Publications by authors named "Rafael O Martins"

Developing novel sorbent phases has advanced solid-based sample preparation techniques, improving analytical performance in complex matrices. Carbon-based sorbents, known for their high surface area, thermal and mechanical stability, and modifiability due to abundant organic functional groups, have emerged as exceptional materials in this field. Due to their versatile characteristics, carbon-based materials have been extensively investigated as promising materials for anchoring and functionalization with biopolymers, resulting in innovative hybrid materials, so-called carbon-based biosorbents.

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The advancement of traditional sample preparation techniques has brought about miniaturization systems designed to scale down conventional methods and advocate for environmentally friendly analytical approaches. Although often referred to as green analytical strategies, the effectiveness of these methods is intricately linked to the properties of the sorbent utilized. Moreover, to fully embrace implementing these methods, it is crucial to innovate and develop new sorbent or solid phases that enhance the adaptability of miniaturized techniques across various matrices and analytes.

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Background: One of the primary objectives in green analytical practices is the seamless integration of extraction and separation steps, resulting in the augmentation of both analytical throughput and method performance. Consequently, the exploration of prospective sorbent materials has drawn significant attention in the scientific community, particularly concerning the potential for online procedures. Employing the optimal sorbent material within an automated analytical approach holds the promise of elevating the precision of the analytical evaluation.

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The imaging of biological tissues can offer valuable information about the sample composition, which improves the understanding of analyte distribution in such complex samples. Different approaches using mass spectrometry imaging (MSI), also known as imaging mass spectrometry (IMS), enabled the visualization of the distribution of numerous metabolites, drugs, lipids, and glycans in biological samples. The high sensitivity and multiple analyte evaluation/visualization in a single sample provided by MSI methods lead to various advantages and overcome drawbacks of classical microscopy techniques.

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Naphthenic acids comprise one of the most toxic compounds of the produced water released from offshore oil platforms. Therefore, developing and applying faster, simpler, and more efficient analytical methods for analyzing naphthenic acids are urgently needed. Electromembrane extraction (EME) uses the electrokinetic migration of target ions through a porous membrane.

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Traditionally, creatinine determination is made by a spectrophotometric method; however, some compounds present in biological samples can interfere with creatinine determination, decreasing the sensitivity of the method in urine samples. Consequently, we report the development of a new molecularly imprinted polymer as a sorbent phase for disposable pipette extraction to determine creatinine in urine samples by high-performance liquid chromatography with UV detection. The synthesized polymer showed a high superficial area and presented a first-order kinetic reaction and a high selectivity for creatinine extraction compared to the non-molecularly imprinted polymer.

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Monolithic polymers are described as continuous and highly porous materials. They have been gaining popularity as an effective extracting phase for some sample preparation methods, due to their variety of functionalities, such as wide pH range tolerance, good permeability, and its ability to allow changes into their surface. Polypyrrole represents an interesting alternative for the modification in extraction phases due to its well related ability to perform multiple interactions, such as acid-base, π - π, ion exchange, interactions with hydrophobic affinities or polar functional groups.

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Analytical methods such as liquid chromatography (LC) and mass spectrometry (MS) are widely used techniques for the analyses of different classes of compounds. This is due to their highlighted capacity for separating and identifying components in complex matrices such food samples. However, in most cases, effective analysis of the target analyte becomes challenging due to the complexity of the sample, especially for quantification of trace concentrations.

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This study proposed the developed of a molecularly imprinted polymer for the extraction and determination of condensed tannins from the barks of Red Angico (Anadenanthera macrocarpa), Jabuticaba (Myrciaria jabuticaba) and Umbu (Spondias tuberosa). The polymer was synthesized using the condensed tannin extracted from the Red Angico bark as the template molecule, as well as, catechin standard solution. Selectivity and characterization tests for the molecularly imprinted polymers and a non-imprinted polymer were performed.

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Objective: To evaluate the prevalence of rotator cuff tears and describe the profile of reoperated patients, causes of repeated tendon tears, tear evolution and range of times between surgical procedures.

Method: This was a cross-sectional study involving 604 surgical procedures performed at two regional referral hospitals between January 2006 and December 2012. After approval by the ethics committee, data describing the patients' epidemiological profile were gathered at a single time, using Cofield's classification to measure the extent of the tears, all of which underwent arthroscopic surgery.

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Objectives: The aim of this study was to evaluate the results from arthroscopic tenodesis of the long head of the biceps brachii (LHBB) on the tendon of the subscapularis muscle, with regard to the presence of pain, subscapularis lesion, presence of Popeye's sign and patient satisfaction.

Methods: A prospective cohort study was conducted on 32 patients with LHBB lesions, through preoperative interviews and physical examinations, which were repeated six months after the operation. The main variables studied were the belly press, bear hug and lift-off tests, Popeye's sign, anterior pain and satisfaction.

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Objective: To evaluate the influence of treatment with different doses of methylprednisolone on the mechanical resistance and possible histological alterations of the rotator cuff tendon in rats.

Methods: Male Wistar rats were divided randomly into four treatment groups: sham, vehicle or 0.6 mg/kg or 6.

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Background: Locus of pain control (LPC) is characterized by the behavior of people coping with their health problems, as a result of their own actions (internal control) or external factors or other people (external control). This parameter can be associated with medication adherence, in addition to other psychosocial factors that may also influence this behavior. This study was performed to investigate the influence of the LPC on medication adherence in patients undergoing an orthopedic procedure.

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A cross-sectional study via interviews was conducted in the city of Tubarão in the state of Santa Catarina in order to identify the association between prescription indicators and the profile of the healthcare users and their understanding of medical prescriptions among patients attended by the Unified Health System. Information was collected on the profile of the healthcare users, the prescription indicators recommended by the World Health Organization and the understanding of drug prescriptions. Three hundred subjects were interviewed and the associated factors were identified using the Chi-square test.

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