Growth of zinc-blende GaN on muscovite mica by molecular beam epitaxy.

The mechanisms of plasma-assisted molecular beam epitaxial growth of GaN on muscovite mica were investigated. Using a battery of techniques, including scanning and transmission electron microscopy, atomic force microscopy, cathodoluminescence, Raman spectroscopy and x-ray diffraction, it was possible to establish that, in spite of the lattice symmetry mismatch, GaN grows in epitaxial relationship with mica, with the [11-20] GaN direction parallel to [010] direction of mica. GaN layers could be easily detached from the substrate via the delamination of the upper layers of the mica itself, discarding the hypothesis of a van der Waals growth mode. Mixture of wurtzite (hexagonal) and zinc blende (ZB) (cubic) crystallographic phases was found in the GaN layers with ratios highly dependent on the growth conditions. Interestingly, almost pure ZB GaN epitaxial layers could be obtained at high growth temperature, suggesting the existence of a specific GaN nucleation mechanism on mica and opening a new way to the growth of the thermodynamically less stable ZB GaN phase.

The role of surface diffusion in the growth mechanism of III-nitride nanowires and nanotubes.

The spontaneous growth of GaN nanowires (NWs) in absence of catalyst is controlled by the Ga flux impinging both directly on the top and on the side walls and diffusing to the top. The presence of diffusion barriers on the top surface and at the frontier between the top and the sidewalls, however, causes an inhomogeneous distribution of Ga adatoms at the NW top surface resulting in a GaN accumulation in its periphery. The increased nucleation rate in the periphery promotes the spontaneous formation of superlattices in InGaN and AlGaN NWs. In the case of AlN NWs, the presence of Mg can enhance the otherwise short Al diffusion length along the sidewalls inducing the formation of AlN nanotubes.

[Differential impact and heterogeneous needs. A peer-led training program for improving chronic patients' health status and health behaviors]. / Impacto diferencial, necesidades heterogéneas. La formación entre iguales para mejorar la salud y los hábitos de vida de los pacientes crónicos.

OBJECTIVE: To measure the impact of the peer-led training for chronic patients on their health status and behaviors. DESIGN: Descriptive, transversal pretest and posttest quantitative approach. PLACEMENT: Andalusia. PARTICIPANTS: Nine hundred sixty-four patients with Diabetes, fibromyalgia and heart failure, trained at the School of Patients between 2013 and 2015. INTERVENTIONS: Peer-training intervention for self-efficacy for chronic patients. MAIN MEASUREMENT: Self-reported health status, activity limitation, diet and physical activity. Statistical analysis included descriptive and bivariate statistics, correlation coefficient and net gains for paired variables. RESULTS: Health status improved after the training, with less limitations and better diet and physical activity, with significant differences by sex, chronic illness, education level and marriage status. Improvement areas where identified for the training strategy, with special attention on the needs of more vulnerable groups (women, people with less education level). CONCLUSIONS: The peer training had a positive impact, with differences depending on social profiles. 1-year and 2-years posttest measurements are needed and a qualitative study is required in order to better evaluate the peer-led strategy and to adapt it to participants' needs and expectations.

Summary of Spanish recommendations on intensive care to facilitate organ donation.

With the aim of consolidating recommendations about the practice of initiating or continuing intensive care to facilitate organ donation (ICOD), an ad hoc working group was established, comprising 10 intensivists designated by the Spanish Society of Intensive Care and Coronary Units (SEMICYUC) and the Spanish National Transplant Organization (ONT). Consensus was reached in all recommendations through a deliberative process. After a public consultation, the final recommendations were institutionally adopted by SEMICYUC, ONT, and the Transplant Committee of the National Health-Care System. This article reports on the resulting recommendations on ICOD for patients with a devastating brain injury for whom the decision has been made not to apply any medical or surgical treatment with a curative purpose on the grounds of futility. Emphasis is made on the systematic referral of these patients to donor coordinators, the proper assessment of the likelihood of brain death and medical suitability, and on transparency in communication with the patient's family. The legal and ethical aspects of ICOD are addressed. ICOD is considered a legitimate practice that offers more patients the opportunity of donating their organs upon their death and helps to increase the availability of organs for transplantation.

Nonanuclear Spin-Crossover Complex Containing Iron(II) and Iron(III) Based on a 2,6-Bis(pyrazol-1-yl)pyridine Ligand Functionalized with a Carboxylate Group.

The synthesis and magnetostructural characterization of [Fe(III)3(µ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](ClO4)13·(CH3)2CO)6·(solvate) (2) are reported. This compound is obtained as a secondary product during synthesis of the mononuclear complex [Fe(II)(bppCOOH)2](ClO4)2 (1). The single-crystal X-ray diffraction structure of 2 shows that it contains the nonanuclear cluster of the formula [Fe(III)3(µ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](13+), which is formed by a central Fe(III)3O core coordinated to six partially deprotonated [Fe(II)(bppCOOH)(bppCOO)](+) complexes. Raman spectroscopy studies on single crystals of 1 and 2 have been performed to elucidate the spin and oxidation states of iron in 2. These studies and magnetic characterization indicate that most of the iron(II) complexes of 2 remain in the low-spin (LS) state and present a gradual and incomplete spin crossover above 300 K. On the other hand, the Fe(III) trimer shows the expected antiferromagnetic behavior. From the structural point of view, 2 represents the first example in which bppCOO(-) acts as a bridging ligand, thus forming a polynuclear magnetic complex.

Evaluation of the last 2 decades in the characteristics of presentation, management and prognosis of serious spontaneous intracerebral hemorrhage in a third level hospital.

OBJECTIVE: To analyze the change in the characteristics of presentation, evolution and treatment in the ICU, as well as the functional evolution at 12 months of spontaneous intracranial hemorrhages (ICHs) treated in an ICU reference center. PATIENT AND METHODS: Descriptive, retrospective study in a Neurocritical Reference Hospital. All admissions of patients with HICE during three periods are studied: 1999-2001 (I), 2015-2016 (II) and 2020-2021 (III). Evolution in the three periods of demographic variables, baseline characteristics of the patients, clinical variables and characteristics of bleeding, evolutionary data in the ICU are studied. At one year we assessed the GOS scale (Glasgow Outcome Score) according to whether they had a poor (GOS 1-3) or good (GOS 4-5) prognosis. RESULTS: 300 admitted patients, distributed in periods: I: 28.7%, II: 36.3% and III: 35%. 56.7% were males aged 66 (55.5-74) years; ICH score 2 (1-3). The ICU stay was 5 (2-14) days with a mortality of 36.8%. GOS 1-3 a year in 67.3% and GOS 4-5 in 32.7%. Comparing the three periods, we observed a higher prevalence in women, and the presence of cardiovascular factors; no changes in etiology; in relation to the location, it increases cerebellar hemorrhage and in the brainstem. Although the severity was greater, the stay in the ICU, the use of invasive mechanical ventilation and tracheostomy were lower. Open surgery has decreased its use by 50%. Mortality continues to be high, stagnating in the ICU at 35% and entails a high degree of disability one year after assessment. CONCLUSIONS: Severe ICH is a complex pathology that has changed some characteristics in the last two decades, with more severe patients, with more cardiovascular history and a greater predominance of brainstem and cerebellar hemorrhage. Despite the increase in severity, better parameters during the ICU stay, with open surgery used 50% less. Mortality remains stagnant at 35% with high disability per year.

Economic Analysis of Cochlear Implants in Adults With Bilateral Severe-to-Profound Hearing Loss. A Systematic Review of the Literature.

OBJECTIVE: To determine the cost-effectiveness or cost-utility of cochlear implants (CI) in adults with severe to profound bilateral hearing loss. DATABASES REVIEWED: PubMed (Medline), The Cochrane Library, Embase via Elsevier, EBSCOhost CINAHL, and Scopus. METHODS: The study included adult participants with severe to profound bilateral neurosensory hearing loss. The analysis encompassed quality of life improvements, costs, cost-effectiveness, cost-utility, cost-benefit, quality-adjusted life year (QALY), incremental cost-effectiveness ratio (ICER), and incremental cost-utility ratio (ICUR). Systematic reviews, meta-analyses, case series, and prospective or retrospective cohort studies published in English between 2010 and 2023 were retrieved. Exclusion criteria included incomplete studies, abstracts, clinical cases, editorials, letters, studies involving pediatric populations, single-side deafness, methodology research, noneconomic aspects of CI, mixed child and adult data, and studies published before 2010. The risk of bias was assessed following the criteria outlined in Appendix I of the economic evaluation's quality assessment as per the NICE Guideline Development Method. RESULTS: Ten articles met the criteria and were included in the qualitative synthesis. One study conducted a prospective cost-utility analyses, one carried out a cost-benefit analyses, one was a randomized controlled clinical trial focusing on cost-utility, and another was a clinical trial addressing cost-effectiveness. Six studies employed Markov models, and one study utilized uniquely the Monte Carlo method. None quantified the economic impact of improved hearing on cognitive function. CONCLUSIONS: The heterogeneity of sources impacted data quality. Unilateral and sequential bilateral CI appeared to be cost-effective when compared with bilateral hearing aids or nontechnological support. When properly indicated, simultaneous bilateral CIs are cost-effective compared to no interventions and to unilateral cochlear implantation through differential discounting or variations from the base cases, especially with a life expectancy of 5-10 years or longer.

[Aspiration thrombectomy for acute pulmonary embolism with an intermediate-high risk]. / Trombectomía mecánica en la tromboembolia pulmonar aguda de riesgo intermedio-alto.

INTRODUCTION AND PURPOSE: The treatment of acute pulmonary embolism (PE) with an intermediate-high risk of mortality at 30 days is still not well defined, recommending the latest clinical guidelines of the European Society of Cardiology 2019 exclusively anticoagulant treatment, reducing the indication for mechanical thrombectomy to high-risk patients or intermediate-high risk patients with poor hemodynamic evolution. Our purpose is to determine the safety and efficacy of aspiration thrombectomy in intermediate-high risk patients with PE and to analyze possible differences in these results between hemodynamically unstable patients (massive PE) and hemodynamically stable patients (submassive PE). METHODS: We analyzed all patients who underwent aspiration thrombectomy for PE at our tertiary university hospital during a 34-month period. We compared echocardiographic parameters (right ventricular diameter, tricuspid plane annular plane systolic excursion (TAPSE), S' wave, and pulmonary hypertension), respiratory parameters (PaO2/FiO2 ratio), and clinical parameters recorded before and 24h after the procedure. We also analyzed bleeding complications and mortality. RESULTS: In the 42 patients included (16 with massive PE and 26 with submassive PE), aspiration thrombectomy resulted in significant improvements in right ventricular diameter, TAPSE, S' wave, andPaO2/FiO2 ratio. Of the 8 patients administered fibrinolysis, 4 developed bleeding complications. Only one direct complication of the procedure was observed (pulmonary artery rupture). Eight patients died in the acute phase. CONCLUSIONS: Aspiration thrombectomy for PE is safe and effective, significantly improving respiratory and hemodynamic parameters in the first 24h after the procedure with a low rate of complications compared to fibrinolysis.

Pulmonary ridge coverage and device-related thrombosis after left atrial appendage occlusion.

AIMS: The aim of this study was to evaluate the impact of pulmonary ridge (PR) coverage on both clinical and imaging follow-up outcomes in patients undergoing left atrial appendage occlusion (LAAO). METHODS AND RESULTS: The study included consecutive patients with non-valvular atrial fibrillation who underwent LAAO with disc and lobe devices. Patients were classified into two groups according to the PR coverage. A total of 147 patients were included. Among these, the PR was covered in 109 (74%) and uncovered in 38 (26%). Successful implantation was achieved in 98.6%. No differences in procedural outcomes were observed between the groups. The rate of procedural major adverse events was 3% (only major bleedings and/or vascular access complications). No device embolisation, cardiac tamponade or in-hospital mortality was observed. After a mean follow-up of 1.77±2.2 years, the annualised ischaemic stroke and major bleeding rate was 1.3%/year and 6.5%/year, respectively, without differences between groups. At follow-up, patients with a covered PR presented a lower incidence of device-related thrombosis (DRT) (1%) than those with an uncovered PR (27%); p<0.001. In multivariable analysis, the presence of PR coverage emerged as an independent predictor of DRT. CONCLUSIONS: Pulmonary ridge coverage was associated with a lower incidence of DRT after LAAO. Procedural and follow-up clinical outcomes did not differ between covered PR and uncovered PR patients.

Soluble Megalin is Reduced in Cerebrospinal Fluid Samples of Alzheimer's Disease Patients.

Megalin or low-density lipoprotein receptor-related protein-2 is a member of the low-density lipoprotein receptor family, which has been linked to Alzheimer's disease (AD) by clearing brain amyloid ß-peptide (Aß) across the blood-cerebrospinal fluid barrier at the choroid plexus. Here, we found a soluble form of megalin secreted from choroid plexus epithelial cells. Soluble megalin levels were also localized in the human cerebrospinal fluid (CSF), being reduced in AD patients. We have also shown that soluble megalin binding to Aß is decreased in the CSF of AD patients, suggesting that decreased sequestration of Aß in the CSF could be associated with defective clearance of Aß and an increase of brain Aß levels. Thus, therapies, which increase megalin expression, at the choroid plexus and/or enhance circulating soluble megalin hold potential to control brain Aß-related pathologies in AD.

[Fibromyalgia: Patient perception on their disease and health system. Qualitative research study]. / Fibromialgia: percepción de pacientes sobre su enfermedad y el sistema de salud. Estudio de investigación cualitativa.

OBJECTIVE: To know the experiences and expectations of persons with fibromyalgia towards the health system and its professionals. METHODS: Qualitative study with three focal groups. The first focal group included patients with fibromyalgia, 20 women and 1 man, receiving care in the public health system, with different assistance paths and progression. Informed Consent was required. Content analysis was done. RESULTS: Patients describe a difficult experience, with symptoms that may involve incapacity for daily activities. Until knowing their diagnosis, they feel a lack of understanding and also loneliness. They develop different coping strategies, as looking for information or association. From the health system they expect: attention and a fast diagnosis, accessibility to consultations, medical exams and therapies or an impulse for research. They want trained professionals, proactive attitudes, interest, empathy and information. DISCUSSION: Qualitative methods seem suitable for delving into patient experience. Health assistance must improve patients' quality of life, facilitating their assistance process and offering companionship, interest, comprehension and support.