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1.
Ear Hear ; 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38783420

RESUMO

OBJECTIVES: The study compared the utility of two approaches for collecting real-world listening experiences to predict hearing-aid preference: a retrospective questionnaire (Speech, Spatial, and Qualities of Hearing Scale [SSQ]) and in-situ Ecological Momentary Assessment (EMA). The rationale being that each approach likely provides different and yet complementary information. In addition, it was examined how self-reported listening activity and hearing-aid data-logging can augment EMAs for individualized and contextualized hearing outcome assessments. DESIGN: Experienced hearing-aid users (N = 40) with mild-to-moderate symmetrical sensorineural hearing loss completed the SSQ questionnaire and gave repeated EMAs for two wear periods of 2-weeks each with two different hearing-aid models that differed mainly in their noise reduction technology. The EMAs were linked to a self-reported listening activity and sound environment parameters (from hearing-aid data-logging) recorded at the time of EMA completion. Wear order was randomized by hearing-aid model. Linear mixed-effects models and Random Forest models with five-fold cross-validation were used to assess the statistical associations between listening experiences and end-of-trial preferences, and to evaluate how accurately EMAs predicted preference within individuals. RESULTS: Only 6 of the 49 SSQ items significantly discriminated between responses made for the end-of-trial preferred versus nonpreferred hearing-aid model. For the EMAs, questions related to perception of the sound from the hearing aids were all significantly associated with preference, and these associations were strongest in EMAs completed in sound environments with predominantly low SNR and listening activities related to television, people talking, nonspecific listening, and music listening. Mean differences in listening experiences from SSQ and EMA correctly predicted preference in 71.8% and 72.5% of included participants, respectively. However, a prognostic classification of single EMAs into end-of-trial preference with a Random Forest model achieved a 93.8% accuracy when contextual information was included. CONCLUSIONS: SSQ and EMA predicted preference equally well when considering mean differences, however, EMAs had a high prognostic classifications accuracy due to the repeated-measures nature, which make them ideal for individualized hearing outcome investigations, especially when responses are combined with contextual information about the sound environment.

2.
Vascular ; : 17085381241247881, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38630458

RESUMO

OBJECTIVES: Coronary artery disease (CAD) and abdominal aortic aneurysm (AAA) are common arterial pathologies that might occur simultaneously; however, there is not enough evidence about the optimal strategy for patients with concomitant indications of coronary artery bypass grafting (CABG) and open repair of the AAA (AAOR). This study aims to present the outcomes in low and moderate cardiac surgical risk patients who underwent one-stage or two-stage elective CABG and AAOR in a middle-income country. METHODS: An observational, retrospective case series study was conducted. Patients who had low and moderate cardiac surgical risk (less than 8% mortality risk on the STS score) and had the concomitant indication for CABG and AAOR between December 2005 and August 2021 were included. Patients were assigned to one of three strategies: Group 1 underwent one-stage surgery for CABG and AAOR, Group 2 underwent two-stage surgery within the same in-patient stay, and Group 3 underwent two-stage surgery in a new in-patient stay within 6 months. RESULTS: Twenty seven, patients with simultaneous requirements of CABG and AAOR were identified, with a mean age of 69.5 ± 6.1 years and 92.6% were male. The most common comorbidities were hypertension at 77.8% and dyslipidemia at 55.6%. The average mortality risk calculated by the STS score was 2.09% ± 1.53%. In Group 1 (n = 9), 1/9 had in-hospital mortality and no reinterventions were needed. In Group 2 (n = 10), 1/10 had in-hospital mortality, and the most common postoperative complication was acute kidney injury 2/10. Furthermore, 2/10 required a reintervention. In Group 3 (n = 8), no in-hospital mortality was present, however, complications such as sepsis, atrial fibrillation, and acute kidney injury occurred in 2/8 patients each, and 2/8 required a reintervention. CONCLUSION: Patients with CAD and AAA that need a concomitant surgical correction with CABG and an AAOR are uncommon in contemporary practice, given the advances in endovascular therapy. When indicated, one-stage surgery can be performed in patients with low cardiac surgical risk, proper patient selection plays a fundamental role and might be performed in experienced centers. However, two-staged surgeries at the same or different inpatient stay may be considered for asymptomatic AAA with close monitoring during the postoperative period. These findings can hold significance for addressing sociodemographic barriers in low and middle-income countries. More robust and extensive studies are needed to make clear comparisons between the different strategies.

3.
Rev Med Chil ; 151(4): 453-460, 2023 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-38687520

RESUMO

INTRODUCTION: Poisonings are a worldwide preventable public health problem that affects the general population. OBJECTIVE: To epidemiologically characterize BZ and AD poisonings registered in Chile between 2002 and 2019. METHODS: An observational retrospective study of poisonings registered in the medical outcome report system of the Chilean Ministry of Health was conducted. The World Health Organization International Classification of Disease codes T42.2, T43.0 and T43.2 were included. RESULTS: 22,807 poisonings associated with BZ or AD were identified, representing 0.08% of all hospitalizations. Poisoning rates distribution were established at regional and national level. There were 9.8% of accidental events, 63.7% of intentional events, and 26.5% of undetermined cases. The highest accidental and intentional poisoning rates were estimated at the ages of 0 to 4 and 15 to 19 years old respectively. Poisoned patients remained hospitalized on average for 3.4 days. 0.3% of cases were related to death of patients. CONCLUSIONS: Poisoning events were characterized according to the studied variables. National poisoning rates decreased over the years with prevalence of those intentional events linked to women. Efforts should be made in creating poisoning prevention campaigns focused on age-based groups in the general population.


Assuntos
Antidepressivos , Benzodiazepinas , Humanos , Chile/epidemiologia , Feminino , Adolescente , Masculino , Estudos Retrospectivos , Benzodiazepinas/intoxicação , Adulto , Adulto Jovem , Criança , Lactente , Pré-Escolar , Pessoa de Meia-Idade , Antidepressivos/intoxicação , Idoso , Distribuição por Idade , Distribuição por Sexo , Hospitalização/estatística & dados numéricos , Prevalência , Intoxicação/epidemiologia , Recém-Nascido
4.
Inorg Chem ; 60(18): 13990-14001, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34496217

RESUMO

This study presents the influence of polymorphism on the magnetic properties of Co5TeO8. This compound with a spinel-like structure [Co2]A[Co3Te]BO8 was synthesized into two polymorphs: one disordered within a cubic Fd3̅m structure, where Co2+ and Te6+ ions are randomly distributed on the octahedral B sites [the disordered polymorph can also be presented as an inverse spinel of the formula Co(Co1.5Te0.5)O4] and the other ordered with a cubic P4332 structure where Co2+ and Te6+ ions are ordered on the B sites. The macroscopic magnetic measurements showed that both polymorphs present a ferrimagnetic ordering, below ∼40 K, and a second transition is also observed at 27 K for the ordered polymorph. Neutron powder diffraction data between room temperature and 1.7 K showed as well the presence of short-range magnetic ordered clusters, which appears for both polymorphs below 200 K. At lower temperature, these short-range orders are transformed into long-range ferrimagnetic orders. Below TC = 40 K, the colinear ferrimagnetic structure of the disordered polymorph is described with the I41/am'd' space group. The ordered polymorph undergoes an incommensurate ferrimagnetic spiral spin ordering below TC1 = 45 K, followed by a second magnetic phase transition at TC2 = 27 K. This last transition is associated with the emergence of an additional ferrimagnetic component and an abrupt change in the magnitude of the magnetic propagation vector k = [0, 0, γ] from γ = 0.086 at T = 30 K to γ ≈ 0.14 in the range between 27 and 1.7 K. The magnetic symmetry of the ordered polymorph is described with the P43(00γ)0 magnetic superspace group. We evidenced that the ordering of Co2+/Te6+ on the B sites changes all of the Co-Co and Co-O distances and thus all JAB, JAA, and JBB exchange interactions, between the A and B sites, which are able to stabilize the incommensurate spin modulation in the ordered polymorph.

5.
Int J Gynecol Cancer ; 31(10): 1317-1325, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34493587

RESUMO

OBJECTIVE: The objective of the ConCerv Trial was to prospectively evaluate the feasibility of conservative surgery in women with early-stage, low-risk cervical cancer. METHODS: From April 2010 to March 2019, a prospective, single-arm, multicenter study evaluated conservative surgery in participants from 16 sites in nine countries. Eligibility criteria included: (1) FIGO 2009 stage IA2-IB1 cervical carcinoma; (2) squamous cell (any grade) or adenocarcinoma (grade 1 or 2 only) histology; (3) tumor size <2 cm; (4) no lymphovascular space invasion; (5) depth of invasion <10 mm; (6) negative imaging for metastatic disease; and (7) negative conization margins. Cervical conization was performed to determine eligibility, with one repeat cone permitted. Eligible women desiring fertility preservation underwent a second surgery with pelvic lymph node assessment, consisting of sentinel lymph node biopsy and/or full pelvic lymph node dissection. Those not desiring fertility preservation underwent simple hysterectomy with lymph node assessment. Women who had undergone an 'inadvertent' simple hysterectomy with an unexpected post-operative diagnosis of cancer were also eligible if they met the above inclusion criteria and underwent a second surgery with pelvic lymph node dissection only. RESULTS: 100 evaluable patients were enrolled. Median age at surgery was 38 years (range 23-67). Stage was IA2 (33%) and IB1 (67%). Surgery included conization followed by lymph node assessment in 44 women, conization followed by simple hysterectomy with lymph node assessment in 40 women, and inadvertent simple hysterectomy followed by lymph node dissection in 16 women. Positive lymph nodes were noted in 5 patients (5%). Residual disease in the post-conization hysterectomy specimen was noted in 1/40 patients-that is, an immediate failure rate of 2.5%. Median follow-up was 36.3 months (range 0.0-68.3). Three patients developed recurrent disease within 2 years of surgery-that is, a cumulative incidence of 3.5% (95% CI 0.9% to 9.0%). DISCUSSION: Our prospective data show that select patients with early-stage, low-risk cervical carcinoma may be offered conservative surgery.


Assuntos
Adenocarcinoma/cirurgia , Carcinoma de Células Escamosas/cirurgia , Tratamento Conservador/métodos , Neoplasias do Colo do Útero/cirurgia , Adulto , Idoso , Conização/métodos , Conização/estatística & dados numéricos , Estudos de Viabilidade , Feminino , Humanos , Histerectomia/métodos , Histerectomia/estatística & dados numéricos , Laparoscopia , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos
6.
Inorg Chem ; 59(24): 17896-17905, 2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33245662

RESUMO

The present work is dedicated to characterization of the structural phase transition and incommensurate magnetic structure of the [CH3NH3][Ni(COOH)3] (1) perovskite-like metal-organic compound. The structural and magnetic characterization has been performed through variable-temperature single-crystal and powder neutron diffraction. Compound 1 crystallizes in the orthorhombic Pnma space group at room temperature. Below 84 K, a new phase has been observed. The occurrence of new reflections, which can be indexed with a wavevector along the c axis [q = 0.1426(2)c*], suggests the occurrence of an incommensurately modulated crystal structure. The structure was determined using the superspace group formalism on the Pnma(00γ)0s0 space group. This incommensurate phase remains unchanged with a decrease of the temperature up to the base temperature (ca. 2 K). Moreover, the magnetic susceptibility data, collected under zero-field-cooled and field-cooled conditions at different applied magnetic fields, show that compound 1 exhibits antiferromagnetic behavior below 34 K. In the current paper, we have confirmed that compound 1 presents the coexistence of nuclear and proper magnetic incommensurability below TN.

7.
Inorg Chem ; 59(1): 287-307, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31876414

RESUMO

SbPO4 is a complex monoclinic layered material characterized by a strong activity of the nonbonding lone electron pair (LEP) of Sb. The strong cation LEP leads to the formation of layers piled up along the a axis and linked by weak Sb-O electrostatic interactions. In fact, Sb has 4-fold coordination with O similarly to what occurs with the P-O coordination, despite the large difference in ionic radii and electronegativity between both elements. Here we report a joint experimental and theoretical study of the structural and vibrational properties of SbPO4 at high pressure. We show that SbPO4 is not only one of the most compressible phosphates but also one of the most compressible compounds of the ABO4 family. Moreover, it has a considerable anisotropic compression behavior, with the largest compression occurring along a direction close to the a axis and governed by the compression of the LEP and the weak interlayer Sb-O bonds. The strong compression along the a axis leads to a subtle modification of the monoclinic crystal structure above 3 GPa, leading from a 2D to a 3D material. Moreover, the onset of a reversible pressure-induced phase transition is observed above 9 GPa, which is completed above 20 GPa. We propose that the high-pressure phase is a triclinic distortion of the original monoclinic phase. The understanding of the compression mechanism of SbPO4 can aid to improve the ion intercalation and catalytic properties of this layered compound.

8.
Rev Med Chil ; 147(4): 458-464, 2019 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-31344207

RESUMO

BACKGROUND: Placing central venous lines under ultrasonographic guidance reduces the complications of the procedure. AIM: To compare prevalences of complications of central venous line placements with or without ultrasonographic guidance. MATERIAL AND METHODS: Descriptive study that contemplated the comparison of two groups of patients subjected to a central venous line placement at a nephrology service for renal replacement therapy. In one group of 100 patients, the line was placed without ultrasonographic guidance between 2008 and 2012. Between 2015 and 2017 the line was placed in 138 patients using ultrasonographic guidance. The prevalences of complications with both types of procedures were recorded. RESULTS: The frequency of complications of procedures with and without ultrasonographic guidance was 0.7 and 18% respectively (prevalence ratio 0.04, 95% confidence interval 0-0.3). Ninety five percent of recorded complications were arterial puncture, followed by hematomas in 10% and pneumothorax in 5%. The higher prevalence of complications was observed in emergency line placement without ultrasonographic guidance. There was a direct association between the number of line placement attempts in a single procedure and the prevalence of complications. CONCLUSIONS: Ultrasonographic guidance is associated with a reduction in the prevalence of central venous line complications.


Assuntos
Cateterismo Venoso Central/efeitos adversos , Cateteres Venosos Centrais/efeitos adversos , Complicações Intraoperatórias/epidemiologia , Complicações Intraoperatórias/etiologia , Diálise Renal/efeitos adversos , Adulto , Idoso , Cateterismo Venoso Central/instrumentação , Cateterismo Venoso Central/métodos , Chile/epidemiologia , Estudos Transversais , Feminino , Hematoma/epidemiologia , Hematoma/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Pneumotórax/epidemiologia , Pneumotórax/etiologia , Prevalência , Diálise Renal/instrumentação , Diálise Renal/métodos , Distribuição por Sexo , Ultrassonografia de Intervenção/métodos
9.
Chemistry ; 24(2): 388-399, 2018 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-28858419

RESUMO

The characterization of the crystal structure, phase transitions, magnetic structure and dielectric properties has been carried out on [CH3 NH3 ][Co(COOH)3 ] (1) perovskite-like metal-organic compound through variable-temperature single-crystal and powder neutron and X-ray diffraction and relative permittivity measurements. The paraelectric to antiferroelectric-like phase transition observed at around 90 K is triggered by a structural phase transition; the structural studies show a change from Pnma space group at RT (1A) to P21 /n space group at low temperature (1B). This phase transition involves the occurrence of small distortions in the framework and counterions. Neutron diffraction studies have shown a magnetic order showing spontaneous magnetization below 15 K, due to the occurrence of a non-collinear antiferromagnetic structure with a weak ferromagnetic component, mainly due to the single-ion anisotropy of the CoII ions.

10.
Inorg Chem ; 57(20): 12827-12835, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30256100

RESUMO

It has recently been reported that the ordered aeschynite-type polar ( Pna21) magnets RFeWO6 (R = Eu, Tb, Dy, Y) exhibit type II multiferroic properties below TN ∼ 15-18 K. Herein, we report a comprehensive investigation of the isostructural oxide DyCrWO6 and compare the results with those of DyFeWO6. The cation-ordered oxide DyCrWO6 crystallizes in the same polar orthorhombic structure and undergoes antiferromagnetic ordering at TN = 25 K. Contrary to DyFeWO6, only a very weak dielectric anomaly and magnetodielectric effects are observed at the Néel temperature and, more importantly, there is no induced polarization at TN. Furthermore, analysis of the low-temperature neutron diffraction data reveals a collinear arrangement of Cr spins but a noncollinear Dy-spin configuration due to single-ion anisotropy. We suggest that the collinear arrangement of Cr spins may be responsible for the absence of electric polarization in DyCrWO6. A temperature-induced magnetization reversal and magnetocaloric effects are observed at low temperatures.

11.
J Surg Oncol ; 115(5): 615-618, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28168717

RESUMO

Cervical cancer is a preventable disease with a known etiology (human papillomavirus), effective preventive vaccines, excellent screening methods, and a treatable pre-invasive phase. Surgery is the primary treatment for pre-invasive and early-stage disease and can safely be performed in many low-resource settings. However, cervical cancer rates remain high in many areas of Latin America. This article presents a number of evidence-based strategies being implemented to improve cervical cancer outcomes in Latin America.


Assuntos
Neoplasias do Colo do Útero/terapia , Feminino , Acessibilidade aos Serviços de Saúde , Humanos , América Latina/epidemiologia , Programas de Rastreamento , Infecções por Papillomavirus/diagnóstico , Vacinas contra Papillomavirus/uso terapêutico , Prevenção Primária , Consulta Remota , Neoplasias do Colo do Útero/epidemiologia , Neoplasias do Colo do Útero/virologia
12.
Inorg Chem ; 56(1): 197-207, 2017 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-27935298

RESUMO

A study of the magnetic structure of the [NH2(CH3)2]n[FeIIIMII(HCOO)6]n niccolite-like compounds, with MII = CoII (2) and MnII (3) ions, has been carried out using neutron diffraction and compared with the previously reported FeII-containing compound (1). The inclusion of two different metallic atoms into the niccolite-like structure framework leads to the formation of isostructural compounds with very different magnetic behaviors due to the compensation or not of the different spins involved in each lattice. Below TN, the magnetic order in these compounds varies from ferrimagnetic behavior for 1 and 2 to an antiferromagnetic behavior with a weak spin canting for 3. Structure refinements of 2 and 3 at low temperature (45 K) have been carried out combining synchrotron X-ray and high-resolution neutron diffraction in a multipattern approach. The magnetic structures have been determined from the difference patterns between the neutron data in the paramagnetic and the magnetically ordered regions. These difference patterns have been analyzed using a simulated annealing protocol and symmetry analysis techniques. The obtained magnetic structures have been further rationalized by means of ab initio DFT calculations. The direction of the magnetic moment of each compound has been determined. The easy axis of the MII for compound 1 (FeII) is along the c axis; for compound 2 (CoII), the moments are mainly within the ab plane; finally, for compound 3 (MnII), the calculations show that the moments have components both in the ab plane and along the c axis.

13.
Inorg Chem ; 55(22): 11760-11769, 2016 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-27805387

RESUMO

We report herein on the magnetic properties and structures of orthorhombic Li2M(SO4)2 (M = Co, Fe) and their oxidized phases LixFe(SO4)2 (x = 1, 1.5), which were previously studied as potential cathode materials for Li-ion batteries. The particular structure of these orthorhombic compounds (space group Pbca) consists of a three-dimensional network of isolated MO6 octahedra enabling solely super-super-exchange interactions between transition metals. We studied the magnetic properties of these phases via temperature-dependent susceptibility measurements and applied neutron powder diffraction experiments to solve their magnetic structures. All compounds present an antiferromagnetic long-range ordering of the magnetic spins below their Néel temperature. Their magnetic structures are collinear and follow a spin sequence (+ + - - - - + +), with the time reversal associated with the inversion center, a characteristic necessary for a linear magneto-electric effect. We found that the orientation of the magnetic moments varies with the nature of M. While Li2Co(SO4)2 and Li1Fe(SO4)2 adopt the magnetic space group Pb'c'a', the magnetic space group for Li2Fe(SO4)2 and Li1.5Fe(SO4)2 is P1121'/a, which might hint for a possible monoclinic distortion of their nuclear structure. Moreover we compared the orthorhombic phases to their monoclinic counterparts as well as to the isostructural orthorhombic Li2Ni(SO4)2 compound. Finally, we show that this possible magneto-electric feature is driven by the topology of the magnetic interactions.

14.
Sensors (Basel) ; 16(6)2016 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-27294938

RESUMO

This paper evaluates different wavelet-based cross-spectral image fusion strategies adopted to merge visible and infrared images. The objective is to find the best setup independently of the evaluation metric used to measure the performance. Quantitative performance results are obtained with state of the art approaches together with adaptations proposed in the current work. The options evaluated in the current work result from the combination of different setups in the wavelet image decomposition stage together with different fusion strategies for the final merging stage that generates the resulting representation. Most of the approaches evaluate results according to the application for which they are intended for. Sometimes a human observer is selected to judge the quality of the obtained results. In the current work, quantitative values are considered in order to find correlations between setups and performance of obtained results; these correlations can be used to define a criteria for selecting the best fusion strategy for a given pair of cross-spectral images. The whole procedure is evaluated with a large set of correctly registered visible and infrared image pairs, including both Near InfraRed (NIR) and Long Wave InfraRed (LWIR).

15.
Rev Med Chil ; 144(11): 1417-1423, 2016 Nov.
Artigo em Espanhol | MEDLINE | ID: mdl-28394958

RESUMO

BACKGROUND: Central airway obstruction caused by malignant or benign lesions, associated in some cases with hemoptysis, is a condition with high morbidity and mortality. The use of electrocautery by flexible bronchoscopy is an initial treatment option with immediate improvement of obstruction symptoms. It is as effective as Nd: YAG laser. AIM: To describe the usefulness of electrocautery in the management of central obstruction of the airway and hemoptysis. MATERIAL AND METHODS: A retrospective, descriptive study of patients referred for management of central airway obstruction or associated hemoptysis. Diagnoses, symptoms (dyspnea, cough, and hemoptysis) and radiology before and after the procedures were analyzed. RESULTS: Eighteen patients aged 59 ± 12 years (66% males) were evaluated, registering 25 endoscopic procedures. Three conditions were found: partial or complete airway obstruction, hemoptysis and post lung transplant bronchial stenosis. Seventy two percent presented with dyspnea, 61% with cough and 33% with hemoptysis. Sixty six percent of patients had airway obstruction caused by malignant metastatic lesions. After electrocautery, 17 patients (94.4%) improved their symptoms and achieved complete airway clearing. Three patients had significant bronchial stenosis after lung transplant achieving subsequent clearing after electrocautery. CONCLUSIONS: Electrocautery during flexible bronchoscopy is an effective and safe procedure for the management of central airway obstruction and associated hemoptysis.


Assuntos
Obstrução das Vias Respiratórias/cirurgia , Broncoscopia/métodos , Eletrocoagulação/métodos , Hemoptise/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Obstrução das Vias Respiratórias/etiologia , Brônquios/fisiopatologia , Brônquios/cirurgia , Tosse , Gerenciamento Clínico , Dispneia , Feminino , Hemoptise/etiologia , Humanos , Lasers de Estado Sólido , Neoplasias Pulmonares/complicações , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
16.
Faraday Discuss ; 179: 227-33, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25865697

RESUMO

Understanding the crystallization of enantiomorphically pure systems can be relevant to diverse fields such as the study of the origins of life or the purification of racemates. Here we report on polycrystalline epitaxial thin films of quartz on Si substrates displaying two distinct types of chiral habits that never coexist in the same film. We combine Atomic Force Microscopy (AFM) analysis and computer-assisted crystallographic calculations to make a detailed study of these habits of quartz. By estimating the surface energies of the observed crystallites we argue that the films are enantiomorphically pure and we briefly outline a possible mechanism to explain the habit and chiral selection in this system.


Assuntos
Nanoestruturas/química , Quartzo/química , Cristalização , Microscopia de Força Atômica , Silício/química , Propriedades de Superfície
17.
Inorg Chem ; 53(11): 5674-83, 2014 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-24832918

RESUMO

A novel cobalt(II) complex of formula [Co2(cbut)(H2O)3]n (1) (H4cbut = 1,2,3,4-cyclobutanetetracarboxylic acid) has been synthesized under hydrothermal conditions and its crystal structure has been determined by means of synchrotron radiation and neutron powder diffraction. The crystal structure of 1 consists of layers of cobalt(II) ions extending in the bc-plane which are pillared along the crystallographic a-axis through the skeleton of the cbut(4-) ligand. Three crystallographically independent cobalt(II) ions [Co(1), Co(2), and Co(3)] occur in 1. They are all six-coordinate with four carboxylate-oxygens [Co(1)-Co(3)] and two cis-[Co(1)] or trans-water molecules [Co(2) and Co(3)] building distorted octahedral surroundings. Regular alternating double oxo(carboxylate) [between Co(1) and Co(1a)] and oxo(carboxylate) plus one aqua and a syn-syn carboxylate bridges [between Co(1) and Co(2)] occur along the crystallographic b-axis, the values of the cobalt-cobalt separation being 3.1259(8) and 3.1555(6) Å, respectively. These chains are connected to the Co(3) atoms through the OCO carboxylate along the [011] direction leading to the organic-inorganic bc-layers with Co(1)-OCO(anti-syn)-Co(3) and Co(2)-OCO(anti-anti)-Co(3) distances of 5.750(2) and 4.872(1) Å. The shortest interlayer cobalt-cobalt separation through the cbut(4-) skeleton along the crystallographic a-axis is 7.028(2) Å. Variable-temperature magnetic susceptibility measurements show the occurrence of antiferromagnetic ordering with a Néel temperature of 5.0 K, followed by a field-induced ferromagnetic transition under applied dc fields larger than 1500 Oe. The magnetic structure of 1 has been elucidated at low temperatures in zero field by neutron powder diffraction measurements and was found to be formed by ferromagnetic chains running along the b-axis which are antiferromagnetically coupled with the Co(3) ions through the c-axis giving rise to noncompensated magnetic moments within each bc-layer (ferrimagnetic plane). The occurrence of an antitranslation operation between these layers produces a weak interlayer antiferromagnetic coupling along the a-axis which is overcome by dc fields greater than 1500 Oe resulting in a phase transition toward a ferromagnetic state (metamagnetic behavior).

18.
Mar Drugs ; 12(5): 2668-99, 2014 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-24821625

RESUMO

Diverse actinomycetes produce a family of structurally and biosynthetically related non-ribosomal peptide compounds which belong to the chromodepsipeptide family. These compounds act as bisintercalators into the DNA helix. They give rise to antitumor, antiparasitic, antibacterial and antiviral bioactivities. These compounds show a high degree of conserved modularity (chromophores, number and type of amino acids). This modularity and their high sequence similarities at the genetic level imply a common biosynthetic origin for these pathways. Here, we describe insights about rules governing this modular biosynthesis, taking advantage of the fact that nowadays five of these gene clusters have been made public (thiocoraline, triostin, SW-163 and echinomycin/quinomycin). This modularity has potential application for designing and producing novel genetic engineered derivatives, as well as for developing new chemical synthesis strategies. These would facilitate their clinical development.


Assuntos
Actinobacteria/química , Antibióticos Antineoplásicos/biossíntese , Substâncias Intercalantes , Actinobacteria/metabolismo , Animais , Antibióticos Antineoplásicos/síntese química , Antibióticos Antineoplásicos/farmacologia , Humanos , Substâncias Intercalantes/síntese química , Substâncias Intercalantes/farmacologia , Relação Estrutura-Atividade
19.
Am J Audiol ; : 1-12, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38354098

RESUMO

PURPOSE: Noise reduction technologies in hearing aids provide benefits under controlled conditions. However, differences in their real-life effectiveness are not established. We propose that a deep neural network (DNN)-based noise reduction system trained on naturalistic sound environments will provide different real-life benefits compared to traditional systems. METHOD: Real-life listening experiences collected with Ecological Momentary Assessments (EMAs) of participants who used two premium models of hearing aid are compared. One hearing aid model (HA1) used traditional noise reduction; the other hearing aid model (HA2) used DNN-based noise reduction. Participants reported listening experiences several times a day while ambient SPL, SNR, and hearing aid volume adjustments were recorded. Forty experienced hearing aid users completed a total of 3,614 EMAs and recorded 6,812 hr of sound data across two 14-day wear periods. RESULTS: Linear mixed-effects analysis document that participants' assessments of ambient noisiness were positively associated with SPL and negatively associated with SNR but were not otherwise affected by hearing aid model. Likewise, mean satisfaction with the two models did not differ. However, individual satisfaction ratings for HA1 were dependent on ambient SNR, which was not the case for HA2. CONCLUSIONS: Hearing aids with DNN-based noise reduction resulted in consistent sound satisfaction regardless of the level of background noise compared to hearing aids implementing noise reduction based on traditional statistical models. While the two hearing aid models also differed on other parameters (e.g., shape), these differences are unlikely to explain the difference in how background noise impacts sound satisfaction with the aids. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.25114526.

20.
J Cardiothorac Surg ; 19(1): 323, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38849906

RESUMO

BACKGROUND: Marfan Syndrome is an autosomal dominant disease caused by pathogenetic variants in the FBN1 gene. The progressive dilatation of the aorta and the potential risk of acute aortic syndromes influence the prognosis of these patients. We aim to describe population characteristics, long-term survival, and re-intervention patterns in patients who underwent aortic surgery with a previously confirmed clinical diagnosis of Marfan Syndrome in a middle-income country. METHODS: A retrospective single-center case series study was conducted. All Marfan Syndrome patients who underwent aortic procedures from 2004 until 2021 were included. Qualitative variables were frequency-presented, while quantitative ones adopted mean ± standard deviation. A subgroup analysis between elective and emergent procedures was conducted. Kaplan-Meier plots depicted cumulative survival and re-intervention-free. Control appointments and government data tracked out-of-hospital mortality. RESULTS: Fifty patients were identified. The mean age was 38.79 ± 14.41 years, with a male-to-female ratio of 2:1. Common comorbidities included aortic valve regurgitation (66%) and hypertension (50%). Aortic aneurysms were observed in 64% without dissection and 36% with dissection. Surgical procedures comprised elective (52%) and emergent cases (48%). The most common surgery performed was the David procedure (64%), and the Bentall procedure (14%). The in-hospital mortality rate was 4%. Complications included stroke (10%), and acute kidney injury (6%). The average follow-up was 8.88 ± 5.78 years. Survival rates at 5, 10, and 15 years were 89%, 73%, and 68%, respectively. Reintervention rates at 1, 2.5, and 5 years were 10%, 14%, and 17%, respectively. The emergent subgroup was younger (37.58 ± 14.49 years), had the largest number of Stanford A aortic dissections, presented hemodynamic instability (41.67%), and had a higher requirement of reinterventions in the first 5 years of follow-up (p = 0.030). CONCLUSION: In our study, surveillance programs played a pivotal role in sustaining high survival rates and identifying re-intervention requirements. However, challenges persist, as 48% of the patients required emergent surgery. Despite not affecting survival rates, a greater requirement for reinterventions was observed, emphasizing the necessity of timely diagnosis. Enhanced educational initiatives for healthcare providers and increased patient involvement in follow-up programs are imperative to address these concerns.


Assuntos
Síndrome de Marfan , Humanos , Síndrome de Marfan/complicações , Síndrome de Marfan/cirurgia , Masculino , Feminino , Estudos Retrospectivos , Adulto , Pessoa de Meia-Idade , Dissecção Aórtica/cirurgia , Adulto Jovem , Aneurisma Aórtico/cirurgia
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