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Resting memory B cells can be divided into classical or atypical groups, but the heterogenous marker expression on activated memory B cells makes similar classification difficult. Here, by longitudinal analysis of mass cytometry and CITE-seq data from cohorts with COVID-19, bacterial sepsis, or BNT162b2 mRNA vaccine, we observe that resting B cell memory consist of classical CD45RB+ memory and CD45RBlo memory, of which the latter contains of two distinct groups of CD11c+ atypical and CD23+ non-classical memory cells. CD45RB levels remain stable in these cells after activation, thereby enabling the tracking of activated B cells and plasmablasts derived from either CD45RB+ or CD45RBlo memory B cells. Moreover, in both COVID-19 patients and mRNA vaccination, CD45RBlo B cells formed the majority of SARS-CoV2 specific memory B cells and correlated with serum antibodies, while CD45RB+ memory are activated by bacterial sepsis. Our results thus identify that stably expressed CD45RB levels can be exploited to trace resting memory B cells and their activated progeny, and suggest that atypical and non-classical CD45RBlo memory B cells contribute to SARS-CoV-2 infection and vaccination. Activated memory B cells express a variety of markers. Here, by mass cytometry and CITE-seq, the authors identify differential expression of CD45RB as a marker distinguishing classical and atypical/non-classical memory B cells, with the former being more prominent during sepsis, while the latter being more abundant in COVID-19 infection or vaccination. [ABSTRACT FROM AUTHOR]

Summary: Background and Aims: Although metabolic dysfunction‐associated steatotic liver disease (MASLD) patients with a Fib‐4 index >1.3 are recommended for fibrosis evaluation via elastography or biopsy, a more convenient method identifying high‐risk populations requiring follow‐up is needed. We explored the utility of serum levels of growth differentiation factor‐15 (GDF15), a cell stress‐responsive cytokine related to metabolic syndrome, for stratifying the risk of clinical events in MASLD patients. Methods: Serum GDF15 levels were measured in 518 biopsy‐performed MASLD patients, 216 MASLD patients for validation, and 361 health checkup recipients with MASLD. Results: In the biopsy‐MASLD cohort, multivariate analysis indicated that the serum GDF15 level was a risk factor for liver cancer, independent of the fibrosis stage or Fib‐4 index. Using a GDF15 cutoff of 1.75 ng/mL based on the Youden index, high‐GDF15 patients, regardless of fibrosis status, had a higher liver cancer incidence rate. While patients with a Fib‐4 index <1.3 or low‐GDF15 rarely developed liver cancer, high‐GDF15 patients with a Fib‐4 index >1.3 developed liver cancer and decompensated liver events at significantly higher rates and had poorer prognoses. In the validation cohort, high‐GDF15 patients had significantly higher incidences of liver cancer and decompensated liver events and poorer prognoses than low‐GDF15 patients, whether limited to high‐Fib‐4 patients. Among health checkup recipients with MASLD, 23.0% had a Fib‐4 index >1.3, 2.7% had a Fib‐4 index >1.3 and >1.75 ng/mL GDF15. Conclusions: Serum GDF15 is a biomarker for liver cancer with high predictive capability and is useful for identifying MASLD patients requiring regular surveillance. [ABSTRACT FROM AUTHOR]

This article, titled "Featured Cover," discusses a study conducted by Shusuke Kumazaki et al. on the use of serum growth differentiation factor 15 (GDF15) as a biomarker for liver cancer occurrence in patients with metabolic-associated fatty liver disease (MASLD), regardless of liver fibrosis. The study found that GDF15 showed high predictive capability for liver cancer in these patients. The authors of the study include a diverse group of researchers from various institutions. The article provides a valuable resource for library patrons researching liver cancer and its biomarkers. [Extracted from the article]

Background: Resting energy expenditure (REE) measurement of critically ill patients is essential for better nutrition management. Younger people increase their oxygen delivery (ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$) to meet energy demands, but few reports have investigated oxygen uptake kinetics in elderly patients, which are the main target population in today's intensive care units (ICUs). In this study, we evaluated REE, ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$, and oxygen extraction ratio (O2 Ext: oxygen consumption [V̇O2${\dot{{\rm{V}}}}{{\rm{O}}_2}$]/ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$) to clarify appropriate energy needs and consumption in elderly ICU patients. Methods: This retrospective observational study included ventilated ICU patients who were divided into elderly participants (age ≥ 65 years) and nonelderly participants (age ≤64 years). V̇O2${\dot{{\rm{V}}}}{{\rm{O}}_2}$, CO2 production, and cardiac output were measured by indirect calorimetry and noninvasive hemodynamic monitoring for up to 5 days. The initial values of REE, ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$, and O2 Ext were compared between elderly and nonelderly patients. Results: This study included 102 patients, of whom 52% (n = 53) were elderly. The absolute deviation of measured REE per ideal body weight (IBW) was significantly higher in elderly than in nonelderly patients (9.3 ± 6.9 vs 6.3 ± 6.6 kcal/kg; P <.01). ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ had a strong negative correlation with age (P <.01). The O2 Ext value was significantly higher in elderly than in nonelderly patients (37 ± 19% vs 29 ± 13%; P =.03). Conclusions: Elderly critically ill patients were characterized by higher deviations in REE, lower ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$, and higher O2 Ext. In elderly patients, O2 Ext rather than ḊO2${\dot{{\rm{D}}}}{{\rm{O}}_2}$ could be increased to meet energy consumption demands. [ABSTRACT FROM AUTHOR]

An efficient method for numerical simulation of tape floating behavior in VTR has been developed. Parameter survey examples for tape floating height control in some drum-guide tape systems have been shown. The spacing between a drum and a tape is one of the most important topics regarding the tape/head interface problem for a VTR. The spacing is caused by air film lubrication and can be determined by using the Reynolds equation for air and the elastic equation for a tape. Each equation is discretized, using the finite element method, and solved by the Newton-Raphson method. The results, calculated by the present method, show good agreement with experimental results. The authors also investigated tape floating behavior for several drum-guide tape systems, which are intended to decrease tape/drum spacing, especially in the head entrance region, as follows; (1) Guidepost twist effect; (2) Difference between a rotary drum configuration and a rotary center drum configuration; (3) A new groove location for tape floating height equalization.