The I–V curve tracer is an instrument that captures the I–V characteristics of photovoltaic (PV) generators corresponding to variable environmental conditions. The device is widely used to evaluate ...power generation performance and detect the fault conditions of PV power generators. Various I–V tracer techniques have been developed and proposed to trace the IV characteristics and ensure high accuracy and fast speeds. A comprehensive classification and analysis was undertaken to identify the advantages and disadvantages of different technologies. This study proposes and uses five performance indices to evaluate the performance of I–V tracers. The quantitative fidelity of commercial I–V tracers were also reviewed and evaluated. This paper serves as a valuable reference tool that should be used to guide the direction of future research and lead future improvements in the field.
Abstract Painful peripheral neuropathies produced by nerve trauma are accompanied by substantial axonal degeneration and by a response in spinal cord microglia that is characterized by hypertrophy ...and increased expression of several intracellular and cell-surface markers, including ionizing calcium-binding adapter molecule 1 (Iba1) and Cd11b (a complement receptor 3 antigen recognized by the OX42 antibody). The microglia response has been hypothesized to be essential for the pathogenesis of the neuropathic pain state. In contrast, the painful peripheral neuropathies produced by low doses of cancer chemotherapeutics do not produce degeneration of axons in the peripheral nerve, although they do cause partial degeneration of the sensory axons' distal-most tips, that is the intraepidermal nerve fibers that form the axons' terminal receptor arbors. The question thus arises as to whether the relatively minor and distal axonal injury characterizing the chemotherapy-evoked neuropathies is sufficient to evoke the microglial response that is seen after traumatic nerve injury. We examined the lumbar spinal cord of rats with painful peripheral neuropathies due to the anti-neoplastic agents, paclitaxel, vincristine, and oxaliplatin, and the anti-retroviral agent, 2′,3′-dideoxycytidine (ddC), and compared them to rats with a complete sciatic nerve transection and the partial sciatic nerve injury produced in the chronic constriction injury model (CCI). As expected, microglia hypertrophy and increased expression of Iba1 were pronounced in the nerve transection and CCI animals. However, there was no microglia hypertrophy or increased Iba1 staining in the animals treated with paclitaxel, vincristine, oxaliplatin, or ddC. These results suggest that the mechanisms that produce neuropathic pain after exposure to chemotherapeutics may be fundamentally different than those operating after nerve trauma.
Abstract Anti-neoplastic agents in the platinum-complex, taxane, vinca alkaloid, and proteasome-inhibitor classes induce a dose-limiting, chronic, distal, symmetrical, sensory peripheral neuropathy ...that is often accompanied by neuropathic pain. Clinical descriptions suggest that these conditions are very similar, but clinical data are insufficient to determine the degree of similarity and to determine if they share common pathophysiological mechanisms. Animal models do not have the limitations of clinical studies and so we have characterized a rat model of chronic painful peripheral neuropathy induced by a platinum-complex agent, oxaliplatin, in order to compare it with a previously characterized model of chronic painful peripheral neuropathy induced by a taxane agent, paclitaxel. The oxaliplatin model evokes mechano-allodynia, mechano-hyperalgesia, and cold-allodynia that have a delayed onset, gradually increasing severity, a distinct delay to peak severity, and duration of about 2.5 months. There is no effect on heat sensitivity. Electron microscopy (EM) analyses found no evidence for axonal degeneration in peripheral nerve, and there is no upregulation of activating transcription factor-3 in the lumbar dorsal root ganglia. There is a statistically significant loss of intraepidermal nerve fibers in the plantar hind paw skin. Oxaliplatin treatment causes a significant increase in the incidence of swollen and vacuolated mitochondria in peripheral nerve axons, but not in their Schwann cells. Nerve conduction studies found significant slowing of sensory axons, but no change in motor axons. Single fiber recordings found an abnormal incidence of A- and C-fibers with irregular, low-frequency spontaneous discharge. Prophylactic dosing with two drugs that are known to protect mitochondria, acetyl- l -carnitine and olesoxime, significantly reduced the development of pain hypersensitivity. Our results are very similar to those obtained previously with paclitaxel, and support the hypothesis that these two agents, and perhaps other chemotherapeutics, produce very similar conditions because they have a mitotoxic effect on primary afferent neurons.
Many of the most effective anti-cancer drugs induce a dose-limiting peripheral neuropathy that compromises therapy. Evidence from animal models of chemotherapy-induced painful peripheral neuropathy ...produced by the taxane agent, paclitaxel, and the platinum-complex agent, oxaliplatin, indicate that they produce neuropathy via a common mechanism—a toxic effect on the mitochondria in primary afferent sensory neurons. Bortezomib is from the proteasome-inhibitor class of chemotherapeutics. It also produces a dose-limiting peripheral neuropathy, but its effects on neuronal mitochondria are unknown. To investigate this, we developed a model of bortezomib-induced painful peripheral neuropathy in the rat and assessed mitochondrial function (respiration and ATP production) in sciatic nerve samples harvested at two time points: day 7, which is three days after treatment and before pain appears, and day 35, which is one month post-treatment and the time of peak pain severity. We found significant deficits in Complex I-mediated and Complex II-mediated respiration, and in ATP production at both time points. Prophylactic treatment with acetyl-l-carnitine, which has previously been shown to prevent paclitaxel- and oxaliplatin-induced mitochondrial dysfunction and pain, completely blocked bortezomib's effects on mitochondria and pain. These results suggest that mitotoxicity may be the core pathology for all chemotherapy-induced peripheral neuropathy and that drugs that protect mitochondrial function may be useful chemotherapy adjuncts.
► The proteasome-inhibitor, bortezomib, induces a painful peripheral neuropathy in rat. ► Bortezomib causes chronic mitochondrial dysfunction in primary afferent neurons. ► Mitotoxicity is a likely cause of chemotherapy-induced peripheral neuropathy.
Conventional photovoltaic (PV) systems make use of series-connection of PV panels, arranged into strings, in order to provide a voltage-stack at the input of grid-tied inverters. The string solution ...forces all PV modules to share the same current which results in power loss in presence of any mismatching condition. The emergence of Distributed Maximum Power Point Tracking (DMPPT) PV systems, which increase the level of MPPT fineness, provided an effective solution to mitigate the mismatch impact on energy harvest. The earlier DMPPT systems consisted of module-level power electronic solutions such as microinverter, DC Power Optimizer (DCPO), and Differential Power Processor (DPP). The recent studies increase the level of MPPT granularity and focus further to the submodule-level in order to alleviate the intra-panel mismatch problem and maximize solar energy harvest. The research on the topic resulted in a group of DMPPT systems that are classified as the submodule integrated converters (subMICs), submodule-level DPP (subDPP) and submodule-level isolated-port DPP (subIPDPP). This study focuses on the various implementations of these architectures and provides an in-depth analysis regarding to their advantages and limitations.
Within the chiral unitary approach and with the constraints of heavy quark spin symmetry, we study the coupled channel interactions of D (*) Σc (*) channels, close to whose thresholds three ...pentaquarklike P c states have been reported by the LHCb Collaboration. In the present work, we take into account the contributions of pion exchanges via box diagrams to the interaction potentials, and therefore lift the degeneracy in the masses of D ∗ Σc (*) spin multiplets. Fitting the J/ψp invariant mass distributions in the Λ0b → J/ψK − p decay, we find that the LHCb pentaquark states cannot be reproduced in the direct J/ψp production in the Λ0b decay, and can only be indirectly produced in the final state interactions of the Λ0b decay products, D (*) Σc (*), which further supports the nature of these states as D (*) Σc molecules. Based on the fit results obtained, we study the partial decay widths/branching ratios to the other decay channels, D ∗ Λc, D Λc, and ηcN, and the corresponding invariant mass distributions. The resonances with JP = 1/2 −, Pc (4312), Pc (4440) and the one of D ∗ Σ∗c around 4500 MeV, have large partial decay width into ηcN, and thus can be easily seen in the ηcN invariant mass distributions. By contrast, the states with JP = 3/2 −, Pc (4457), the (predicted) narrow Pc (4380), and the bound state of ¯ D∗Σ∗c with a mass of about 4520 MeV do not decay into ηcN. Therefore, the ηcN channel should be studied in the future to provide further insights into the nature of these states, especially that of Pc (4440) and Pc (4457) .
The objective of this study is to analyse the factors affecting late toxicity for nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT).
Seven hundred and ...eighty-nine consecutive NPC patients treated with IMRT at our centre from January 2003 to February 2008 were retrospectively analysed. Radiotherapy-related complications were categorised using the RTOG Late Radiation Morbidity Scoring Criteria and the Common Terminology Criteria for Adverse Events (Version 3.0). Two hundred and thirty-three patients were treated with IMRT alone (group 1) and 556 patients underwent cisplatin-based chemotherapy (group 2).
Median follow-up was 65 months (range, 4-106 months). The 5-year major late toxicity rate was significantly greater in group 2 than group 1 (63.2% vs 42.0%, P<0.001). Multivariate analyses showed that N category, T category and chemotherapy were significant factors. The maximal dose (Dmax) to the temporal lobe was a significant factor affecting temporal lobe injury (TLI), with a hazard ratio of 1.26 (95% confidence interval (CI), 1.18-1.35; P<0.001) per 1-Gy increase. The 5-year TLI rate increased from 0.8% for 284 lobes with Dmax <65.77 Gy to 27.1% for 176 lobes with greater doses (P<0.001). Logistic regression showed that the hazard ratio attributed to the parotid gland mean dose was 1.36 (95% CI, 1.21-1.53; P<0.001) per 1-Gy increase. Chemotherapy was not a significant factor (P=0.211).
With the application of IMRT, the incidence of radiation-related complications has been reduced except for TLI. The significant factors affecting the risk of TLI included T category, chemotherapy and Dmax.
Osteoarthritis (OA) is a multifactorial arthritic disease of weight-bearing joints concomitant with chronic and intolerable pain, loss of locomotion and impaired quality of life in the elderly ...population. Although the prevalence of OA increases with age, its specific mechanisms have not been elucidated and effective therapeutic disease-modifying drugs have not been developed. As essential organelles in chondrocytes, mitochondria supply energy and play vital roles in cellular metabolism, proliferation and apoptosis. Mitochondrial quality control (MQC) is the key mechanism to coordinate various mitochondrial biofunctions, primarily through mitochondrial biogenesis, dynamics, autophagy and the newly discovered mitocytosis. An increasing number of studies have revealed that a loss of MQC homeostasis contributes to the cartilage damage during the occurrence and development of OA. Several master MQC-associated signaling pathways and regulators exert chondroprotective roles in OA, while cartilage damage-related molecular mechanisms have been partially identified. In this review, we summarized known mechanisms mediated by dysregulated MQC in the pathogenesis of OA and latent bioactive ingredients and drugs for the prevention and treatment of OA through the maintenance of MQC.
The application of transition metal fluorides as energy-dense cathode materials for lithium ion batteries has been hindered by inadequate understanding of their electrochemical capabilities and ...limitations. Here, we present an ideal system for mechanistic study through the colloidal synthesis of single-crystalline, monodisperse iron(ii) fluoride nanorods. Near theoretical capacity (570 mA h g−1) and extraordinary cycling stability (>90% capacity retention after 50 cycles at C/20) is achieved solely through the use of an ionic liquid electrolyte (1 m LiFSI/Pyr1,3FSI), which forms a stable solid electrolyte interphase and prevents the fusing of particles. This stability extends over 200 cycles at much higher rates (C/2) and temperatures (50 °C). High-resolution analytical transmission electron microscopy reveals intricate morphological features, lattice orientation relationships and oxidation state changes that comprehensively describe the conversion mechanism. Phase evolution, diffusion kinetics and cell failure are critically influenced by surface-specific reactions. The reversibility of the conversion reaction is governed by topotactic cation diffusion through an invariant lattice of fluoride anions and the nucleation of metallic particles on semicoherent interfaces. This new understanding is used to showcase the inherently high discharge rate capability of FeF2.The application of metal fluorides as cathodes for lithium ion batteries has been hindered by inadequate understanding of their electrochemical capabilities. Reversible conversion reaction in iron fluoride nanocrystals is shown to be due to topotactic cation diffusion and nucleation of metallic particles.
Gene-expression profiling of 574 cases of diffuse large B-cell lymphoma revealed four new subtypes based on the co-occurrence of mutation patterns. The subtypes had prognostic influence beyond the ...usual clinical prognostic factors and may aid in directing targeted therapy.
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