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1.
Nature ; 543(7645): 397-401, 2017 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-28300118

RESUMEN

In the cold dark matter cosmology, the baryonic components of galaxies-stars and gas-are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark-matter halo. In the local (low-redshift) Universe, the mass of dark matter within a galactic disk increases with disk radius, becoming appreciable and then dominant in the outer, baryonic regions of the disks of star-forming galaxies. This results in rotation velocities of the visible matter within the disk that are constant or increasing with disk radius-a hallmark of the dark-matter model. Comparisons between the dynamical mass, inferred from these velocities in rotational equilibrium, and the sum of the stellar and cold-gas mass at the peak epoch of galaxy formation ten billion years ago, inferred from ancillary data, suggest high baryon fractions in the inner, star-forming regions of the disks. Although this implied baryon fraction may be larger than in the local Universe, the systematic uncertainties (owing to the chosen stellar initial-mass function and the calibration of gas masses) render such comparisons inconclusive in terms of the mass of dark matter. Here we report rotation curves (showing rotation velocity as a function of disk radius) for the outer disks of six massive star-forming galaxies, and find that the rotation velocities are not constant, but decrease with radius. We propose that this trend arises because of a combination of two main factors: first, a large fraction of the massive high-redshift galaxy population was strongly baryon-dominated, with dark matter playing a smaller part than in the local Universe; and second, the large velocity dispersion in high-redshift disks introduces a substantial pressure term that leads to a decrease in rotation velocity with increasing radius. The effect of both factors appears to increase with redshift. Qualitatively, the observations suggest that baryons in the early (high-redshift) Universe efficiently condensed at the centres of dark-matter haloes when gas fractions were high and dark matter was less concentrated.

2.
Niger J Clin Pract ; 26(9): 1388-1392, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37794555

RESUMEN

This case report presents a five-year follow-up and the management of a necrotic, immature incisor tooth treated by a novel platelet-rich plasma/platelet extract solution and platelet-rich fibrin (PRP-PES/PRF) and the restoration by using a stress-reduced direct composite restoration (SRDC) technique. The patient with a broken maxillary lateral tooth was referred to our clinic. Extra/intra-oral examinations were within normal limits. The nonvital tooth having an apical lesion and open-apical apex was treated with a regenerative endodontic treatment procedure (REP), and further root development with continued apical closure was shown in the follow-ups up to 60 months. In conclusion, the SRDC and PRP-PES/PRF combination can be an opportunity for the teeth requiring post-restoration. In contrast to the treatment strategy susceptible to weakening or fracturing the patient's tooth root, the REP approach may lead to a better prognosis for the patient's tooth.


Asunto(s)
Fibrina Rica en Plaquetas , Plasma Rico en Plaquetas , Endodoncia Regenerativa , Humanos , Incisivo , Estudios de Seguimiento
3.
J Endocrinol Invest ; 40(8): 841-850, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28326509

RESUMEN

PURPOSE: Liquid-chromatography tandem mass-spectrometry (LC-MS/MS) was developed in parallel to Immunoassays (IAs) and today is proposed as the "gold standard" for steroid assays. Leydig cells of men with Klinefelter syndrome (KS) are able to respond to human chorionic gonadotropin (hCG) stimulation, even if testosterone (T) production was impaired. The aim was to evaluate how results obtained by IAs and LC-MS/MS can differently impact on the outcome of a clinical research on gonadal steroidogenesis after hCG stimulation. METHODS: A longitudinal, prospective, case-control clinical trial. (clinicaltrial.gov NCT02788136) was carried out, enrolling KS men and healthy age-matched controls, stimulated by hCG administration. Serum steroids were evaluated at baseline and for 5 days after intramuscular injection of 5000 IU hCG using both IAs and LC-MS/MS. RESULTS: 13 KS patients (36 ± 9 years) not receiving T replacement therapy and 14 controls (32 ± 8 years) were enrolled. T, progesterone, cortisol, 17-hydroxy-progesterone (17OHP) and androstenedione, were significantly higher using IAs than LC-MS/MS. IAs and LC-MS/MS showed direct correlation for all five steroids, although the constant overestimation detected by IAs. Either methodology found the same 17OHP and T increasing profile after hCG stimulation, with equal areas under the curves (AUCs). CONCLUSIONS: Although a linearity between IA and LC-MS/MS is demonstrated, LC-MS/MS is more sensitive and accurate, whereas IA shows a constant overestimation of sex steroid levels. This result suggests the need of reference intervals built on the specific assay. This fundamental difference between these two methodologies opens a deep reconsideration of what is needed to improve the accuracy of steroid hormone assays.


Asunto(s)
Gonadotropina Coriónica/uso terapéutico , Hormonas Esteroides Gonadales/sangre , Inmunoensayo/métodos , Síndrome de Klinefelter/sangre , Espectrometría de Masas en Tándem/métodos , 17-alfa-Hidroxiprogesterona/sangre , Adolescente , Adulto , Estudios de Casos y Controles , Humanos , Hidrocortisona/sangre , Síndrome de Klinefelter/tratamiento farmacológico , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Progesterona/sangre , Estudios Prospectivos , Testosterona/sangre , Adulto Joven
4.
Int Endod J ; 47(12): 1123-32, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24506847

RESUMEN

AIM: To evaluate the effect of NaOCl, EDTA and MTAD on the stress distribution and levels in roots with flared canals and three different aesthetic post systems using finite element stress analysis (FEA). METHODOLOGY: Three-dimensional (3D) FEA models simulating a maxillary incisor with excessive structural loss and flared root canals were created. The dentine of the first models of each post group was assumed as homogenous, whereas the others were deemed as having their elastic modulus affected up to 100 µm deep as a result of irrigation protocol (5.25 NaOCl, 17% EDTA and MTAD for 2 h). A sound incisor tooth model was used as the control. Restorations were created according to the post system used (pre-fabricated fibre post (PFP)), polyethylene fibre (Ribbond) post and core build-up (RBP), and one-piece milled zirconia post and core (ZP). Ceramic crowns were added to the models. A 300-N static load was applied at the centre of the palatal surface of the models to calculate the stress distributions. The SolidWorks/Cosmosworks structural analysis programmes were used for FEA analysis. Results were presented by considering von Mises criteria. RESULTS: The analysis of the von Mises stresses revealed that RBP created less stress in the remaining root dentine when compared to PFP and ZP. ZP maintained the stresses inside its body and reduced stress on the palatal surface of the root; however, it forwarded more stress towards the apical area. NaOCl-, EDTA- and MTAD-treated dentine increased the stresses within the root structure regardless of the effect of the post system used (11-15.4 MPa for PFP, 9.5-13.02 MPa for RBP and 14.2 MPa for ZP). Amongst the irrigation solutions used, EDTA and MTAD increased the stresses more than NaOCl in all models. All the irrigation solutions showed the same stress levels and distributions in the ZP model. CONCLUSION: NaOCl-, EDTA- and MTAD- treated dentine and a rigid post with high elastic modulus may increase fracture risk in roots with flared canals by increasing the stresses within root dentine. Therefore, solutions that alter the elastic modulus of dentine less (such as NaOCl) or an individually shaped post-core system constructed with a material that has an elastic modulus close to dentine (polyethylene fibre) should be used in weak roots.


Asunto(s)
Ácido Cítrico/administración & dosificación , Dentina , Doxiciclina/administración & dosificación , Ácido Edético/administración & dosificación , Polisorbatos/administración & dosificación , Técnica de Perno Muñón , Tratamiento del Conducto Radicular , Hipoclorito de Sodio/administración & dosificación , Estrés Fisiológico
5.
Acta Chir Belg ; 114(1): 52-7, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24720139

RESUMEN

PURPOSE: The aim of our study was to assess our modified Dufourmentel flap outcomes in a standardized patient group (a symptom duration of equal to or greater than 60 months, presence of equal to or more than 3 sinus ostia or presence of sinus ostia fistulized equal to or greater than 2 cm laterally, and a normal body mass index) with extensive pilonidal sinus. METHODS: Patients who were diagnosed with chronic pilonidal sinus disease and gave consent to surgical repair with modified Dufourmentel flap were enrolled. Patients were assessed with respect to age, sex, body mass index, presenting symptom, symptom duration, number of previous operations, number of sinus ostia, length of flap rims, depth of intergluteal sulcus, distance of sinus from anus, duration of operation, time of drain removal, length of hospital stay, early postoperative complications, postoperative pain, loss of labor, length of follow-up, and recurrences. RESULTS: A total of 42 patients were enrolled. Average duration of presenting symptoms was 64.4 +/- 4.7 months and average length of follow-up was 29.4 +/- 3.6 months. Average length of hospital stay was 4.2 +/- 0.8 days, and time to return to work was 16.3 +/- 2.1 days. Two patients (4.7%) developed postoperative wound infection, one patient (2.4%) developed seroma, and three patients (7.1%) had wound dehiscence. There was no recurrence. CONCLUSION: Modified Dufourmentel flap application can be safely used in the treatment of extensive pilonidal sinus disease.


Asunto(s)
Seno Pilonidal/cirugía , Colgajos Quirúrgicos , Adulto , Enfermedad Crónica , Femenino , Estudios de Seguimiento , Humanos , Tiempo de Internación/tendencias , Masculino , Seno Pilonidal/diagnóstico , Estudios Retrospectivos , Resultado del Tratamiento , Cicatrización de Heridas , Adulto Joven
6.
West Indian Med J ; 63(6): 678-80, 2014 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-25803391

RESUMEN

We report a rare case of sinonasal intestinal-type adenocarcinoma in the nasal cavity. A 31-year old man represented with headache and epistaxis. We identified a malignant tumour, which is a rare pathology, with detailed physical examination, anterior rhinoscopy, computed tomography scan, magnetic resonance imaging and histopathologic examination. Endoscopic excision of the tumour was performed. After three years of follow-up of the patient in our clinic, there was no sign of any recurrence.

7.
Hipertens Riesgo Vasc ; 41(3): 170-178, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38693013

RESUMEN

Pheochromocytomas and paragangliomas (PPGL) are neuroendocrine tumors characterized by the excessive production of catecholamines. This study aims to describe the clinical characteristics of PPGL cases in Argentina over recent decades. A multicenter retrospective cross-sectional analysis was carried out using a database comprising both pediatric and adult patients with confirmed PPGL diagnoses based on pathological reports. A cohort of 486 patients with PPGL was recruited. Women represent 58.4% of the patients, with a mean age of 38.3 years old at the time of diagnosis and 15.2% of the patients were under the age of 18. Hypertension, as well as classic signs and symptoms, were present in 80.9% of the patients. The adrenal incidentaloma, as a mode of presentation, increased in the last two decades rising from 3.9% (1953-2000) to 21.8% (2001-2022), p<0.001. Most tumors were located within the adrenal glands, accounting 83.0% of the cases, with bilateral occurrences noted in 20.0%. The median tumor size was 4.8cm. Local recurrence and metastases were observed in 10.9% and 12.2%. Out of 412 patients, 87.0% exhibited urinary excretion elevation of catecholamines and/or their metabolites. Furthermore, 148 patients, representing 30.4% of the study population, displayed a distinct genetic profile indicative of hereditary syndromes. The distribution of hereditary syndromes revealed that MEN2, VHL, and PGL4 constituted the most prevalent syndromes. This population-based study, spanning seven decades, offers valuable insights into the demographic and clinical characteristics of PPGL patients in Argentina.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales , Bases de Datos Factuales , Paraganglioma , Feocromocitoma , Humanos , Feocromocitoma/patología , Feocromocitoma/epidemiología , Argentina , Neoplasias de las Glándulas Suprarrenales/epidemiología , Neoplasias de las Glándulas Suprarrenales/patología , Femenino , Masculino , Estudios Retrospectivos , Adulto , Paraganglioma/patología , Estudios Transversales , Persona de Mediana Edad , Adolescente , Adulto Joven , Niño , Anciano , Recurrencia Local de Neoplasia/epidemiología , Preescolar , Hipertensión/epidemiología
8.
Int Endod J ; 46(3): 242-52, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23005923

RESUMEN

AIM: To investigate cell viability and gene expression of cementoblasts (OCCM.30) exposed to extractable components released by resin-based sealers with different chemical composition Hybrid Root Seal (HRS), SimpliSeal (SS), Real Seal (RS) and AH Plus (AH) and by a MTA-based sealers Tech Biosealer Endo (TBE). METHODOLOGY: Discs of all materials were prepared and allowed to set in humid conditions at 37° for 48 h. The discs were then incubated for 72 h at 37 °C to obtain material extracts (1/1) in DMEM. The extracts containing the components released by the sealers were filtered and other dilutions (1/2, 1/4) were prepared from the original solution (1/1). Original and diluted solutions were tested on the cementoblasts. Impedance-based real-time cell analysis (RTCA) was used to evaluate cell viability, quantitative real-time polymerase chain reaction (QRT-PCR) was used to examine the expression of mineralization-related genes (osteocalcin; OCN, Runt-related transcription factor-2; Runx2, collagen type 1; COL I, alkaline phosphatase; ALP). For statistical analysis, one-way analysis of variance (anova) and Tukey's honestly significant difference (HSD) tests were used. RESULTS: TBE (1/2), RS (1/2, 1/4), and HRS (1/2, 1/4) significantly decreased cell viability (P < 0.001). AH (1/2, 1/4) and SS (1/2, 1/4) had similar cell viability to the control at 30 h. All tested materials significantly decreased cell viability when compared to the control group except AH (1/2, 1/4) and SS (1/4) at 90 h. All of the tested sealers reduced COL I mRNA expressions when compared to the control. SS was associated with significant increases in OCN and Runx2 mRNA expressions when compared to the control (P < 0.001). Whereas all of the dilutions of TBE, RS and HRS significantly decreased BSP mRNA expressions (P < 0,001), 1/2 and 1/4 dilutions of SS increased BSP mRNA expression (P < 0,001). Except the 1/4 dilutions of AH and SS, all the sealer dilutions significantly reduced ALP mRNA expression in cementoblasts (P < 0,001). CONCLUSIONS: SimpliSeal and AH Plus resulted in more favourable response to cementoblasts because of their regulation potential on the mineralized tissue-associated protein's mRNA expressions.


Asunto(s)
Compuestos de Calcio/farmacología , Fosfatos de Calcio/farmacología , Cemento Dental/efectos de los fármacos , Cementos de Resina/farmacología , Materiales de Obturación del Conducto Radicular/farmacología , Cemento de Silicato/farmacología , Silicatos/farmacología , Fosfatasa Alcalina/análisis , Compuestos de Aluminio/química , Compuestos de Aluminio/farmacología , Animales , Compuestos de Calcio/química , Fosfatos de Calcio/química , Línea Celular , Forma de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Colágeno Tipo I/análisis , Resinas Compuestas/química , Resinas Compuestas/farmacología , Subunidad alfa 1 del Factor de Unión al Sitio Principal/análisis , Combinación de Medicamentos , Resinas Epoxi/química , Resinas Epoxi/farmacología , Humedad , Sialoproteína de Unión a Integrina/análisis , Ratones , Osteocalcina/análisis , Óxidos/química , Óxidos/farmacología , ARN Mensajero/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa , Cementos de Resina/química , Materiales de Obturación del Conducto Radicular/química , Cemento de Silicato/química , Silicatos/química , Temperatura , Factores de Tiempo
9.
West Indian Med J ; 62(8): 778-80, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25014869

RESUMEN

We report a rare case of sinonasal mucosal malignant melanoma in the nasal cavity. The patient had respiratory difficulty, continuous epistaxis and nasal pain. We identified a malignant tumour which is a rare pathology with detailed physical examination, anterior rhinoscopy, computed tomography (CT) scan, magnetic resonance imaging (MRI) and histopathologic examination. The patient did not accept surgical procedures and was referred for chemotherapy orimmunotherapy. Continued follow-up of this is necessary.

10.
West Indian Med J ; 62(5): 481-6, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24756665

RESUMEN

AIM: The purpose of the study was to examine psychopathological traits and psychiatric co-morbidities in seekers of cosmetic rhinoplasty. SUBJECTS AND METHODS: Fifty persons seeking cosmetic rhinoplasty and 50 control subjects were admitted to the study. Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Symptom Checklist-90 [Revised] (SCL-90-R) were administered to people who requested cosmetic rhinoplasty and control subjects. All participants were also screened by the Structured Clinical Interview for DSM-IV-(SCIDI/CV, SCID-II). RESULTS: Thirteen cosmetic rhinoplasty seekers [CRS] (26%) and three control subjects (6%) had at least one psychiatric diagnosis. There was a significant difference between the two groups (p = 0.006). Beck depression inventory (p = 0.002) and BAI (p = 0.046) levels above the cut-off point were significantly higher in the CRS group than in the normal control. Somatoform disorders were statistically higher in the CRS than control group (p = 0.007). Nine CRS (18%) and two control subjects (4%) had at least one personality disorder. There were differences between the two groups (p = 0.025). The average of SCL-90-R was significantly higher in the CRS than in the control subjects (p < 0.001). The most prevalent somatoform disorders of the CRS were six with body dysmorphic disorder [BDD] (12%). The most prevalent personality disorders of the CRS were three with avoidant (6%) and three with narcissistic (6%) personality. CONCLUSION: Assessment of detailed psychopathological aspects and psychiatric co-morbidities could help to define the clinical profile of people requesting cosmetic rhinoplasty in cosmetic surgery settings. Research into these factors may be important as it is essential to detect crucial problems such as personality disorders and BDD before surgery.


Asunto(s)
Trastornos Mentales/diagnóstico , Rinoplastia/psicología , Adolescente , Adulto , Estudios de Casos y Controles , Comorbilidad , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Turquía
11.
J Chem Phys ; 137(12): 124506, 2012 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-23020342

RESUMEN

Due to remarkable advances in colloid synthesis techniques, systems of squares and cubes, once an academic abstraction for theorists and simulators, are nowadays an experimental reality. By means of a free minimization of the free-energy functional, we apply fundamental measure theory to analyze the phase behavior of parallel hard squares and hard cubes. We compare our results with those obtained by the traditional approach based on the Gaussian parameterization, finding small deviations and good overall agreement between the two methods. For hard squares, our predictions feature at intermediate packing fraction a smectic phase, which is however expected to be unstable due to thermal fluctuations. Due to this inconsistency, we cannot determine unambiguously the prediction of the theory for the expected fluid-to-crystal transition of parallel hard squares, but we deduce two alternative scenarios: (i) a second-order transition with a coexisting vacancy-rich crystal or (ii) a higher-density first-order transition with a coexisting crystal characterized by a lower vacancy concentration. In accordance with previous studies, a second-order transition with a high vacancy concentration is predicted for hard cubes.

12.
Int Endod J ; 45(3): 240-8, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22007644

RESUMEN

AIM: To compare the effect of several materials on the attachment of periodontal ligament (PDL) fibroblasts to experimentally perforated root surfaces. METHODOLOGY: Root specimens (size 5 × 5 mm) were obtained from extracted human molar teeth and perforations with a 1 mm diameter were created. One group was kept as a control and the rest were repaired with the following materials: Amalgam, Dyract, IRM, Super Bond C&B and Mineral trioxide aggregate (MTA). PDL fibroblasts were placed at a density of 8 × 10(4) cells on the root specimens, incubated on tissue culture inserts (48 h) and then transferred to 48 well-plates. MTT assays were performed at 48 and 96 h for PDL fibroblast survival. Cell attachment was observed using confocal microscopy on days 2 and 5. Total RNAs from the root specimens were isolated on day 5 and type I collagen (COL I) and Runt-related transcription factor 2 (Runx2) mRNA expressions were checked using Quantitative-Polymerase Chain Reaction (QPCR). For the MTT assay and QPCR, one-way analysis of variance (anova) and Tukey HSD multiple comparison tests were used to compare the groups. RESULTS: Mineral trioxide aggregate resulted in a significantly higher cell density (P < 0.001). Dyract, IRM and Super Bond C&B groups had a lower cell density when compared with the control and MTA groups at 48 h (P < 0.001). Confocal microscopy revealed that, among the experimental groups, the MTA group had the largest viable cell population over the restoration site when compared with the other materials; however, reduced cell attachment was noted in all groups when compared with the control. Increased Runx2 mRNA expressions were noted in MTA (P < 0.001) and IRM (P < 0.01) groups when compared with control and other tested materials. COL I transcripts were increased in IRM (P < 0.01), D, C&B and MTA (P < 0.001) when compared with the control. CONCLUSION: Mineral trioxide aggregate provided a more favorable environment for PDL cell adhesion and growth.


Asunto(s)
Fibroblastos/efectos de los fármacos , Ligamento Periodontal/efectos de los fármacos , Materiales de Obturación del Conducto Radicular/uso terapéutico , Raíz del Diente/lesiones , Compuestos de Aluminio/uso terapéutico , Compuestos de Boro/uso terapéutico , Compuestos de Calcio/uso terapéutico , Adhesión Celular/efectos de los fármacos , Recuento de Células , Técnicas de Cultivo de Célula , Supervivencia Celular/efectos de los fármacos , Colágeno Tipo I/análisis , Colorantes , Compómeros/uso terapéutico , Subunidad alfa 1 del Factor de Unión al Sitio Principal/análisis , Amalgama Dental/uso terapéutico , Combinación de Medicamentos , Fibroblastos/fisiología , Humanos , Ensayo de Materiales , Metacrilatos/uso terapéutico , Metilmetacrilatos/uso terapéutico , Microscopía Confocal , Óxidos/uso terapéutico , Ligamento Periodontal/citología , Reacción en Cadena en Tiempo Real de la Polimerasa , Silicatos/uso terapéutico , Sales de Tetrazolio , Tiazoles , Cemento de Óxido de Zinc-Eugenol/uso terapéutico
13.
West Indian Med J ; 61(2): 149-53, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23155961

RESUMEN

OBJECTIVE: The goal of this review is to discuss possible underlying psychopathological situations in patients requesting surgical cosmetic rhinoplasty operation and to examine potential problems that might arise. SUBJECTS AND METHODS: An extensive search was conducted through PubMed, Ambase and Psychlnfo by using related keywords in English, like "rhinoplasty and psychiatric comorbidities", "rhinoplasty and psychopathology". RESULTS: Patients who demand cosmetic rhinoplasty operation appealed to the surgeon since they wanted to feel better about themselves after the surgery. Indeed, some long-term studies determined that such a situation can take place at high rates. However, some studies reported the possibility of serious psychological disorders after such surgical operations. Studies relating to the analysis of psychopathologic symptoms are quite limited. Research has shown that psychopathologic evaluation conducted preoperatively is especially important to identify serious psychopathologies such as personality disorders and body dysmorphic disorder (BDD). CONCLUSIONS: Exclusion of patients possessing serious psychopathologies from operations provides better results in the long term. The lack of sufficient research in this area necessitates new and comprehensive studies.


Asunto(s)
Trastornos Mentales/diagnóstico , Rinoplastia/psicología , Trastorno Dismórfico Corporal/diagnóstico , Humanos , Satisfacción del Paciente
14.
Phys Rev Lett ; 107(14): 148303, 2011 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-22107241

RESUMEN

Inspired by the observations of a remarkably stable biaxial nematic phase [van den Pol et al., Phys. Rev. Lett. 103, 258301 (2009)], we investigate the effect of size polydispersity on the phase behavior of a suspension of boardlike particles. By means of Onsager theory within the restricted orientation (Zwanzig) model we show that polydispersity induces a novel topology in the phase diagram, with two Landau tetracritical points in between which oblate uniaxial nematic order is favored over the expected prolate order. Additionally, this phenomenon causes the opening of a huge stable biaxiality regime in between uniaxial nematic and smectic states.

15.
Int Endod J ; 44(5): 407-15, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21219366

RESUMEN

AIM: To compare mean cusp movement in molar teeth with endodontic access and mesial-occlusal-distal (MOD) cavities before and after restoration with several fibre-reinforced composite restoration techniques under loading and to evaluate the effect of restoration technique on fracture strength. METHODOLOGY: Reference points were marked at the mesial cusp ridges of extracted human mandibular molar teeth. Digital images were taken under loading (300 N) using a stereomicroscope (Leica MZ16A; Wetzlar, Germany). Three-dimensional (3D) distances between the reference points were recorded (Leica, Stereo-Explorer, 2.1) as controls. Standard MOD cavities were prepared and restored as follows (n = 10), group 1: composite restoration (Clearfil AP-X; Kuraray, Tokyo, Japan); group 2: cavity lined with polyethylene fibre (Ribbond, Ribbond Inc., Seattle, WA, USA) in combination with flowable resin (Protect-Liner F; Kuraray, Tokyo, Japan) before composite restoration; group 3: polyethylene fibre inserted on occlusal surface of the tooth from buccal to lingual after finishing the composite restoration; group 4: missing walls were restored with composite resin and inner surfaces of the axial walls were then reinforced with polyethylene fibre placed circumferentially before the composite restoration. The restored teeth were re-loaded, digital images were re-taken and the 3D distance between the reference points was recorded in µm. Comparisons of the restoration techniques, the effectiveness of restoration for each group were analysed statistically (Kruskall-Wallis, paired-samples t-test). The teeth were then loaded until failure (5 mm min(-1) ), the data were recorded (N) and analysed statistically (Kruskall-Wallis test). RESULTS: A significant difference occurred amongst the groups in terms of cusp movement (P = 0.018). All the groups revealed a decrease in inter-cuspal width when compared to their initial records. The mean values of these decreases were as follows: group 1 17.6 (P = 0.003), group 2 6.7 (not sig), group 3 6.6 (not sig) and group 4 0.85 (not sig) µm. No significant difference was found amongst the fracture strength values (P = 0.22). In group 1, 90% of the fractures were non-restorable, whereas in group 3 100% of the fractures were restorable. CONCLUSIONS: Regardless of restoration technique, fibre reinforcement of composite restorations decreased cusp movement in molar teeth with MOD and endodontic access cavities but did not affect fracture strength.


Asunto(s)
Resinas Compuestas/uso terapéutico , Caries Dental/terapia , Fracaso de la Restauración Dental , Restauración Dental Permanente/métodos , Corona del Diente/patología , Fracturas de los Dientes/prevención & control , Resinas Compuestas/química , Recubrimiento de la Cavidad Dental , Análisis del Estrés Dental , Vidrio , Humanos , Mandíbula , Metacrilatos/química , Metacrilatos/uso terapéutico , Diente Molar , Tratamiento del Conducto Radicular/instrumentación , Tratamiento del Conducto Radicular/métodos , Estadísticas no Paramétricas , Estrés Mecánico
16.
Int Endod J ; 44(9): 817-26, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21504437

RESUMEN

AIM: To investigate using finite element stress analysis (FEA) primary, secondary and tertiary monoblocks created either by adhesive resin sealers or by different adhesive posts and to evaluate the effect of interfaces on stress distribution in incisor models. METHODOLOGY: Seven maxillary incisor FEA models representing different monoblocks using several materials were created as follows: (a) primary monoblock with Mineral Trioxide Aggregate; (b) secondary monoblock with sealer (MetaSEAL) and Resilon; (c) tertiary monoblock with EndoREZ; (d) primary monoblock with polyethylene fibre post-core (Ribbond); (e) secondary monoblock with glass-fibre post and resin cement; (f) tertiary monoblock with bondable glass-fibre post; (g) tertiary monoblock with silane-coated ceramic post. A 300 N load was applied from the palatal surface of the crown with a 135° angle to the tooth long axis. Materials used in the study were assumed to be homogenous and isotropic except the glass-fibre post; the results are expressed in terms of von Mises criteria. RESULTS: Maximum stresses were concentrated on force application areas (18-22.1 MPa). The stresses within the models increased with the number of interfaces both for the monoblocks created by the sealers (1.67-8.33 MPa) and for the monoblocks created by post-core systems (1.67-11.7 MPa). CONCLUSIONS: Stresses within roots increased with an increase in the number of the adhesive interfaces. Creation of a primary monoblock within the root canal either by an endodontic sealer or with an adhesive post-core system can reduce the stresses that occur inside the tooth structure.


Asunto(s)
Análisis del Estrés Dental , Incisivo , Técnica de Perno Muñón , Materiales de Obturación del Conducto Radicular/química , Obturación del Conducto Radicular/métodos , Compuestos de Aluminio , Fenómenos Biomecánicos , Compuestos de Calcio , Resinas Compuestas/química , Simulación por Computador , Cementos Dentales/química , Cavidad Pulpar , Fracaso de la Restauración Dental , Combinación de Medicamentos , Análisis de Elementos Finitos , Humanos , Maxilar , Metacrilatos/química , Modelos Biológicos , Óxidos , Polietilenos/química , Silicatos , Estrés Mecánico
17.
Clin Exp Obstet Gynecol ; 38(1): 63-6, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21485730

RESUMEN

AIM: The aim of this study is to describe our 10-year experience in patients with urogynecological and colorectal carcinomas with radiation enteropathy treated surgically as an emergency, and to reassess symptoms and mortality. PATIENTS AND METHODS: The study included 17 patients receiving emergency surgery for complications of radiotherapy. Data about the patients and outcomes of the treatment alternatives used were retrospectively analyzed. RESULTS: Of 17 patients, nine had colorectal cancer, six had gynecological cancer, and two had cancer of the urinary system. As an emergency, 12 patients had ileus only, one patient had intestinal fistulae and ileus, two patients had bleeding and ileus and two patients had perforation on admission. Seven patients underwent resection and anastomosis, two patients intestinal by-pass, four patients resection and ostomy and four patients bridectomy. Morbidity (75% for early complications and 100% for late complications) and mortality in the early postoperative period (25%) were higher in the patients undergoing bridectomy than in the patients undergoing other surgical methods. The rate of early and late complications (71.4% and 66.6%, respectively) was lower in the patients undergoing resection-anastomosis with a higher of quality life. Only 11 patients survived during a long follow-up period (64.7%). CONCLUSION: As the postoperative complication rate, overall and operative mortality of patients treated for radiation enteropaties as emergent surgery are high, specialists following this group of patients may favor removal of the pathologic tissue to avoid complications in the early and late postoperative period.


Asunto(s)
Neoplasias Colorrectales/radioterapia , Enteritis/cirugía , Neoplasias de los Genitales Femeninos/radioterapia , Traumatismos por Radiación/cirugía , Adulto , Anciano , Femenino , Humanos , Persona de Mediana Edad , Complicaciones Posoperatorias , Calidad de Vida , Radioterapia/efectos adversos , Estudios Retrospectivos
18.
J Oral Rehabil ; 37(8): 615-23, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20406354

RESUMEN

The aim of this in vitro study was to test the effect of different post systems on fracture strength of roots with re-attached fragments. Root canals of eighty extracted single-rooted human teeth were instrumented (ProFile) and randomly divided into two groups. The roots in the first group were vertically cracked, and the fragments were re-attached using Super Bond C&B (Sun Medical, Tokya, Japan). The roots in the second group were kept sound. Obturation of the roots was performed with MetaSEAL (Sun Medical) and gutta-percha. Post spaces were prepared, and the roots were restored with one of the followings: UniCore (Ultradent), Everstick (Stick Tech), Ribbond (Ribbond), ParaPost (Coltene/Whaledent) (n = 10). Four mm high build-ups were created (Clearfil DC Bond Core; Kuraray, Tokyo, Japan). Compressive loading of the samples was performed after 24 h (1 mm min(-1)). Mean load necessary to fracture each sample was recorded (Newton) and statistically analysed (One-way anova, t-tests). ParaPost showed the highest fracture strength among the roots with re-attached fragments (P < 0.05). UniCore and ParaPost systems showed similar fracture strength in the sound roots (P > 0.05). Re-attached fragments significantly reduced the fracture strength of roots in UniCore group (P = 0.000). Ribbond post showed mostly repairable fractures. Metal post (ParaPost) showed the highest fracture strength in the roots with re-attached fragments; however, fracture pattern was 41% non-repairable. Re-attached fragments significantly reduced the fracture strength of the roots in UniCore group. Prefabricated posts showed similar fracture strength in the sound roots. Customized post systems EverStick and Ribbond showed mostly repairable failure after loading in sound roots or roots with re-attached fragments.


Asunto(s)
Restauración Dental Permanente/métodos , Técnica de Perno Muñón/instrumentación , Fracturas de los Dientes/fisiopatología , Raíz del Diente/fisiopatología , Compuestos de Boro/química , Resinas Compuestas/química , Aleaciones Dentales/química , Materiales Dentales/química , Reparación de Prótesis Dental , Cavidad Pulpar/fisiopatología , Fracaso de la Restauración Dental , Gutapercha/uso terapéutico , Humanos , Ensayo de Materiales , Metacrilatos/química , Metacrilatos/uso terapéutico , Metilmetacrilatos/química , Polietilenos/química , Cementos de Resina/química , Materiales de Obturación del Conducto Radicular/uso terapéutico , Obturación del Conducto Radicular/métodos , Preparación del Conducto Radicular/métodos , Estrés Mecánico , Factores de Tiempo , Fracturas de los Dientes/terapia , Raíz del Diente/lesiones
20.
J Med Genet ; 44(12): 750-62, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17766364

RESUMEN

Using array comparative genome hybridisation (CGH) 41 de novo reciprocal translocations and 18 de novo complex chromosome rearrangements (CCRs) were screened. All cases had been interpreted as "balanced" by conventional cytogenetics. In all, 27 cases of reciprocal translocations were detected in patients with an abnormal phenotype, and after array CGH analysis, 11 were found to be unbalanced. Thus 40% (11 of 27) of patients with a "chromosomal phenotype" and an apparently balanced translocation were in fact unbalanced, and 18% (5 of 27) of the reciprocal translocations were instead complex rearrangements with >3 breakpoints. Fourteen fetuses with de novo, apparently balanced translocations, all but two with normal ultrasound findings, were also analysed and all were found to be normal using array CGH. Thirteen CCRs were detected in patients with abnormal phenotypes, two in women who had experienced repeated spontaneous abortions and three in fetuses. Sixteen patients were found to have unbalanced mutations, with up to 4 deletions. These results suggest that genome-wide array CGH may be advisable in all carriers of "balanced" CCRs. The parental origin of the deletions was investigated in 5 reciprocal translocations and 11 CCRs; all were found to be paternal. Using customized platforms in seven cases of CCRs, the deletion breakpoints were narrowed down to regions of a few hundred base pairs in length. No susceptibility motifs were associated with the imbalances. These results show that the phenotypic abnormalities of apparently balanced de novo CCRs are mainly due to cryptic deletions and that spermatogenesis is more prone to generate multiple chaotic chromosome imbalances and reciprocal translocations than oogenesis.


Asunto(s)
Deleción Cromosómica , Trastornos de los Cromosomas/genética , Translocación Genética , Anomalías Múltiples/genética , Aborto Habitual/genética , Adulto , Preescolar , Rotura Cromosómica , Trastornos de los Cromosomas/patología , Pintura Cromosómica , Femenino , Enfermedades Fetales/genética , Humanos , Hibridación Fluorescente in Situ , Recién Nacido , Discapacidad Intelectual/genética , Masculino , Hibridación de Ácido Nucleico , Oogénesis , Fenotipo , Diagnóstico Prenatal , Espermatogénesis
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