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1.
Vet Surg ; 53(4): 603-612, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38240128

RESUMO

OBJECTIVE: To describe fluoroscopically-assisted closed reduction and percutaneous fixation of sacroiliac-luxation (SIL) in cats and report radiographic results and long-term functional outcomes. STUDY DESIGN: Retrospective clinical study. ANIMALS: Eleven cats. METHODS: Percutaneous fixation of 17 SILs in 11 cats was performed with 2.4 mm headless cannulated compression screws under fluoroscopic guidance. Luxation-reduction, screw placement and purchase within the sacral body, pelvic canal diameter ratio (PCDR) and hemipelvic canal width ratio (HCWR) were assessed on pre- and postoperative radiographs. Radiographic follow-up was performed to assess the same parameters when available. Long-term clinical outcome was evaluated with an owner questionnaire. Wilcoxon paired-test was performed for comparison. RESULTS: Mean age and bodyweight of the cats were 3.3 ± 2.6 years and 4.0 ± 0.82 kg, respectively. Nine cats presented with concurrent pelvic injuries. Median luxation-reduction was 94.1% (IQR = 13.9) and median screw-purchase within the sacral body was 73.3% (IQR = 17.0) immediately postoperatively. One screw exited the sacral body caudally. Upon 7-week radiographic follow-up, luxation-reduction (88.3%, IQR = 20.1) and screw-purchase (70.7%, IQR = 12.8) had decreased compared to immediately postoperatively (p = .008 and p = .013 respectively). Screw migration was not observed. PCDR and HCWR measured on postoperative radiographs indicated successful restoration of the pelvic canal width. Owners reported an excellent long-term functional outcome (mean postoperative time: 19 ± 5 months). CONCLUSION: Fluoroscopically-assisted closed reduction and fixation of feline SIL using 2.4 mm headless cannulated compression screws allowed good reduction and optimal screw purchase within the sacral body. An excellent functional outcome was reported. CLINICAL SIGNIFICANCE: Minimally invasive reduction and fixation with headless compression screws should be considered in cats with SIL.


Assuntos
Parafusos Ósseos , Luxações Articulares , Articulação Sacroilíaca , Animais , Gatos , Parafusos Ósseos/veterinária , Estudos Retrospectivos , Masculino , Feminino , Fluoroscopia/veterinária , Articulação Sacroilíaca/cirurgia , Articulação Sacroilíaca/lesões , Luxações Articulares/veterinária , Luxações Articulares/cirurgia , Resultado do Tratamento , Fixação Interna de Fraturas/veterinária , Fixação Interna de Fraturas/métodos , Fixação Interna de Fraturas/instrumentação
2.
BMC Nephrol ; 24(1): 198, 2023 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-37391713

RESUMO

BACKGROUND: Ferritin levels are used to make decisions on therapy of iron deficiency in patients with chronic kidney disease (CKD). Hyperferritinaemia, common among patients with CKD from the Northern Territory (NT) of Australia, makes use of ferritin levels as per clinical guidelines challenging. No gold standard assay exists for measuring ferritin levels. Significant variability between results from different assays creates challenges for clinical decision-making regarding iron therapy. In the NT, different laboratories use different methods. In 2018, Territory Pathology changed the assay from Abbott ARCHITECT i1000 (AA) to Ortho-Clinical Diagnostics Vitros 7600 (OCD). This was during the planning of the INtravenous iron polymaltose for First Nations Australian patients with high FERRitin levels on haemodialysis (INFERR) clinical trial. The trial design was based on AA assay ferritin levels. We compared the two assays' level of agreement in measuring ferritin levels in CKD patients. METHODS: Samples from INFERR clinical trial participants were analysed. Other samples from patients whose testing were completed the same day on OCD analyzers and run within 24 h on AA analyzers were added to ensure wide range of ferritin levels, adding statistical strength to the comparison. Ferritin levels from both assays were compared using Pearson's correlation, Bland-Altman, Deming and Passing-Bablok regression analyses. Differences between sample types, plasma and serum were assessed. RESULTS: Sixty-eight and 111 (179) samples from different patients from Central Australia and Top End of Australia, respectively, were analyzed separately and in combination. The ferritin levels ranged from 3.1 µg/L to 3354 µg/L and 3 µg/L to 2170 µg/L for AA and OCD assays respectively. Using Bland-Altman, Deming and Passing-Bablok regression methods for comparison, ferritin results were consistently 36% to 44% higher with AA than OCD assays. The bias was up to 49%. AA ferritin results were the same in serum and plasma. However, OCD ferritin results were 5% higher in serum than plasma. CONCLUSIONS: When making clinical decisions, using ferritin results from the same assay in patients with CKD is critical. If the assay is changed, it is essential to assess agreement between results from the new and old assays. Further studies to harmonize ferritin assays are required.


Assuntos
Tomada de Decisão Clínica , Plasma , Humanos , Administração Intravenosa , Ferritinas , Northern Territory
3.
Phys Rev Lett ; 128(1): 013902, 2022 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-35061473

RESUMO

Here, inspired by the operation of conventional semiconductor transistors, we introduce a novel class of bulk materials with nonreciprocal and non-Hermitian electromagnetic response. Our analysis shows that material nonlinearities combined with a static electric bias may lead to a linearized permittivity tensor that lacks the Hermitian and transpose symmetries. Remarkably, the material can either dissipate or generate energy, depending on the relative phase of the electric field components. We introduce a simple design for an electromagnetic isolator based on an idealized "MOSFET-metamaterial" and show that its performance can in principle surpass conventional Faraday isolators due to the material gain. Furthermore, it is suggested that analogous material responses may be engineered in natural media in nonequilibrium situations. Our solution determines an entirely novel paradigm to break the electromagnetic reciprocity in a bulk nonlinear material using a static electric bias.

4.
Intern Med J ; 52(2): 288-294, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33251718

RESUMO

BACKGROUND: Indigenous Australians are disproportionately affected by end stage kidney disease. Despite this, they face significant delays being assessed and waitlisted for kidney transplant. AIMS: To examine the kidney transplant waitlisting process in our region, to compare the workup process between Indigenous Australians and non-Indigenous patients, and identify major sources of delay. METHODS: We analysed the records of all patients being treated by our service who were on the kidney transplant waitlist between January 2017 and June 2018. Between-group differences were used to compare the time between commencement of dialysis and completion of each component of assessment. Patients who had more than 1 year between commencement of dialysis and waitlisting were further analysed for major sources of delay. RESULTS: Twenty-five patients were included (20 Indigenous Australians and 5 non-Indigenous). The median time to waitlisting for transplant after commencing dialysis was significantly longer in the Indigenous group (1215 vs 264 days, P = 0.032). Indigenous Australian patients waited longer before commencing the transplant assessment process and before completing dental assessment, tissue typing and review by the transplant nephrologist and surgeon. Five patients (two Indigenous Australians, three non-Indigenous) were waitlisted within 1 year of commencing dialysis. Among the remaining 20 patients, cardiac and systems issues were the two most common major sources of delay. CONCLUSION: Indigenous Australian patients face significant delays accessing the kidney transplant waitlist. Cardiac assessment and systems issues are prominent sources of delay and efforts to address these areas may help to improve equity of access to kidney transplantation.


Assuntos
Serviços de Saúde do Indígena , Falência Renal Crônica , Transplante de Rim , Austrália/epidemiologia , Humanos , Falência Renal Crônica/cirurgia , Havaiano Nativo ou Outro Ilhéu do Pacífico , Diálise Renal
5.
Childs Nerv Syst ; 38(5): 961-970, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35274185

RESUMO

BACKGROUND: MRI-guided laser interstitial thermal therapy (MRgLITT) is a promising alternative to open surgery for treatment of drug-resistant epilepsy, offering significant advantages over traditional approaches for candidate patients, including minimally invasive approach, shorter hospitalization, and decreased patient post-operative discomfort. LITT uses a stereotactically placed fiber optic laser probe to ablate tissue under real-time MR thermometry. METHODS: Retrospective chart review of intraoperative and perioperative characteristics was performed for 28 cases of MRgLITT in 25 pediatric patients, ages 4-21 years old, at our institution between 2019 and 2021. MRgLITT ablation of the mesial temporal lobe was performed in 8 cases, extratemporal epileptogenic foci in 9 cases, and for corpus callosotomy in 11 cases. RESULTS: At 1 year of follow-up, 53% of all patients experienced improvement in seizure frequency (Engel I or II) (class I: 38%, class II: 15%, class III: 17%, class IV: 31%), including 37% of MTL ablations and 80% extratemporal SOZ ablations. After MRgLITT corpus callosotomy, 71% of patients were free from atonic seizures at most recent follow-up. Median length of hospitalization was 2 days (1-3), including a median ICU stay of 1 day (1-2). CONCLUSION: This series demonstrates the safety of MRgLITT as an approach for seizure control in drug-resistant epilepsy. We provide additional evidence that MRgLITT is an effective procedure that is well-tolerated by pediatric patients and is accompanied by an acceptable rate of complications and relatively short hospital stay.


Assuntos
Epilepsia Resistente a Medicamentos , Terapia a Laser , Adolescente , Adulto , Criança , Pré-Escolar , Epilepsia Resistente a Medicamentos/cirurgia , Humanos , Imageamento Tridimensional , Terapia a Laser/efeitos adversos , Terapia a Laser/métodos , Estudos Retrospectivos , Convulsões/cirurgia , Adulto Jovem
6.
Intern Med J ; 51(9): 1479-1484, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33462991

RESUMO

BACKGROUND: The majority of patients living in remote communities of Central Australia must relocate to Alice Springs for their dialysis treatments. There is limited information available about the challenges and barriers that Aboriginal patients encounter in the process of returning back to their communities after renal transplantation. AIM: To determine the length of stay of patients in Alice Springs and challenges faced subsequent to renal transplantation, before they could safely return to their remote communities. METHODS: All transplant recipients from 2012 who are aged 18 years were analysed retrospectively. RESULTS: Thirty-six patients received renal transplantation from Central Australia. Of them, 25 were from very remote communities of whom 24 were Aboriginal. Average length of stay in Alice Springs post-transplantation prior to returning to community was 17.2 weeks (121 days). The most common challenge faced prior to returning to community was the need for monitoring and titration of immunosuppressive medication (100%) followed by infections (90%) and admissions to hospital (85%). The other common barrier was optimising glycaemic control (80%). Less common barriers included proficiency with self-monitoring of blood sugar levels (50%), social factors (40%), blood pressure control (25%), leukopenia (25%), safe housing (20%) and rejection episodes (15%). CONCLUSIONS: Multiple challenges are faced during post-transplantation period in Alice Springs that prolong the time before recipients from remote communities can return home. Some barriers such as titration of immunosuppression are inherent in the transplant journey. However, some factors might be modifiable prior to transplantation.


Assuntos
Transplante de Rim , Austrália/epidemiologia , Humanos , Havaiano Nativo ou Outro Ilhéu do Pacífico , Diálise Renal , Estudos Retrospectivos
7.
Sensors (Basel) ; 21(10)2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34067640

RESUMO

The success of a software application is related to users' willingness to keep using it. In this sense, evaluating User eXperience (UX) became an important part of the software development process. Researchers have been carrying out studies by employing various methods to evaluate the UX of software products. Some studies reported varied and even contradictory results when applying different UX evaluation methods, making it difficult for practitioners to identify which results to rely upon. However, these works did not evaluate the developers' perspectives and their impacts on the decision process. Moreover, such studies focused on one-shot evaluations, which cannot assess whether the methods provide the same big picture of the experience (i.e., deteriorating, improving, or stable). This paper presents a longitudinal study in which 68 students evaluated the UX of an online judge system by employing AttrakDiff, UEQ, and Sentence Completion methods at three moments along a semester. This study reveals contrasting results between the methods, which affected developers' decisions and interpretations. With this work, we intend to draw the HCI community's attention to the contrast between different UX evaluation methods and the impact of their outcomes in the software development process.

8.
Water Sci Technol ; 80(5): 961-969, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31746803

RESUMO

The efficiency of electrolysis (EC/Cl2) and photo-assisted electrolysis (EC/UV/Cl2) methods, in the presence of chloride, for the abatement of real dairy waste from a producer in the Triangulo Mineiro region of Brazil, was evaluated. A complete 23 factorial design was performed for the variables time, pH and current. After determining the ideal pH, a Central Compound Design (CCD) was performed, where the applied current (533.42 mA) and treatment time (60.45 minutes) were maximized. The effluent was subsequently submitted to prolonged EC/Cl2 and EC/UV/Cl2 treatment in order to evaluate the behaviour of specific environmental parameters over time. The EC/UV/Cl2 method was more efficient than simple EC/Cl2 treatment. The EC/UV/Cl2 method resulted in a reduction of all environmental parameters investigated to levels within legal standards for effluent discharge. A relatively low cost of treatment is obtained with Energy per Order (EEO) values of 0.89 and 1.22 kWh m-3 order-1 for the EC/UV/Cl2 and EC/Cl2 treatments, respectively. The electrochemical production of free chlorine species followed by subsequent photolysis and production of radical species can convert a simple electrochemical process into an advanced oxidation process (AOP).


Assuntos
Poluentes Químicos da Água , Purificação da Água , Brasil , Cloretos , Eletrólise , Oxirredução , Eliminação de Resíduos Líquidos , Águas Residuárias
9.
Neuroimage ; 178: 57-68, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29758339

RESUMO

A comprehensive map of the structural connectome in the human brain has been a coveted resource for understanding macroscopic brain networks. Here we report an expert-vetted, population-averaged atlas of the structural connectome derived from diffusion MRI data (N = 842). This was achieved by creating a high-resolution template of diffusion patterns averaged across individual subjects and using tractography to generate 550,000 trajectories of representative white matter fascicles annotated by 80 anatomical labels. The trajectories were subsequently clustered and labeled by a team of experienced neuroanatomists in order to conform to prior neuroanatomical knowledge. A multi-level network topology was then described using whole-brain connectograms, with subdivisions of the association pathways showing small-worldness in intra-hemisphere connections, projection pathways showing hub structures at thalamus, putamen, and brainstem, and commissural pathways showing bridges connecting cerebral hemispheres to provide global efficiency. This atlas of the structural connectome provides representative organization of human brain white matter, complementary to traditional histologically-derived and voxel-based white matter atlases, allowing for better modeling and simulation of brain connectivity for future connectome studies.


Assuntos
Atlas como Assunto , Conectoma/métodos , Imagem de Tensor de Difusão/métodos , Rede Nervosa/anatomia & histologia , Substância Branca/anatomia & histologia , Adulto , Feminino , Humanos , Masculino , Rede Nervosa/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto Jovem
10.
Mol Cell ; 38(1): 54-66, 2010 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-20385089

RESUMO

Upon gene activation, we found that RNA polymerase II transcription machinery assembles sequentially with the nucleotide excision repair (NER) factors at the promoter. This recruitment occurs in absence of exogenous genotoxic attack, is sensitive to transcription inhibitors, and depends on the XPC protein. The presence of these repair proteins at the promoter of activated genes is necessary in order to achieve optimal DNA demethylation and histone posttranslational modifications (H3K4/H3K9 methylation, H3K9/14 acetylation) and thus efficient RNA synthesis. Deficiencies in some NER factors impede the recruitment of others and affect nuclear receptor transactivation. Our data suggest that there is a functional difference between the presence of the NER factors at the promoters (which requires XPC) and the NER factors at the distal regions of the gene (which requires CSB). While the latter may be a repair function, the former is a function with respect to transcription unveiled in the current study.


Assuntos
Cromatina/metabolismo , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Mutagênicos/metabolismo , Regiões Promotoras Genéticas , Transcrição Gênica , Montagem e Desmontagem da Cromatina , Dano ao DNA , Metilação de DNA , Proteínas de Ligação a DNA/genética , Células HeLa , Histonas/metabolismo , Humanos , Modelos Moleculares , Xeroderma Pigmentoso/genética , Xeroderma Pigmentoso/metabolismo
11.
Nephrology (Carlton) ; 22(5): 403-411, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27062647

RESUMO

AIM: Acute postinfectious glomerulonephritis is common in indigenous communities in the Northern Territory, Australia. It is a major risk factor for the high prevalence of chronic kidney disease. We aimed to analyse the clinical presentation, pathological spectra, treatment and outcomes of biopsy-proven acute postinfectious glomerulonephritis in the Northern Territory. METHODS: We performed a retrospective cohort analysis of all adult patients (≥18 years) who were diagnosed with acute postinfectious glomerulonephritis on native renal biopsies from 01/01/2004 to 31/05/2014. The outcome measure was end-stage renal disease requiring long-term dialysis. RESULTS: Forty-three of 340 patients who had renal biopsies had acute postinfectious glomerulonephritis. Most were Aboriginals (88.4%). They had co-morbidities; diabetes mellitus (60.5%), hypertension (60.5%) and smoking (56.4%). Forty-nine per cent had multiple pathologies on biopsy. Predominant histological pattern was diffuse proliferative glomerulonephritis (72%). Main sites of infections were skin (47.6%) and upper respiratory tract infection (26.2%) with streptococcus and staphylococcus as predominant organisms. Fifty per cent of patients developed end-stage renal disease. On multivariable logistic regression analysis, those on dialysis had higher baseline creatinine (P = 0.003), higher albumin/creatinine ratio at presentation (P = 0.023), higher serum creatinine at presentation (P = 0.02) and lower estimated glomerular filtration rate at presentation (P = 0.012). CONCLUSION: Overall, most patients had pre-existing pathology with superimposed acute postinfectious glomerulonephritis that led to poor outcomes in our cohort.


Assuntos
Doenças Transmissíveis/etnologia , Glomerulonefrite/etnologia , Glomerulonefrite/patologia , Rim/patologia , Havaiano Nativo ou Outro Ilhéu do Pacífico , Doença Aguda , Adulto , Biópsia , Doenças Transmissíveis/diagnóstico , Comorbidade , Progressão da Doença , Feminino , Imunofluorescência , Glomerulonefrite/fisiopatologia , Glomerulonefrite/terapia , Humanos , Rim/fisiopatologia , Falência Renal Crônica/etnologia , Falência Renal Crônica/patologia , Falência Renal Crônica/terapia , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Northern Territory/epidemiologia , Diálise Renal , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
12.
BMC Nephrol ; 16: 181, 2015 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-26520140

RESUMO

BACKGROUND: This study will assess measures of vascular health and inflammation in Aboriginal Australian adults with chronic kidney disease (CKD), and determine if intensive periodontal intervention improves cardiovascular health, progression of renal disease and periodontal health over a 24-month follow-up. METHODS: The study will be a randomised controlled trial. All participants will receive the periodontal intervention benefits, with the delayed intervention group receiving periodontal treatment 24 months following baseline. Inclusion criteria include being an Aboriginal Australian, having CKD (a. on dialysis; b. eGFR levels of < 60 mls/min/1.73 m(2) (CKD Stages 3 to 5); c. ACR ≥ 30 mg/mmol irrespective of eGFR (CKD Stages 1 and 2); d. diabetes plus albuminuria (ACR ≥ 3 mg/mmol) irrespective of eGFR), having moderate or severe periodontal disease, having at least 12 teeth, and living in Central Australia for the 2-year study duration. The intervention involves intensive removal of dental plaque biofilms by scaling, root-planing and removal of teeth that cannot be saved. The intervention will occur in three visits; baseline, 3-month and 6-month follow-up. The primary outcome will be changes in carotid intima-media thickness (cIMT). Secondary outcomes will include progression of CKD or death as a consequence of CKD/cardiovascular disease. Progression of CKD will be defined by time to the development of the first of: (1) new development of macroalbuminuria; (2) 30 % loss of baseline eGFR; (3) progression to end stage kidney disease defined by eGFR < 15 mLs/min/1.73 m(2); (4) progression to end stage kidney disease defined by commencement of renal replacement therapy. A sample size of 472 is necessary to detect a difference in cIMT of 0.026 mm (SD 0.09) at the significance criterion of 0.05 and a power of 0.80. Allowing for 20 % attrition, 592 participants are necessary at baseline, rounded to 600 for convenience. DISCUSSION: This will be the first RCT evaluating the effect of periodontal therapy on progression of CKD and cardiovascular disease among Aboriginal patients with CKD. Demonstration of a significant attenuation of CKD progression and cardiovascular disease has the potential to inform clinicians of an important, new and widely available strategy for reducing CKD progression and cardiovascular disease for Australia's most disadvantaged population. TRIAL REGISTRATION: This trial is registered with the Australian New Zealand Clinical Trial Registry ANZCTR12614001183673.


Assuntos
Doenças Cardiovasculares/mortalidade , Havaiano Nativo ou Outro Ilhéu do Pacífico/etnologia , Havaiano Nativo ou Outro Ilhéu do Pacífico/estatística & dados numéricos , Doenças Periodontais/mortalidade , Doenças Periodontais/terapia , Insuficiência Renal Crônica/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Austrália/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Causalidade , Comorbidade , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prognóstico , Insuficiência Renal Crônica/prevenção & controle , Fatores de Risco , Taxa de Sobrevida , Resultado do Tratamento , Adulto Jovem
13.
Anal Bioanal Chem ; 406(24): 5989-95, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25023972

RESUMO

In this work, a new approach is proposed to verify the differentiating characteristics of five bacteria (Escherichia coli, Enterococcus faecalis, Streptococcus salivarius, Streptococcus oralis, and Staphylococcus aureus) by using digital images obtained with a simple webcam and variable selection by the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA). In this sense, color histograms in the red-green-blue (RGB), hue-saturation-value (HSV), and grayscale channels and their combinations were used as input data, and statistically evaluated by using different multivariate classifiers (Soft Independent Modeling by Class Analogy (SIMCA), Principal Component Analysis-Linear Discriminant Analysis (PCA-LDA), Partial Least Squares Discriminant Analysis (PLS-DA) and Successive Projections Algorithm-Linear Discriminant Analysis (SPA-LDA)). The bacteria strains were cultivated in a nutritive blood agar base layer for 24 h by following the Brazilian Pharmacopoeia, maintaining the status of cell growth and the nature of nutrient solutions under the same conditions. The best result in classification was obtained by using RGB and SPA-LDA, which reached 94 and 100 % of classification accuracy in the training and test sets, respectively. This result is extremely positive from the viewpoint of routine clinical analyses, because it avoids bacterial identification based on phenotypic identification of the causative organism using Gram staining, culture, and biochemical proofs. Therefore, the proposed method presents inherent advantages, promoting a simpler, faster, and low-cost alternative for bacterial identification.


Assuntos
Bactérias/química , Bactérias/classificação , Técnicas de Tipagem Bacteriana/métodos , Fotografação/métodos , Bactérias/isolamento & purificação , Técnicas de Tipagem Bacteriana/instrumentação , Análise Discriminante , Análise dos Mínimos Quadrados , Fotografação/instrumentação
14.
Food Res Int ; 170: 112830, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37316036

RESUMO

Cachaça is a Brazilian beverage obtained from the fermentation of sugarcane juice (sugarcane spirit) and is considered one of the most consumed alcoholic beverages in the world with a strong economic impact on the northeastern Brazil, more specifically in the Brejo. This microregion produces sugarcane spirits with high quality associated to edaphoclimatic conditions. In this sense, analysis for sample authentication and quality control that uses solvent-free, environmentally friendly, rapid and non-destructive methods is advantageous for cachaça producers and production chain. Thus, in this work commercial cachaça samples using near-infrared spectroscopy (NIRS) were classified based on geographical origin using one-class classification Data-Driven in Soft Independent Modelling of Class Analogy (DD-SIMCA) and One-Class Partial Least Squares (OCPLS) and predicted quality parameters of alcohol content and density based on different chemometric algorithms. A total of 150 sugarcane spirits samples were purchased from the Brazilian retail market being 100 from Brejo and 50 from other regions of Brazil. The one-class chemometric classification model was obtained with DD-SIMCA using the Savitzky-Golay derivative with first derivative, 9-point window and 1st degree polynomial as preprocessing algorithm and sensibility was 96.70 % and specificity 100 % in the spectral range 7,290-11,726 cm-1. Satisfactory results were obtained in the model constructs for density and the chemometric model, iSPA-PLS algorithm with baseline offset as preprocessing, obtained root mean square errors of prediction (RMSEP) of 0.0011 mg/L and Relative Error of Prediction (REP) of 0.12 %. The chemometric model for alcohol content prediction used the iSPA-PLS algorithm with Savitzky-Golay derivative with first derivative, 9-point window and 1st degree polynomial as algorithm as preprocessing obtaining RMSEP and REP of 0.69 and 1.81 % (v/v), respectively. Both models used the spectral range from 7,290-11,726 cm-1. The results reflected the potential of vibrational spectroscopy coupled with chemometrics to build reliable models for identifying the geographical origin of cachaça samples for predicting quality parameters in cachaça samples.


Assuntos
Saccharum , Espectroscopia de Luz Próxima ao Infravermelho , Quimiometria , Algoritmos , Grão Comestível
15.
Food Chem ; 421: 136164, 2023 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-37099954

RESUMO

Tea (Camellia sinensis) fraud has been frequently identified and involves tampering with the labelling of inferior products or without geographical origin certification and even mixing them with superior quality teas to mask an adulteration. Consequently, economic losses and health damage to consumers are observed. Thus, a Chemometrics-assisted Color Histogram-based Analytical System (CACHAS) was employed a simple, cost-effective, reliable, and green analytical tool to screen the quality of teas. Data-Driven Soft Independent Modeling of Class Analogy was used to authenticate their geographical origin and category simultaneously, recognizing correctly all Argentinean and Sri Lankan black teas and Argentinean green teas. For the determination of moisture, total polyphenols, and caffeine, Partial Least Squares obtained satisfactory predictive abilities, with values of root mean squared error of prediction (RMSEP) of 0.50, 0.788, and 0.25 mg kg-1, rpred of 0.81, 0.902, and 0.81, and relative error of prediction (REP) of 6.38, 9.031, and 14.58%., respectively. CACHAS proved to be a good alternative tool for environmentally-friendly non-destructive chemical analysis.


Assuntos
Camellia sinensis , Quimiometria , Chá , Cafeína/análise , Polifenóis/análise
16.
J Phys Chem A ; 116(34): 8768-74, 2012 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-22900477

RESUMO

The effect of (60)Co gamma rays irradiation on the polymetallayne [-Pt(PBu(3))-C≡C-C(6)H(4)-C(6)H(4)-C≡C-](n) (Pt-DEBP) of defined chain length corresponding to 10 repeat units, has been studied in detail. The UV-vis absorption spectra of Pt-DEBP have been recorded in solution upon exposure of the polymetallayne at increasing radiation doses in the range up to 90 Gy, with special care to the features related to low doses. Complex modifications of the chemical structure of Pt-DEBP could be accessed through NMR, FTIR, GPC, and XPS characterizations, which support the attack of Cl and H radicals coming from the radiolysis of the solvent, CHCl(3), to the triple C≡C bonds of the backbone, leading to the formation of chlorinated double and single C-C bonds, with a concomitant increase of the molecular weight due to a recombinant effect of oligomer fragments upon irradiation. The presence of vinyl and single chlorinated moieties has been sustained from the simulation of the UV-vis spectra based on theoretical calculations.


Assuntos
Alcinos/química , Raios gama , Compostos Organoplatínicos/química , Clorofórmio/química , Modelos Moleculares , Conformação Molecular
17.
Food Chem ; 370: 131072, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34537434

RESUMO

Food analysis covers aspects of quality and detection of possible frauds to ensure the integrity of the food. The arsenal of analytical instruments available for food analysis is broad and allows the generation of a large volume of information per sample. But this instrumental information may not yet give the desired answer; it must be processed to provide a final answer for decision making. The possibility of discarding non-informative and/or redundant signals can lead to models of better accuracy, robustness, and chemical interpretability, in line with the principle of parsimony. Thus, in this tutorial review, we cover aspects of variable selection in food analysis, including definitions, theoretical aspects of variable selection, and case studies showing the advantages of variable selection-based models concerning the use of a wide range of non-informative and redundant instrumental information in the analysis of food matrices.


Assuntos
Análise de Alimentos , Fraude
18.
Anal Chim Acta ; 1206: 339411, 2022 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-35473880

RESUMO

The monitoring of total suspended (TSS) and settleable (SetS) solids in wastewater is essential to maintain the quality parameters for aquatic biota because they can transport pollutants and block light penetration. Determining them by their respective reference methods, however, is laborious, expensive, and time consuming. To overcome this, we developed a new analytical instrument called Solids in Wastewater's Machine Vision-based Automatic Analyzer (SWAMVA), which is equiped with an automatic sampler and a software for real-time digital movie capture to quantify sequentially the TSS and SetS contents in wastewater samples. The machine vision algorithm (MVA) coupled with the Red color plane (derived from color histograms in the Red-Green-Blue (RGB) system) showed the best prediction results with R2 of 0.988 and 0.964, and relative error of prediction (REP) of 6.133 and 9.115% for TSS and SetS, respectively. The constructed models were validated by Analysis of Variance (ANOVA), and the accuracy and precision of the predictions by the t- and F-tests, respectively, at a 0.05 significance level. The elliptical joint confidence region (EJCR) test confirmed the accuracy, while the coefficient of variation (CV) of 6.529 and 10.908% confirmed the good precisions, respectively. Compared with the reference method (Standard Methods For the Examination of Water and Wastewater), the proposed method reduced the analysis volume from 1.5 L to just 15 mL and the analysis time from 12 h to 24 s per sample. Therefore, SWAMVA can be considered an important alternative to the determination of TSS and SetS in wastewater as an automatic, fast, and low-cost analytical tool, following the principles of Green Chemistry and exploiting Industry 4.0 features such as intelligent processing, miniaturization, and machine vision.


Assuntos
Águas Residuárias
19.
Food Chem ; 368: 130843, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34418692

RESUMO

This works proposed a feasibility study on NIR spectroscopy and chemometrics-assisted color histogram-based analytical systems (CACHAS) to determine and authenticate the cassava starch content in wheat flour. Prediction results of partial least squares (PLS) achieved coefficient of correlation (rpred) of 0.977 and root mean square error of prediction (RMSEP) of 1.826 mg kg-1 for the certified additive-free wheat flour, while rpred of 0.995 and RMSEP of 1.004 mg kg-1 were obtained for the commercial wheat flour containing chemical additives. Additionally, Data-Driven Soft Independent Modelling of Class Analogy (dd-SIMCA) presented similar predictive ability using NIR and CACHAS for the certified wheat flour, authenticating all target samples, besides correctly recognizing samples that could represent a fraud. No satisfactory results were obtained for the commercial wheat flour. Therefore, NIR spectroscopy is more useful to offer definitive quantitative and qualitative analysis, while CACHAS can only provide an alternative preliminary analysis.


Assuntos
Farinha , Manihot , Pão , Estudos de Viabilidade , Farinha/análise , Análise dos Mínimos Quadrados , Espectroscopia de Luz Próxima ao Infravermelho , Amido , Triticum
20.
Food Chem ; 365: 130467, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34243118

RESUMO

This work proposes the use of UV-Vis spectroscopy and one-class classifiers to authenticate honey in terms of their individual and simultaneous adulterations with corn syrup, agave syrup, and sugarcane molasses. Then, spectra of aqueous authentic (n = 73) and adulterated (n = 162) honey samples were recorded. Before the construction of OC-PLS and DD-SIMCA models, different pre-processing techniques were used to removed baseline shifts. The best result obtained by DD-SIMCA using offset correction, correctly classifying all the samples in the test set. Therefore, the proposed methodology can be used as a promising tool to authenticate honey and prevent fraudulent labeling, affording security to consumers and providing an alternative to regulatory agencies. Moreover, it avoids laborious sample preparation and additional operational costs, since the analytical information is acquired using a routine instrumental technique, without the need for any sample preparation step, other than dilution of the samples in water alone.


Assuntos
Mel , Carboidratos , Contaminação de Alimentos/análise , Mel/análise , Análise Espectral , Açúcares
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