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1.
Aten Primaria ; 56(12): 103006, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38889596

RESUMO

OBJECTIVE: To analyze the impact of COVID-19 lockdown on serum glucose levels of pregnant women. DESIGN: A retrospective analysis of O'Sullivan test in pregnant women who underwent COVID-19 lockdown compared to controls. SITE: Poniente Primary Health Care center in Córdoba (Spain). PARTICIPANTS: 235 pregnant women from 23+0 to 25+0 weeks of gestation without diabetes mellitus. INTERVENTIONS: Gestational diabetes mellitus screening with O'Sullivan test and 3-h oral glucose tolerance test. MAIN MEASUREMENTS: Pregnant women who underwent gestational diabetes mellitus screening with O'Sullivan test before (control group) and during COVID-19 Lockdown (Lockdown group) in Córdoba (Spain) were investigated. Lockdown group was divided in early and late lockdown. An additional, control group from data of the same months of the Lockdown in the previous year were recorded to discarded seasonally (adjusted seasonally control) this group was also divided in early and late seasonally adjusted. A logistic regression model for O'Sullivan test has been performed to analyze potential cofounders. Kolgomorov-Smirnov and Kruskal-Wallis test comparing pregnant women who underwent COVID-19 lockdown with the two types of controls. RESULTS: Statistically significant differences were found in serum glucose after O'Sullivan test between lockdown group and control group (123.51±26.02mg/dL and 112.86±31.28mg/dL; p=0.017). When early lockdown group and control group were compared no differences were found (119.64±26.18mg/dL vs. 112.86±31.28mg/dL; p>0.05) whereas differences were observed in late lockdown group and control group (127.22±25.59mg/dL vs. 112.86±31.28mg/dL; p=0.009). Statistical trends were also found between lockdown group and seasonally adjusted group and between lockdown and late seasonally adjusted group (p=0.089). A higher proportion of positive O'Suvillan pregnant women who were subsequently diagnosed with GDM were found in lockdown group compared to the seasonally adjusted control group (60% vs. 26.06% respectively; p<0.05). CONCLUSIONS: The COVID-19 lockdown was associated with an increase in serum glucose levels after the O'Sullivan test as well as a higher GDM diagnosis risk in pregnant women. The findings of our study emphasize the essential requirement for comprehensive maternal services and the accessibility to community's health assets during future lockdown scenarios to pregnant women.

3.
Artigo em Inglês | MEDLINE | ID: mdl-38881234

RESUMO

OBJECTIVE: To analyze the success rate of external cephalic version (ECV) in pregnant women with a history of previous cesarean section, as well as to describe the rate of complications associated with the procedure. METHODS: A retrospective cohort study of women who were offered an ECV at "Virgen de la Arrixaca" Clinic University Hospital (Murcia, Spain) between January 2014 and December 2023. We collected data for previous cesarean delivery, obstetric history, fetal presentation, amniotic fluid volume, ECV success rate, complications related to ECV, mode of delivery, and neonatal outcomes. The study confidently performed ECV under sedation with propofol and tocolysis with ritodrine. Univariate and multivariate analyses were conducted to compare the success rate of ECV, ECV complications, and mode of delivery between women with and without previous cesarean sections. RESULTS: Of 1116 pregnant women who were offered ECV, 911 were included in the study, with 42 having a previous cesarean section. The success rate of ECV in pregnant women with a previous cesarean section was 78.6% (adjusted odds ratio 1.18; 95% confidence interval 0.49-2.86; P = 0.708), with a low complication rate of 9.5%, such as non-reassuring fetal heart rate (7.1%) or major vaginal bleeding (2.4%). Of the women who attempted a vaginal delivery after ECV, 80.8% were successful. CONCLUSIONS: These findings support that ECV is a safe and effective option for women with a previous cesarean section, with success rates comparable to those in women without a previous cesarean section.

4.
Pflugers Arch ; 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38822875

RESUMO

Spontaneous activity refers to the firing of action potentials by neurons in the absence of external stimulation. Initially considered an artifact or "noise" in the nervous system, it is now recognized as a potential feature of neural function. Spontaneous activity has been observed in various brain areas, in experimental preparations from different animal species, and in live animals and humans using non-invasive imaging techniques. In this review, we specifically focus on the spontaneous activity of dorsal horn neurons of the spinal cord. We use a historical perspective to set the basis for a novel classification of the different patterns of spontaneous activity exhibited by dorsal horn neurons. Then we examine the origins of this activity and propose a model circuit to explain how the activity is generated and transmitted to the dorsal horn. Finally, we discuss possible roles of this activity during development and during signal processing under physiological conditions and pain states. By analyzing recent studies on the spontaneous activity of dorsal horn neurons, we aim to shed light on its significance in sensory processing. Understanding the different patterns of activity, the origins of this activity, and the potential roles it may play, will contribute to our knowledge of sensory mechanisms, including pain, to facilitate the modeling of spinal circuits and hopefully to explore novel strategies for pain treatment.

7.
Blood ; 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38776489

RESUMO

Delays and risks associated with neurosurgical biopsies preclude timely diagnosis and treatment of central nervous system (CNS) lymphoma and other CNS neoplasms. We prospectively integrated targeted rapid genotyping of cerebrospinal fluid (CSF) into the evaluation of 70 patients with CNS lesions of unknown etiology. Participants underwent genotyping of CSF-derived DNA using a qPCR-based approach for parallel detection of single-nucleotide variants in the MYD88, TERT promoter, IDH1, IDH2, BRAF and H3F3A genes within 80 minutes of sample acquisition. Canonical mutations were detected in 42% of patients with neoplasms, including cases of primary and secondary CNS lymphoma, glioblastoma, IDH-mutant brainstem glioma and H3K27M-mutant diffuse midline glioma. Genotyping results eliminated the need for surgical biopsies in 7/33 (21.2%) cases of newly diagnosed neoplasms, resulting in significantly accelerated initiation of disease-directed treatment (median 3 vs 12 days; p = 0.027). This assay was then implemented in a Clinical Laboratory Improvement Amendments (CLIA) environment, with 2-day median turnaround for diagnosis of central nervous system lymphoma from 66 patients across 4 clinical sites. Our study prospectively demonstrates that targeted rapid CSF genotyping influences oncologic management for suspected CNS tumors.

8.
Ann Vasc Surg ; 106: 377-385, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38821470

RESUMO

BACKGROUND: Series detailing complications after carotid endarterectomy (CEA) and transfemoral carotid stenting (tfCAS) for patients presenting with neurologic symptoms that are treated with systemic thrombolysis (ST) are sparse. We sought to determine if treatment with ST was associated with a higher rate of post-carotid intervention complications. METHODS: A multispecialty, institutional, prospectively maintained database was queried for symptomatic patients treated with CEA or tfCAS from 2007 to 2019. The primary outcomes of interest were bleeding complications (access/wound complications, hematuria, intracranial hemorrhage) or need for reintervention, stroke, and death. We compared rates of these outcomes between patients who were and were not treated with ST. To adjust for preoperative patient factors and confounding variables, propensity scores for assignment to ST and non-ST were calculated. RESULTS: There were 1,139 patients included (949 [82%] CEA and 190 [17%] tfCAS. All treated lesions were symptomatic (550 [48%] stroke, 603 [52%] transient ischemic attack). Fifty-six patients (5%) were treated with ST. Fifteen of 56 patients also underwent catheter-based intervention for stroke. ST was administered 0 to 1 day preoperatively in 21 (38%) patients, 2 to 6 days preoperatively in 27 (48%) patients, and greater than 6 days preoperatively in 8 (14%) patients. ST patients were more likely to present with stroke (93% vs. 45%; P < 0.001) and have higher preoperative Rankin scores. Unadjusted rate of bleeding/return to operating room was 3% for ST group and 3% for non-ST group (P = 0.60). Unadjusted rate of stroke was 4% for ST group and 3% for the non-ST group (P = 0.91), while perioperative mortality was 5% for ST group and 1% for non-ST group (P = 0.009). After adjusting for patient factors, preoperative antiplatelet/anticoagulation, and operative factors, ST was not associated with an increased odds of perioperative bleeding/return to the operating room (odds ratio 0.37; 95% confidence interval: 0.02-1.63; P = 0.309) or stroke (odds ratio 0.62; 95% confidence interval: 0.16-2.40; P = 0.493). CONCLUSIONS: ST does not convey a higher risk of complications after CEA or tfCAS. After controlling for other factors, patients that received ST had similar rates of local complications and stroke when compared to non-ST patients. Early carotid intervention is safe in patients that have received ST, and delays should be avoided in symptomatic patients given the high risk of recurrent stroke.

10.
Mar Environ Res ; 197: 106464, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38583356

RESUMO

Seagrass meadows are biodiversity hotspots for invertebrate species including decapods. Understanding the drivers of species abundance, richness and diversity of decapod assemblages is crucial for the conservation of such hotspots, but how drivers act across multiple spatial scales remains unexplored. Here we describe the decapod assemblages of Posidonia oceanica seagrass meadows and assess the influence of attributes from three increasing spatial scales (habitat, landscape, and geographical levels) on the assemblages' structure and composition, as well as the variability partitioning among each one of these levels. Overall, geographical level attributes (i.e., inlet aperture, confinement) affected the most the decapod assemblages, while we only found a modest contribution from habitat (e.g., detritus biomass, sediment organic matter) and landscape attributes (e.g., fragmentation). We suggest that decapod assemblages are driven by the interaction of multiple processes occurring at different scales and other highly stochastic phenomena such as larval dispersion and recruitment.


Assuntos
Alismatales , Decápodes , Animais , Ecossistema , Biodiversidade , Biomassa
11.
Artigo em Inglês | MEDLINE | ID: mdl-38571333

RESUMO

BACKGROUND: Post-publication handling of integrity concerns in randomized clinical trials (RCTs) is a contentious matter. OBJECTIVES: We undertook a scoping systematic review to map the literature regarding post-publication integrity issues in RCTs. SEARCH STRATEGY AND SELECTION CRITERIA: Following prospective registration (https://osf.io/pgxd8) we initially searched PubMed and Scopus but subsequently extended it to include the Cochrane Library, and Google Scholar databases without language, article type or publication time restriction until November 2022. Reviewers independently selected published articles covering any aspect of post-publication research integrity concerns in RCTs. DATA COLLECTION AND ANALYSIS: The study findings grouped within domains relating to issues concerning post-publication integrity were extracted in duplicate, verified by a third reviewer, and then tabulated. MAIN RESULTS: The initial search captured 3159 citations, of which 89 studies were included in the review. Cross-sectional studies constituted the majority of included studies (n = 34, 38.2%), followed by systematic reviews (n = 10, 11.2%), methodology reviews/studies (n = 9, 10.1%) and other types of descriptive studies (n = 8, 9.0%). A total of 21 articles (23.6%) covered the domain on general issues, 25 (28.1%) in the journal's instructions and policies domain, eight (9.0%) in the editorial and peer review domain, one (1.1%) in the correspondence and complaints (post-publication peer review) domain, 12 (13.5%) in the investigation for concerns domain, six (6.7%) in the post-investigation decisions and sanctions domain, none in the critical appraisal guidance domain, five (5.6%) in the integrity assessment in systematic reviews domain, and 26 (29.2%) in the recommendations for future research domain. A total of 12 of the selected articles (13.5%) covered two (n = 9) or three (n = 3) different domains. CONCLUSIONS: Various research integrity domains and issues covering post-publication aspects of RCT integrity were captured and gaps were identified, mostly related with the necessary implications for all stakeholders to improve research transparency. There is an urgent need for a multistakeholder consensus towards creating specific statements for addressing post-publication integrity concerns in RCTs.

12.
J Clin Med ; 13(7)2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38610889

RESUMO

Background: In pregnant women, COVID-19 can alter the metabolic environment, cell metabolism, and oxygen supply of trophoblastic cells and, therefore, have a negative influence on essential mechanisms of fetal development. The purpose of this study was to investigate, for the first time, the effects of COVID-19 infection during pregnancy with regard to the bone turnover and endocrine function of several metabolic biomarkers in colostrum and placenta. Methods: One hundred and twenty-four pregnant mothers were recruited from three hospitals between June 2020 and August 2021 and assigned to two groups: Control group and COVID-19 group. Metabolism biomarkers were addressed in placental tissue and colostrum. Results: Lipocalin-2 and resistin levels were higher in the placenta, revealing an underlying pro-inflammatory status in the gestation period for mothers suffering from COVID-19; a decrease in GLP-1 and leptin was also observed in this group. As for adiponectin, resistin, and insulin, their concentrations showed an increase; a decrease in GLP-1, leptin, and PYY was also reported in the colostrum of mothers suffering from COVID-19 compared with the control group. Conclusions: As for bone turnover, placental samples from mothers with COVID-19 showed lower levels of OPG, while DKK-1 increased compared with the control group. Colostrum samples showed higher levels of OPG, SOST, and PTH in the COVID-19 group, a fact that could have noteworthy implications for energy metabolism, fetal skeletal development, and postnatal bone density and mineralization. Further research is needed to explain the pathogenic mechanism of COVID-19 that may affect pregnancy, so as to assess the short-term and long-term outcomes in infants' health.

13.
Cancers (Basel) ; 16(8)2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38672604

RESUMO

BACKGROUND: We have conducted cooperative campaigns focusing on albino patients in a rural area of Malawi. What have we learned? METHODS: Three surgical campaigns were performed in Nkhotakota district (2019-2023). Albino clinical and tumor characteristics were collected. RESULTS: Between 22 and 75 albinos were evaluated in each campaign (mean age < 28 years old). Most patients did not use sunscreen in a way that provided optimal photoprotection. Regarding tumors, the proportion of basal and squamous cell carcinomas ranged from 1:1 to almost 2:1. Of 156 albino patients, 34 attended more than once. However, of the 19 patients with 30 tumors operated on in 2021, only seven were assessed the following year (12 were lost to follow-up). At least 14 albinos with locally advanced tumors were evaluated. CONCLUSIONS: Distributing photoprotective clothing could be more efficient or perhaps an earlier measure of sunscreen in rural Africa as it does not require permanent repositioning. Very-high-risk patients (previous interventions with positive margins or high-risk tumors, intense actinic damage, and new tumors constantly appearing, especially those presenting SCCs) require close follow-up and treatment and represent our main target. Secondary prevention with Malawian collaboration and the use of teledermatology is essential for patient tracking, as they are able to offer curative treatments.

14.
Nefrologia (Engl Ed) ; 44(2): 256-267, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38555207

RESUMO

RATIONALE AND OBJECTIVES: Increased central (aortic) arterial stiffness has hemodynamic repercussions that affect the incidence of cardiovascular and renal disease. In chronic kidney disease (CKD) there may be an increase in aortic stiffness secondary to multiple metabolic alterations including calcification of the vascular wall (VC). The objective of this study was to analyze the association of central aortic pressures and aortic stiffness with the presence of VC in abdominal aorta (AAC) and coronary arteries(CAC). MATERIALS AND METHODS: We included 87 pacientes with CKD stage 3 and 4. Using applanation tonometry, central aortic pressures and aortic stiffness were studied. We investigated the association of aortic pulse wave velocity (Pvc-f) and Pvc-f adjusted for age, blood pressure, sex and heart rate (Pvc-f index) with AAC obtained on lumbar lateral radiography and CAC assessed by multidetector computed tomography. AAC and CAC were scored according to Kauppila and Agatston methods, respecti-vely. For the study of the association between Pvc-f index, Kauppila score, Agatston score, central aortic pressures, clinical parameters and laboratory data, multiple and logistic regression were used. We investigated the diagnosis performance of the Pvc-f index for prediction of VC using receiver-operating characteristic (ROC). RESULTS: Pvc-f and Pvc-f index were 11.3 ± 2.6 and 10.6 m/s, respectively. The Pvc-f index was higher when CKD coexisted with diabetes mellitus (DM). AAC and CAC were detected in 77% and 87%, respectively. Albuminuria (ß = 0.13, p = 0.005) and Kauppila score (ß = 0.36, p = 0.001) were independently associated with Pvc-f index. In turn, Pvc-f index (ß = 0.39, p = 0.001), DM (ß = 0.46, p = 0.01), and smoking (ß = 0.53; p = 0.006) were associated with Kauppila score, but only Pvc-f index predicted AAC [OR: 3.33 (95% CI: 1.6-6.9; p = 0.001)]. The Kauppila score was independently associated with the Agatston score (ß = 1.53, p = 0.001). The presence of AAC identified patients with CAC with a sensitivity of 73%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 38%. The Vpc-f index predicted the presence of CAC [OR: 3.35 (95% CI: 1.04-10.2, p = 0.04)]. In the ROC curves, using the Vpc-f index, the AUC for AAC and CAC was 0.82 (95%CI: 0.71-0.93, p = 0.001) and 0.81 (95% CI: 0.67-0.96, p = 0.02), respectively. CONCLUSIONS: When stage 3-4 CKD coexists with DM there is an increase in aortic stiffness determined by the Vpc-f index. In stage 3-4 CKD, AAC and CAC are very prevalent and both often coexist. The Vpc-f index is independently associated with AAC and CAC and may be useful in identifying patients with VC in these territories.


Assuntos
Aorta Abdominal , Insuficiência Renal Crônica , Calcificação Vascular , Rigidez Vascular , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/fisiopatologia , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/fisiopatologia , Calcificação Vascular/etiologia , Aorta Abdominal/diagnóstico por imagem , Aorta Abdominal/fisiopatologia , Idoso , Índice de Gravidade de Doença , Estudos Transversais , Análise de Onda de Pulso , Doença da Artéria Coronariana/fisiopatologia , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/complicações , Doenças da Aorta/diagnóstico por imagem , Doenças da Aorta/fisiopatologia , Doenças da Aorta/complicações , Doenças da Aorta/etiologia
15.
Glia ; 72(6): 1096-1116, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38482984

RESUMO

The medial prefrontal cortex (mPFC) is involved in cognitive functions such as working memory. Astrocytic cannabinoid type 1 receptor (CB1R) induces cytosolic calcium (Ca2+) concentration changes with an impact on neuronal function. mPFC astrocytes also express adenosine A1 and A2A receptors (A1R, A2AR), being unknown the crosstalk between CB1R and adenosine receptors in these cells. We show here that a further level of regulation of astrocyte Ca2+ signaling occurs through CB1R-A2AR or CB1R-A1R heteromers that ultimately impact mPFC synaptic plasticity. CB1R-mediated Ca2+ transients increased and decreased when A1R and A2AR were activated, respectively, unveiling adenosine receptors as modulators of astrocytic CB1R. CB1R activation leads to an enhancement of long-term potentiation (LTP) in the mPFC, under the control of A1R but not of A2AR. Notably, in IP3R2KO mice, that do not show astrocytic Ca2+ level elevations, CB1R activation decreases LTP, which is not modified by A1R or A2AR. The present work suggests that CB1R has a homeostatic role on mPFC LTP, under the control of A1R, probably due to physical crosstalk between these receptors in astrocytes that ultimately alters CB1R Ca2+ signaling.


Assuntos
Astrócitos , Canabinoides , Camundongos , Animais , Receptores de Canabinoides , Receptor A2A de Adenosina , Plasticidade Neuronal , Receptor CB1 de Canabinoide/genética
16.
Plant Physiol Biochem ; 209: 108520, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38522131

RESUMO

In Arabidopsis, the plastidial isoform of phosphoglucose isomerase, PGI1, mediates growth and photosynthesis, likely due to its involvement in the vascular production of cytokinins (CK). To examine this hypothesis, we characterized pgi1-2 knockout plants impaired in PGI1 and pgi1-2 plants specifically expressing PGI1 in root tips and vascular tissues. Moreover, to investigate whether the phenotype of pgi1-2 plants is due to impairments in the plastidial oxidative pentose phosphate pathway (OPPP) or the glycolytic pathway, we characterized pgl3-1 plants with reduced OPPP and pfk4pfk5 knockout plants impaired in plastidial glycolysis. Compared with wild-type (WT) leaves, pgi1-2 leaves exhibited weaker expression of photosynthesis- and 2-C-methyl-D-erythritol 4-P (MEP) pathway-related proteins, and stronger expression of oxidative stress protection-related enzymes. Consistently, pgi1-2 leaves accumulated lower levels of chlorophyll, and higher levels of tocopherols, flavonols and anthocyanins than the WT. Vascular- and root tip-specific PGI1 expression countered the reduced photosynthesis, low MEP pathway-derived CK content, dwarf phenotype and the metabolic characteristics of pgi1-2 plants, reverting them to WT-like levels. Moreover, pgl3-1, but not pfk4pfk5 plants phenocopied pgi1-2. Histochemical analyses of plants expressing GUS under the control of promoter regions of genes encoding plastidial OPPP enzymes exhibited strong GUS activity in root tips and vascular tissues. Overall, our findings show that root tip and vascular PGI1-mediated plastidial OPPP activity affects photosynthesis and growth through mechanisms involving long-distance modulation of the leaf proteome by MEP pathway-derived CKs.


Assuntos
Arabidopsis , Via de Pentose Fosfato , Antocianinas/metabolismo , Fotossíntese , Arabidopsis/metabolismo , Citocininas/metabolismo
17.
J Magn Reson ; 360: 107632, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38382405

RESUMO

Serial NMR experiments are commonly applied in variable-temperature studies, reaction monitoring, and other tasks. The resonance frequencies often shift linearly over the series, and the shift rates help to characterize the studied system. They can be determined using a classical fitting of peak positions or a more advanced method of Radon transform. However, the optimal procedure for data collection remains to be determined. In this paper, we discuss how to invest experimental time, i.e., whether to measure more scans at the expense of the number of spectra or vice versa. The results indicate that classical fitting provides slightly less error than the Radon transform, although the latter can be the method of choice for a low signal-to-noise ratio. We demonstrate this fact through theoretical consideration, simulations, and an experiment. Finally, we extend our considerations to the linear fitting of peak amplitudes. Interestingly, the optimal setup for measuring peak height changes differs from the one for resonance frequency changes - fewer spectra with more scans provide better results.

18.
Neuroinformatics ; 22(2): 163-175, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38424371

RESUMO

Performing group analysis on magnetic resonance imaging (MRI) data with linear mixed-effects (LME) models is challenging due to its large dimensionality and inherent multi-level covariance structure. In addition, as large-scale collaborative projects become commonplace in neuroimaging, data must increasingly be stored and analyzed from different locations. In such settings, substantial overhead can occur in terms of data transfer and coordination between participating research groups. In some cases, data cannot be pooled together due to privacy or regulatory concerns. In this work, we propose a decentralized LME model to perform a large-scale analysis of data from different collaborations without data pooling. This method is efficient as it overcomes the hurdles of data sharing and has lower bandwidth and memory requirements for analysis than the centralized modeling approach. We evaluate our model using features extracted from structural magnetic resonance imaging (sMRI) data. Results highlight gray matter reductions in the temporal lobe/insula and medial frontal regions in schizophrenia, consistent with prior studies. Our analysis also demonstrates that decentralized LME models achieve similar performance compared to the models trained with all the data in one location. We also implement the decentralized LME approach in COINSTAC, an open source, decentralized platform for federating neuroimaging analysis, providing an easy to use tool for dissemination to the neuroimaging community.


Assuntos
Neuroimagem , Esquizofrenia , Humanos , Neuroimagem/métodos , Imageamento por Ressonância Magnética/métodos , Substância Cinzenta , Modelos Lineares
19.
Analyst ; 149(7): 1998-2003, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38421293

RESUMO

NMR spectroscopy is one of the most potent methods in analytical chemistry. NMR titration experiments are particularly useful since they measure molecular binding affinities and other concentration-dependent effects. These experiments, however, require a long series of measurements. An alternative to these serial measurements has recently been presented, exploiting a pH (or generally - a concentration) gradient along the NMR tube. The proposed experiment, although efficient, was based on the sensitivity- and hardware-demanding chemical shift imaging (CSI) method. Thus, it is practically limited to high-resolution NMR spectrometers. This paper proposes modifying and adapting the approach to the popular and cost-efficient benchtop NMR machines. Instead of CSI, we use a device that shifts the NMR tube vertically to measure the spectra of different sample volumes, which have different pH values due to the established gradient along the tube. We demonstrate the potential of the method on the test samples of L-tyrosine and 2,6-lutidine, and two real samples from the food industry - an infant formula and an energy drink. The proposed method boosts spectral resolution and allows for the sampling of a broader range of pH values when compared to the original approach.

20.
Meat Sci ; 212: 109463, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38401357

RESUMO

Pork belly brining is a time-consuming step of bacon production that needs to be studied and enhanced through suitable technologies. In this sense, this study aimed at evaluating the impact of ultrasound (US), mechanical agitation (AG), and static brine (SB) on the kinetics of water loss (WL), solids gain (SG), and salt content (SC) of pork belly during brining under different temperatures. Mathematical models were used to estimate mass transfer rates, equilibrium parameters, and thermodynamic properties. Peleg model was chosen as the most suitable model to predict the kinetics experimental data (Radj2 ≥ 0.979 and RMSE ≤ 0.014). The increase in the brine temperature increased WL, SG, and SC for all treatments. Nonlinear effects of temperature were observed for WL, SG, and SC, following an Arrhenius-type behavior. The assistance of ultrasound significantly enhanced the velocity of WL, SG, and SC by 32-56%, while AG improved by 18-39% both compared to SB. Brining was considered an endothermic and non-spontaneous process through the thermodynamic assessment. The increase in temperature and the AG and US processes accelerated the formation of the activated complex. The application of ultrasound was considered the most suitable technology to reduce the brining time. However, significant improvements can be obtained by mechanical agitation. Therefore, both methods can be used to reduce the time processing of pork belly aiming at accelerating the bacon production process.


Assuntos
Carne de Porco , Carne Vermelha , Animais , Carne Vermelha/análise , Sais , Cloreto de Sódio , Cloreto de Sódio na Dieta , Suínos
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