effective lithium stabilization.
To overcome the limitation of simple empirical cycle life models based on only equivalent circuits, we attempt to couple a conventional empirical capacity loss model with Newman's porous composite ...electrode model, which contains both electrochemical reaction kinetics and material/charge balances. In addition, an electrolyte depletion function is newly introduced to simulate a sudden capacity drop at the end of cycling, which is frequently observed in real lithium-ion batteries (LIBs). When simulated electrochemical properties are compared with experimental data obtained with 20 Ah-level graphite/LiFePO4 LIB cells, our semi-empirical model is sufficiently accurate to predict a voltage profile having a low standard deviation of 0.0035 V, even at 5C. Additionally, our model can provide broad cycle life color maps under different c-rate and depth-of-discharge operating conditions. Thus, this semi-empirical model with an electrolyte depletion function will be a promising platform to predict long-term cycle lives of large-format LIB cells under various operating conditions.
•Semi-empirical cycle life model with electrolyte depletion function is developed.•Our model is compared with a conventional semi-empirical model.•The broad cycle life color maps at various c-rate and DOD are offered.
In this study, we present a modeling approach to estimate the combined effects of cyclable lithium loss and electrolyte depletion on the capacity and discharge power fades of lithium-ion batteries ...(LIBs). The LIB cell based on LiNi0.6Co0.2Mn0.2O2 (NCM622) was used to model the discharge behavior in the multiple degradation modes. The discharge voltages for nine different levels of cyclable lithium loss and electrolyte depletion were measured experimentally. When there was no cyclable lithium loss, the 50% of electrolyte depletion brought about 5% reduction in discharge capacity at 0.05 C discharge rate, while it resulted in 46% reduction when it was coupled with 30% of cyclable lithium loss. The 50% of electrolyte depletion with no cyclable lithium loss caused 1% reduction in discharge power during 0.5 C discharge at the state of charge (SOC) level of 0.8, while it resulted in 13% reduction when it was coupled with 30% of cyclable lithium loss. The modeling results obtained by using the one-dimensional finite element method were compared with the experimental data. The justification of the modeling methods is demonstrated by the high degree of concordance between the predicted and experimental values. Using the validated modeling methodology, the discharge capacity and usable discharge power can be estimated effectively under various combined degradation modes of cyclable lithium loss and electrolyte depletion in the LIB cell.
The rapid charging and/or discharging of electrochemical cells can lead to localized depletion of electrolyte concentration. This depletion can significantly impact the system's time dependent ...resistance. For systems with porous electrodes, electrolyte depletion can limit the rate of charging and increase energy dissipation. Here we propose a theory to control and avoid electrolyte depletion by tailoring the value and spatial distribution of resistance in a porous electrode. We explore the somewhat counterintuitive idea that increasing local spatial resistances of the solid electrode itself leads to improved charging rate and minimal change in energy loss. We analytically derive a simple expression for an electrode matrix resistance profile that leads to highly uniform electrolyte depletion. We use numerical simulations to explore this theory and simulate spatiotemporal dynamics of electrolyte concentration in the case of a supercapacitor with various tailored electrode matrix resistance profiles which avoid localized depletion. This increases charging rate up to ∼2-fold with minimal effect on overall dissipated energy in the system.
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•Reduced electrode conductivity to avoid ion depletion and achieve uniform charging.•A transport model capturing the effect of electrode conductivity distributions.•Reduction in ion depletion results in 2-fold increase in average charging rate.
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