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1.
Cerebellum ; 23(2): 341-354, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36802021

RESUMEN

Impairment of hand motor function is a frequent consequence after a stroke and strongly determines the ability to regain a self-determined life. An influential research strategy for improving motor deficits is the combined application of behavioral training and non-invasive brain stimulation of the motor cortex (M1). However, a convincing clinical translation of the present stimulation strategies has not been achieved yet. One alternative and innovative approach is to target the functionally relevant brain network-based architecture, e.g., the dynamic interactions within the cortico-cerebellar system during learning. Here, we tested a sequential multifocal stimulation strategy targeting the cortico-cerebellar loop. Anodal transcranial direct current stimulation (tDCS) was applied simultaneously to a hand-based motor training in N = 11 chronic stroke survivors during four training sessions on two consecutive days. The tested conditions were: sequential multifocal (M1-cerebellum (CB)-M1-CB) vs. monofocal control stimulation (M1-sham-M1-sham). Additionally, skill retention was assessed 1 and 10 days after the training phase. Paired-pulse transcranial magnetic stimulation data were recorded to characterize stimulation response determining features. The application of CB-tDCS boosted motor behavior in the early training phase in comparison to the control condition. No faciliatory effects on the late training phase or skill retention were detected. Stimulation response variability was related to the magnitude of baseline motor ability and short intracortical inhibition (SICI). The present findings suggest a learning phase-specific role of the cerebellar cortex during the acquisition of a motor skill in stroke and that personalized stimulation strategies encompassing several nodes of the underlying brain network should be considered.


Asunto(s)
Accidente Cerebrovascular , Estimulación Transcraneal de Corriente Directa , Humanos , Destreza Motora/fisiología , Mano , Accidente Cerebrovascular/terapia , Cerebelo/fisiología
2.
Angew Chem Int Ed Engl ; 62(14): e202218094, 2023 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-36744674

RESUMEN

Metal coordination compound (MCC) glasses [e.g., metal-organic framework (MOF) glass, coordination polymer glass, and metal inorganic-organic complex (MIOC) glass] are emerging members of the hybrid glass family. So far, a limited number of crystalline MCCs can be converted into glasses by melt-quenching. Here, we report a universal wet-chemistry method, by which the super-sized supramolecular MIOC glasses can be synthesized from non-meltable MOFs. Alcohol and acid were used as agents to inhibit crystallization. The MIOC glasses demonstrate unique features including high transparency, shaping capability, and anisotropic network. Directional photoluminescence with a large polarization ratio (≈47 %) was observed from samples doped with organic dyes. This crystallization-suppressing approach enables fabrication of super-sized MCC glasses, which cannot be achieved by conventional vitrification methods, and thus allows for exploring new MCC glasses possessing photonic functionalities.

3.
Ann Surg ; 276(5): 929-934, 2022 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-35894426

RESUMEN

OBJECTIVE: We aimed to investigate the postoperative trend in blood pressure (BP)-related outcomes [BP and antihypertensive (AHT) drug use] during the year following adrenalectomy for primary aldosteronism (PA) to determine the optimal timing for outcome assessment and to determine the necessary follow-up length. BACKGROUND: Since the course of BP-related outcomes after adrenalectomy is unknown, the optimal timing of outcome assessment and follow-up duration are not clear. METHODS: In this retrospective single center cohort study, we used a prospectively collected database with all patients referred for difficult-to-control-hypertension-analysis. All patients diagnosed with PA who underwent adrenalectomy were included. AHT drug use [in defined daily dose (DDD)] and home blood pressure measurements (HBPMs) during the first postoperative year were collected. A mixed-effects model was developed to assess the stability of DDD and HBPM over time and adjust for potential confounders. RESULTS: In total 1784 patients were assessed for difficult-to-control-hypertension of whom 41 were included. Both the DDD and HBPM showed the strongest decrease in the first postoperative month (mean 1.6DDD; mean 140/85 mm Hg) compared with preoperative values (4.5DDD; 153/92 mm Hg). Thereafter, both outcomes showed a stable course from 4 to 6 months (1.6DDD; 136/86 mm Hg) up to 12 months postoperatively (2.0DDD; 136/83 mm Hg). CONCLUSIONS: This study showed that AHT drug use and HBPM decreased substantially within the first month after adrenalectomy for PA and afterwards generally remained stable during the year following adrenalectomy. We propose that BP-related outcomes can be assessed reliably early after adrenalectomy and question the need for routine long-term follow-up in referral centers.


Asunto(s)
Hiperaldosteronismo , Hipertensión , Humanos , Adrenalectomía , Antihipertensivos/uso terapéutico , Estudios de Cohortes , Hiperaldosteronismo/diagnóstico , Hiperaldosteronismo/cirugía , Estudios Retrospectivos
4.
Ann Surg Oncol ; 28(8): 4387-4399, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33521900

RESUMEN

BACKGROUND: Little is known about complications after major duodenopancreatic surgery for duodenopancreatic neuroendocrine tumors (dpNETs) in multiple endocrine neoplasia type 1 (MEN1). Therefore, the incidence and severity of complications after major surgery for MEN1-related dpNETs were assessed. METHODS: Patients were selected from the population-based Dutch MEN1 database if they had undergone a Whipple procedure or total pancreatectomy from 2003 to 2017. Complications were graded according to the Clavien-Dindo classification (grade III or higher complications were considered a severe complication) and definitions from the International Study Group of Pancreatic Surgery. The Cumulative Complication Index (CCI®) was calculated as the sum of all complications weighted for their severity. Univariable logistic regression was performed to assess potential associations between predictor candidates and a severe complication. RESULTS: Twenty-seven patients (median age 43 years) underwent a major duodenopancreatic resection, including 14 Whipple procedures and 13 total pancreatectomies. Morbidity and mortality were 100% (27/27) and 4% (1/27), respectively. A severe complication occurred in 17/27 (63%) patients. The median CCI® was 47.8 [range 8.7-100]. Grade B/C pancreatic fistulas, delayed gastric emptying, bile leakage, hemorrhage, and chyle leakage occurred in 7/14 (50%), 10/27 (37%), 1/27 (4%), 7/27 (26%), 3/27 (11%) patients, respectively. Patients with a severe complication had longer operative time and higher blood loss. After Whipple, new-onset endocrine and exocrine insufficiency occurred in 1/13 and 9/14 patients, respectively. CONCLUSIONS: Major duodenopancreatic surgery in MEN1 is associated with a very high risk of severe complications and cumulative burden of complications and should therefore be reserved for a select subgroup of patients with MEN1-related dpNETs.


Asunto(s)
Neoplasia Endocrina Múltiple Tipo 1 , Tumores Neuroendocrinos , Neoplasias Pancreáticas , Adulto , Humanos , Neoplasia Endocrina Múltiple Tipo 1/cirugía , Tumores Neuroendocrinos/cirugía , Pancreatectomía , Neoplasias Pancreáticas/cirugía , Pancreaticoduodenectomía/efectos adversos
5.
World J Surg ; 44(6): 1905-1915, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32025781

RESUMEN

BACKGROUND: Various diagnostic tests are available to establish the primary aldosteronism (PA) diagnosis and to determine the disease laterality. Combined with the controversies in the literature, unawareness of guidelines and technical demands and high costs of some of these diagnostics, this could lead to significant differences in work-up strategies worldwide. Therefore, we investigated the work-up before surgery for PA in daily clinical practice within a multicenter study. METHODS: Patients who underwent unilateral adrenalectomy for PA within 16 centers in Europe, Canada, Australia and the USA between 2010 and 2016 were included. We did not exclude patients based on the performed diagnostic tests during work-up to make our data representative for current clinical practice. Adherence to the Endocrine Society Guideline and variables associated with not performing adrenal venous sampling (AVS) were analyzed. RESULTS: In total, 435 patients were eligible. An aldosterone-to-renin ratio, confirmatory test, computed tomography (CT), magnetic resonance imaging and AVS were performed in 82.9%, 32.9%, 86.9%, 17.0% and 65.3% of patients, respectively. A complete work-up, as recommended by the guideline, was performed in 13.1% of patients. Bilateral disease or normal adrenal anatomy on CT (OR 16.19; CI 3.50-74.99), smaller tumor size on CT (OR 0.06; CI 0.04-0.08) and presence of hypokalemia (OR 2.00; CI 1.19-3.32) were independently associated with performing AVS. CONCLUSIONS: This study is the first to examine the daily clinical practice work-up of PA within a worldwide cohort of surgical patients. The results demonstrate significant variability in work-up strategies and low adherence to The Endocrine Society guideline.


Asunto(s)
Adrenalectomía/métodos , Adhesión a Directriz , Hiperaldosteronismo/cirugía , Adulto , Anciano , Aldosterona/sangre , Femenino , Humanos , Hiperaldosteronismo/diagnóstico por imagen , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Renina/sangre , Tomografía Computarizada por Rayos X
6.
World J Surg ; 44(1): 323, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31489476

RESUMEN

In the original article, two of the International CONNsortium Study Group collaborator's names are spelled wrong: Anton F. Engelsman and Els J.M. Nieveen van Dijkum. The spellings are correct as reflected here.

7.
World J Surg ; 43(10): 2459-2468, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31270571

RESUMEN

INTRODUCTION: Complete resolution of hypertension after adrenalectomy for primary aldosteronism is far from a certainty. This stresses the importance of adequate preoperative patient counseling. The aldosteronoma resolution score (ARS) is a simple and easy to use prediction model only including four variables: ≤ 2 antihypertensive medications, body mass index ≤ 25 kg/m2, duration of hypertension ≤ 6 years and female sex. However, because the model was developed and validated within the USA over a decade ago, the applicability in modern practice and outside of the USA is questionable. Therefore, we aimed to validate the ARS in current clinical practice within an international cohort. MATERIALS AND METHOD: Patients who underwent unilateral adrenalectomy, between 2010 and 2016, in 16 medical centers from the USA, Europe (EU), Canada (CA) and Australia (AU) were included. Resolution of hypertension was defined as normotension without antihypertensive medications. RESULTS: In total, 514 patients underwent adrenalectomy and 435 (85%) patients were eligible. Resolution of hypertension was achieved in 27% patients within the total cohort and in 22%, 30%, 40% and 38% of patients within USA, EU, CA and AU, respectively (p = 0.015). The area under the curve (AUC) for the complete cohort was 0.751. Geographic validation displayed a AUC within the USA, EU, CA and AU of 0.782, 0.681, 0.811 and 0.667, respectively. DISCUSSION: The ARS is an easy to use prediction model with a moderate to good predictive performance within current clinical practice. The model showed the highest predictive performance within North America but potentially has less predictive performance in EU and AU.


Asunto(s)
Neoplasias de la Corteza Suprarrenal/cirugía , Adrenalectomía , Adenoma Corticosuprarrenal/cirugía , Hiperaldosteronismo/cirugía , Hipertensión/etiología , Neoplasias de la Corteza Suprarrenal/complicaciones , Adenoma Corticosuprarrenal/complicaciones , Adulto , Antihipertensivos/uso terapéutico , Área Bajo la Curva , Índice de Masa Corporal , Femenino , Humanos , Hiperaldosteronismo/clasificación , Hiperaldosteronismo/etiología , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos
8.
Endocr Res ; 42(4): 302-310, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28509618

RESUMEN

PURPOSE: Differentiated thyroid cancer is the most common endocrine malignancy. Recurrences (5-20%) are the main reason for follow-up. Thyroglobulin (Tg) has proven to be an excellent disease marker, but thyroglobulin-antibodies (Tg-Ab) may interfere with Tg measurement, leading to over or underestimation. It is proposed that the Tg-Ab trend can be used as a marker for disease recurrence, yet few studies define trend and have a long-term follow-up. The objective of our study was to investigate the value of a well-defined Tg-Ab trend as a surrogate marker for disease recurrence during long-term follow-up. METHODS: We retrospectively studied patients treated at the Nuclear Department of the University Medical Center Utrecht from 1998 to 2010 and the Netherlands Cancer Institute from 2000 to 2009. All patients with Tg-Ab 12 months after treatment were included. The definition of a rise was >50% increase of the Tg-Ab value in a 2 year time period. A decline as >50% decrease of the Tg-Ab value. RESULTS: Twenty-five patients were included. None of the patients with declining or stable Tg-Ab without a concomitant rise in Tg developed a recurrence. Four patients did suffer a recurrence. Three of these patients had a rising Tg-Ab trend, in two of these patients Tg was undetectable. CONCLUSIONS: Tg-Ab trend can be used as a crude surrogate marker for long-term follow-up of Tg-Ab patients. A rising trend in Tg-Ab warrants further investigation to detect recurrent disease. Stable or declining Tg-Ab levels do not seem to reflect a risk for recurrence.


Asunto(s)
Autoanticuerpos/análisis , Biomarcadores de Tumor/sangre , Recurrencia Local de Neoplasia/sangre , Glándula Tiroides/inmunología , Neoplasias de la Tiroides/sangre , Regulación hacia Arriba , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Inmunoensayo , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/epidemiología , Recurrencia Local de Neoplasia/inmunología , Recurrencia Local de Neoplasia/prevención & control , Estadificación de Neoplasias , Países Bajos/epidemiología , Estudios Retrospectivos , Factores de Riesgo , Glándula Tiroides/patología , Neoplasias de la Tiroides/epidemiología , Neoplasias de la Tiroides/prevención & control , Neoplasias de la Tiroides/terapia
9.
Anaesthesist ; 66(1): 45-51, 2017 Jan.
Artículo en Alemán | MEDLINE | ID: mdl-27942783

RESUMEN

BACKGROUND: The "Notfallsanitätergesetz" (the law pertaining to paramedics), which came into effect in January 2014, has fundamentally changed the training of health personnel in German prehospital emergency medicine. The apprenticeship now takes 3 years including 720 h of practical training in eligible hospitals. To date, however, there has been little experience of how the contents of the guidelines for practical training ("Ausbildungs- und Prüfungsverordnung") can be reasonably applied in the teaching hospitals. METHODS: In a total of nine interdisciplinary working group meetings between October 2014 and June 2016, we developed a curriculum concerning the practical training of paramedics to implement the contents of the guidelines for practical training in a didactically and an organizationally meaningful way. RESULTS: The implementation of the practical training of paramedics is an excellent chance for the teaching hospitals to contribute to higher quality prehospital emergency medicine. Otherwise, the teaching hospitals face an organizational and personal effort that is not to be underestimated. Thus, a modular curriculum constitutes the possibility of standardizing practical training and simultaneously reducing the time and expenditure for the participating hospitals. CONCLUSION: The development of a unique curriculum for the practical training of paramedics may contribute to standardized, high-quality, and cost-efficient training.


Asunto(s)
Técnicos Medios en Salud/educación , Medicina de Emergencia/educación , Hospitales de Enseñanza , Técnicos Medios en Salud/legislación & jurisprudencia , Competencia Clínica , Curriculum , Servicios Médicos de Urgencia/legislación & jurisprudencia , Medicina de Emergencia/legislación & jurisprudencia , Alemania , Guías como Asunto , Humanos , Comunicación Interdisciplinaria
11.
Surg Endosc ; 30(3): 1051-9, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26092019

RESUMEN

BACKGROUND: Since the 1950s, preoperative medical preparation has been widely applied in patients with pheochromocytoma to improve intraoperative hemodynamic instability and postoperative complications. However, advancements in preoperative imaging, laparoscopic surgical techniques, and anesthesia have considerably improved management in patients with pheochromocytoma. In consequence, there is no validated consensus on current predictive factors for postoperative morbidity. The aim of this study was to determine perioperative factors which are predictive for postoperative morbidity in patients undergoing laparoscopic adrenalectomy for pheochromocytoma. STUDY DESIGN: It is a retrospective analysis of prospectively maintained databases in five medical centers from 2002 to 2013. Inclusion criteria were consecutive patients who underwent non-converted laparoscopic unilateral total adrenalectomy for pheochromocytoma. RESULTS: Two-hundred and twenty-five patients were included. All-cause and cardiovascular postoperative morbidity rates were 16% (n = 36) and 4.8% (n = 11), respectively. Preinduction blood pressure normalization after preoperative medical preparation had no impact on postoperative morbidity. However, past medical history of coronary artery disease (OR [CI95%] = 3.39; [1.317-8.727]) and incidence of intraoperative hemodynamic instability episodes (both SBP ≥ 160 mmHg and MAP < 60 mmHg) (OR [CI95%] = 3.092; [1.451-6.587]) remained independent predictors for postoperative all-cause morbidity. Similarly, past medical history of coronary artery disease (OR [CI95%] = 14.41; [3.119-66.57]), female sex (OR [CI95%] = 12.05; [1.807-80.31]), and incidence of intraoperative hemodynamic instability episodes (both SBP ≥ 200 mmHg and MAP < 60 mmHg) (OR [CI95%] = 4.13; [1.009-16.90]) remained independent predictors for postoperative cardiovascular morbidity. CONCLUSIONS: This study identifies risk factors for cardiovascular and all-cause postoperative morbidity after laparoscopic adrenalectomy in current clinical setting. These data can help physicians to guide intra-operative blood pressure management and have to be taken into account in further studies.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales/cirugía , Adrenalectomía/métodos , Laparoscopía , Feocromocitoma/cirugía , Complicaciones Posoperatorias/etiología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/epidemiología , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento
12.
Endocr Pract ; 22(5): 561-6, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26720251

RESUMEN

OBJECTIVE: The time between the moment of referral for the diagnostic workup for thyroid nodules and the outcome can be worrisome for patients. In general, patients experience high levels of anxiety during the evaluation of a lesion suspicious for cancer. Therefore, the implementation of same-day fine-needle aspiration cytology (FNAC) diagnosis is becoming standard-of-care for many solid tumors. Our aim was to assess the feasibility of same-day FNAC diagnosis for thyroid nodules and to assess patient anxiety during the diagnostic process. METHODS: For feasibility of same-day FNAC diagnosis, we assessed the proportion of patients receiving a diagnosis at the end of the visit. Accuracy was measured by comparing histology with the FNAC result. Patient anxiety was measured by the State Trait Anxiety Inventory at 6 moments during the diagnostic workup. RESULTS: Of the 131 included patients, 112 (86%) were female, and the mean age was 53 years. All patients, except those with a nondiagnostic FNAC result (n = 26; 20%), had a diagnosis at the end of the day. There were only two discordant results. Anxiety levels at the beginning of the day were high throughout the group, State Trait Anxiety Inventory (STAI) score 43.1 (SD 2.0) and decreased significantly more in patients with a benign FNAC result (STAI score 30.2), compared to patients with a malignant or indeterminate result (STAI score 39.6). CONCLUSION: Distress of patients with a thyroid nodule undergoing same-day FNAC diagnostics was high. Same-day FNAC diagnosis is feasible and accurate for the evaluation of thyroid nodules. Therefore, same-day FNAC diagnosis seems a safer, more patient-friendly approach to diagnose thyroid nodules.


Asunto(s)
Ansiedad/epidemiología , Citodiagnóstico/métodos , Citodiagnóstico/psicología , Nódulo Tiroideo/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Biopsia con Aguja Fina/efectos adversos , Biopsia con Aguja Fina/métodos , Biopsia con Aguja Fina/psicología , Citodiagnóstico/efectos adversos , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estrés Psicológico/epidemiología , Estrés Psicológico/etiología , Nódulo Tiroideo/epidemiología , Nódulo Tiroideo/psicología , Factores de Tiempo , Adulto Joven
13.
Chem Mater ; 36(6): 2756-2766, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38558915

RESUMEN

Water is one of the most reactive and abundant molecules on Earth, and it is thus crucial to understand its reactivity with various material families. One of the big unknown questions is how water in liquid and vapor forms impact the fast-emerging class of metal-organic frameworks (MOFs). Here, we discover that high-pressure water vapor drastically modifies the structure and hence the dynamic, thermodynamic, and mechanical properties of MOF glasses. In detail, we find that an archetypical MOF (ZIF-62) is extremely sensitive to heat treatments performed at 460 °C and water vapor pressures up to ∼110 bar. Both the melting and glass transition temperatures decrease remarkably (by >100 °C), and simultaneously, hardness and Young's modulus increase by up to 100% under very mild treatment conditions (<20 bar of hydrothermal pressure). Structural analyses suggest water to partially coordinate to Zn in the form of a hydroxide ion by replacing a bridging imidazolate-based linker. The work provides insight into the role of hot-compressed water in influencing the structure and properties of MOF glasses and opens a new route for systematically changing the thermodynamics and kinetics of MOF liquids and thus altering the thermal and mechanical properties of the resulting MOF glasses.

14.
Nat Genet ; 7(2 Spec No): 220-45, 1994 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7920646

RESUMEN

We have constructed a genetic map of the mouse genome containing 4,006 simple sequence length polymorphisms (SSLPs). The map provides an average spacing of 0.35 centiMorgans (cM) between markers, corresponding to about 750 kb. Approximately 90% of the genome lies within 1.1 cM of a marker and 99% lies within 2.2 cM. The markers have an average polymorphism rate of 50% in crosses between laboratory strains. The markers are distributed in a relatively uniform fashion across the genome, although some deviations from randomness can be detected. In particular, there is a significant underrepresentation of markers on the X chromosome. This map represents the two-thirds point toward our goal of developing a mouse genetic map containing 6,000 SSLPs.


Asunto(s)
Mapeo Cromosómico , Genoma , Ratones/genética , Polimorfismo Genético , Animales , Cruzamientos Genéticos , Femenino , Marcadores Genéticos , Masculino , Cromosoma X
15.
Int Marit Health ; 74(1): 1-14, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36974488

RESUMEN

BACKGROUND: This study investigates how Faroese deep-sea fishers' exposure to work-related stressors affects their sleep, sleepiness, and levels of fatigue. Being constantly exposed to the unpredictable and harsh North Atlantic Ocean, having long work hours and split sleep for up to 40 days consecutively, they will arguably suffer from fatigue. MATERIALS AND METHODS: One hundred and fifty seven fishers participated in this study, and data was gathered throughout 202 days at sea. Subjective data was collected at the start and end of trips via questionnaires, sleep and sleepiness diaries and supplemented by objective sleep data through actigraphs. Ship movements were logged with a gyroscope connected to a laptop. A noise metre measured each work station and resting area, and noise exposure profiles were calculated based on each participant's activity and location. Linear mixed-effect models investigated the effects of work exposure variables on sleep efficiency, and cumulative link mixed models measured effects on the Karolinska Sleepiness Scale and physical fatigue scale. RESULTS: Time of day followed by ship movement were the exposure variables with the highest impact on the outcome variables of sleep efficiency, sleepiness and physical fatigue. The number of days at sea revealed correlations to outcome variables either by itself or interacting with the sleep periods per day. Crew size, shift system or noise did not impact outcome variables when in the model with other variables. Larger catches improved sleep efficiency but did not affect sleepiness and physical fatigue ratings. CONCLUSIONS: The findings indicate a chronically fatigued fisher population, and recommends urgent attention being paid to improving the structure of vessels and installing stabilators for greater stability at sea; work schedules being evaluated for protection of health; and work environments being designed that fulfill human physiological requirements in order to ensure the wellbeing and safety of those at sea.


Asunto(s)
Tolerancia al Trabajo Programado , Condiciones de Trabajo , Humanos , Somnolencia , Sueño/fisiología , Fatiga/epidemiología
16.
Chem Commun (Camb) ; 59(79): 11871-11874, 2023 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-37723944

RESUMEN

The high-density amorphous phases (HDAs) of bimetallic zeolitic imidazolate frameworks (Zn/Co-ZIF-4) were prepared. The temperature dependence of the isobaric heat capacity (Cp) of ZIF-4 HDAs was measured to determine the glass transition temperature (Tg) of HDAs. The Tg non-linearly decreases with the molar ratio R, where R is Co/(Co + Zn), indicating the presence of a mixed-metal node effect. This effect arises from the non-linear increase of the degree of configurational freedom in the HDA as R increases. The degree of configurational freedom is inversely correlated with the network connectivity, which is, in turn, affected by variations in the MN4 (M: Zn or Co; N: nitrogen) tetrahedral symmetry in the ZIF-4 HDA. Overall, this work offers valuable insights into the glass transition of metal-organic frameworks.

17.
Brain Stimul ; 15(4): 968-979, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35792318

RESUMEN

BACKGROUND: Healthy older adults show a decrease in motor performance and motor learning capacity as well as in working memory (WM) performance. WM has been suggested to be involved in motor learning processes, such as sequence learning. Correlational evidence has shown the involvement of the frontoparietal network (FPN), a network underlying WM processes, in motor sequence learning. However, causal evidence is currently lacking. Non-invasive brain stimulation (NIBS) studies have focused so far predominantly on motor-related areas to enhance motor sequence learning while areas associated with more cognitive aspects of motor learning have not yet been addressed. HYPOTHESIS: In this study, we aim to provide causal evidence for the involvement of WM processes and the underlying FPN in the successful performance of a motor sequence learning task by using theta transcranial alternating current stimulation (tACS) targeting the FPN during a motor sequence learning task. METHODS: In a cohort of 20 healthy older adults, we applied bifocal tACS in the theta range to the FPN during a sequence learning task. With the use of a double-blind, cross-over design, we tested the efficacy of active compared to sham stimulation. Two versions of the motor task were used: one with high and one with low WM load, to explore the efficacy of stimulation on tasks differing in WM demand. Additionally, the effects of stimulation on WM performance were addressed using an N-back task. The tACS frequency was personalized by means of EEG measuring the individual theta peak frequency during the N-back task. RESULTS: The application of personalized theta tACS to the FPN improved performance during the motor sequence learning task with high WM load (p < .001), but not with low WM load. Active stimulation significantly improved both speed (p < .001), and accuracy (p = .03) during the task with high WM load. In addition, the stimulation paradigm improved performance on the N-back task for the 2-back task (p = .013), but not for 1-back and 3-back. CONCLUSION: The performance during a motor sequence learning task can be enhanced by means of personalized bifocal theta tACS to the FPN when WM load is high, indicating that the efficacy of this stimulation paradigm is dependent on the cognitive demand during the learning task. These data provide further causal evidence for the critical involvement of WM processes and the FPN during the execution of a motor sequence learning task in healthy older. These findings open new exciting possibilities to counteract the age-related decline in motor performance, learning capacity and WM performance.


Asunto(s)
Corteza Motora , Estimulación Transcraneal de Corriente Directa , Anciano , Cognición/fisiología , Estudios Cruzados , Método Doble Ciego , Humanos , Aprendizaje/fisiología , Memoria a Corto Plazo/fisiología
18.
Nat Sci Sleep ; 14: 347-362, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35264889

RESUMEN

Purpose: Faroese fishers have four times more accidents than workers on land. The aim was to understand fishers' fatigue better and how their work and sleep patterns influenced their sleepiness levels and cognitive performance. Materials and Methods: A total of 157 Faroese fishers wore wrist-worn actigraphs at sea and one week on land and filled in sleep and sleepiness diaries during the trip. Furthermore, a 3-minute simple reaction time (SRT) test was completed at the beginning and end of the trip. The ship's movement and noise were also logged. The actiwatch results were analysed with mixed methods repeated measures. The sleepiness registrations and performance on the SRT-test were analysed with paired t-test. The ship movements (Pitch and roll) were divided into approximately three same-sized groups (lowest 1/3, medium 1/3, and highest 1/3) and compared against the Karolinska Sleepiness Scores (KSS ranging from 1-9) ≥7 and physical tiredness (ranging from 1-9) scores ≥7. Chi-square tests were used to determine the significance of these differences. Mean sleepiness scores at sea, and the proportion of sleepiness scores ≥7 were calculated, as well as sleepiness scores as a function of the time of day. Results: While at sea, fishers had more split sleep, slept less, and had lower sleep efficiency than onshore. Sleepiness was higher at the end of the trip, and cognitive decline was found. The number of major lapses was higher at the end of the trip, but with no significant difference between the median reaction times. Conclusion: The crew on-board the freezer longliner, who worked 8-8 shifts, slept the most, had the longest continuous sleep periods, the highest sleep efficiency, the lowest sleepiness levels, and the highest noise exposure during their time off.

19.
Int Marit Health ; 73(3): 150-161, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36217969

RESUMEN

BACKGROUND: This study examines the impact of work-related exposure on the cognitive performance of Faroese deep-sea fishers. Faroese fishing crews work long hours in demanding and noisy environments amidst highly uncertain and challenging weather conditions. These factors, together with compromised patterns of rest and sleep, are known to increase fatigue. Our aim was to study if changes could be measured in fishers' cognitive performance at the end of the trip when compared with the baseline measure at the beginning. MATERIALS AND METHODS: Data was collected over 15 months (May 2017 to July 2018) from 157 fishers on 18 fishing trips which involved 202 investigative days on board. Questionnaires and six computerised cognitive tests: Simple Reaction Time, Numeric Working Memory, Corsi Blocks, Rapid Visual Information Processing, Digit Vigilance, and Card Sorting Test were used for data collection at the beginning and end of the trip. Differences between the outcomes on the two test points were analysed with one-way ANOVA comparing the performances at the beginning and end of the voyage, and two-way ANOVA to examine the interactive effect of chronotype and test occasions on the outcomes. Mixed models were used to test for the effects of predictor variables. RESULTS: Significant declines in cognitive performance were observed from the beginning to the end of the trip, with decreases in visuospatial memory and reaction times, and increases in cognitive lapses. Furthermore, slowing in response times was observed in the second half of the Digit Vigilance test when comparing the halves. CONCLUSIONS: Declines in performance were observed from the start to the end of the trip. Furthermore, fishers performed significantly worse in the second half of some parted tests, and evening types seem less influenced by irregular work hours. These findings call for improving the safety of the vessels and their crew.


Asunto(s)
Explotaciones Pesqueras , Sueño , Cognición , Fatiga , Humanos , Tiempo (Meteorología)
20.
RSC Adv ; 12(17): 10815-10824, 2022 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-35424998

RESUMEN

We synthesized two series of bimetallic (zinc and cobalt) zeolitic imidazolate frameworks (ZIF-62) under different solvothermal conditions. It is found that the structure of the derived ZIF crystals is highly sensitive to synthesis conditions. One series possesses the standard ZIF-62 structure, whereas the other has a mixed structure composed of both the standard structure and an unknown one. The standard series exhibits a slight negative deviation from linearity of melting temperature (T m) and glass transition temperature (T g) with the substitution of Co for Zn. In contrast, the new series displays a stronger negative deviation. These negative deviations from linearity indicate the mixed metal node effect in bimetallic ZIF-62 due to the structural mismatch between Co2+ and Zn2+ and to the difference in their electronic configurations. The new series involves both cobalt-rich and zinc-rich phases, whereas the standard one shows one homogeneous phase. Density functional theory calculations predict that the substitution of Co for Zn increases the bulk modulus of the ZIF crystals. This work indicates that the structure, melting behaviour, and mechanical properties of ZIFs can be tuned by metal node substitution and by varying the synthetic conditions. Both series of ZIFs have higher glass forming abilities due to their higher T g/T m ratios (0.77-0.84) compared to most good glass formers.

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