BackgroundPlasma insulin levels are predominantly the product of the morphological mass of insulin producing beta cells in the pancreatic islets of Langerhans and the functional status of each of these beta cells. Thus, deficiency in either beta cell mass or function, or both, can lead to insufficient levels of insulin, resulting in hyperglycemia and diabetes. Nonetheless, the precise contribution of beta cell mass and function to the pathogenesis of diabetes as well as the underlying mechanisms are still unclear. In the past, this was largely due to the restricted number of technologies suitable for studying the scarcely accessible human beta cells. However, in recent years, a number of new platforms have been established to expand the available techniques and to facilitate deeper insight into the role of human beta cell mass and function as cause for diabetes and as potential treatment targets.Scope of ReviewThis review discusses the current knowledge about contribution of human beta cell mass and function to different stages of type 1 and type 2 diabetes pathogenesis. Furthermore, it highlights standard and newly developed technological platforms for the study of human beta cell biology, which can be used to increase our understanding of beta cell mass and function in human glucose homeostasis.Major ConclusionsIn contrast to early disease models, recent studies suggest that in type 1 and type 2 diabetes impairment of beta cell function is an early feature of disease pathogenesis while a substantial decrease in beta cell mass occurs more closely to clinical manifestation. This suggests that, in addition to beta cell mass replacement for late stage therapies, the development of novel strategies for protection and recovery of beta cell function could be most promising for successful diabetes treatment and prevention. The use of today's developing and wide range of technologies and platforms for the study of human beta cells will allow for a more detailed investigation of the underlying mechanisms and will facilitate development of treatment approaches to specifically target human beta cell mass and function.

The proximal flow convergence method demonstrates that regurgitant flow and orifice area vary throughout systole in distinct patterns characteristic of the underlying mechanism of mitral incompetence. Therefore, in addition to the potential of the method as a tool to quantify mitral regurgitation, it allows analysis of the pathophysiology of regurgitation in the individual patient, which may be helpful in clinical decision making. Calculating mitral regurgitant flow rate and volume from the time-varying proximal flow field (ie, without assuming a constant orifice area that would produce overestimation in individual patients) provides excellent agreement with independent te

Although Ni-rich layered oxides are considered a candidate of next-generation cathode materials, their inherent properties, such as surface lithium residues and structural destruction, cause detrimental electrochemical performance, especially at elevated temperatures. Here, a facile ball-milling method is proposed to remove the lithium residues and enhance the electrochemical performance of LiNi0.6Co0.2Mn0.2O2. After NH4VO3 treatment, a lithium ion-conductive Li3VO4 coating layer is found on the LiNi0.6Co0.2Mn0.2O2 surface at heat-treatment temperatures of 300 and 450 °C, with a small part of vanadium ions diffusing into the surface lattice. When the temperature surpasses 600 °C, almost all vanadium ions dope into the bulk structure. The complex relationships between the post-sintering temperature and surface structure and their impact on electrochemical properties are discussed in detail. Electrochemical tests show that 0.5 wt% NH4VO3 treated LiNi0.6Co0.2Mn0.2O2 at 450 °C exhibits much improved cycling stability (96.1% cycling retention at 0.5C after 100 cycles and 97.2% after 50 cycles at 55 °C), rate capability (117.0 mA h g-1 at 5C), and storage property (4683 ppm lithium residue amount after storing in air for 7 days). Such superior performance is ascribed to the Li3VO4 coating layer that inhibits the electrolyte decomposition and helps create a stable and thinner cathode-electrolyte interface, resulting in decreased interfacial resistance. In addition, this coating layer suppresses internal micro-stress and phase transformation from a layered to spinel and rock-salt structure, which increases the structural integrity of LiNi0.6Co0.2Mn0.2O2 during repeated charge-discharge cycling.

Emerging insulin resistance is normally compensated by increased insulin production of pancreatic β-cells, thereby maintaining normoglycemia. However, it is unclear whether this is achieved by adaptation of β-cell function, mass, or both. Most importantly, it is still unknown which of these adaptive mechanisms fail when type 2 diabetes develops. We performed longitudinal in vivo imaging of β-cell calcium dynamics and islet mass of transplanted islets of Langerhans throughout diet-induced progression from normal glucose homeostasis, through compensation of insulin resistance, to prediabetes. The results show that compensation of insulin resistance is predominated by alterations of β-cell function, while islet mass only gradually expands. Hereby, functional adaptation is mediated by increased calcium efficacy, which involves Epac signaling. Prior to prediabetes, β-cell function displays decreased stimulated calcium dynamics, whereas islet mass continues to increase through prediabetes onset. Thus, our data reveal a predominant role of islet function with distinct contributions of triggering and amplifying pathway in the in vivo processes preceding diabetes onset. These findings support protection and recovery of β-cell function as primary goals for prevention and treatment of diabetes and provide insight into potential therapeutic targets.

Highlights d Pancreas tissue slices from surgical resections allow study of b cells in T2D d b cell dysfunction develops early and deteriorates further in T2D pathogenesis d Basal and first-phase insulin is altered in impaired glucosetolerant donor tissue d b cell mass in tissue slices appears intact throughout the progression to T2D

Like all rechargeable battery systems, conventional Li-ion batteries (LIB) inevitably suffer from capacity losses during operation. This also holds for all-solid-state LIB. In this contribution an in operando Neutron Depth Profiling (NDP) method is developed to investigate the degradation mechanism of all-solid-state, thin film Si-Li 3 PO 4 -LiCoO 2 batteries. Important aspects of the long-term degradation mechanisms are elucidated. It is found that the capacity losses in these thin film batteries are mainly related to lithium immobilization in the solid-state electrolyte, starting to grow at the anode/electrolyte interface during initial charging. The Li-immobilization layer in the electrolyte is induced by silicon penetration from the anode into the solid-state electrolyte and continues to grow at a lower rate during subsequent cycling. X-ray Photoelectron Spectroscopy (XPS) depth profiling and Transmission Electron Microscopy (TEM) analyses confirm the formation of such immobilization layer, which favorably functions as an ionic conductor for lithium ions. As a result of the immobilization process, the amount of free moveable lithium ions is reduced, leading to the pronounced storage capacity decay. Insights gained from this research shed interesting light on the degradation mechanisms of thin film, all-solid-state LIB and facilitate potential interfacial modifications which finally will lead to substantially improved battery performance.

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Cure of type 1 diabetes (T1D) by immune intervention at disease onset depends on the restoration of insulin secretion by endogenous b-cells. However, little is known about the potential of b-cell mass and function to recover after autoimmune attack ablation. Using a longitudinal in vivo imaging approach, we show how functional status and mass of b-cells adapt in response to the onset and remission of T1D. We demonstrate that infiltration reduces b-cell mass prior to onset and, together with emerging hyperglycemia, affects b-cell function. After immune intervention, persisting hyperglycemia prevents functional recovery but promotes b-cell mass increase in mouse islets. When blood glucose levels return to normoglycemia b-cell mass expansion stops, and subsequently glucose tolerance recovers in combination with b-cell function. Similar to mouse islets, human islets exhibit cell exhaustion and recovery in response to transient hyperglycemia. However, the effect of hyperglycemia on human islet mass increase is minor and transient. Our data demonstrate a major role of functional exhaustion and recovery of b-cells during T1D onset and remission. Therefore, these findings support early intervention therapy for individuals with T1D.Successful therapy at the onset of type 1 diabetes (T1D) not only requires an effective block of the pathological autoimmune process, but also the restoration of adequate insulin levels. Most promising for optimal glucose control is endogenous b-cell activity, which even at low levels reduces the risk for complications and hypoglycemic events (1). Therefore, preserved b-cell function and mass at diagnosis and their potential to recover after immune intervention are a crucial aspect of T1D therapy. Initially, b-cell mass was suggested to be almost completely destroyed at T1D onset (2,3), which questioned the justification of immune intervention at this late time point (4). However, more recent data demonstrate preserved b-cell mass and function in patients with newly diagnosed (5-7) and long-standing T1D (8,9). These observations raise the question of whether immune intervention at T1D onset will allow functional and morphological recovery of the residual b-cells. Indications of a potential recovery are the so-called "honeymoon phase" observed after initial insulin treatment (10), as well as the reported detection of b-cell proliferation in patients with T1D (11). However, it is unclear if b-cell mass and function have the capability to recover after immune intervention, and their distinct roles in the remission process have not been shown.Here we take advantage of a noninvasive in vivo imaging platform (12,13), and the possibility of successful immune intervention in mouse models of T1D (14), to study functional and morphological changes of b-cells and islets during the onset and remission of T1D. Our results demonstrate substantial morphological and functional b-cell plasticity before and after immune intervention. We furthermore show that b-cell mass and function differentially progress duri...