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The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi2MoO6 (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method by altering the solvent. The morphology of the BMO material is mainly influenced by the solvent used in the synthesis (H2O, ethanol, and ethylene glycol or their mixtures) and to a lesser extent by subsequent thermal annealing. BMO with aggregated spheres and nanoplate-like structures hydrothermally synthesized in ethylene glycol (EG) and subsequently calcined at 400 °C (BMO-400 (EG)) showed the highest adsorption capacity and photocatalytic activity compared to other synthesized morphologies. Complete degradation of 2,4-D on BMO upon irradiation with a blue light-emitting diode (LED, λmax = 467 nm) was reached within 150 min, resulting in 2,4-dichlorophenol (2,4-DCP) as the main degradation product. Holes (h+) and superoxide radicals (â O2-) are assumed to be the reactive species observed for the rapid conversion of 2,4-D to 2,4-DCP. The addition of H2O2 to the reaction mixture not only accelerates the degradation of 2,4-DCP but also significantly reduces the total organic carbon (TOC) content, indicating that hydroxyl radicals are crucial for the rapid mineralization of 2,4-D. Under optimal conditions, the TOC value was reduced by 84.5% within 180 min using BMO-400 (EG) and H2O2. The improved degradation performance of BMO-400 (EG) can be attributed to its particular morphology leading to lower charge transfer resistance, higher electron-hole separation, and larger specific surface area.
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INTRODUCTION: Prospective studies assessing the relation between endodontic inflammatory disease and subsequent cardiovascular events are few. The present aim was to explore associations between endodontic variables and future cardiovascular events in patients with myocardial infarction and matched controls participating in the PAROKRANK (Periodontitis and Its Relation to Coronary Artery Disease) study. METHODS: Eight-hundred five patients hospitalized for a first myocardial infarction and 805 controls were recruited between 2010 and 2014. Signs of endodontic inflammatory disease were assessed in panoramic radiographs taken at baseline. Mortality and morbidity data during the approximately 8 years of follow up were obtained from national registries. The risk for future cardiovascular events (first of mortality and nonfatal myocardial infarction, stroke, or hospitalization for heart failure) was analyzed with the log-rank test and Cox proportional hazards regression adjusted for the following confounders: sex, age, smoking, myocardial infarction, diabetes, education, marital status, family history of cardiovascular disease, and marginal periodontitis. RESULTS: In total, 285 future events were observed during the follow-up period. Unadjusted analyses revealed that ≥1 root-filled tooth increased the risk of a future event. After adjustment, the number of remaining teeth and non-root-filled teeth decreased the risk of future events, whereas a higher Decayed, Missing and Filled Teeth score increased the risk and ≥1 primary apical periodontitis decreased the risk of suffering cardiovascular events. A higher Decayed, Missing and Filled Teeth score and decayed teeth increased the risk of all-cause mortality. CONCLUSIONS: Tooth loss is a strong indicator of an increased risk for future cardiovascular events. Root-filled teeth seem of limited value as a risk indicator when accounting for other risk factors. The potential effect of dental interventions on future events should be assessed in future research.
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Infarto del Miocardio , Humanos , Masculino , Femenino , Persona de Mediana Edad , Infarto del Miocardio/mortalidad , Anciano , Estudios Prospectivos , Factores de Riesgo , Enfermedades Cardiovasculares/mortalidad , Periodontitis Periapical/complicaciones , Periodontitis Periapical/mortalidad , Periodontitis Periapical/epidemiología , Estudios de Casos y Controles , Periodontitis/complicacionesRESUMEN
Introduction: Lateral ankle sprain is the most common ankle injury and up to 40% of those who sustain a lateral ankle sprain will develop chronic ankle instability (CAI). The aim of this study was to explore the thoughts and expectations of CAI-patients concerning their condition and expectations of care in an orthopedic setting.â¯. Study Design: Qualitative study. Methods: Nine semi-structured one-to-one interviews were conducted with CAI-patients who were referred to an orthopedic setting. Interviews were recorded, transcribed, and analyzed using systematic text condensation with an inductive goal free approach.â¯. Results: Seven themes emerged. The themes were Injury history and symptoms (Lateral ankle sprain during sport, pain and instability), Information from health professional (conflicting information about management and prognosis), Management (mental and physical challenges), Expectation and hope (explanation of symptoms, prognosis and imaging to provide clarification of condition), Activity and participation (restriction in sport and daily life and feelings of uncertainty), Support (support from family/friends) and Identity (low ability to participate in sport and social life result in loss of identity).â¯. Conclusion: The impact of CAI exceeds an experience of pain and instability. Patients experienced loss of identity, having to manage uncertainty regarding their diagnosis and prognosis and had hopes of being able to explain their condition.â¯. Level of Evidence: Not applicable.
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A protocol for efficient N-alkylation of benzamides with alcohols in the presence of cobalt-nanocatalysts is described. Key to the success of this general methodology is the use of highly dispersed cobalt nanoparticles supported on carbon, which are obtained from the pyrolysis of cobalt(ii) acetate and o-phenylenediamine as a ligand at suitable temperatures. The catalytic material shows a broad substrate scope and good tolerance to functional groups. Apart from the synthesis of a variety of secondary amides (>45 products), the catalyst allows for the conversion of more challenging aliphatic alcohols and amides, including biobased and macromolecular amides. The practical applicability of the catalyst is underlined by the successful recycling and reusability.
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OBJECTIVES: Poor oral health and dental infections can jeopardize medical treatment and be life-threatening. Due to this, patients with head and neck malignancies, generalized tumor spread, organ transplant, or severe infection are referred for a clinical oral and radiographic examination. The aim of this study was to compare the diagnostic agreement of three radiographic modalities: intraoral radiographs (IO), panoramic radiographs (PX), and cone beam computed tomography (CBCT) for diagnosis of dental diseases. MATERIALS AND METHODS: Three hundred patients were examined with IO, PX, and CBCT. Periapical lesions, marginal bone level, and caries lesions were diagnosed separately by four oral radiologists. All observers also assessed six teeth in 30 randomly selected patients at two different occasions. Kappa values and percent agreement were calculated. RESULTS: The highest Kappa value and percent agreement were for diagnosing periapical lesions (0.76, 97.7%), and for the assessment of marginal bone level, it varied between 0.58 and 0.60 (87.8-89.3%). In CBCT, only 44.4% of all teeth were assessable for caries (Kappa 0.68, 93.4%). The intra-observer agreement, for all modalities and diagnoses, showed Kappa values between 0.5 and 0.93 and inter-observer agreement varied from 0.51 to 0.87. CONCLUSIONS: CBCT was an alternative to IO in diagnosing periapical lesions. Both modalities found the same healthy teeth in 93.8%. All modalities were performed equally regarding marginal bone level. In caries diagnosis, artifacts were the major cause of fallout for CBCT. CLINICAL RELEVANCE: Intraoral radiography is the first-hand choice for diagnosing dental disease. For some rare cases where intraoral imaging is not possible, a dedicated panoramic image and/or CBCT examination is an alternative.
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Caries Dental , Tomografía Computarizada de Haz Cónico Espiral , Humanos , Radiografía , Tomografía Computarizada de Haz Cónico , Caries Dental/diagnóstico por imagen , ArtefactosRESUMEN
AIM: To explore associations between root filled teeth, primary and secondary apical periodontitis, and levels of inflammatory markers in blood from patients with a first myocardial infarction and matched controls. METHODOLOGY: Between May 2010 and February 2014, 805 patients with a first myocardial infarction and 805 controls, matched for sex, age, and postal code area, were recruited to the multicentre case-control study PAROKRANK (periodontitis and its relation to coronary artery disease). All participants underwent a physical and oral examination, as well as blood sampling. Using panoramic radiography, root filled teeth, primary apical periodontitis, and secondary apical periodontitis were assessed by three independent observers. Blood samples were analysed with enzyme-linked immunosorbent assay method for the following inflammatory markers: interleukin-1ß (IL-1ß), IL-2, IL-6, IL-8, IL-12p70, tumour necrosis factor-α, and high-sensitivity C-reactive protein (hsCRP). Additionally, white blood cell count and plasma-fibrinogen were analysed. Associations between endodontic variables and the levels of inflammatory markers were statistically analysed with Mann-Whitney U-test and Spearman correlation, adjusted for confounding effects of baseline factors (sex, age, myocardial infarction, current smoking, diabetes, family history of cardiovascular disease, education, marital status, and periodontal disease). RESULTS: Mean age of the cohort was 62 years, and 81% were males. Root fillings were present in 8.4% of the 39 978 examined teeth and were associated with higher levels of hsCRP, fibrinogen, and leukocyte count, but lower levels of IL-2 and IL-12p70. After adjusting for confounders, root filled teeth remained associated with higher levels of fibrinogen, but lower levels of IL-1ß, IL-2, IL-6, and IL-12p70. Primary apical periodontitis was found in 1.2% of non-root filled teeth and associated with higher levels of IL-8 (correlation 0.06, p = .025). Secondary apical periodontitis was found in 29.6% of root filled teeth but did not relate to the levels of any of the inflammatory markers. CONCLUSIONS: This study supports the notion that inflammation at the periapex is more than a local process and that systemic influences cannot be disregarded. Whether the observed alterations in plasma levels of inflammatory markers have any dismal effects on systemic health is presently unknown but, considering the present results, in demand of further investigation.
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Infarto del Miocardio , Periodontitis Periapical , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteína C-Reactiva/análisis , Estudios de Casos y Controles , Fibrinógeno/análisis , Interleucina-2 , Interleucina-6 , Interleucina-8 , Tratamiento del Conducto Radicular , SueciaRESUMEN
Improving the selectivity in the oxidative coupling of methane to ethane/ethylene poses a significant challenge for commercialization. The required improvements are hampered by the uncertainties associated with the reaction mechanism due to its complexity. Herein, we report about 90 % selectivity to the target products at 11 % methane conversion over Gd2O3-based catalysts at 700 °C using N2O as the oxidant. Sophisticated kinetic studies have suggested the nature of adsorbed oxygen species and their binding strength as key parameters for undesired methane oxidation to carbon oxides. These descriptors can be controlled by a metal oxide promoter for Gd2O3.
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In a late Swedish Viking Age population dating from around 10th-12th century AD, the prevalence, distribution and location of dental caries were studied. Tooth wear, other dental pathology and anatomical variations were identified and recorded clinically and radiographically. A total of 3293 teeth were analyzed from 171 individuals with complete and partial dentitions, of which 133 were permanent and 38 deciduous/mixed dentition. The dentitions were studied clinically, using a dental probe under a strong light source, and radiographs were taken for 18 of the individuals to verify and complement the clinical caries registration. Almost half the population, 83 of 171 individuals (49%), had at least one carious lesion. All individuals with deciduous or mixed dentitions were caries-free. The number of teeth affected by caries among adults was 424 (13%) and the surface most susceptible to caries was the root surface. The tooth most commonly affected by caries was the first mandibular molar. Other findings included apical infections, which were detected clinically in 4% of the teeth, and one case of filed front teeth. The findings gave a unique understanding of life and death in this early Christian Viking community and indicated that it was common to suffer from dental caries, tooth loss, infections of dental origin and tooth pain. These Vikings also manipulated their teeth through filing, tooth picking and other occupational behaviors.
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Caries Dental , Diente Primario , Adulto , Humanos , Suecia/epidemiología , Prevalencia , Caries Dental/epidemiología , Caries Dental/patología , Susceptibilidad a Caries DentariasRESUMEN
Catalytic hydrogenations are important and widely applied processes for the reduction of organic compounds both in academic laboratories and in industry. To perform these reactions in sustainable and practical manner, the development and applicability of non-noble metal-based heterogeneous catalysts is crucial. Here, we report highly active and air-stable nickel nanoparticles supported on mesoporous silica (MCM-41) as a general and selective hydrogenation catalyst. This catalytic system allows for the hydrogenation of carbonyl compounds, nitroarenes, N-heterocycles, and unsaturated carbonâcarbon bonds in good to excellent selectivity under very mild conditions (room temperature to 80°C, 2 to 10 bar H2). Furthermore, the optimal nickel/meso-silicon dioxide catalyst is reusable (4 cycles) without loss of its catalytic activity.
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PURPOSE: To explore a weighted composite of endodontic inflammatory disease (EID) as a risk factor for suffering a first myocardial infarction (MI). MATERIALS AND METHODS: Seven tooth-specific conditions related to EID were assessed radiographically in 797 patients suffering a first MI and 796 controls. A weighted composite of EID was calculated as the sum of all teeth, excluding third molars. Using maximum likelihood estimation, each condition was assigned a specific weight. With multivariable conditional regression, EID variables, periodontal disease, and missing teeth were assessed as predictors of a first MI. RESULTS: Periodontal disease (OR 1.38; 95% CI 1.13-1.69, p = 0.0016) and missing teeth (OR 1.03; 95% CI 1.002-1.05, p = 0.034) were related to the risk of a first MI, while none of the EID-related conditions individually were. However, when assessed as an aggregate, a weighted composite of EID (OR 1.97; 95% CI 1.23-3.17, p = 0.0050) and periodontal disease (OR 1.34; 95% CI 1.09-1.63, p = 0.0046) was associated with the risk of MI. Missing teeth did not remain a statistically significant predictor of MI in the final model. CONCLUSIONS: A weighted composite of EID was associated with the risk of MI and strengthens the evidence for a direct connection between oral inflammatory diseases and cardiovascular disorders.
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Infarto del Miocardio , Enfermedades Periodontales , Pérdida de Diente , Humanos , Factores de Riesgo , Infarto del Miocardio/complicaciones , Enfermedades Periodontales/complicacionesRESUMEN
Bone healing is a complex process orchestrated by various factors, such as mechanical, chemical and electrical cues. Creating synthetic biomaterials that combine several of these factors leading to tailored and controlled tissue regeneration, is the goal of scientists worldwide. Among those factors is piezoelectricity which creates a physiological electrical microenvironment that plays an important role in stimulating bone cells and fostering bone regeneration. However, only a limited number of studies have addressed the potential of combining piezoelectric biomaterials with state-of-the-art fabrication methods to fabricate tailored scaffolds for bone tissue engineering. Here, we present an approach that takes advantage of modern additive manufacturing techniques to create macroporous biomaterial scaffolds based on a piezoelectric and bioactive ceramic-crystallised glass composite. Using binder jetting, scaffolds made of barium titanate and 45S5 bioactive glass are fabricated and extensively characterised with respect to their physical and functional properties. The 3D-printed ceramic-crystallised glass composite scaffolds show both suitable mechanical strength and bioactive behaviour, as represented by the accumulation of bone-like calcium phosphate on the surface. Piezoelectric scaffolds that mimic or even surpass bone with piezoelectric constants ranging from 1 to 21 pC/N are achieved, depending on the composition of the composite. Using MC3T3-E1 osteoblast precursor cells, the scaffolds show high cytocompatibility coupled with cell attachment and proliferation, rendering the barium titanate/45S5 ceramic-crystallised glass composites promising candidates for bone tissue engineering.
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Current standard wound care involves dressings that provide moisture and protection; however, dressings providing active healing are still scarce and expensive. We aimed to develop an ecologically sustainable 3D printed bioactive hydrogel-based topical wound dressing targeting healing of hard-to-heal wounds, such as chronic or burn wounds, which are low on exudate. To this end, we developed a formulation composed of renewable marine components; purified extract from unfertilized salmon roe (heat-treated X, HTX), alginate from brown seaweed, and nanocellulose from tunicates. HTX is believed to facilitate the wound healing process. The components were successfully formulated into a 3D printable ink that was used to create a hydrogel lattice structure. The 3D printed hydrogel showed a HTX release profile enhancing pro-collagen I alpha 1 production in cell culture with potential of promoting wound closure rates. The dressing has recently been tested on burn wounds in Göttingen minipigs and shows accelerated wound closure and reduced inflammation. This paper describes the dressings development, mechanical properties, bioactivity, and safety.
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OBJECTIVES: Exercise-induced hypoalgesia (EIH) is characterized by an increase in pain threshold following acute exercise. EIH is reduced in some individuals with chronic musculoskeletal pain, although the mechanisms are unknown. It has been hypothesized that this may relate to whether exercises are performed in painful or non-painful body regions. The primary aim of this randomized experimental crossover study was to investigate whether the presence of pain per se in the exercising muscles reduced the local EIH response. The secondary aim was to investigate if EIH responses were also reduced in non-exercising remote muscles. METHODS: Pain-free women (n=34) participated in three separate sessions. In session 1, the maximal voluntary contraction (MVC) for a single legged isometric knee extension exercise was determined. In sessions 2 and 3, pressure pain thresholds (PPT) were assessed at the thigh and shoulder muscles before and after a 3-min exercise at 30â¯% of MVC. Exercises were performed with or without thigh muscle pain, which was induced by either a painful injection (hypertonic saline, 5.8â¯%) or a non-painful injection (isotonic saline, 0.9â¯%) into the thigh muscle. Muscle pain intensity was assessed with an 11-point numerical rating scale (NRS) at baseline, after injections, during and after exercises. RESULTS: PPTs increased at thigh and shoulder muscles after exercise with painful (14.0-24.9â¯%) and non-painful (14.3-19.5â¯%) injections and no significant between-injection EIH differences were observed (p>0.30). Muscle pain intensity was significantly higher following the painful injection compared to the non-painful injection (p<0.001). CONCLUSIONS: Exercising painful muscles did not reduce the local or remote hypoalgesic responses, suggesting that the pain-relieving effects of isometric exercises are not reduced by exercising painful body regions. ETHICAL COMMITTEE NUMBER: S-20210184. TRIAL REGISTRATION NUMBER: NCT05299268.
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Contracción Isométrica , Mialgia , Humanos , Femenino , Estudios Cruzados , Mialgia/terapia , Contracción Isométrica/fisiología , Ejercicio Físico/fisiología , Músculo Esquelético , HipoestesiaRESUMEN
OBJECTIVES: This retrospective study aimed to evaluate long-term clinical and radiologic performance of anodized surface implants supporting single implant restorations. MATERIALS AND METHODS: Patients who received at least one anodized surface implant for a single-tooth restoration between 2003 and 2004 in the Brånemark clinic (Göteborg, Sweden) were included in the study. The assessed outcomes included implant survival, biological and technical complications, as well as marginal bone levels (MBL) based on radiographs. Baseline data on patient demographics, implant placement, and surgery details were also collected. The cumulative survival rate (CSR) was calculated using the Kaplan-Meier survival analysis. RESULTS: The study included 97 patients with 129 implants. Mean patient age at the time of implant placement was 31.7 ± 16.4 years. All implants were placed in a two-stage approach with delayed loading. The last follow-up visit was on average 13.4 ± 4.8 years after implant insertion. Three implants failed, yielding the implant-level 15-year CSR of 97.4%. Majority of the implants had no biological (70.5%) nor technical (81.4%) complications. The mean MBL was -1.0 ± 0.7 mm (n = 101) at prosthetic placement and -1.8 ± 1.0 mm (n = 80) at the last follow-up, while the mean marginal bone loss (MBL) from prosthetic placement to last follow-up was 0.6 ± 1.1 mm (n = 65). CONCLUSIONS: Moderately rough anodized implants have shown favorable long-term outcomessingle-tooth indication, with high survival and a low rate of technical complications. Furthermore, long-term studies are needed to present longitudinal data on peri-implantitis.
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Pérdida de Hueso Alveolar , Implantes Dentales , Humanos , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Estudios Retrospectivos , Estudios de Seguimiento , Implantación Dental Endoósea/efectos adversos , Estudios Longitudinales , Prótesis Dental de Soporte Implantado/efectos adversos , Fracaso de la Restauración Dental , Pérdida de Hueso Alveolar/diagnóstico por imagen , Pérdida de Hueso Alveolar/etiología , Diseño de Prótesis Dental/efectos adversosRESUMEN
OBJECTIVES: To investigate the validity and reliability of marginal bone level measurements on cone-beam computed tomography (CBCT) images of thin bony structures using various reconstruction techniques, two image resolutions, and two viewing modes. MATERIALS AND METHODS: CBCT and histologic measurements of the buccal and lingual aspects of 16 anterior mandibular teeth from 6 human specimens were compared. Multiplanar (MPR) and three-dimensional (3D) reconstructions, standard and high resolutions, and gray scale and inverted gray scale viewing modes were assessed. RESULTS: Validity of radiologic and histologic comparisons were highest using the standard protocol, MPR, and the inverted gray scale viewing mode (mean difference = 0.02 mm) and lowest using a high-resolution protocol and 3D-rendered images (mean difference = 1.10 mm). Mean differences were significant (P < .05) at the lingual surfaces for both reconstructions, viewing modes (MPR windows), and resolutions. CONCLUSIONS: Varying the reconstruction technique and viewing mode does not improve the observer's ability to visualize thin bony structures in the anterior mandibular region. The use of 3D-reconstructed images should be avoided when thin cortical borders are suspected. The small difference when using a high-resolution protocol is unjustified due to the higher radiation dose required. Previous studies have focused on technical parameters; the present study explores the next link in the imaging chain.
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The selective hydrogenation of benzofurans in the presence of a heterogeneous non-noble metal catalyst is reported. The developed optimal catalytic material consists of cobalt-cobalt oxide core-shell nanoparticles supported on silica, which has been prepared by the immobilization and pyrolysis of cobalt-DABCO-citric acid complex on silica under argon at 800 °C. This novel catalyst allows for the selective hydrogenation of simple and functionalized benzofurans to 2,3-dihydrobenzofurans as well as related heterocycles. The versatility of the reported protocol is showcased by the reduction of selected drugs and deuteration of heterocycles. Further, the stability, recycling, and reusability of the Co-nanocatalyst are demonstrated.
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Partial-thickness thermal burn wounds are characterized by a prolonged inflammatory response, oxidative stress, tissue damage, and secondary necrosis. An optimal dressing for burn wounds would reduce inflammation and oxidative stress while providing a moist, absorbent, and protective cover. We have developed an extract from unfertilized salmon roe containing components with potential anti-inflammatory and antioxidative properties, called HTX. HTX has been combined with alginate from brown algae and nanocellulose from tunicates, and 3D printed into a solid hydrogel wound dressing called Collex. Here, Collex was tested on partial thickness burn wounds in Göttingen minipigs compared to Jelonet, and a variant of Collex without HTX. We found that dermal treatment of burn wounds with Collex resulted in accelerated healing at a majority of measured points over 23 days, compared to treatment with Jelonet. In comparison to Collex without HTX, Collex enhanced healing in the first week after trauma where wound progression was pronounced. Notably, Collex reduced the inflammatory response in the early post-injury phase. The anti-inflammatory response of Collex was investigated in more detail on activated M1 macrophages. We found that Collex, as well as HTX alone, significantly reduced the secretion of pro-inflammatory interleukin-1ß as well as intracellular levels of oxidative stress. The results from this study indicate that Collex is a potent dressing for the treatment of burn wounds, with the anti-inflammatory effect of HTX beneficial in the initial phase, and the moist qualities of the hydrogel favorable both in the initial and the proceeding proliferative phase of wound healing.
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Quemaduras , Porcinos , Animales , Quemaduras/tratamiento farmacológico , Alginatos/uso terapéutico , Alginatos/farmacología , Porcinos Enanos , Cicatrización de Heridas , Vendajes , Inflamación , Hidrogeles , SalmónRESUMEN
OBJECTIVE: The aim of the study is to investigate the labor market participation of patients with concurrent substance use and mental health disorder before treatment, as well as the strength of the barriers to re-enter the labor market. METHODS: The study population is composed of individuals with concurrent substance use and mental health disorder at a psychiatric unit in 1996, 2001, 2006, 2011, and 2016. The number of self-supported years 20 years back in time, as well as present and subsequent employment, was calculated. RESULTS: From 1996 to 2016, there was a decrease by 43.8% in self-supported years before treatment and by 36.4% in the fraction of patients working at the time of admission. CONCLUSIONS: The results point to increasing difficulties with regard to labor market attachment among individuals with mental illnesses.
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Trastornos Mentales , Trastornos Relacionados con Sustancias , Humanos , Salud Mental , Trastornos Relacionados con Sustancias/epidemiología , Trastornos Mentales/epidemiología , HospitalesRESUMEN
Background: Underwater rugby is a team sport where players try to score points with a negatively buoyant ball while submerged in a swimming pool. Reports of syncope incidents at the Swedish Championships led to us to investigate end-tidal oxygen and carbon dioxide levels during simulated match play. Methods: Eight male underwater rugby club players of varying experience participated. Repetitive measurements were made while players were defending during simulated match play. Each time a player surfaced they exhaled through a mouthpiece connected to a flow meter and a gas analyzer to measure tidal volume, PETO2 and PETCO2. Results: Measurements were made over 12 dives, with an average dive duration of 18.5 seconds. The mean maximal PETCO2 across the eight participants was 10.0 kPa (~75 mmHg) (range, 9.1-11.7 [~68-88]). The corresponding mean minimum PETO2 was 7.6 kPa (~57 mmHg) (6.3-10.4 [~47-78)). PETCO2 drifted upward, with the mean upward change from the first to last dive for each participant being +1.8 (~13.5 mmHg) (SD 1.74) kPa. A similar trend for PETO2 was not detected, with a mean change of -0.1 (~0.75 mmHg) (SD 3.79) kPa. Conclusion: Despite high PETCO2 values that were close to narcotic being recorded, these players seemed to regulate their urge to breathe based on hypoxia rather than hypercapnia.
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Buceo , Hipercapnia , Dióxido de Carbono , Buceo/fisiología , Humanos , Hipoxia , Masculino , Rugby , Volumen de Ventilación PulmonarRESUMEN
Alkali metal promoters have been widely employed for preparation of heterogeneous catalysts used in many industrially important reactions. However, the fundamentals of their effects are usually difficult to access. Herein, we unravel mechanistic and kinetic aspects of the role of alkali metals in CO2 hydrogenation over Fe-based catalysts through state-of-the-art characterization techniques, spatially resolved steady-state and transient kinetic analyses. The promoters affect electronic properties of iron in iron carbides. These carbide characteristics determine catalyst ability to activate H2 , CO and CO2 . The Allen scale electronegativity of alkali metal promoter was successfully correlated with the rates of CO2 hydrogenation to higher hydrocarbons and CH4 as well as with the rate constants of individual steps of CO or CO2 activation. The derived knowledge can be valuable for designing and preparing catalysts applied in other reactions where such promoters are also used.