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The bulk aerosol emissions excited by externally focused femtosecond laser filaments are characterized using time-resolved plasma imaging and spectroscopy. Images of N2 and N2+ plasma fluorescence are used to characterize the filament dimensions. Emission profiles from bulk Sr aerosols are studied, showing that several localized emission regions in the filament begin to develop for lower repetition rates and higher pulse energies. Plasma temperature and electron density profiles are determined using particle emissions along the length of short- and long-focused filaments, and results are compared for on-axis and side-collected spectra. The use of on-axis collection enables the sampling of light emitted over the entire length of the filament; however, the necessary back-propagation of light makes on-axis collection susceptible to self-absorption as the optical path is extended through the filament plasma column formed in bulk aerosols.
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Multi-filament structures produced by vortical high-power femtosecond pulses propagating through clouds and fog can simultaneously clear two channels with cylindrical and annular profile. We present a method to achieve Free Space Optical (FSO) communications through such highly scattering media by propagating appropriately shaped laser modes through these channels. As a proof of concept, we implemented a Laguerre-Gaussian beam as information signal carrier to demonstrate transmission of 543-nm CW laser beam through a 1-m long cloud chamber using both channels. The low power of the information signal in this experiment allows considering applications in Earth-satellite FSO communication.
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Structured intense laser beams offer degrees of freedom that are highly attractive for high-field science applications. However, the performance of high-power laser beams in these applications is often hindered by deviations from the desired spatiotemporal profile. This study reports the wavefront optimization of ultrafast Laguerre-Gaussian beams through the synergy of adaptive optics and genetic algorithm-guided feedback. The results indicate that the intensity fluctuations along the perimeter of the target ring-shaped profile can be reduced up to â¼15%. Furthermore, the radius of the ring beam profile can be tailored to a certain extent by establishing threshold fitting criteria. The versatility of this approach is experimentally demonstrated in conjunction with different focusing geometries.
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We present a broadband light source based on near-infrared chirped-pulse difference-frequency mixing that is suitable for seeding long-wave-infrared (LWIR) optical parametric chirped-pulse amplification (OPCPA). A nitrocellulose pellicle is used in a Ti:sapphire regenerative amplifier to generate dual-frequency output pulses, which are subsequently mixed in a 0.4-mm thick AgGaS2 crystal. LWIR pulses with â¼1 µm full width at half maximum (FWHM) bandwidth centered at 10.5 µm are generated by mixing transform-limited pulses. Assisted by genetic algorithm optimization, the bandwidth is broadened to â¼3 µm FWHM within the 8-12 µm atmospheric transmission window. The seed source paves the path towards tabletop ultrafast terawatt-class passively carrier-envelope-phase stabilized OPCPA in the LWIR region.
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We demonstrate a novel single-shot method to determine the detonation energy of laser-induced plasma and investigate its performance. This approach can be used in cases where there are significant shot-to-shot variations in ablation conditions, such as laser fluctuations, target inhomogeneity, or multiple filamentation with ultrashort pulses. The Sedov blast model is used to fit two time-delayed shadowgrams measured with a double-pulse laser. We find that the reconstruction of detonation parameters is insensitive to the choice of interpulse delay in double-pulse shadowgraphy. In contrast, the initial assumption of expansion dimensionality has a large impact on the reconstructed detonation energy. The method allows for a reduction in the uncertainties of blast wave energy measurements as a diagnostic technique employed in various laser ablation applications.
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PURPOSE: Photodynamic diagnosis and white-light TURB with adjuvant intravesical chemotherapy (ICT) is widely used in treatment of bladder cancer. This non-inferiority trial is designed to demonstrate non-inferiority regarding recurrence-free survival (RFS) of Hexvix® TURB followed by immediate instillation compared to white-light TURB with immediate instillation followed by maintenance ICT. METHODS: Between 07/2010 and 12/2016, 129 patients with EORTC intermediate risk non-muscle invasive bladder cancer treated with TURB were included in this multicentre phase III study. Patients were randomized and received either white-light TURB with immediate ICT followed by maintenance ICT (n = 62, 20 mg Mitomycin weekly for 6 weeks as induction phase, afterwards 20 mg/month for 6 months) or Hexvix® TURB with immediate ICT only (n = 67, 40 mg Mitomycin). Primary study endpoint was RFS after 12 months. Hexvix® TURB was counted as non-inferior to white light alone if the upper limit of the one-sided 95% confidence interval of hazard ratio was lower than 1.676. Due to the non-inferiority design, the per-protocol population was used as the primary analysis population (n = 113) RESULTS: Median follow-up was 1.81 years. Hexvix® group showed more events (recurrence or death) than white-light group (19 vs. 10) resulting in a HR of 1.29 (upper limit of one-sided 95%-CI = 2.45; pnon-inferiority = 0.249). The ITT population yielded similar results (HR = 1.67); 3.18], pnon-inferiority = 0.493). There was no significant difference in overall survival between both groups (p = 0.257). CONCLUSION: Non-inferiority of Hexvix® TURB relative to white-light TURB with maintenance Mitomycin instillation in intermediate risk urothelial carcinoma of the bladder was not proven. Hence a higher effect of maintenance ICT is to assume compared to a Hexvix®-improved TURB only, confirming its important role in patient treatment.
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Ácido Aminolevulínico/análogos & derivados , Antineoplásicos/administração & dosagem , Carcinoma/terapia , Cistectomia , Fármacos Fotossensibilizantes/administração & dosagem , Neoplasias da Bexiga Urinária/terapia , Administração Intravesical , Adulto , Idoso , Idoso de 80 Anos ou mais , Ácido Aminolevulínico/administração & dosagem , Carcinoma/mortalidade , Carcinoma/patologia , Quimioterapia Adjuvante , Cistoscopia , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mitomicina/administração & dosagem , Fotoquimioterapia , Estudos Prospectivos , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/patologiaRESUMO
Filament-induced ablation represents an attractive scheme for long-range material identification via optical spectroscopy. However, the delivery of laser energy to the target can be severely hindered by the stochastic nature of multiple-filamentation, ionization of ambient gas, and atmospheric turbulence. In order to mitigate some of these adverse effects, we examine the utility of beam shaping for femtosecond filament-induced breakdown spectroscopy with Gaussian and structured (Laguerre-Gaussian, Airy, and Bessel-Gaussian) beams in the nonlinear regime. Interaction of filaments with copper, zinc, and brass targets was studied by recording axially-resolved broadband emission from the filament-induced plasma. The laser-solid coupling efficacy was assessed by inferring thermodynamic parameters such as excitation temperature and electron density. While under our experimental conditions the ablation rate with Gaussian- and Laguerre-Gaussian beams is found to be similar, the Airy and Bessel-Gaussian beams offer the advantage of longitudinally extended working zones. These results provide insights into potential benefits of structuring ultrafast laser beams for standoff sensing applications.
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OBJECTIVES: To validate the adherence of urologists to chemotherapy recommendations given in the EAU guidelines on PeCa. The European Association of Urology (EAU) guidelines on penile cancer (PeCa) are predominantly based on retrospective studies with low level of evidence. MATERIALS AND METHODS: A 14-item-survey addressing general issues of PeCa treatment was developed and sent to 45 European hospitals. 557 urologists participated in the survey of which 43.5%, 19.3%, and 37.2% were in-training, certified, and in leading positions, respectively. Median response rate among participating departments was 85.7% (IQR 75-94%). Three of 14 questions addressed clinical decisions on neoadjuvant, adjuvant, and palliative chemotherapy. Survey results were analyzed by bootstrap-adjusted multivariate logistic-regression-analysis to identify predictors for chemotherapy recommendations consistent with the guidelines. RESULTS: Neoadjuvant, adjuvant, and palliative chemotherapy was recommended according to EAU guidelines in 21%, 26%, and 48%, respectively. For neoadjuvant chemotherapy, urologists holding leading positions or performing chemotherapy were more likely to recommend guideline-consistent treatment (OR 1.85 and 1.92 with p(bootstrap) = 0.007 and 0.003, respectively). Supporting resources (i.e., guidelines, textbooks) were used by 23% of survey participants and significantly improved consistency between treatment recommendations and Guideline recommendations in all chemotherapy settings (p(bootstrap) = 0.010-0.001). Department size and university center status were no significant predictors for all three endpoints. CONCLUSIONS: In this study, we found a very low rate of adherence to the EAU guidelines on systemic treatment for PeCa. Further investigations are needed to clarify whether this missing adherence is a consequence of limited individual knowledge level or of the low grade of guideline recommendations.
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Antineoplásicos/administração & dosagem , Fidelidade a Diretrizes/estatística & dados numéricos , Pesquisas sobre Atenção à Saúde , Neoplasias Penianas/tratamento farmacológico , Urologia , Europa (Continente) , Humanos , Masculino , Guias de Prática Clínica como Assunto , Sociedades MédicasRESUMO
BACKGROUND: Radical cystectomy (RC) is associated with substantial postoperative mortality. In this study, we analyzed early (30-day; 30 M) and late (30-90-day; 30-90 M) mortality after RC in a Dutch tertiary referral center and determined factors associated with 30 M, 30-90 M and 90-day mortality (90 M). PATIENTS AND METHODS: We identified 823 patients who underwent RC for bladder cancer in the Netherlands Cancer Institute between 1997 and 2017. Predictive factors for mortality were analyzed to identify patients with a higher mortality risk. Multivariate logistic regression analysis was performed to examine the influence of patient, surgical and histopathological variables on 30 M, 30-90 M and 90 M. RESULTS: Thirty-day mortality was 1.9% and 90 M was 6.0%. Multivariable analysis showed that age (OR 1.08, 95% CI 1.01-1.1, p = 0.002) and ASA 3-4 (OR 3.57, 95% CI 1.25-10.16, p = 0.002) were significant predictors of 30 M while higher ASA score (OR 2.9, 95% CI 1.31-6.5, p = 0.009) and higher pathological T stage (OR 8.8, 95% CI 1.9-40.4, p = 0.005) were associated with 30-90 M. Risk of 90 M was increased in patients with ASA 3-4 (OR 2.4, 95% CI 1.2-4.9, p = 0.01), pT3-4 (OR 3.1, 95% CI 1.27-7.57, p = 0.01) and positive LNs (OR 2.5, 95% CI 1.25-4.98, p = 0.009). CONCLUSIONS: Patient-related factors predicted 30 M whereas both patient-related and cancer-related factors predicted 30-90 M. This suggests that patient mix, i.e. patient- vs. cancer-related factors for 30 M and 30-90 M, should be taken into account if mortality rates are to be compared between hospitals.
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Cistectomia , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/cirurgia , Idoso , Idoso de 80 Anos ou mais , Institutos de Câncer , Cistectomia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Fatores de TempoRESUMO
In multivariate analysis, GS of the regular prostatectomy specimen was the only statistically significant parameter for pT2R1 prostate cancer.
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AIM: This study compared functional outcomes between anatomical shaped fibular plates and intramedullary nail fixation of adult patients who sustained unstable ankle fractures. METHODS: A prospective randomized control trial was conducted between November 2013 and December 2016 on patients that presented with an unstable ankle fractures. They were randomized into a plate-and-screw group and a fibula nail group. At each post-operative visit the wounds were reviewed, and specific outcome measures were recorded, which included (i) the patient reported outcome measure (PROM) Olerud and Molander functional score, (ii) the Grimby score, (iii) swelling around the malleoli, (iv) plantar flexion, (v) dorsiflexion, (vi) inversion, and (vi) eversion. RESULTS: Significant differences were observed in scar size (p < 0.001) and screening time (p < 0.001) whilst no differences were observed in functional and PROM measures. Although not statistically significant, of clinical value is one deep infection that occurred in the plate group, whilst no infections occurred in the nail group. CONCLUSION: Both fixation methods yielded very similar functional results with differences only in scar size, screening time and swelling. Although none of these warrant a change in surgical decision-making processes, taken together, these factors potentially influence the decisions made in terms of surgical modalities used.
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Fraturas do Tornozelo/cirurgia , Fixação Interna de Fraturas/métodos , Adulto , Fraturas do Tornozelo/diagnóstico por imagem , Articulação do Tornozelo/diagnóstico por imagem , Articulação do Tornozelo/cirurgia , Placas Ósseas , Parafusos Ósseos , Feminino , Fíbula/diagnóstico por imagem , Fíbula/cirurgia , Fixação Intramedular de Fraturas/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Medidas de Resultados Relatados pelo Paciente , Estudos Prospectivos , Resultado do TratamentoRESUMO
PURPOSE: The aim of this study was to quantify the overall burden of orthopaedic gunshot-related injuries at our institution over a four year period. Secondary aims included identifying complications from gunshot-related injuries and the additional burden it places on healthcare services. METHODS: A retrospective review was conducted on all patients with gunshot injuries presenting to our hospital's trauma unit between January 2014 and December 2017. Patient data was recorded, and demographic data, number and type of implants, blood products used, duration of hospital admission, duration of ICU admission, radiological studies performed, and prevalence of complications were analysed. RESULTS: A total of 1449 patients with a mean age of 28.2 ± 9.7 years (range 2.0-71.0) were included in this study. The majority of these gunshot-related orthopaedic injuries were sustained to the lower extremities and were treated non-operatively. The median duration of hospital stay was 7.0 (IQR 4.0-12.0). The most common complications identified were nerve injury (8.3%), vascular injury (6.5%), fracture-related infection (3.2%), non-union (3.1%), and compartment syndrome (1.6%). The total cost of care was ZAR 53,568,537 (USD 4,320,043) with an average cost per patient of ZAR 37,031 (USD 2986). CONCLUSION: This study highlighted the burden of gunshot injuries presenting to our hospital and the strain it places on its healthcare resources. The prevalence of complications was comparable to international studies on the subject. With improved understanding of this burden, more healthcare resources can be allocated to this problem and better prevention strategies can be planned.
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Ortopedia , Ferimentos por Arma de Fogo , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , África do Sul/epidemiologia , Centros de Traumatologia , Ferimentos por Arma de Fogo/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Besides public awareness and specialist knowledge and training of physicians, their self-confidence plays a key role for clinical decision-making in the respective area. OBJECTIVE: This exploratory study investigated the influence of the discipline on differences in self-confidence in dealing with antibiotics and in the self-rated knowledge. METHODS: In 2015 the multi-institutional reconnaissance of practice with multiresistant bacteria (MR2) questionnaire containing items on antibiotic prescription and multiresistant pathogens was sent out to 1061 physicians working in departments for internal medicine, general surgery, gynecology and obstetrics and urology. In 2017 a similar MR2 survey was sent to 1268 specialist and assistant physicians in anesthesiology in Germany. Besides demographic data 4 items on self-confidence in the use of antibiotic treatment and 11 items concerning self-rated knowledge about rational antibiotic therapy and multiresistant pathogens were included in the present analysis. Logistic regression analysis, the χ2-test and the Kruskal-Wallis test were used for statistical analysis of the influence of the discipline on these items. RESULTS: The response rates were 43% (456 out of 1061) from the non-anesthetists and 56% (705 out of 1268) from the anesthetists. Of the non-anesthetists 44% and 57% of the anesthetists had had no advanced training on antibiotic stewardship during the year before the study. In the overall analysis anesthetists (mean±SD: 2.53±0.54) were significantly less self-confident about antibiotics than colleagues from other departments (internal medicine: 3.10±0.50, general surgery: 2.97±0.44, gynecology and obstetrics: 3.12±0.42 and urology: 3.15±0.44) in the unadjusted (all p<0.001) and adjusted comparison. The analysis of self-rated knowledge about rational antibiotic prescription showed similar results. Senior consultant status and advanced training in infectiology were significantly associated with self-confidence and self-rated knowledge about antibiotics. CONCLUSION: Anesthetists showed significantly less self-confidence in dealing with antibiotics than colleagues from other disciplines. Advanced training on a rational prescription of antibiotics was associated with a greater self-confidence, so that the implementation of compulsory courses on rational antibiotic stewardship in the respective residency curriculum needs to be considered.
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Antibacterianos/uso terapêutico , Médicos/estatística & dados numéricos , Especialização/estatística & dados numéricos , Anestesiologistas/estatística & dados numéricos , Atitude do Pessoal de Saúde , Alemanha , Hospitais , Humanos , Prescrições , Autoimagem , Inquéritos e QuestionáriosRESUMO
Work-related injuries date back to antiquity. Attempts to resolve these work-related challenges have, inter alia, led to the establishment of the professions of Ergonomics, Occupational Therapy, Physiotherapy, Occupational Hygiene, and Biokinetics. The objective of this article is to illustrate the value of Ergonomic principles as an adjunct to the profession of Biokinetics. Insofar as Ergonomics addresses the physical and environmental risks which predispose and precipitate injuries, the profession of Ergonomics is primarily concerned with the practice of eradicating work-related challenges that impede human-machine interfacing, and which adversely influence work productivity and employee health. While Occupational Therapy and Biokinetics, by rehabilitating work-related injuries, assist in improving working conditions, little is known about the exact interface between the professions of Ergonomics and Biokinetics. The Google Scholar database was consulted in order to determine the relationship between Ergonomics and Biokinetics. The key words used were ergonomics and biokinetics and lead to the identification of 545 records, none of which pertained to the aforementioned subject. A subsequent search was conducted using the key words work-related musculoskeletal injuries and biokinetics. This search identified 925 records, the number of which were reduced to 42 (4.76%) after the exclusion of patents (n = 24), citations (n = 3), and nonbiokinetic work-related injury research (n = 856). Given that many work-related injuries are managed through the use of biokinetic rehabilitation, knowledge of the physical ergonomic risk factors at play will afford biokineticists an enhanced understanding of the etiology of work-related injuries, thereby helping to improve the vigor of the rehabilitation.
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Ergonomia/métodos , Sistema Musculoesquelético/lesões , Traumatismos Ocupacionais/prevenção & controle , Terapia Ocupacional/métodos , Fenômenos Biomecânicos , Meio Ambiente , Humanos , Traumatismos Ocupacionais/reabilitaçãoRESUMO
BACKGROUND: Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial. OBJECTIVE: To bring together a large multidisciplinary group of experts to develop consensus statements on controversial topics in bladder cancer management. DESIGN: A steering committee compiled proposed statements regarding advanced and variant bladder cancer management which were assessed by 113 experts in a Delphi survey. Statements not reaching consensus were reviewed; those prioritised were revised by a panel of 45 experts before voting during a consensus conference. SETTING: Online Delphi survey and consensus conference. PARTICIPANTS: The European Association of Urology (EAU), the European Society for Medical Oncology (ESMO), experts in bladder cancer management. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Statements were ranked by experts according to their level of agreement: 1-3 (disagree), 4-6 (equivocal), 7-9 (agree). A priori (level 1) consensus was defined as ≥70% agreement and ≤15% disagreement, or vice versa. In the Delphi survey, a second analysis was restricted to stakeholder group(s) considered to have adequate expertise relating to each statement (to achieve level 2 consensus). RESULTS AND LIMITATIONS: Overall, 116 statements were included in the Delphi survey. Of these, 33 (28%) statements achieved level 1 consensus and 49 (42%) statements achieved level 1 or 2 consensus. At the consensus conference, 22 of 27 (81%) statements achieved consensus. These consensus statements provide further guidance across a broad range of topics, including the management of variant histologies, the role/limitations of prognostic biomarkers in clinical decision making, bladder preservation strategies, modern radiotherapy techniques, the management of oligometastatic disease and the evolving role of checkpoint inhibitor therapy in metastatic disease. CONCLUSIONS: These consensus statements provide further guidance on controversial topics in advanced and variant bladder cancer management until a time where further evidence is available to guide our approach.
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Consenso , Oncologia/normas , Guias de Prática Clínica como Assunto , Neoplasias da Bexiga Urinária/terapia , Urologia/normas , Técnica Delphi , Europa (Continente) , Humanos , Cooperação Internacional , Oncologia/métodos , Estadiamento de Neoplasias , Sociedades Médicas/normas , Participação dos Interessados , Inquéritos e Questionários , Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/patologia , Urologia/métodosRESUMO
We investigate the oxidation of uranium (U) species, the physical conditions leading to uranium monoxide (UO) formation and the interplay between plume hydrodynamics and plasma chemistry in a laser-produced U plasma. Plasmas are produced by ablation of metallic U using nanosecond laser pulses. An ambient gas environment with varying oxygen partial pressures in 100 Torr inert Ar gas is used for controlling the plasma oxidation chemistry. Optical emission spectroscopic analysis of U atomic and monoxide species shows a reduction in the emission intensity and persistence with increasing oxygen partial pressure. Spectral modelling is used for identifying the physical conditions in the plasma that favor UO formation. The optimal temperature for UO formation is found to be in the temperature range of â¼1500-5000 K. The spectrally integrated and spectrally filtered (monochromatic) imaging of U atomic and molecular species reveals the evolutionary paths of various species in the plasma. Our results also highlight that oxidation in U plasmas predominantly occurs at the cooler periphery and is delayed with respect to plasma formation, and the dissipation of molecular species strongly depends on oxygen partial pressure.
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BACKGROUND: The Health and Safety Executive's new Health and Work Strategy is based on an up-to-date assessment of workplace health priorities. Rather than replicating traditional prioritization approaches, a broader assessment of health and work priorities was carried out using a range of stakeholders. AIMS: To develop a set of health priorities for further research and intervention activity. METHODS: Four exercises were carried out, including internal prioritization, two external web-hosted questionnaire studies of younger workers and occupational health professionals, focus groups and tele-depth interviews with workplace health and safety professionals. RESULTS: The highest rated internal priorities (weighted priority scores) were identified as mesothelioma (70), lung cancer (69.25), chronic obstructive pulmonary disease (COPD; 69), musculoskeletal disorders (MSDs; 66.25), hearing loss (65.75), stress (65.5), asthma (64.5) and hand-arm vibration syndrome (61.5). Using the three highest ranked criteria developed by occupational health professionals ((i) the preventability of the condition, (ii) the impact of the condition and (iii) the number of workers affected), mesothelioma, lung cancer, COPD, MSDs, hearing loss, stress and asthma were identified as the top seven priorities. Generic issues identified included ageing and work, obesity, newer technologies, and ethnicity and cultures of workforces. Apprentices identified stress, depression, anxiety, musculoskeletal and respiratory disorders, fatigue and workload as important workplace health considerations. CONCLUSIONS: This process identified a number of expected and new areas of health research interest. We believe the findings reflect the real world requirements of work as assessed by occupational health and safety practitioners and workers.
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Doença Crônica/terapia , Prática Clínica Baseada em Evidências/organização & administração , Prioridades em Saúde/organização & administração , Doenças Profissionais/terapia , Saúde Ocupacional , Grupos Focais , Pessoal de Saúde , Humanos , Neoplasias Pulmonares , Doenças Musculoesqueléticas , Neoplasias MesoteliaisRESUMO
VEGF induces normal or aberrant angiogenesis depending on its dose in the microenvironment around each producing cell in vivo. This transition depends on the balance between VEGF-induced endothelial stimulation and PDGF-BB-mediated pericyte recruitment, and co-expression of PDGF-BB normalizes aberrant angiogenesis despite high VEGF doses. We recently found that VEGF over-expression induces angiogenesis in skeletal muscle through an initial circumferential vascular enlargement followed by longitudinal splitting, rather than sprouting. Here we investigated the cellular mechanism by which PDGF-BB co-expression normalizes VEGF-induced aberrant angiogenesis. Monoclonal populations of transduced myoblasts, expressing similarly high levels of VEGF alone or with PDGF-BB, were implanted in mouse skeletal muscles. PDGF-BB co-expression did not promote sprouting and angiogenesis that occurred through vascular enlargement and splitting. However, enlargements were significantly smaller in diameter, due to a significant reduction in endothelial proliferation, and retained pericytes, which were otherwise lost with high VEGF alone. A time-course of histological analyses and repetitive intravital imaging showed that PDGF-BB co-expression anticipated the initiation of vascular enlargement and markedly accelerated the splitting process. Interestingly, quantification during in vivo imaging suggested that a global reduction in shear stress favored the initiation of transluminal pillar formation during VEGF-induced splitting angiogenesis. Quantification of target gene expression showed that VEGF-R2 signaling output was significantly reduced by PDGF-BB co-expression compared to VEGF alone. In conclusion, PDGF-BB co-expression prevents VEGF-induced aberrant angiogenesis by modulating VEGF-R2 signaling and endothelial proliferation, thereby limiting the degree of circumferential enlargement and enabling efficient completion of vascular splitting into normal capillary networks despite high VEGF doses.
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Becaplermina/metabolismo , Proliferação de Células , Células Endoteliais , Músculo Esquelético , Neovascularização Fisiológica , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Camundongos , Camundongos SCID , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
Studies of high-power ultrashort laser pulse interaction with matter are not only of fundamental scientific interest, but are also highly relevant to applications in the domain of remote sensing. Here, we investigate the effect of laser wavelength on coupling of femtosecond laser filaments to solid targets. Three central wavelengths have been used to produce filaments: 0.4, 0.8, and 2.0 µm. We find that, unlike the case of conventional tight focusing, use of shorter wavelengths does not necessarily produce more efficient ablation. This is explained by increased multi-photon absorption arising in near-UV filamentation. Investigations of filament-induced plasma dynamics and its thermodynamic parameters provide the foundation for unveiling the interplay between wavelength-dependent filament ablation mechanisms. In this way, strategies to increase the sensitivity of material detection via this technique may be better understood, thereby improving the analytical performance in this class of applications.
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We perform optical emission spectroscopy of ultrafast laser filament-produced air plasmas in the multiple filament regime at driving wavelengths of 400 nm and 800 nm. The spatiotemporal structure of the emission from the plasmas are observed and the emission spectra are used to estimate plasma temperature and density for a range of laser parameters. Plasma temperatures are determined from the molecular nitrogen fluorescence, while the electron densities are estimated from Stark broadening of the oxygen-I 777.19-nm line. Electron temperatures are determined to be in the range of 5000-5200 K and they do not vary significantly along the length of the filament, nor are they sensitive to incident laser energy or wavelength. Electron densities are on order of 1016 cm-3 and show a greater variation with axial position, laser energy, and laser wavelength. We discuss mechanisms responsible for spatial localization of emitting species within the filament. Optical emission spectroscopy offers a simple, non-perturbing method to measure filament properties, that allows the information on the associated molecular transitions and excitation/ionization mechanisms to be extracted.