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1.
Rev Esp Enferm Dig ; 115(12): 720-721, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36809923

RESUMO

We present a sclerosing angiomatoid nodular transformation (SANT) case report in a 60 year-old-woman. SANT is an extremely rare benign disease of the spleen that it is radiologically similar to malignant tumors, and clinically difficult to differentiate from other splenic diseases. Splenectomy is both diagnostic and therapeutic in symptomatic cases. The analysis of the resected spleen is necessary to achieve the final diagnosis of SANT.


Assuntos
Histiocitoma Fibroso Benigno , Esplenopatias , Feminino , Humanos , Pessoa de Meia-Idade , Histiocitoma Fibroso Benigno/diagnóstico por imagem , Histiocitoma Fibroso Benigno/cirurgia , Esplenectomia , Esplenopatias/diagnóstico por imagem , Esplenopatias/cirurgia
2.
Appl Surf Sci ; 598: 153867, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35669218

RESUMO

Herein, we report an electrochemical membrane-based aptasensor for the determination of the SARS-CoV-2 receptor-binding domain (SARS-CoV-2-RBD). For this purpose, the nanoporous anodic aluminium oxide membrane (NPAOM) was first fabricated electrochemically. The NPAOM was then functionalized with 3-mercaptopropyl trimethoxysilane (NPAOM-Si-SH). After that, the NPAOM-Si-SH was decorated with gold nanoparticles by using gold ion and sodium borohydride. The NPAOM-Si-S-Aunano was then attached to the surface of the working electrode of a laser-engraved graphene electrode (LEGE). Subsequently, the LEGE/NPAOM-Si-S-Aunano was fixed inside a flow cell that was made by using a three-dimensional (3D) printer, and then thiolated aptamer was transferred into the flow cell using a pump. The electrochemical behavior of the LEGE/NPAOM-Si-S-Aunano-Aptamer was studied using square wave voltammetry (SWV) in the presence of potassium ferrocyanide as a redox probe. The response of the LEGE/NPAOM-Si-S-Aunano-Aptamer to the different concentrations of the SARS-CoV-2-RBD in human saliva sample was investigated in the concentration range of 2.5-40.0 ng/mL. The limit of the detection was found to be 0.8 ng/mL. The LEGE/NPAOM-Si-S-Aunano-Aptamer showed good selectivity to 5.0 ng/mL of SARS-CoV-2-RBD in the presence of five times of the interfering agents like hemagglutinin and neuraminidase as the influenza A virus major surface glycoproteins.

3.
Int J Mol Sci ; 23(8)2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35457113

RESUMO

Fibrin hydrogels are one of the most popular scaffolds used in tissue engineering due to their excellent biological properties. Special attention should be paid to the use of human plasma-derived fibrin hydrogels as a 3D scaffold in the production of autologous skin grafts, skeletal muscle regeneration and bone tissue repair. However, mechanical weakness and rapid degradation, which causes plasma-derived fibrin matrices to shrink significantly, prompted us to improve their stability. In our study, plasma-derived fibrin was chemically bonded to oxidized alginate (alginate di-aldehyde, ADA) at 10%, 20%, 50% and 80% oxidation, by Schiff base formation, to produce natural hydrogels for tissue engineering applications. First, gelling time studies showed that the degree of ADA oxidation inhibits fibrin polymerization, which we associate with fiber increment and decreased fiber density; moreover, the storage modulus increased when increasing the final volume of CaCl2 (1% w/v) from 80 µL to 200 µL per milliliter of hydrogel. The contraction was similar in matrices with and without human primary fibroblasts (hFBs). In addition, proliferation studies with encapsulated hFBs showed an increment in cell viability in hydrogels with ADA at 10% oxidation at days 1 and 3 with 80 µL of CaCl2; by increasing this compound (CaCl2), the proliferation does not significantly increase until day 7. In the presence of 10% alginate oxidation, the proliferation results are similar to the control, in contrast to the sample with 20% oxidation whose proliferation decreases. Finally, the viability studies showed that the hFB morphology was maintained regardless of the degree of oxidation used; however, the quantity of CaCl2 influences the spread of the hFBs.


Assuntos
Aldeídos , Alginatos , Hidrogéis , Aldeídos/química , Alginatos/química , Cloreto de Cálcio/farmacologia , Fibrina , Humanos , Hidrogéis/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química
4.
Sens Actuators B Chem ; 345: 130377, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34219971

RESUMO

Herein, a photoelectrochemical aptasensor for the quantitive measurement of the severe acute respiratory syndrome coronavirus-2 receptor-binding domain (Sars-Cov-2 RBD) has been reported for the first time. For this purpose, first, graphitic carbon nitride and (gC3N4) and cadmium sulfide (CdS) quantum dots were fabricated and characterized. After that, gC3N4 and CdS were mixed well. The fabricated nanomaterials were characterized by scanning transmission electron microscopy. Then, the CdS QDs-gC3N4 nanocomposite was added to the solution containing chitosan as an amine-rich polymer to generate a Chitosan/CdS-gC3N4 nanocomposite. Subsequently, the surface of the ITO electrode was modified with Chitosan/CdS-gC3N4. After that, the amine-terminal aptamer probes were immobilized on the surface of the Chitosan/CdS QDs-gC3N4/ITO electrode by using glutaraldehyde as an amine-amine crosslinker. The electrochemical performances of the electrodes were studied using cyclic voltammetry (CV), electrochemical Impedance Spectroscopy (EIS), and photo-electrochemistry (PEC). The surface coverage of the immobilized aptamer probe was founded to be 26.2 pmol.cm-2. The obtained results demonstrated that the proposed photo-electrochemical aptasensor can be used for the measurement of Sars-Cov-2 RBD within 0.5-32.0 nM. The limit of detection (LOD) was obtained to be 0.12 nM (at 3σ/slope). The affinity of the Aptamer/Chitosan/CdS QDs-gC3N4/ITO was also founded to be 3.4 nM by using Langmuir-typical adsorption systems. The proposed photo-electrochemical aptasensor was applied for the measurement of the spiked Sars-Cov-2 RBD in human saliva samples at two concentrations. The effect of the interfering biomaterials such as human immunoglobulin G human immunoglobulin A, human immunoglobulin M, and human serum albumin was also studied.

5.
Sensors (Basel) ; 20(21)2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33120866

RESUMO

In this work, we present a multipurpose photonic integrated circuit capable of generating multiheterodyne complex Dual-Combs (DC) THz signals. Our work focuses on translating the functionality of an electro-optic tunable DC system into a photonic chip employing standard building blocks to ensure the scalability and cost efficiency of the integrated device. The architecture we analyze for integration is based on three stages: a seed comb, a mode selection stage and a DC stage. This final DC stage includes a frequency shifter, a key element to improve the final detection of the THz signals and obtain real-time operation. This investigation covers three key aspects: (1) a solution for comb line selection on GHz spaced combs using OIL or OPLL on photonic chips is studied and evaluated, (2) a simple and versatile scheme to produce a frequency shift using the double sideband suppressed carrier modulation technique and an asymmetric Mach Zehnder Interferometer to filter one of the sidebands is proposed, and (3) a multipurpose architecture that can offer a versatile effective device, moving from application-specific PICs to general-purpose PICs. Using the building blocks (BBs) available from an InP-based foundry, we obtained simulations that offer a high-quality Dual-Comb frequency shifted signal with a side mode suppression ratio around 21 dB, and 41 dB after photodetection with an intermediate frequency of 1 MHz. We tested our system to generate a Dual-Comb with 10 kHz of frequency spacing and an OOK modulation with 5 Gbps which can be down-converted to the THz range by a square law detector. It is also important to note that the presented architecture is multipurpose and can also be applied to THz communications. This design is a step to enable a commercial THz photonic chip for multiple applications such as THz spectroscopy, THz multispectral imaging and THz telecommunications and offers the possibility of being fabricated in a multi-project wafer.

6.
Sensors (Basel) ; 20(19)2020 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-33049961

RESUMO

From electronic devices to large-area electronics, from individual cells to skin substitutes, printing techniques are providing compelling applications in wide-ranging fields. Research has thus fueled the vision of a hybrid, printing platform to fabricate sensors/electronics and living engineered tissues simultaneously. Following this interest, we have fabricated interdigitated-electrode sensors (IDEs) by inkjet printing to monitor epithelial cell cultures. We have fabricated IDEs using flexible substrates with silver nanoparticles as a conductive element and SU-8 as the passivation layer. Our sensors are cytocompatible, have a topography that simulates microgrooves of 300 µm width and ~4 µm depth, and can be reused for cellular studies without detrimental in the electrical performance. To test the inkjet-printed sensors and demonstrate their potential use for monitoring laboratory-growth skin tissues, we have developed a real-time system and monitored label-free proliferation, migration, and detachment of keratinocytes by impedance spectroscopy. We have found that variations in the impedance correlate linearly to cell densities initially seeded and that the main component influencing the total impedance is the isolated effect of the cell membranes. Results obtained show that impedance can track cellular migration over the surface of the sensors, exhibiting a linear relationship with the standard method of image processing. Our results provide a useful approach for non-destructive in-situ monitoring of processes related to both in vitro epidermal models and wound healing with low-cost ink-jetted sensors. This type of flexible sensor as well as the impedance method are promising for the envisioned hybrid technology of 3D-bioprinted smart skin substitutes with built-in electronics.


Assuntos
Impedância Elétrica , Eletrodos , Células Epiteliais/citologia , Nanopartículas Metálicas , Células Cultivadas , Condutividade Elétrica , Humanos , Prata
7.
Sensors (Basel) ; 20(7)2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32290334

RESUMO

Cell functions and behavior are regulated not only by soluble (biochemical) signals but also by biophysical and mechanical cues within the cells' microenvironment. Thanks to the dynamical and complex cell machinery, cells are genuine and effective mechanotransducers translating mechanical stimuli into biochemical signals, which eventually alter multiple aspects of their own homeostasis. Given the dominant and classic biochemical-based views to explain biological processes, it could be challenging to elucidate the key role that mechanical parameters such as vibration, frequency, and force play in biology. Gaining a better understanding of how mechanical stimuli (and their mechanical parameters associated) affect biological outcomes relies partially on the availability of experimental tools that may allow researchers to alter mechanically the cell's microenvironment and observe cell responses. Here, we introduce a new device to study in vitro responses of cells to dynamic mechanical stimulation using a piezoelectric membrane. Using this device, we can flexibly change the parameters of the dynamic mechanical stimulation (frequency, amplitude, and duration of the stimuli), which increases the possibility to study the cell behavior under different mechanical excitations. We report on the design and implementation of such device and the characterization of its dynamic mechanical properties. By using this device, we have performed a preliminary study on the effect of dynamic mechanical stimulation in a cell monolayer of an epidermal cell line (HaCaT) studying the effects of 1 Hz and 80 Hz excitation frequencies (in the dynamic stimuli) on HaCaT cell migration, proliferation, and morphology. Our preliminary results indicate that the response of HaCaT is dependent on the frequency of stimulation. The device is economic, easily replicated in other laboratories and can support research for a better understanding of mechanisms mediating cellular mechanotransduction.


Assuntos
Movimento Celular , Proliferação de Células , Estresse Mecânico , Linhagem Celular , Movimento Celular/efeitos da radiação , Núcleo Celular/fisiologia , Proliferação de Células/efeitos da radiação , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Processamento de Imagem Assistida por Computador , Queratinócitos/citologia , Queratinócitos/metabolismo , Queratinócitos/patologia , Microscopia de Fluorescência , Ondas de Rádio
8.
Opt Express ; 27(10): 14716-14724, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31163916

RESUMO

We investigate the high frequency modulation characteristics of mid-infrared surface-emitting ring and edge-emitting ridge quantum cascade lasers (QCLs). In particular, a detailed comparison between circular ring devices and ridge-QCLs from the same laser material, which have a linear waveguide in a "Fabry-Pérot (FP) type" cavity, reveals distinct similarities and differences. Both device types are single-mode emitting, based on either 2 nd- (ring-QCL) or 1 st-order (ridge-QCL) distributed feedback (DFB) gratings with an emission wavelength around 7.56 µm. Their modulation characteristics are investigated in the frequency-domain using an optical frequency-to-amplitude conversion technique based on the ro-vibrational absorptions of CH 4. We observe that the amplitude of frequency tuning Δf over intensity modulation index m as function of the modulation frequency behaves similarly for both types of devices, while the ring-QCLs typically show higher values. The frequency-to-intensity modulation (FM-IM) phase shift shows a decrease starting from ∼72 ∘ at a modulation frequency of 800 kHz to about 0 ∘ at 160 MHz. In addition, we also observe a quasi single-sideband (qSSB) regime for modulation frequencies above 100 MHz, which is identified by a vanishing -1 st-order sideband for both devices. This special FM-state can be observed in DFB QCLs and is in strong contrast to the behavior of regular DFB diode lasers, which do not achieve any significant sideband suppression. By analyzing these important high frequency characteristics of ring-QCLs and comparing them to ridge DFB-QCLs, it shows the potential of intersubband devices for applications in e.g. novel spectroscopic techniques and highly-integrated and high-bitrate free-space data communication. In addition, the obtained results close an existing gap in literature for high frequency modulation characteristics of QCLs.

9.
Opt Lett ; 44(2): 415-418, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30644914

RESUMO

An absolute-frequency terahertz (THz) dual-frequency comb spectrometer based on electro-optic modulators for tunable, high-resolution, and real-time rapid acquisition is presented. An optical line of a master frequency comb (filtered via optical injection locking) serves as the seed to electro-optically generate a pair of new frequency combs (probe and local oscillator). Photomixing both combs with another coherent line from the same original master comb generates a narrow linewidth THz dual-comb with teeth frequencies that can be referenced to a radio-frequency standard. The system is validated with a proof-of-principle measurement of a microwave filter in the W-band.

10.
Sensors (Basel) ; 19(15)2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31366169

RESUMO

Diabetes is a very complex condition affecting millions of people around the world. Its occurrence, always accompanied by sustained hyperglycemia, leads to many medical complications that can be greatly mitigated when the disease is treated in its earliest stage. In this paper, a novel sensing approach for the early non-invasive detection and monitoring of sustained hyperglycemia is presented. The sensing principle is based on millimeter-wave transmission spectroscopy through the skin and subsequent statistical analysis of the amplitude data. A classifier based on functional principal components for sustained hyperglycemia prediction was validated on a sample of twelve mice, correctly classifying the condition in diabetic mice. Using the same classifier, sixteen mice with drug-induced diabetes were studied for two weeks. The proposed sensing approach was capable of assessing the glycemic states at different stages of induced diabetes, providing a clear transition from normoglycemia to hyperglycemia typically associated with diabetes. This is believed to be the first presentation of such evolution studies using non-invasive sensing. The results obtained indicate that gradual glycemic changes associated with diabetes can be accurately detected by non-invasively sensing the metabolism using a millimeter-wave spectral sensor, with an observed temporal resolution of around four days. This unprecedented detection speed and its non-invasive character could open new opportunities for the continuous control and monitoring of diabetics and the evaluation of response to treatments (including new therapies), enabling a much more appropriate control of the condition.


Assuntos
Glicemia/isolamento & purificação , Diabetes Mellitus Experimental/diagnóstico , Hiperglicemia/diagnóstico , Análise Espectral/métodos , Animais , Diabetes Mellitus Experimental/metabolismo , Humanos , Hiperglicemia/metabolismo , Camundongos
11.
Rev Esp Enferm Dig ; 111(1): 34-39, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30284910

RESUMO

INTRODUCTION: delayed gastric emptying (DGE) is the most common complication after pancreaticoduodenectomy (PD) and it occurs in 50% of cases. OBJECTIVES: the endpoint was to determine if there were any differences in the incidence of DGE between Roux-en-Y gastrojejunostomy (ReY) and Billroth II gastrojejunostomy (BII) in PD with pancreaticogastrostomy (PG). METHODS: this was a case-control prospective randomized study of all PD cases between 2013 and 2016. Sixty-four patients were included, 32 in each group. An intention-to-treat statistical analysis was performed. RESULTS: no significant differences were found with regard to morbidity and mortality or hospital stay. DGE was present in 25% of the patients in the BII group in comparison to 15.6% in the ReY group, which was not statistically significant (p = 0.35). There was a higher percentage of patients with primary DGE in the BII group, 12.5% versus 6.2%, but this was not statistically significant (p = 0.53). No difference in DGE severity was observed. Male gender (OR 8.38 [1.1; 129]), abdominal complications (OR 15 [1.7; 396.9]), pre-operative malnutrition (OR 99.7 [3.3, 11,126]) and hemorrhage (OR 9.4 [1.37, 107.94]) were the main risk factors for DGE according to the multivariate analysis. CONCLUSIONS: there were no significant differences in the incidence or severity of DGE between BII or ReY after PD with PG.


Assuntos
Gastroparesia/epidemiologia , Pancreaticoduodenectomia/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Adenocarcinoma/cirurgia , Idoso , Idoso de 80 Anos ou mais , Anastomose em-Y de Roux/efeitos adversos , Estudos de Casos e Controles , Feminino , Derivação Gástrica/efeitos adversos , Esvaziamento Gástrico , Gastroenterostomia/efeitos adversos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/cirurgia , Pancreaticoduodenectomia/estatística & dados numéricos , Cuidados Pós-Operatórios , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Fatores de Risco , Fatores Sexuais
12.
Rev Esp Enferm Dig ; 111(4): 322, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30746953

RESUMO

Pancreas divisum is a congenital anomaly present in 5-10% of the population and is usually asymptomatic. Pancreatic intraductal papillary mucinous neoplasms (IPMN) are mucinous cystic tumors that have malignant potential and are classified according to their location as IPMN of the main duct, branch duct or mixed type. Larger lesions and those originating in the main duct have an increased risk of malignancy. The real incidence is unknown as most lesions are asymptomatic.


Assuntos
Adenocarcinoma Mucinoso/diagnóstico por imagem , Carcinoma Ductal Pancreático/diagnóstico por imagem , Pâncreas/anormalidades , Neoplasias Pancreáticas/diagnóstico por imagem , Idoso , Ducto Colédoco/anormalidades , Humanos , Achados Incidentais , Imageamento por Ressonância Magnética , Masculino , Pâncreas/diagnóstico por imagem
13.
Rev Esp Enferm Dig ; 111(9): 677-682, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31317752

RESUMO

INTRODUCTION: an increasing number of elderly patients undergo urgent abdominal surgery and this population has a higher risk of mortality. The main objective of the study was to identify mortality-associated factors in elderly patients undergoing abdominal surgery and to design a mortality scoring tool, the Urgent Surgery Elderly Mortality risk score (the USEM score). PATIENTS AND METHODS: this was a retrospective study using a prospective database. Patients > 65 years old that underwent urgent abdominal surgery were included. Risk factors for 30-day mortality were identified using multivariate regression analysis and weights assigned using the odds ratios (OR). A mortality score was derived from the aggregate of weighted scores. Model calibration and discrimination were judged using the receiver operating characteristics curves and the Hosmer-Lemeshow test. RESULTS: in the present study, 4,255 patients were included with an 8.5% mortality rate. The risk factors significantly associated with mortality were American Society of Anesthesiologists (ASA) score, age, preoperative diagnosis (OR: 37.82 for intestinal ischemia, OR: 5.01 for colorectal perforation, OR: 6.73 for intestinal obstruction), surgical wound classification and open or laparoscopic surgery. A risk score was devised from these data for the estimation of the probability of survival in each patient. The area under the ROC curve (AUROC) for this score was 0.84 (95% CI: 0.82-0.86) and the AUROC correct was 0.83 (0.81-0.85). CONCLUSIONS: a simple score that uses five clinical variables predicts 30-day mortality. This model can assist surgeons in the initial evaluation of an elderly patient undergoing urgent abdominal surgery.


Assuntos
Abdome/cirurgia , Tratamento de Emergência/mortalidade , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Emergências , Feminino , Humanos , Obstrução Intestinal/mortalidade , Perfuração Intestinal/mortalidade , Intestinos/irrigação sanguínea , Isquemia/mortalidade , Laparoscopia/métodos , Laparoscopia/mortalidade , Masculino , Período Pós-Operatório , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Ferida Cirúrgica/classificação , Ferida Cirúrgica/mortalidade , Fatores de Tempo
14.
Rev Esp Enferm Dig ; 111(8): 609-614, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31317756

RESUMO

INTRODUCTION: pancreatic adenocarcinoma is the most common malignancy in the periampullary region, with a five-year survival rate around 20%. OBJECTIVE: the goal of our study was to determine the survival and safety data of a number of patients that underwent a cephalic duodenopancreatectomy (CDP) with total mesopancreas excision (TMPE). MATERIAL AND METHODS: a prospective observational study was performed of 114 patients with pancreatic adenocarcinoma who underwent duodenopancreatectomy and TMPE over the period 2008-2017. Demographic variables, tumor stage, number of lymph nodes excised, lymph node ratio, R classification, the prognostic factor disease-free interval and survival were all assessed in a multivariate analysis. RESULTS: complications were reported for 54 (47.3%) patients, of which 22 (19.3%) were categorized as serious. The mortality rate was 4.3% and the mean follow-up was 26.2 months. During this period, 73 (64%) patients relapsed after a mean interval of 40.9 months. The relapse pattern was mainly hepatic (26.3%), followed by local relapse (20%). Mean survival was 40.38 and actuarial survival was 26.6% at five years. Relapse-related factors included stage T3 or higher (RR 8.1 [1.1-61]) and an R1 resection (RR 13.4 [2.7-66.5]) and survival-related factors included an R1 resection (RR 10.7 [2.5-46.2]). CONCLUSION: TMPE ensures an adequate lymphadenectomy and lymph node ratio according to reported standards. The survival of patients that have undergone surgery for pancreatic adenocarcinoma in our institution is 68.4% at one year and 26.6% at five years. An R1 resection is the primary factor for both relapse and survival.


Assuntos
Adenocarcinoma/mortalidade , Pâncreas/cirurgia , Neoplasias Pancreáticas/mortalidade , Pancreaticoduodenectomia/mortalidade , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Humanos , Excisão de Linfonodo/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Recidiva Local de Neoplasia , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/cirurgia , Pancreaticoduodenectomia/efeitos adversos , Pancreaticoduodenectomia/métodos , Estudos Prospectivos
15.
Rev Esp Enferm Dig ; 111(11): 817-822, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31599639

RESUMO

INTRODUCTION: there is controversy about the effect of a preoperative biliary prosthesis (PBP) on complications of pancreaticoduodenectomy (PD). There are no recommendations for antibiotic prophylaxis in these patients. The objective of the study was to analyze the association of PBP, bacteriology and the development of complications after PD. METHODS: this was a retrospective observational study with 90 consecutive patients that underwent DP between 2015 and 2018. PBP was indicated in patients with total bilirubin levels > 12 mg/dl who could not be operated on within a reasonable time. Antibiotic prophylaxis with cefoxitin was administered in patients without PBP and a five-day treatment with piperacillin-tazobactam for PBP. A bile culture was systematically performed. RESULTS: the average age of the patient cohort was 69 years. Fifty-one patients suffered complications (56%), with a mortality rate of 3%. The average hospital stay was eleven days and PBP was placed in 51 patients (56%). Antibiotic prophylaxis was adequate in 62 patients (69%). The most frequently isolated bacteria were E. faecium (30%), E. coli (20%) and E. faecalis (19%). Patients with PBP had a significantly higher percentage of positive cultures (98% vs 25%, p < 0.01), a higher number of bacteria (2.9 vs 0.5, p < 0.01) and perioperative sepsis (31% vs 12%, p = 0.03), but without an increased hospital stay or overall morbidity. CONCLUSIONS: PBPs increase the risk of perioperative sepsis, the percentage of positive cultures and the average number of isolated bacteria. The protocol of prophylaxis with cefoxitin and the administration of pipercillin-tazobactan with PBP adequately treated 69% of patients. With this protocol, PBPs do not imply an increase in complications or hospital stay.


Assuntos
Antibioticoprofilaxia , Infecções Bacterianas/etiologia , Infecções Bacterianas/prevenção & controle , Ductos Biliares/cirurgia , Pancreaticoduodenectomia/efeitos adversos , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/prevenção & controle , Próteses e Implantes , Idoso , Idoso de 80 Anos ou mais , Infecções Bacterianas/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Cuidados Pré-Operatórios , Desenho de Prótese , Estudos Retrospectivos
16.
Opt Express ; 26(8): 9700-9713, 2018 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-29715918

RESUMO

Electro-optic dual-comb spectrometers have proved to be a promising technology for sensitive, high-resolution and rapid spectral measurements. Electro-optic combs possess very attractive features like simplicity, reliability, bright optical teeth, and typically moderate but quickly tunable optical spans. Furthermore, in a dual-comb arrangement, narrowband electro-optic combs are generated with a level of mutual coherence that is sufficiently high to enable optical multiheterodyning without inter-comb stabilization or signal processing systems. However, this valuable tool still presents several limitations; for instance, on most systems, absolute frequency accuracy and long-term stability cannot be guaranteed; likewise, interferometer-induced phase noise restricts coherence time and limits the attainable signal-to-noise ratio. In this paper, we address these drawbacks and demonstrate a cost-efficient absolute electro-optic dual-comb instrument based on a frequency stabilization mechanism and a novel adaptive interferogram acquisition approach devised for electro-optic dual-combs capable of operating in real-time. The spectrometer, completely built from commercial components, provides sub-ppm frequency uncertainties and enables a signal-to-noise ratio of 10000 (intensity noise) in 30 seconds of integration time.

17.
Anal Chem ; 89(11): 5916-5922, 2017 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-28480710

RESUMO

Molecular dispersion spectroscopy encompasses a group of spectroscopic techniques for gas analysis that retrieve the characteristics of the sample from the measurement of the profile of its refractive index in the vicinity of molecular resonances. This approach, which is in clear contrast to traditional methods based on the detection of absorption, provides inherent immunity to power fluctuations, calibration-free operation, and an output that is linearly dependent on gas concentration. Heterodyne phase-sensitive dispersion spectroscopy (HPSDS) is a very recently proposed technique for molecular dispersion spectroscopy based on tunable lasers that is characterized by a very simple architecture in which data processing and concentration retrieval are straightforward. Different HPSDS implementations have been experimentally validated in the near-IR. Here, we present the first demonstration of HPSDS in the mid-IR using a directly modulated quantum cascade laser for the measurement of CO. The setup is put under test to characterize its response to changing concentrations, pressures, and levels of optical intensity on the detector, and the limit of detection is estimated. Besides this, an experimental comparison with wavelength modulation spectroscopy with second-harmonic detection (2f-WMS) is performed and discussed in detail in order to offer a clear view of the benefits and drawbacks that HPSDS can provide over what we could consider the reference method for gas analysis based on tunable laser spectroscopy.

18.
Appl Opt ; 56(22): 6087-6093, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29047800

RESUMO

In this paper a new laser range finder approach is presented. It is based on a fan of beams of different optical frequencies that are projected to the target. The detected back-reflected beams contain frequency-encoded information about its reflection angles, which are used for the calculation of the range by means of triangulation methods. The fan of beams is generated from a fieldable electro-optic dual optical frequency comb generator and a diffractive optical system, without any moving parts. A proof-of-concept prototype of a range finder based on this approach was implemented and experimentally tested. An analysis of main sources of errors is also presented.

19.
Opt Express ; 24(13): 14986-94, 2016 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-27410649

RESUMO

In this paper, a new approach to dual comb generation based on well-known optical techniques (Gain-Switching and Optical Injection Locking) is presented. The architecture can be implemented using virtually every kind of continuous-wave semiconductor laser source (DFB, VCSEL, QCL) and without the necessity of electro-optic modulators. This way, a frequency-agile and adaptive dual-comb architecture is provided with potential implementation capabilities from mid-infrared to near ultraviolet. With a RF comb comprising around 70 teeth, the system is validated in the 1.5 µm region measuring the absorption feature of H13CN at 1538.523 nm with a minimum integration time of 10 µs.

20.
Opt Lett ; 41(18): 4293-6, 2016 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-27628380

RESUMO

In this work, the generation of dual optical frequency combs based on gain-switching and optical injection locking is experimentally examined. The study reveals that an effective process of optical injection can lead to optimized RF combs in terms of span and signal-to-noise ratio. The system also minimizes the overlap of lines and reduces the number of optical components involved, eliminating the need for any external modulator (electro-optic, acousto-optic). The validation of the system was performed as a dual-comb spectrometer, which allowed for determination of the absorption and dispersion profiles of the molecular transition of H13CN at 1538.523 nm.

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