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- Bjurstrom, Anton, et al.
(författare)
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A Review of Polyolefin-Insulation Materials in High Voltage Transmission; From Electronic Structures to Final Products
- 2024
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095.
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Forskningsöversikt (refereegranskat)abstract
- This review focuses on the use of polyolefins in high-voltage direct-current (HVDC) cables and capacitors. A short description of the latest evolution and current use of HVDC cables and capacitors is first provided, followed by the basics of electric insulation and capacitor functions. Methods to determine dielectric properties are described, including charge transport, space charges, resistivity, dielectric loss, and breakdown strength. The semicrystalline structure of polyethylene and isotactic polypropylene is described, and the way it relates to the dielectric properties is discussed. A significant part of the review is devoted to describing the state of art of the modeling and prediction of electric or dielectric properties of polyolefins with consideration of both atomistic and continuum approaches. Furthermore, the effects of the purity of the materials and the presence of nanoparticles are presented, and the review ends with the sustainability aspects of these materials. In summary, the effective use of modeling in combination with experimental work is described as an important route toward understanding and designing the next generations of materials for electrical insulation in high-voltage transmission.
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| 3. |
- Bjurstrom, M. F., et al.
(författare)
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Cerebrospinal Fluid Cytokines and Neurotrophic Factors in Human Chronic Pain Populations : A Comprehensive Review
- 2016
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Ingår i: Pain Pract. ; 16:2, s. 183-203
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Tidskriftsartikel (refereegranskat)abstract
- Chronic pain is a prevalent and debilitating condition, conveying immense human burden. Suffering is caused not only by painful symptoms, but also through psychopathological and detrimental physical consequences, generating enormous societal costs. The current treatment armamentarium often fails to achieve satisfying pain relief; thus, research directed toward elucidating the complex pathophysiological mechanisms underlying chronic pain syndromes is imperative. Central neuroimmune activation and neuroinflammation have emerged as driving forces in the transition from acute to chronic pain, leading to central sensitization and decreased opioid efficacy, through processes in which glia have been highlighted as key contributors. Under normal conditions, glia exert a protective role, but in different pathological states, a deleterious role is evident--directly and indirectly modulating and enhancing pain transmission properties of neurons, and shaping synaptic plasticity in a dysfunctional manner. Cytokines and neurotrophic factors have been identified as pivotal mediators involved in neuroimmune activation pathways and cascades in various preclinical chronic pain models. Research confirming these findings in humans has so far been scarce, but this comprehensive review provides coherent data supporting the clear association of a mechanistic role of altered central cytokines and neurotrophic factors in a number of chronic pain states despite varying etiologies. Given the importance of these factors in neuropathic and inflammatory chronic pain states, prospective therapeutic strategies, and directions for future research in this emerging field, are outlined.
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| 4. |
- Dietz, N., et al.
(författare)
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90-Day Bundled Payment Simulation, Health Care Utilization, and Complications following Craniopharyngioma Resection in Adult Patients
- 2022
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Ingår i: J Neurol Surg B Skull Base. ; 83:5, s. 515-525
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Tidskriftsartikel (refereegranskat)abstract
- Context Bundled payment and health care utilization models inform cost optimization and surgical outcomes. Economic analysis of payment plans for craniopharyngioma resection is unknown. Objective This study aimed to identify impact of endocrine and nonendocrine complications (EC and NEC, respectively) on health care utilization and bundled payments following craniopharyngioma resection. Design This study is presented as a retrospective cohort analysis (2000-2016) with 2 years of follow-up. Setting The study included national inpatient hospitalization and outpatient visits. Patients Patients undergoing craniopharyngioma resection were divided into the following four groups: group 1, no complications (NC); group 2, only EC; group 3, NEC; and group 4, both endocrine and nonendocrine complications (ENEC). Interventions This study investigated transphenoidal or subfrontal approach for tumor resection. Main Outcome Hospital readmission, health care utilization up to 24 months following discharge, and 90-day bundled payment performances are primary outcomes of this study. Results Median index hospitalization payments were significantly lower for patients in NC cohort ($28,672) compared with those in EC ($32,847), NEC ($36,259), and ENEC ($32,596; p < 0.0001). Patients in ENEC incurred higher outpatient services and overall median payments at 6 months (NC: 38,268; EC: 49,844; NEC: 68,237; and ENEC: 81,053), 1 year (NC: 46,878; EC: 58,210; NEC: 81,043; and ENEC: 94,768), and 2 years (NC: 58,391; EC: 70,418; NEC: 98,838; and ENEC: 1,11,841; p < 0.0001). The 90-day median bundled payment was significantly different among the cohorts with the highest in ENEC ($60,728) and lowest in the NC ($33,089; p < 0.0001). Conclusion ENEC following surgery incurred almost two times the overall median payments at 90 days, 6 months, 1 year. and 2 years compared with those without complications. Bundled payment model may not be a feasible option in this patient population. Type of complications and readmission rates should be considered to optimize payment model prediction following craniopharyngioma resection.
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| 5. |
- Dietz, N., et al.
(författare)
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Health Care Utilization and Associated Economic Burden of Postoperative Surgical Site Infection after Spinal Surgery with Follow-Up of 24 Months
- 2023
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Ingår i: J Neurol Surg A Cent Eur Neurosurg. ; 84:1, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Surgical site infection (SSI) may lead to vertebral osteomyelitis, diskitis, paraspinal musculoskeletal infection, and abscess, and remains a significant concern in postoperative management of spinal surgery. SSI is associated with greater postoperative morbidity and increased health care payments. METHODS: We conducted a retrospective analysis using MarketScan to identify health care utilization payments and risk factors associated with SSI that occurs postoperatively. Known patient- or procedure-related risk factors were searched across those receiving spine surgery who developed postoperative infection. RESULTS: A total of 33,061 patients who developed infection after spinal surgery were identified in Marketscan. Overall payments at 6 months, including index hospitalization for those with infection, were $53,573 and $46,985 for the cohort with no infection. At 24 months, the infection group had overall payments of $83,280 and $66,221 for no infection. Risk factors with largest effect size most likely to contribute to infection versus no infection were depression (4.6%), diabetes (3.7), anemia (3.3%), two or more levels (2.8%), tobacco use (2.2%), trauma (2.1%), neoplasm (1.8%), congestive heart failure (1.3%), instrumentation (1.1%), renal failure (0.9%), intravenous drug use (0.8%), and malnutrition (0.5%). CONCLUSIONS: SSIs were associated with significant health care utilization payments at 24 months of follow-up. The following clinical and procedural risk factors appear to be predictive of postoperative SSI: depression, diabetes, anemia, two or more levels, tobacco use, trauma, neoplasm, congestive heart failure, instrumentation, renal failure, intravenous drug use, and malnutrition. Interpretation of modifiable and nonmodifiable risk factors for infection informs surgeons of expected postoperative course and preoperative risk for this most common and deleterious postoperative complication to spinal surgery.
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| 6. |
- Giron, S. E., et al.
(författare)
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Increased Central Nervous System Interleukin-8 in a Majority Postlaminectomy Syndrome Chronic Pain Population
- 2018
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Ingår i: Pain Med. ; 19:5, s. 1033-1043
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Multiple processes have been identified as potential contributors to chronic pain, with increasing evidence illustrating an association with aberrant levels of neuroimmune mediators. The primary objectives of the present study were to examine central nervous system cytokines, chemokines, and growth factors present in a chronic pain population and to explore patterns of the same mediator molecules over time. Secondary objectives explored the relationship of central and peripheral neuroimmune mediators while examining the levels of anxiety, depression, sleep quality, and perception of pain associated with the chronic pain patient experience. METHODS: Cerebrospinal fluid (CSF) from a population of majority postlaminectomy syndrome patients (N = 8) was compared with control CSF samples (N = 30) to assess for significant differences in 10 cytokines, chemokines, and growth factors. The patient population was then followed over time, analyzing CSF, plasma, and psychobehavioral measures. RESULTS: The present observational study is the first to demonstrate increased mean CSF levels of interleukin-8 (IL-8; P < 0.001) in a small population of majority postlaminectomy syndrome patients, as compared with a control population. Over time in pain patients, CSF levels of IL-8 increased significantly (P < 0.001). CONCLUSIONS: These data indicate that IL-8 should be further investigated and psychobehavioral components considered in the overall chronic pain paradigm. Future studies examining the interactions between these factors and IL-8 may identify novel targets for treatment of persistent pain states.
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| 7. |
- Glinghammar, B, et al.
(författare)
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Proliferative and molecular effects of the dual PPARalpha/gamma agonist tesaglitazar in rat adipose tissues: relevance for induction of fibrosarcoma
- 2011
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Ingår i: Toxicologic pathology. - : SAGE Publications. - 1533-1601 .- 0192-6233. ; 39:2, s. 325-336
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Tidskriftsartikel (refereegranskat)abstract
- The dual peroxisome-proliferator-activated receptor (PPAR) α/γ agonist tesaglitazar has been shown to produce fibrosarcomas in rats. Here, the authors studied morphology, proliferation, differentiation, and inflammation markers in adipose tissue from rats exposed to 1, 3, or 10 µmol/kg tesaglitazar for 2 or 12 weeks, including recovery groups (12 weeks treatment followed by 12 weeks recovery), and 3 or 10 µmol/kg tesaglitazar for 24 weeks. Subcutaneous white and brown fat revealed reversible dose-related histopathological alterations and after 12 and 24 weeks developed areas of thickened skin (fatty lumps). There was a dose-dependent increase in proliferation of interstitial cells in white and brown fat as shown by increased mitotic index in all dose groups after 2 weeks. This was limited to the high dose after 12 and 24 weeks in white fat. Gene expression analyses showed that while tesaglitazar induced differentiation of adipose tissue characterized with a switch in cyclin D1 and D3 mRNA by 12 weeks, longer exposure at high doses reversed this differentiation concurrent with a reappearance of early adipocyte and inflammatory markers. These data suggest that sustained increased turnover of mesenchymal cells in adipose tissues, concomitant with onset of inflammation and fibrosis, drives development of fibrosarcomas in rats treated with tesaglitazar.
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