Interface thermal conductivities induced by van der Waals interactions

The interface heat transfer of two layers induced by van der Waals (vdW) contacts is theoretically investigated, based on first-principles calculations at low temperatures. The results suggest that out-of-plane acoustic phonons with low frequencies dominate the interface thermal transport due to the vdW interaction. The interface thermal conductivity is proportional to the cubic of temperature at very low temperatures, but becomes linearly proportional to temperature as temperature increases. We show that manipulating the strain alters vdW coupling, leading to increased interfacial thermal conductivity at the interface. Our findings provide valuable insights into the interface heat transport in vdW heterostructures and support further design and optimization of electronic and optoelectronic nanodevices based on vdW contacts.

[Effects of enhancing the expression of aryl hydrocarbon receptor in post-traumatic mice macrophages on the inflammatory cytokine level and bactericidal ability]

Objective: To explore the expression pattern of aryl hydrocarbon receptor (AhR) in mice peritoneal macrophages (PMs) after major trauma and analyze the effects of enhanced AhR expression on the inflammatory cytokine level and bactericidal ability after trauma. Methods: The experimental study method was used. Forty 6-8-week-old male C57BL/6J mice (the same mouse age, sex, and strain below) were divided into control group, post trauma hour (PTH) 2 group, PTH 6 group, and PTH 12 group according to the random number table (the same grouping method below), with 10 mice in each group. Mice in the latter 3 groups were constructed as severe trauma model with fracture+blood loss, while mice in control group were left untreated. The primary PMs (the same cells below) were extracted from the mice in control group, PTH 2 group, PTH 6 group, and PTH 12 group when uninjured or at PTH 2, 6, and 12, respectively. Then the protein and mRNA expressions of AhR were detected by Western blotting and real-time fluorescence quantitative reverse transcription polymerase chain reaction, respectively, and the gene expressions of AhR signaling pathway related molecules were analyzed by transcriptome sequencing. Twenty mice were divided into control group and PTH 6 group, with 10 mice in each group, and the PMs were extracted. The level of ubiquitin of AhR was detected by immunoprecipitation. Twelve mice were divided into dimethyl sulfoxide (DMSO) alone group, PTH 6+DMSO group, MG-132 alone group, and PTH 6+MG-132 group, with 3 mice in each group. After the corresponding treatment, PMs were extracted, and the protein expression of AhR was detected by Western blotting. Twenty mice were constructed as PTH 6 model. Then, the PMs were extracted and divided into empty negative control adenovirus (Ad-NC) group and AhR overexpression adenovirus (Ad-AhR) group. The protein expression of AhR was detected by Western blotting at 36 h after some PMs were transfected with the corresponding adenovirus. The rest cells in Ad-NC group were divided into Ad-NC alone group and Ad-NC+endotoxin/lipopolysaccharide (LPS) group, and the rest cells in Ad-AhR group were divided into Ad-AhR alone group and Ad-AhR+LPS group. The expressions of interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) in the cell supernatant were detected by enzyme-linked immunosorbent assay at 12 h after the corresponding treatment (n=6). Twenty mice were obtained to extract PMs. The cells were divided into control+Ad-NC group, PTH 6+Ad-NC group, control+Ad-AhR group, and PTH 6+Ad-AhR group, and the intracellular bacterial load was detected by plate spread method after the corresponding treatment (n=6). Data were statistically analyzed with one-way analysis of variance, least significant difference test, analysis of variance for factorial design, and independent sample t test. Results: Compared with 1.16±0.28 of control group, the protein expressions of AhR in PMs in PTH 2 group (0.59±0.14), PTH 6 group (0.72±0.16), and PTH 12 group (0.71±0.17) were all significantly decreased (P<0.05). The overall comparison of the difference of AhR mRNA expression in PMs among control group, PTH 2 group, PTH 6 group, and PTH 12 group showed no statistical significance (P>0.05). The AhR signaling pathway related molecules included AhR, AhR inhibitor, cytochrome P450 family member 1b1, cytochrome P450 family member 11a1, heat shock protein 90, aryl hydrocarbon receptor-interaction protein, and heat shock protein 70 interaction protein. The heat shock protein 90 expression of PMs in PTH 2 group was higher than that in control group, while the expressions of other molecules did not change significantly after trauma. Compared with that in control group, the level of ubiquitin of AhR in PMs in PTH 6 group was increased. Compared with that in DMSO alone group, the protein expression of AhR in PMs in PTH 6+DMSO group was decreased, while that in PMs in MG-132 alone group had no significant change. Compared with that in PTH 6+DMSO group, the protein expression of AhR in PMs in PTH 6+MG-132 group was up-regulated. At transfection hour 36, compared with that in Ad-NC group, the protein expression of AhR in PMs in Ad-AhR group was increased. At treatment hour 12, compared with those in Ad-NC+LPS group, the expressions of IL-6 and TNF-α in PM supernatant of Ad-AhR+LPS group were significantly decreased (with t values of 4.80 and 3.82, respectively, P<0.05). The number of intracellular bacteria of 1×106 PMs in control+Ad-NC group, PTH 6+Ad-NC group, control+Ad-AhR group, and PTH 6+Ad-AhR group was (3.0±1.8), (41.8±10.2), (1.8±1.2), and (24.2±6.3) colony forming unit, respectively. Compared with that in PTH 6+Ad-NC group, the number of intracellular bacteria of PMs in PTH 6+Ad-AhR group was significantly decreased (t=3.61, P<0.05). Conclusions: Ubiquitin degradation of AhR in PMs of mice after major trauma results in decreased protein expression of AhR. Increasing the expression of AhR in post-traumatic macrophages can reduce the expressions of LPS-induced inflammatory cytokines IL-6 and TNF-α, and improve the bactericidal ability of macrophages after trauma.

Early prediction of delirium upon intensive care unit admission: Model development, validation, and deployment

STUDY OBJECTIVE

To develop, validate, and deploy models for predicting delirium in critically ill adult patients as early as upon intensive care unit (ICU) admission.

DESIGN

Retrospective cohort study.

SETTING

Single university teaching hospital in Taipei, Taiwan.

PATIENTS

6238 critically ill patients from August 2020 to August 2021.

MEASUREMENTS

Data were extracted, pre-processed, and split into training and testing datasets based on the time period. Eligible variables included demographic characteristics, Glasgow Coma Scale, vital signs parameters, treatments, and laboratory data. The predicted outcome was delirium, defined as any positive result (a score ≥ 4) of the Intensive Care Delirium Screening Checklist that was assessed by primary care nurses in each 8-h shift within 48 h after ICU admission. We trained models to predict delirium upon ICU admission (ADM) and at 24 h (24H) after ICU admission by using logistic regression (LR), gradient boosted trees (GBT), and deep learning (DL) algorithms and compared the models' performance.

MAIN RESULTS

Eight features were extracted from the eligible features to train the ADM models, including age, body mass index, medical history of dementia, postoperative intensive monitoring, elective surgery, pre-ICU hospital stays, and GCS score and initial respiratory rate upon ICU admission. In the ADM testing dataset, the incidence of ICU delirium occurred within 24 h and 48 h was 32.9% and 36.2%, respectively. The area under the receiver operating characteristic curve (AUROC) (0.858, 95% CI 0.835-0.879) and area under the precision-recall curve (AUPRC) (0.814, 95% CI 0.780-0.844) for the ADM GBT model were the highest. The Brier scores of the ADM LR, GBT, and DL models were 0.149, 0.140, and 0.145, respectively. The AUROC (0.931, 95% CI 0.911-0.949) was the highest for the 24H DL model and the AUPRC (0.842, 95% CI 0.792-0.886) was the highest for the 24H LR model.

CONCLUSION

Our early prediction models based on data obtained upon ICU admission could achieve good performance in predicting delirium occurred within 48 h after ICU admission. Our 24-h models can improve delirium prediction for patients discharged >1 day after ICU admission.

Distribution and quantitative analysis of CIDEa and CIDEc in broiler chickens: accounting for differential fat deposition between strains

1. Differences in the expression of CIDEa and CIDEc in 20 different tissues were examined. Both CIDEa and CIDEc mRNA transcripts were predominantly but variably expressed in white adipose tissue (WAT) but were also expressed at moderate levels in the kidney and liver and at lower levels in the ovary. Interestingly, among WAT types, both CIDEa and CIDEc were expressed at the lowest levels in heart coronary WAT. 2. To better understand the roles of CIDEa and CIDEc in the fat deposition of broiler chickens, the differences in lipid droplet (LD) size and mRNA levels of CIDEa and CIDEc between lean-type and fat-type broiler chicken lines were studied. LD sizes were larger in fat-type broiler lines, and CIDEa and CIDEc mRNA levels in white adipose, kidney and liver tissues were significantly higher in fat-type broiler lines than in their lean counterparts. 3. Developmental expression patterns of CIDEa and CIDEc mRNA were analysed in different tissue types (WAT, liver and kidney) in Arbor Acres broiler chickens, and CIDEa and CIDEc mRNA expression levels increased during sequential developmental stages, achieving peak expression levels at week 6. 4. These observations suggest that the functions of CIDEa and CIDEc reflect inherent characteristics of lipid metabolism that contribute to the differences in fat deposition between strains. The results in this study contribute to a more robust understanding of the tissue distribution and expression patterns of CIDEa and CIDEc mRNA and facilitate further research concerning the molecular mechanism underlying fat deposition in broiler chickens.

GFI1B mutation causes a bleeding disorder with abnormal platelet function

BACKGROUND

GFI1B is a transcription factor important for erythropoiesis and megakaryocyte development but previously unknown to be associated with human disease.

METHODS

A family with a novel bleeding disorder was identified and characterized. Genetic linkage analysis and massively parallel sequencing were used to localize the mutation causing the disease phenotype on chromosome 9. Functional studies were then performed in megakaryocytic cell lines to determine the biological effects of the mutant transcript.

RESULTS

We have identified a family with an autosomal dominant bleeding disorder associated with macrothrombocytopenia, red cell anisopoikilocytosis, and platelet dysfunction. The severity of bleeding is variable with some affected individuals experiencing spontaneous bleeding while other family members exhibit only abnormal bleeding with surgery. A single nucleotide insertion was identified in GFI1B that predicts a frameshift mutation in the fifth zinc finger DNA-binding domain. This mutation alters the transcriptional activity of the protein, resulting in a reduction in platelet α-granule content and aberrant expression of key platelet proteins.

CONCLUSIONS

GFI1B mutation represents a novel human bleeding disorder, and the described phenotype identifies GFI1B as a critical regulator of platelet shape, number, and function.

Influence of selective decontamination of the digestive tract on cell-mediated immune function and bacteria/endotoxin translocation in thermally injured rats

OBJECTIVE

To determine the influence of pretreatment with selective decontamination of the digestive tract (SDD) on systemic immunosuppression, and the relationship between bacteria/endotoxin translocation and abnormalities of immune function in thermally injured rats.

DESIGN, MATERIALS, AND METHODS

Animals were subjected to a 40% full-thickness scald injury, and divided into SDD-treated and control groups. The treatment group received SDD (polymyxin E, tobramycin, and 5-flucytosine) by gavage twice daily for 3 days before the experiment and continued for 5 days after thermal injury. The control group was given the same amount of water. The parameters reflecting cell-mediated immunity, including splenocyte proliferation in response to mitogens, interleukin 2 (IL-2) production, and lymphocyte subpopulation, were measured before injury and 1 and 5 days after burn, respectively.

MEASUREMENTS AND MAIN RESULTS

Thermal injury resulted in marked reduction in splenocyte proliferative response to T-cell mitogens, IL-2 production, and T-helper/suppressor cells (CD4/CD8) ratio. Prophylactic treatment with SDD significantly decreased the incidences of bacterial translocation and endotoxemia, prevented suppressive mitogenic response and inadequate IL-2 production (p < 0.05-0.01) but did not affect the abnormal ratio of CD4 to CD8 T lymphocytes in blood (p > 0.05).

CONCLUSIONS

These results suggest that bacteria/endotoxin translocation from the gut appears to be involved in cell-mediated immune dysfunction as a consequence of thermal injury. Pretreatment with SDD might attenuate postburn immunosuppression by preventing translocation events.

[An experimental study of mitogen-stimulated blastogenic transformation and interleukin-2 in mice after burn injury]

In this study, mitogen-stimulated blastogenic transformation (MSBT) and interleukin 2 (IL-2) production by splenic lymphocytes in mice were measured at various time intervals after unanesthetized burn injury. The results showed that both MSBT and IL-2 production were suppressed after burn injury. There was a significant positive correlation between these two parameters. The postburn serum showed in vitro suppressive activity upon MSBT, IL-2 production and IL-2-IL-2R interaction of normal control. The results indicated that burn injury had a significant effect on lymphocytes.