Normal human CD4+ memory T cells display broad heterogeneity in their activation threshold for cytokine synthesis

CD4+ memory T cells coordinate immune responses against viruses and other pathogens via the Ag-induced secretion of potent effector cytokines. The efficacy of these responses depends on both the overall number of pathogen-specific memory T cells and the particular array of cytokines that these cells are programmed to secrete. Here, we provide evidence that heterogeneity in Ag triggering thresholds constitutes an additional critical determinant of memory T cell function. Using a novel assay that allows single-cell detection of Ag-specific T cell cytokine production, we demonstrate that CMV-specific CD4+ memory cells from human peripheral blood display pronounced differences in their costimulatory requirements for Ag-induced triggering of IFN-gamma and IL-2 secretion, ranging from cells that trigger with little costimulation (e.g., resting APC alone) to cells requiring potent costimulation through multiple pathways (resting APC plus multiple costimulatory mAbs, or activated APC). These differences in costimulatory requirements are independent of clonal differences in TCR signaling intensity, consistent with an intrinsic activation-threshold heterogeneity that is "downstream" from the TCR. Thus, "effective" frequencies of Ag-specific CD4+ memory T cells appear to depend on the activation status of available APC, a dependence that would allow the immune system to rapidly adjust the number of functional Ag-specific memory T cells in a particular effector site according to local conditions.     

Abnormal origin of the vertebral artery from the common carotid artery

An abnormal origin of the vertebral artery from the common carotid artery (VA-CC) may occur on the right or left side with different embryonic mechanisms. We describe a patient with a double developmental anomaly, a right VA-CC and a right aortic arch. The rotation of the aortic arch caused a "twist" of the embryonic mechanisms of VA-CC and misdirected the differential diagnosis of the embryonic mechanisms at first glance. We discuss the pivotal points in differentiating the embryonic mechanisms of VA-CC.     

Medial synovial entrapment syndrome of the hip in Chinese children

BACKGROUND: "Medial synovial entrapment syndrome of the hip" is a preliminary name given by the authors to describe the topic of this paper. The authors hope to elicit the concern of clinicians and further explore the feasibility of this nomenclature for the described syndrome. METHODS: A total of 26 children with synovial disorder of the hip complained of limited motion and pain of various degrees in the hip, and a limp or refusal to bear weight. Clinical presentation, image studies, course and management were thoroughly reviewed and compared with other well-established synovial disorders of the hip. RESULTS: Twenty-two of the patients were cured by bedrest, skin traction and manipulative reduction. The remaining four patients were treated with surgery and had satisfactory results. Because of its unique clinical manifestation and the good results obtained from manipulative reduction, it is difficult to compare this condition with any other well-established disease entities. Thus, the authors suggest medial synovial entrapment syndrome of the hip (SES) as a preliminary name. CONCLUSIONS: Based on the 26 Chinese children with SES studied, the authors used clinical, anatomic and biomechanical bases for deriving this nomenclature. The similarity between transient synovitis and SES is discussed.     

Corrosion Resistances of VT1-0 Titanium and VT6 Titanium Alloy Obtained by the Method of Powder Metallurgy in Aqueous Solutions of Hydrochloric Acid

Materials Science - We analyze the corrosion resistance of VT1-0 titanium and VT6 titanium alloy (Ti–6Al–4V) with residual porosities of 1, 3, and 4% obtained as a result of cold...     

Demand Driven MRP: assessment of a new approach to materials management

Demand driven material requirements planning or DDMRP is a recent and promising material management method that has been developed and implemented in the practitioner world. Essentially, DDMRP represents a rethinking of the basic MRP logic. By incorporating elements drawn from Lean Systems and the Theory of Constraints and by introducing new features such as dynamic buffers, DDMRP modifies the basic MRP logic so that it is better able to satisfy customer demands in an increasingly demanding, turbulent and dynamic environment. Claims have been made by firms that DDMRP represents a superior planning approach. In this paper, we introduce and explore DDMRP. In addition, we evaluate its effectiveness relative to two other widely accepted approaches – MRP II and Kanban/Lean production – through a series of structured computer simulation experiments. The results strongly indicate that DDMRP does represent a superior approach – one that warrants further academic study.     

8. New developments in nitrogen fertilizers for rice

The efficiency of nitrogen (N) fertilizer products and practices currently used on rice is low, and improving this efficiency would be very beneficial to rice-growing countries. The development of new N fertilizers is best achieved by following a logical sequence of testing and evaluation procedures in a variety of settings from the laboratory to the farmer's field. Novel N fertilizers currently at various stages of testing include urea supergranules for deep placement, urea coated with various materials to control the N release rate, mixtures of a urease inhibitor with urea to reduce losses, and organic N sources other than urea.     

Structure and Wear Resistance of Plasma-Sprayed NiCrBSiC–TiCrC Composite Powder Coatings

Powder Metallurgy and Metal Ceramics - The NTC20 and NTC40 composite powders were produced by conglomeration from the NiCrBSiC self-fluxing alloy with additions of 20 and 40 wt.% TiCrC,...