Development of an Apple Snack Enriched with Probiotic Lacticaseibacillus rhamnosus: Evaluation of the Refractance Window Drying Process on Cell Viability.

The objective of this study was to develop a dried apple snack enriched with probiotics, evaluate its viability using Refractance Window (RWTM) drying, and compare it with conventional hot air drying (CD) and freeze-drying (FD). Apple slices were impregnated with Lacticaseibacillus rhamnosus and dried at 45 °C using RWTM and CD and FD. Total polyphenol content (TPC), color (∆E*), texture, and viable cell count were measured, and samples were stored for 28 days at 4 °C. Vacuum impregnation allowed for a probiotic inoculation of 8.53 log CFU/gdb. Retention values of 6.30, 6.67, and 7.20 log CFU/gdb were observed for CD, RWTM, and FD, respectively; the population in CD, RWTM remained while FD showed a decrease of one order of magnitude during storage. Comparing RWTM with FD, ∆E* was not significantly different (p < 0.05) and RWTM presented lower hardness values and higher crispness than FD, but the RWTM-dried apple slices had the highest TPC retention (41.3%). Microstructural analysis showed that RWTM produced a smoother surface, facilitating uniform moisture diffusion and lower mass transfer resistance. The effective moisture diffusion coefficient was higher in RWTM than in CD, resulting in shorter drying times. As a consequence, RWTM produced dried apple snacks enriched with probiotics, with color and TPC retention comparable to FD.

Discovery and Characterization of Two Folded Intermediates for Outer Membrane Protein TolC Biogenesis.

TolC is the outer membrane protein responsible for antibiotic efflux in E. coli. Compared to other outer membrane proteins it has an unusual fold and has been shown to fold independently of commonly used periplasmic chaperones, SurA and Skp. Here we find that the assembly of TolC involves the formation of two folded intermediates using circular dichroism, gel electrophoresis, site-specific disulfide bond formation and radioactive labeling. First the TolC monomer folds, and then TolC assembles into a trimer both in detergent-free buffer and in the presence of detergent micelles. We find that a TolC trimer also forms in the periplasm and is present in the periplasm before it inserts in the outer membrane. The monomeric and trimeric folding intermediates may be used in the future to develop a new approach to antibiotic efflux pump inhibition by targeting the assembly pathway of TolC.

Effect of CO2 Laser Microperforation Pretreatment on the Dehydration of Apple Slices during Refractive Window Drying.

This research studied the use of CO2 LASER microperforation as a pretreatment for the refractive window (RW) drying of apple slices with respect to total polyphenol content (TPC), antioxidant capacity, color ΔE, and product stability under accelerated storage. For this purpose, the processing variables assessed were pore size (200-600 µm), pore density (9-25 pores/cm2), and drying temperature (70-90 °C). As baseline criteria, a comparison with respect to the control without microperforations and samples subjected to conventional tunnel and lyophilization were also considered. The increase in the pore size from 200 to 600 µm resulted in shorter drying times (≤40 min), minimal change in color (ΔE) and loss of TPC, while DPPH was negatively affected by the combined effect of the pore density and the drying temperature. In general, the use of RW with CO2 resulted in apples of higher quality than those obtained in conventional drying and comparable to those obtained through the use of freeze-drying. Finally, during accelerated storage, quality attributes decreased significantly for samples dried at 90 °C regardless of whether microperforations were used, suggesting that a compromise between drying temperature and pore size must be weighed to reduce processing time and to avoid further quality losses during storage.

Ultrasound-assisted enzymatic synthesis of galacto-oligosaccharides using native whey with two commercial ß-galactosidases: Aspergillus oryzae and Kluyveromyces var lactis.

Native whey obtained during casein micelle microfiltration was used as a novel source to produce galacto-oligosaccharides (GOS). Since the presence of macromolecules and other interferers reduces biocatalyst performance, this work evaluated the effect of different ultrasound processing conditions on GOS synthesis using concentrated native whey. Ultrasonic intensities (UI) below 11 W/cm2 tended to increase the activity in the enzyme from Aspergillus oryzae for several minutes but accelerated the inactivation in that from Kluyveromyces lactis. At 40 °C, 40 % w/w native whey, 70 % wave amplitude, and 0.6 s/s duty-cycle, a UI of 30 W/cm2 was achieved, and the increased specific enzyme productivity was similar to the values obtained with pure lactose (∼0.136 g GOS/h/mgE). This strategy allows for obtaining a product containing prebiotics with the healthy and functional properties of whey proteins, avoiding the required purification steps used in the production of food-grade lactose.

Xylan extraction from hardwoods by alkaline pretreatment for xylooligosaccharide production: A detailed fractionation analysis.

In the last decades, the production of value-added products from lignocellulosic biomass (LCB) has gained relevance. Xylans, which are the main hemicellulose compounds in LCB, may be extracted by alkaline pretreatment and employed for xylooligosaccharide (XOS) production. However, xylan extraction currently works as a black box due to the lack of characterization of the involved streams. Therefore, the appropriate operational conditions often remain unclear, especially in hardwoods. In this study, alkaline/thermal pretreatments at different operational conditions were evaluated for xylan extractions from Chilean Nothofagus species sawdust, determining the chemical compositions of the fractions at each step of the process. Results indicated that increasing alkali concentration (NaOH) leads to a higher xylan extraction, but also to high salt production during the acid neutralization step, decreasing xylan's purity and therefore XOS production. In this context, decreasing NaOH concentration and neutralizing it by membrane filtration, allow extracting xylans (62.5 %) of higher-purity (77 %).

Development of solid-state fermentation process of spent coffee grounds for the differentiated obtaining of chlorogenic, quinic, and caffeic acids.

BACKGROUND: Spent coffee grounds (SCGs) are a good source of chlorogenic acid (CGA), which can be hydrolyzed to quinic acid (QA) and caffeic acid (CA). These molecules have antioxidant and neuroprotective capacities, benefiting human health. The hydrolysis of CGA can be done by biotechnological processes, such as solid-state fermentation (SSF). This work evaluated the use of SSF with Aspergillus sp. for the joint release of the three molecules from SCGs. RESULTS: Hydroalcoholic extraction of the total phenolic compounds (TPCs) from SCGs was optimized, obtaining 28.9 ± 1.97 g gallic acid equivalent (GAE) kg-1 SCGs using 0.67 L ethanol per 1 L, a 1:9 solid/liquid ratio, and a 63 min extraction time. Subsequently, SSF was performed for 30 days, achieving the maximum yields for CGA, QA, and TPCs on the 16th day: 7.12 ± 0.01 g kg-1 , 4.68 ± 0.11 g kg-1 , and 54.96 ± 0.49 g GAE kg-1 respectively. CA reached its maximum value on the 23rd day, at 4.94 ± 0.04 g kg-1 . The maximum antioxidant capacity was 635.7 mmol Trolox equivalents kg-1 on the 14th day. Compared with unfermented SCGs extracts, TPCs and CGA increase their maximum values 2.3-fold, 18.6-fold for CA, 14.2 for QA, and 6.4-fold for antioxidant capacity. Additionally, different extracts' profiles were obtained throughout the SSF process, allowing us to adjust the type of enriched extract to be produced based on the SSF time. CONCLUSION: SSF represents an alternative to produce extracts with different compositions and, consequently, different antioxidant capacities, which is a potentially attractive fermentation process for different applications. © 2022 Society of Chemical Industry.

Manejo actual de las metástasis vertebrales: un trabajo en equipo / Current management of vertebral metastases: teamwork

La enfermedad metastásica vertebral es frecuente en los pacientes con cáncer avanzado, y conlleva a complicaciones inherentes a su progresión, como lo son la fractura patológica vertebral y la compresión neural metastásica. Se realizó una revisión de los aspectos terapéuticos actuales del manejo de la progresión y de las complicaciones de la enfermedad metastásica vertebral, enfatizando su enfrentamiento sistémico y personalizado. Nuestro objetivo principal es proporcionar información sobre el tratamiento actual de esta afección y la utilidad del manejo sistémico y multidisciplinario.

Metastatic spinal disease is common in patients with advanced cancer, and leads to complications inherent in its progression, such as pathological vertebral fracture and metastatic neural compression. A review of the current therapeutic aspects regarding the progression and complications of metastatic spinal disease was performed, highlighting its systemic, personalized approach. Our aim is to provide information about the current treatment of this condition and the usefulness of its systemic and multidisciplinary management.

Outcome of patients with primary glioblastoma in Chile: single centre series.

BACKGROUND: Glioblastoma (GBM) is the most common and most aggressive primary malignant brain tumour. The standard of care is surgical resection, followed by radiotherapy with concurrent and adjuvant temozolomide. In Latin America, there is scarcity of information about the incidence of GBM and even less data regarding outcomes. In this study, we describe the clinicopathologic features, management and outcomes of GBM patients. METHODS: We describe a single-centre multidisciplinary team experience in managing GBM patients over an 11-year period (Jan 2005 to Dec 2016). Pathology was reviewed by the pathology collaborator and retrospective chart review performed for treatment and clinical outcomes. RESULTS: We identified 74 patients (50 males) with diagnosis of GBM. Median age at diagnosis was 58 years (range 24-79 years), and median Karnofsky performance status was 80%. Forty-three (58.1%) went to gross total resection, 20 (27%) partial resection and 11 (14.9%) biopsy. Sixty-four (87%) patients received Stupp regimen. The median overall survival (OS) was 13.9 months (standard error (SE) 1.71; 95% confidence interval (CI), 10.56-17.23). In patients treated according to Stupp regimen, the progression-free survival (PFS) was 10 months (SE 1.8; 95% CI, 6.481-13.519), the selfcare survival was 11.8 months (SE 1.61; 95% CI, 8.632-14.968) and the OS was 16.1 months (SE 1.53; 95% CI, 13.01-19.099). CONCLUSIONS: This study reports the most complete analysis of epidemiology, clinical management and outcomes of patients with diagnosis of GBM in Chile treated with Stupp regimen. The PFS and OS are consistent with reports of US and Europe.

High-Yield Preparation of Outer Membrane Protein Efflux Pumps by in Vitro Refolding is Concentration Dependent.

Overexpression of tripartite efflux pump systems in gram-negative bacteria is a principal component of antibiotic resistance. High-yield purification of the outer membrane component of these systems will enable biochemical and structural interrogation of their mechanisms of action and allow testing of compounds that target them. However, preparation of these proteins is typically hampered by low yields, requiring laborious large-scale efforts. If refolding conditions can be found, refolding these proteins from inclusion bodies can lead to increased yields as compared to membrane isolations. A classical method for refolding outer membrane proteins involves unfolding inclusion bodies in urea followed by refolding in lipid or detergent micelles. However, that method has not yet been successful in refolding tripartite efflux pump TolC. Here, we find that refolding TolC from inclusion bodies requires an additional oligomerization enhancing step of sample concentration. We show that by our method of refolding, homotrimeric TolC remains folded in SDS-PAGE, retains binding to an endogenous ligand, and recapitulates the known crystal structure by single particle cryoEM analysis. We find that TolC refolding is concentration dependent. We then extended our method to refolding CmeC, a homologous protein from Campylobacter jejuni, and find that concentration-dependent oligomerization is a general feature of these systems. Because outer membrane efflux pump components are ubiquitous across gram-negative species, we anticipate that incorporating a concentration step in refolding protocols will promote correct refolding allowing for reliable, high-yield preparation of this family of proteins.

Prediction of the Limiting Flux and Its Correlation with the Reynolds Number during the Microfiltration of Skim Milk Using an Improved Model.

Limiting flux (JL) determination is a critical issue for membrane processing. This work presents a modified exponential model for JL calculation, based on a previously published version. Our research focused on skim milk microfiltrations. The processing variables studied were the crossflow velocity (CFV), membrane hydraulic diameter (dh), temperature, and concentration factor, totaling 62 experimental runs. Results showed that, by adding a new parameter called minimum transmembrane pressure, the modified model not only improved the fit of the experimental data compared to the former version (R2 > 97.00%), but also revealed the existence of a minimum transmembrane pressure required to obtain flux (J). This result is observed as a small shift to the right on J versus transmembrane pressure curves, and this shift increases with the flow velocity. This fact was reported in other investigations, but so far has gone uninvestigated. The JL predicted values were correlated with the Reynolds number (Re) for each dh tested. Results showed that for a same Re; JL increased as dh decreased; in a wide range of Re within the turbulent regime. Finally, from dimensionless correlations; a unique expression JL = f (Re, dh) was obtained; predicting satisfactorily JL (R2 = 84.11%) for the whole set of experiments.

Recent advances and perspectives of ultrasound assisted membrane food processing.

Power ultrasound (US) transmits substantial amounts of small mechanical movements serving for particle detaching in membrane filtrations. This topic has been reviewed in recent years mainly focused on the mechanisms by which the flux is improved under specific processing conditions. US also been shown to improve food quality by changing physical properties and modifying the activity of enzymes and microorganisms. Surprisingly, limited information exists regarding on how the application of US results in terms of process and quality during membrane filtration of complex matrices such as liquid foods. This review highlights the recent advances in the use of US in membrane filtration processes focused in the manufacturing of foodstuffs and food ingredients, and perspectives of novel hybrid membrane-US systems that may be quite interesting for this field. The application of US in food membrane processing increases the flux, but the lack of standardization regarding to experimental conditions, make suitable comparisons impossible. In this sense, careful attention must be paid regarding to the ultrasonic intensity (UI), the membrane configuration and type of transducers and volume of the treated solution. Dairy products are the most studied application of US membrane food processing, but research has been mainly focused on flux enhancement; hitherto there have been no reports of how operational variables in these processes affect critical aspects such as quality and food safety. Also, studies performed at industrial scale and economical assessments are still missing. Application of US combined with membrane operations such as reverse osmosis (RO), forward osmosis (FO) and enzyme membrane bioreactors (EMBR) may result interesting for the production of value-added foods. In the perspective of the authors, the stagnation of the development of acoustic filtration systems in food is due more to a prejudice on this subject, rather than actual impedance due to the lack of technological development of transducers. This later has shown important advances in the last years making them suitable for tailor made applications, thus opening several research opportunities to the food engineering not yet explored.

A software to prevent delirium in hospitalised older adults: development and feasibility assessment.

BACKGROUND: non-pharmacological interventions to prevent delirium are useful in hospitalised older adults. However, they are poorly implemented in clinical practice. We aimed to develop a software for bedside use by hospitalised older adults and to improve their access to these interventions. METHODS: a transdisciplinary team composed of healthcare professionals, designers, engineers and older adults participated in the development of the software. Scrum methodology was used to coordinate the work of the team, and the software was evaluated in a feasibility study. RESULTS: a software for touchscreen mobile devices that supports Android 5.0 or later was produced, including modules for time-spatial re-orientation, cognitive stimulation, early mobilisation, sensorial support use promotion, sleep hygiene and pain management optimisation. Horizontal disposition, use of colour contrast and large interaction areas were used to improve accessibility. The software's usability and accessibility were evaluated in 34 older adults (average age 73.2 ± 9.1 years) showing that 91.1% of them got access to all the software functions without previous instructions. The clinical feasibility assessment showed that 83.3% of the 30 enrolled hospitalised patients (76 ± 8 years) completed the 5-day protocol of software usage during hospitalisation. Software use was associated with a decreased trend in delirium incidence of 5 of 32 (15.6%) at baseline to 2 of 30 (6.6%) after its implementation. CONCLUSION: a highly accessible and implementable software, designed to improve access to non-pharmacological interventions to prevent delirium in hospitalised older adults, was developed. The effectiveness of the software will be evaluated in a randomised clinical trial.

Conventional and non-conventional applications of ß-galactosidases.

ß-Galactosidase is one of the most important industrial enzymes, that has been used for many decades in the dairy industry. The main application of ß-galactosidase is related to the production of low-lactose and lactose-free milk and dairy products, which are now common consumer goods in supermarket shelves. This is a well-established market that is expected to keep on growing as these products become more accessible to mid-income people worldwide. However, a fresh air has come into the ß-galactosidase business as non-conventional applications arose in recent decades based on its transgalactosylation activity. This capacity is certainly a major asset for a commodity enzyme that can be used now as a catalyst for the upgrading of readily available and cheap lactose into high added-value glycosides in processes of organic synthesis in tune with green chemistry principles within the framework of sustainability. This is a reflection of a paradigm shift, where enzymes are now being considered as apt catalysts for the synthesis of valuable organic compounds. This article reviews the main applications of ß-galactosidase, going from its conventional use related to its hydrolytic activity to the ongoing non-conventional applications in the synthesis of high added-value oligosaccharides based on its transgalactosylation activity.

Synthesis and purification of galacto-oligosaccharides: state of the art.

Lactose-derived non-digestible oligosaccharides are prominent components of functional foods. Among them, galacto-oligosaccharides (GOS) outstand for being prebiotics whose health-promoting effects are supported on strong scientific evidences, having unique properties as substitutes of human milk oligosaccharides in formulas for newborns and infants. GOS are currently produced enzymatically in a kinetically-controlled reaction of lactose transgalactosylation catalyzed by ß-galactosidases from different microbial strains. The enzymatic synthesis of GOS, although being an established technology, still offers many technological challenges and opportunities for further development that has to be considered within the framework of functional foods which is the most rapidly expanding market within the food sector. This paper presents the current technological status of GOS production, its main achievements and challenges. Most of the problems yet to be solved refer to the rather low GOS yields attainable that rarely exceed 40 %, corresponding to lactose conversions around 60 %. This means that the product or reaction (raw GOS) contains significant amounts of residual lactose and monosaccharides (glucose and galactose). Efforts to increase such yields have been for the most part unsuccessful, even though improvements by genetic and protein engineering strategies are to be expected in the near future. Low yields impose a burden on downstream processing to obtain a GOS product of the required purity. Different strategies for raw GOS purification are reviewed and their technological significance is appraised.

Performance of an ultrafiltration membrane bioreactor (UF-MBR) as a processing strategy for the synthesis of galacto-oligosaccharides at high substrate concentrations.

The performance of an ultrafiltration membrane bioreactor for galacto-oligosaccharides (GOS) synthesis using high lactose concentrations (470 g/L) and ß-galactosidase from Aspergillus oryzae was assessed. Tested processing variables were: transmembrane-pressure (PT), crossflow-velocity (CFV) and temperature. Results showed that processing variables had significant effect on the yield, the enzyme productivity and the flux but did not on GOS concentration and reaction conversion obtained. As expected, the use of high turbulences improved mass transfer and reduced the membrane fouling, but the use of very high crossflow-velocities caused operational instability due to vortex formation and lactose precipitation. The use of a desirability function allowed determining optimal conditions which were: PT (4.38 bar), CFV (7.35 m/s) and temperature (53.1 °C), optimizing simultaneously flux and specific enzyme productivity Under these optimal processing conditions, shear-stress and temperature did not affect the enzyme but long-term operation was limited by flux decay. In comparison to a conventional batch system, at 12.5h of processing time, the continuous GOS synthesis in the UF-MBR increased significantly the amount of processed substrate and a 2.44-fold increase in the amount of GOS produced per unit mass of catalyst was obtained with respect to a conventional batch system. Furthermore, these results can be improved by far by tuning the membranearea/reactionvolume ratio, showing that the use of an UF-MBR is an attractive alternative for the GOS synthesis at very high lactose concentrations.

Intraoperative detection and localization of cylindrical implants in cone-beam CT image data.

PURPOSE: Orthopedic fractures are often fixed using metal implants. The correct positioning of cylindrical implants such as surgical screws, rods and guide wires is highly important. Intraoperative 3D imaging is often used to ensure proper implant placement. However, 3D image interaction is time-consuming and requires experience. We developed an automatic method that simplifies and accelerates location assessment of cylindrical implants in 3D images. METHODS: Our approach is composed of three major steps. At first, cylindrical characteristics are detected by analyzing image gradients in small image regions. Next, these characteristics are grouped in a cluster analysis. The clusters represent cylindrical implants and are used to initialize a cylinder-to-image registration. Finally, the two end points are optimized regarding image contrast along the cylinder axis. RESULTS: A total of 67 images containing 420 cylindrical implants were used for testing. Different anatomical regions (calcaneus, spine) and various image sources (two mobile devices, three reconstruction methods) were investigated. Depending on the evaluation set, the detection performance was between 91.7 and 96.1% true- positive rate with a false-positive rate between 2.0 and 3.2%. The end point distance errors ranged from [Formula: see text] to [Formula: see text] mm and the orientation errors from [Formula: see text] to [Formula: see text] degrees. The average computation time was less than 5 seconds. CONCLUSIONS: An automatic method was developed and tested that obviates the need for 3D image interaction during intraoperative assessment of cylindrical orthopedic implants. The required time for working with the viewing software of cone-beam CT device is drastically reduced and leads to a shorter time under anesthesia for the patient.

Predictive models for pulmonary function changes after radiotherapy for breast cancer and lymphoma.

PURPOSE: To propose multivariate predictive models for changes in pulmonary function tests (ΔPFTs) with respect to preradiotherapy (pre-RT) values in patients undergoing RT for breast cancer and lymphoma. METHODS AND MATERIALS: A prospective study was designed to measure ΔPFTs of patients undergoing RT. Sixty-six patients were included. Spirometry, lung capacity (measured by helium dilution), and diffusing capacity of carbon monoxide tests were used to measure lung function. Two lung definitions were considered: paired lung vs. irradiated lung (IL). Correlation analysis of dosimetric parameters (mean lung dose and the percentage of lung volume receiving more than a threshold dose) and ΔPFTs was carried out to find the best dosimetric predictor. Chemotherapy, age, smoking, and the selected dose-volume parameter were considered as single and interaction terms in a multivariate analysis. Stability of results was checked by bootstrapping. RESULTS: Both lung definitions proved to be similar. Modeling was carried out for IL. Acute and late damage showed the highest correlations with volumes irradiated above ~20 Gy (maximum R(2) = 0.28) and ~40 Gy (maximum R(2) = 0.21), respectively. RT alone induced a minor and transitory restrictive defect (p = 0.013). Doxorubicin-cyclophosphamide-paclitaxel (Taxol), when administered pre-RT, induced a late, large restrictive effect, independent of RT (p = 0.031). Bootstrap values confirmed the results. CONCLUSIONS: None of the dose-volume parameters was a perfect predictor of outcome. Thus, different predictor models for ΔPFTs were derived for the IL, which incorporated other nondosimetric parameters mainly through interaction terms. Late ΔPFTs seem to behave more serially than early ones. Large restrictive defects were demonstrated in patients pretreated with doxorubicin-cyclophosphamide-paclitaxel.

Overview of brachytherapy resources in Latin America: a patterns-of-care survey.

PURPOSE: Relatively little is known about available resources and patterns of practice for brachytherapy (BT) in Latin America. To rectify this situation, we performed a patterns-of-care survey whose aim was to assess the human and material resources available for BT in Latin America and document current clinical practices. METHODS AND MATERIALS: A total of 392 radiotherapy (RT) centers located in 17 Latin American countries were asked to complete an online survey that included detailed questions about BT practices, facilities, and staffing. The study was coordinated through central offices located in Spain and Peru. National coordinators were appointed to manage the survey in each individual country. RESULTS: Overall, 77 of the 392 institutions (20%) completed the questionnaire. Of the 14 countries with at least one response, the participation rate was 35% (77 of 223 RT centers). The average number of patients (RT+BT) per center was 917. The mean number of BT patients per center increased by 46% (from 105 to 153 patients) from 2002 to 2007. Gynecologic localizations (endometrium, cervix, and vagina) accounted for 95% of treatments, and the uterine cervix was the most common tumor site (75% of all treatments). CONCLUSIONS: In Latin America, BT is most commonly used to treat gynecologic tumors, particularly of the cervix. Relatively few interventions were performed for breast and prostate. This was the first study of its kind in this region and should be repeated periodically.