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1.
World Neurosurg X ; 18: 100165, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36825219

RESUMO

Introduction: Evaluation of sagittal balance parameters is a standard assessment before spine surgery. However, these parameters can change during walking. We aimed to describe the behavior of spino-pelvic parameters during walking in healthy subjects. Material and methods: Analyses were performed in 60 healthy subjects. Static spinal sagittal balance parameters were assessed. We performed gait analysis and we used SMART-DX 500® to analyze parameters aimed at defining dynamic sagittal balance, including pelvic tilt angle (PTA), sagittal trunk shift (STS), and trunk angle (TA). We considered rotational and obliquity movements of the pelvis, flexo-extension movements of the hip, trunk, and knees. Analyses were performed in a standing posture and during walking. Results: PTA-cycle, PTA-stance, PTA-swing, STS-cycle, STS-stance, and STS-swing showed good-to-excellent internal reliability (ICC = 0.867; ICC = 0.700; ICC = 0.817, respectively). The parameters with the lowest variability were radiographic PI (CV = 16.53%), PTA-stance (CV = 9.55%), and PTA-swing (CV = 17.22%). PT was directly related to PTA-cycle (r = 0.534, p = .027). PI was inversely correlated with trunk flexo-extension range of motion (r = -0.654, p = .004) and dynamic PT (r = -0.489, p = .047). LL and SS were directly related to knee flexo-extension (r = 0.505, p = .039; r = 0.493, p = .045, respectively). SVA was correlated with the trunk obliquity in dynamics (r = 0.529, p = .029). PTA-cycle was directly related to trunk obliquity (r = 0.538, p = .049). STS and TA in the three phases of step were related to the kinematic parameters of the pelvis. TA was related to flexo-extension of the hip and knee. Conclusions: Variations of dynamic spino-pelvic parameters occur during walking and modify sagittal balance from a static to a dynamic condition.

2.
Eur Spine J ; 30(6): 1574-1584, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33635376

RESUMO

BACKGROUND: C1-C2 injury represents 25-40% of cervical injuries and predominantly occurs in the geriatric population. METHODS: A prospective multicentre study was conducted under the aegis of the french spine surgery society (SFCR) investigating the impact of age, comorbidities, lesion type, and treatment option on mortality, complications, and fusion rates. RESULTS: A total of 417 patients were recruited from 11 participating centres. The mean ± SD age was 66.6 ± 22 years, and there were 228 men (55%); 5.4% presented a neurological deficit at initial presentation. The most frequent traumatic lesion was C2 fracture (n = 308). Overall mortality was 8.4%; it was 2.3% among those aged ≤ 60 years, 5.0% 61-80 years, and 16.0% > 80 years (p < 0.001). Regarding complications, 17.8% of patients ≤ 70 years of age presented with ≥ 1 complication versus 32.3% > 70 years (p = 0.0009). The type of fracture did not condition the onset of complications and/or mortality (p > 0.05). The presence of a comorbidity was associated with a risk factor for both death (p = 0.0001) and general complication (p = 0.008). Age and comorbidities were found to be independently associated with death (p < 0.005). The frequency of pseudoarthrosis ranged from 0 to 12.5% up to 70 years of age and then constantly and progressively increased to reach 58.6% after 90 years of age. CONCLUSIONS: C1-C2 injury represents a serious concern, possibly life-threatening, especially in the elderly. We found a major impact of age and comorbidities on mortality, complications, and pseudarthrosis; injury pattern or treatment option seem to have a minimal effect.


Assuntos
Pseudoartrose , Fraturas da Coluna Vertebral , Fusão Vertebral , Adulto , Idoso , Idoso de 80 Anos ou mais , Vértebras Cervicais/lesões , Feminino , Consolidação da Fratura , Humanos , Masculino , Pessoa de Meia-Idade , Pescoço , Estudos Prospectivos , Fraturas da Coluna Vertebral/cirurgia , Resultado do Tratamento
3.
Nanotechnology ; 31(37): 375204, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32428882

RESUMO

Palladium diselenide ([Formula: see text]) is a recently isolated layered material that has attracted a lot of interest for its pentagonal structure, air stability and electrical properties that are largely tunable by the number of layers. In this work, multilayer [Formula: see text] is used as the channel of back-gate field-effect transistors, which are studied under repeated electron irradiations. Source-drain [Formula: see text] electrodes enable contacts with resistance below [Formula: see text]. The transistors exhibit a prevailing n-type conduction in high vacuum, which reversibly turns into ambipolar electric transport at atmospheric pressure. Irradiation by [Formula: see text] electrons suppresses the channel conductance and promptly transforms the device from n-type to p-type. An electron fluence as low as [Formula: see text] dramatically changes the transistor behavior, demonstrating a high sensitivity of [Formula: see text] to electron irradiation. The sensitivity is lost after a few exposures, with a saturation condition being reached for fluence higher than [Formula: see text]. The damage induced by high electron fluence is irreversible as the device persists in the radiation-modified state for several hours, if kept in vacuum and at room temperature. With the support of numerical simulation, we explain such a behavior by electron-induced Se atom vacancy formation and charge trapping in slow trap states at the [Formula: see text] interface.

4.
Nanotechnology ; 28(49): 495705, 2017 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-29083313

RESUMO

We report the observation of field emission (FE) from InP nanocrystals (NCs) epitaxially grown on an array of p-Si nanotips. We prove that FE can be enhanced by covering the InP NCs with graphene. The measurements are performed inside a scanning electron microscope chamber with a nano-controlled W-thread used as an anode. We analyze the FE by Fowler-Nordheim theory and find that the field enhancement factor increases monotonically with the spacing between the anode and the cathode. We also show that InP/p-Si junction has a rectifying behavior, while graphene on InP creates an ohmic contact. Understanding the fundamentals of such nanojunctions is key for applications in nanoelectronics.

5.
J Gynecol Obstet Biol Reprod (Paris) ; 45(7): 760-6, 2016 Sep.
Artigo em Francês | MEDLINE | ID: mdl-27006008

RESUMO

OBJECTIVES: Compare the number of consultations with the consultation's delay in relation with the sensation of decrease active fetal movements (AFM) in case of late pregnancy, according to the fact if the patients use or not the AFM's count. MATERIALS AND METHODS: We have compared a "control" group made up of 160 patients who received a classic information and observation (from December 18th, 2013 to February 28th, 2014) versus an "educated" group made up of 160 patients who have been educated to the AFM count (from March 1st, 2014 to August 12th, 2014). RESULTS: The consultations for AFM decrease, were significantly more frequent in the "control" group than in the "educated" group (36 versus 8, P=0.0009). Inducing labor due to AFM reduction was not statistically different between both groups (13 patients in the "educated group" versus 7 patients in the "control" group P=0.97). CONCLUSION: Learning a count method seems to decrease the number of consultations for AFM reduction without increasing the perinatal morbidity but maybe at the cost of an increase of obstetric interventions.


Assuntos
Doenças Fetais/diagnóstico , Movimento Fetal , Folhetos , Gravidez Prolongada , Educação Pré-Natal/normas , Adulto , Estudos de Coortes , Feminino , Humanos , Gravidez , Encaminhamento e Consulta/estatística & dados numéricos
6.
Gynecol Obstet Fertil ; 43(10): 640-5, 2015 Oct.
Artigo em Francês | MEDLINE | ID: mdl-26234685

RESUMO

OBJECTIVES: With current diagnostic resources, it is impossible to predict if a patient consulting in the obstetrics emergencies with symptoms of preterm labor, preterm delivery or not. A novel test for the detection of time to spontaneous preterm delivery was developed and would predict imminent delivery in 7 or 14 days from the time of testing. The diagnostic performances of detection test of PAMG-1 have been validated before digital examination. However digital examination is usually made in first line. The objective of this study was to assess the reproducibility of these diagnostic performances after digital examination and transvaginal ultrasound cervical length. METHODS: A prospective and observational study was conducted in a level 3 maternity (University Hospital of Saint-Etienne), from June 2013 to January 2014. Patients consulted in the obstetrics emergencies for threatened preterm birth between 24-34 weeks were enrolled with written and signed consent. Reproducibility of this test was assessed after digital examination, transvaginal ultrasound cervical length and a long time after all investigations. RESULTS: Forty-one patients were included in our study. Average gestational age was 29 weeks, digital examination was changed in 36 patients, whereas cervical length was less than 26mm for only 17 patients. In our study, 100% of tests results remain negative or positive after digital examination and 95,1% after transvaginal ultrasound. Our results confirmed this excellent specificity (97.5% [IC 95%; 86.8-99.9]) and negative predictive value (97.5% [IC 95%; 86.8-99.9]). CONCLUSION: This work allowed to demonstrate the reproducibility of detection test of PAMG-1 after a digital examination. An initial management with detection test of PAMG-1 could allow reducing the rate of unnecessary hospitalization.


Assuntos
Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/análise , Trabalho de Parto Prematuro/diagnóstico , Colo do Útero/diagnóstico por imagem , Feminino , Idade Gestacional , Humanos , Palpação , Gravidez , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Ultrassonografia Pré-Natal/métodos
7.
Acta Anaesthesiol Scand ; 58(2): 235-42, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24410108

RESUMO

BACKGROUND: In health, the hormones amylin and glucagon-like peptide-1 (GLP-1) slow gastric emptying (GE) and modulate glycaemia. The aims of this study were to determine amylin and GLP-1 concentrations in the critically ill and their relationship with GE, glucose absorption and glycaemia. METHODS: In fasted critically ill and healthy subjects (n = 26 and 23 respectively), liquid nutrient, containing 100 mg (13) C-sodium octanoate and 3 g 3-O-methlyglucose (3-OMG), was administered via a nasogastric tube. Amylin, GLP-1, glucose and 3-OMG concentrations were measured in blood samples taken during fasting, and 30 min and 60 min after the 'meal'. Breath samples were taken to determine gastric emptying coefficient (GEC). Intolerance to intragastric feeding was defined as a gastric residual volume of ≥ 250 ml and/or vomiting within the 24 h prior to the study. RESULTS: Although GE was slower (GEC: critically ill 2.8 ± 0.9 vs. health, 3.4 ± 0.2; P = 0.002), fasting blood glucose was higher (7.0 ± 1.9 vs. 5.7 ± 0.2 mmol/l; P = 0.005) and overall glucose absorption was reduced in critically ill patients (3-OMG: 9.4 ± 8.0 vs. 17.7 ± 4.9 mmol/l.60 min; P < 0.001), there were no differences in fasting or postprandial amylin concentrations. Furthermore, although fasting [1.7 (0.4-7.2) vs. 0.7 (0.3-32.0) pmol/l; P = 0.04] and postprandial [3.0 (0.4-8.5) vs. 0.8 (0.4-34.3) pmol/l; P = 0.02] GLP-1 concentrations were increased in the critically ill and were greater in feed intolerant when compared with those tolerating feed [3.7 (0.4-7.2) vs. 1.2 (0.7-4.6) pmol/l; P = 0.02], there were no relationships between GE and fasting amylin or GLP-1 concentrations. CONCLUSION: In the critically ill, fasting GLP-1, but not amylin, concentrations are elevated and associated with feed intolerance. Neither amylin nor GLP-1 appears to substantially influence the rate of GE.


Assuntos
Estado Terminal , Esvaziamento Gástrico/fisiologia , Peptídeo 1 Semelhante ao Glucagon/sangue , Polipeptídeo Amiloide das Ilhotas Pancreáticas/sangue , 3-O-Metilglucose/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Glicemia/metabolismo , Testes Respiratórios , Estudos de Coortes , Feminino , Glucose/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
8.
J Phys Condens Matter ; 25(15): 155303, 2013 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-23528822

RESUMO

We produced graphene-based field-effect transistors by contacting mono- and bi-layer graphene by sputtering Ni or Ti as metal electrodes. We performed electrical characterization of the devices by measuring their transfer and output characteristics. We clearly observed the presence of a double-dip feature in the conductance curve for Ni-contacted transistors, and we explain it in terms of charge transfer and graphene doping under the metal contacts. We also studied the contact resistance between the graphene and the metal electrodes with larger values of ~30 kΩµm(2) recorded for Ti contacts. Importantly, we prove that the contact resistance is modulated by the back-gate voltage.

9.
Nanoscale Res Lett ; 5(11): 1852-1855, 2010 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-21124628

RESUMO

We study memory devices consisting of single-walled carbon nanotube transistors with charge storage at the SiO(2)/nanotube interface. We show that this type of memory device is robust, withstanding over 10(5) operating cycles, with a current drive capability up to 10(-6) A at 20 mV drain bias, thus competing with state-of-the-art Si-devices. We find that the device performance depends on temperature and pressure, while both endurance and data retention are improved in vacuum.

10.
J Phys Condens Matter ; 22(4): 045702, 2010 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-21386321

RESUMO

We have performed scanning tunneling spectroscopy and point contact spectroscopy measurements on the electron-doped superconductor Pr(1-x)LaCe(x)CuO(4-y) (x = 0.12, T(c) is approximately equal 25 K). We address the question of the symmetry of the order parameter and of the amplitude of the energy gap. We compare three possible scenarios, i.e. isotropic s-wave, 'anisotropic' s-wave, and d-wave. Evidence for a d-wave symmetry of the order parameter is given. From the temperature evolution of the dI/dV versus V characteristics we extract a BCS-like temperature dependence of the superconducting energy gap Δ. Despite the variety of measured spectra we give a consistent explanation for the whole set of data, indicating Δ = (3.6 ± 0.2) meV and a ratio 2Δ/K(B)T(C) is approximately equal 3.5 ±0.2. In particular, point contact characteristics showing gap-like features at higher voltages have been interpreted by considering the formation of an intergrain Josephson junction in series with the point contact junction. Further confirmation of the correctness of the model is given by the behavior of the critical current of the intergrain Josephson junction versus temperature which follows the Ambegaokar-Baratoff behavior.

11.
J Phys Condens Matter ; 21(25): 254205, 2009 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-21828429

RESUMO

The fabrication and characterization of superconducting and ferromagnetic heterostructures is an open field due to the fundamental interest in the physics of the coexistence of these two competing orders and their possible applications in the spintronics industry. In this paper we present structural, electrical and magnetic characterization for the single La(0.7)Ca(0.3)MnO(3) (LCMO) thin layer, La(0.7)Ca(0.3)MnO(3)/YBa(2)Cu(3)O(7-x) (LCMO/YBCO) bilayers and the LCMO/YBCO/LCMO trilayers. In particular, we show a detailed magnetic characterization of the LCMO thin films by means of low temperature magnetic force microscopy. We discuss the different dynamics of the magnetic domains observed, depending on the substrate induced strain and on the film thickness.

12.
Nanotechnology ; 19(39): 395701, 2008 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-21832602

RESUMO

The electron field emission characteristics of individual multiwalled carbon nanotubes were investigated by a piezoelectric nanomanipulation system operating inside a scanning electron microscopy chamber. The experimental set-up ensures a precise evaluation of the geometric parameters (multiwalled carbon nanotube length and diameter and anode-cathode separation) of the field emission system. For several multiwalled carbon nanotubes, reproducible and quite stable emission current behaviour was obtained, with a dependence on the applied voltage well described by a series resistance modified Fowler-Nordheim model. A turn-on field of ∼30 V µm(-1) and a field enhancement factor of around 100 at a cathode-anode distance of the order of 1 µm were evaluated. Finally, the effect of selective electron beam irradiation on the nanotube field emission capabilities was extensively investigated.

13.
Hum Reprod ; 15(11): 2319-25, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11056125

RESUMO

The aim of this study was to evaluate the effects of pulsed, extremely low-frequency electromagnetic fields (ELF-EMF) on in-vitro mouse pre-antral follicle development. Pre-antral follicles were cultured for 5 days and exposed to ELF-EMF at the frequencies of 33 or 50 Hz. ELF-EMF application did not affect follicular growth over a 3 day culture period, but on day 5 the growth of 33 Hz-exposed follicles was significantly reduced when compared with controls, while the 50 Hz-exposed follicles were not significantly affected. However, ELF-EMF severely impaired antrum formation at both frequencies, as 79 +/- 3% of control follicles developed antral cavities compared with 30 +/- 6% and 51.6 +/- 4% of 33 or 50 Hz-exposed follicles respectively. The follicles with failed antrum formation showed lower oestradiol release and granulosa cell DNA synthesis, but these effects were not related to granulosa cell apoptosis. Furthermore, a high percentage of the in-vitro grown oocytes obtained from exposed follicles had a reduced ability to resume meiotic maturation when compared with controls. These results suggest that ELF-EMF exposure might impair mammalian female reproductive potentiality by reducing the capacity of the follicles to reach a developmental stage that is an essential pre-requisite for reproductive success.


Assuntos
Campos Eletromagnéticos , Folículo Ovariano/fisiologia , Animais , Apoptose/fisiologia , Divisão Celular/fisiologia , Senescência Celular/fisiologia , Técnicas de Cultura , Estradiol/metabolismo , Feminino , Células da Granulosa/citologia , Células da Granulosa/fisiologia , Meiose/fisiologia , Camundongos , Muco/metabolismo , Oócitos/fisiologia , Folículo Ovariano/citologia
14.
Pediatr Med Chir ; 15(2): 213-5, 1993.
Artigo em Italiano | MEDLINE | ID: mdl-8321728

RESUMO

A case of thyroid ectopy in a 8-years-old girl is here described. The diagnostic course of this case is quite particular. In fact the first sign of the disease was a morphological evidence of thyroid sketch at the basis of the tongue. There has never been evidence of thyroid bad functioning.


Assuntos
Coristoma/diagnóstico , Glândula Tireoide , Neoplasias da Língua/diagnóstico , Criança , Diagnóstico Diferencial , Feminino , Humanos , Hipotireoidismo/diagnóstico
16.
Minerva Med ; 72(29): 1951-8, 1981 Jul 31.
Artigo em Italiano | MEDLINE | ID: mdl-6166903

RESUMO

We have examined the electrocardiograms of 516 patients hospitalized for acute abdomen. We have excluded from this research the younger patients than 14 years, those with shock, those with clinical signs of cardiopathy, those with electrolytic alterations and those executing anti-arythmic or anti-depressing therapy. We have found changes of repolarization and of rhythm. The changes of regularization consisted in flottening-inversion of T wave in the precordial and/or limb leads associated sometimes at negative deflection of the ST tract in the same leads. The changes of rhythm consisted in atrial or ventricular extrasystoles, paroxismal atrial tachycardia, paroxysmal atrial fibrillation. Sometimes the changes of repolarization and rhythm were associated. We have discussed the possible pathogenetic mechanisms answerable for these changes; sympathetic adrenergic activation mediate or no from a parasympathetic reflex, reduction of intra-cellular potassium, activation of enzymatic systems, reabsorption of toxic substaces. The Authors have underlined the benignity of these ECG changes, disappearing after resolution of abdominal disease, and the necessity of a correct interpretation of those, to avoid the arising of a iatrogenic disease.


Assuntos
Abdome Agudo/fisiopatologia , Eletrocardiografia , Abdome Agudo/etiologia , Adolescente , Adulto , Idoso , Fibrilação Atrial/fisiopatologia , Complexos Cardíacos Prematuros/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Taquicardia Paroxística/fisiopatologia
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