A comparison between Hydrochloric acid and Trifluoroacetic acid in hydrolysis method of exopolysaccharide from Ophiocordyceps sinensis in Monosaccharide composition analysis by GC-FID

The monosaccharide composition is one of the crucial factors affecting the bioactivity of exopolysaccharide (EPS) in Cordyceps species. Therefore, many scientists have studied, analyzed monosaccharide composition and structure of EPS from Cordyceps species, especially Ophiocordyceps sinensis (O. sinensis). This study aimed to compare hydrochloric acid (HCl) with trifluoroacetic acid (TFA) in the EPS hydrolysis process in monosaccharide composition analysis by Gas Chromatography with Flame-Ionization Detection (GC-FID). The hydrolysis is a crucial step in forming the acetyl derivative, which helps the GC-FID technique to have good results in monosaccharide composition analysis. The results showed that hydrolysis with HCl gave a higher hydrolysis efficiency and was more suitable than hydrolysis by TFA in pretreatment to EPS for GC-FID. Hydrolysis results were analyzed through thin-layer chromatography and high-performance liquid chromatography (HPLC), then Acetyl derivatives were produced and finally analyzed by GC-FID to determine the monosaccharide composition of EPS. For EPS hydrolyzed by HCl, the analytical results presented that this sample had 6 kinds of monosaccharides, including rhamnose, arabinose, xylose, mannose, glucose, and galactose; the most monosaccharide was glucose. The EPS hydrolyzed by TFA only detected three kinds of monosaccharides, including mannose, arabinose, and galactose, mainly mannose. The study has set a foundation for further analysis of monosaccharide composition and structure of EPS from O. sinensis

Pleural effusion in difficult weaning from mechanical ventilation

International audienceObjectivesTo describe the incidence of pleural effusion in patients who failed a first spontaneous breathing trial (SBT) and to describe the characteristics of these patients.MethodsWe conducted a prospective observational study in three medical ICU. All mechanically ventilated patients were screened daily. In patients who failed their first SBT, a pleural ultrasonography was performed and the presence of PE was qualitatively quantified according to a 4-steps classification: 0: no PE; 1: small PE; 2: moderate PE and 3: large PE. In addition the main clinical characteristics of patients were collected. For statistical analysis, patients with classes 0 and 1 were regrouped, as were patients with classes 2 and 3.ResultsFrom November 2014 to March 2015, 336 patients were screened and 56 (17%) failed their first SBT. Among them, 28 patients (50%) had no PE, 18 patients (32%) had small PE (left or right), 8 (14%) patients had moderate PE and 2 (4%) patients had large PE.Patients with moderate and large PE stayed longer in ICU (19 ± 7 vs. 9 ± 7 days, p 0.05).Shock as the cause of initiation of mechanical ventilation was more frequent in patients with moderate and large PE as compared to patients without and small PE (40% vs. 4%, p < 0.01).Only one patient with a large PE had a pleural evacuation but without clinical improvement.ConclusionsSignificant pleural effusion is often detected in difficult to wean patients (18%), and is associated with shock state as the reason for mechanical ventilation. The interest of pleural drainage in this population deserves further studies

Rare Complication of Strongyloidiasis in Vietnam: A Case of Venous Thromboembolism and Duodenal Obstruction

Strongyloidiasis, a chronic helminth infection caused by the parasitic nematode Strongyloides stercoralis, has various clinical manifestations. Although rare, duodenal obstructions and venous thromboembolism are possible complications of strongyloidiasis. This paper presents the case of a 47-year-old Vietnamese male with a history of right lower limb edema, anorexia, nausea, vomiting, diarrhea, and abdominal discomfort lasting for four months. Venous Doppler ultrasound detected a thrombus in the right femoral vein, while an abdominal CT scan revealed a mass lesion suggestive of a lower bile duct tumor. Esophageogastroduodenoscopy showed a friable duodenal cap mucosa with multiple ulcers and edematous mucosa of the second part of the duodenum that caused a partial lumen obstruction. The final histological examination of the biopsy specimen revealed chronic duodenitis with larvae consistent with Strongyloides stercoralis. The patient was treated with Ivermectin for two weeks and anticoagulation therapy for three months. After treatment and a six-month follow-up, the patient's gastrointestinal symptoms and leg swelling resolved completely. This is the first documented case of a patient in Vietnam with strongyloidiasis who presented with venous thromboembolism and duodenal obstruction

Approach for quality detection of food by RFID-based wireless sensor tag

International audienceA novel wireless sensor for the detection of food quality is presented. The main idea is to transform radio frequency identification (RFID) tags into RFID sensors, owing to a specific design of the tag antenna. From knowledge of the variation of the permittivity of food over time through experimental characterisation, it is possible to detect the time from which the food becomes improper for consumption based on the read-range measurement of the designed sensing tags. This low-cost ultra-high frequency (UHF) RFID passive sensor was designed and experimentally tested on plastic-film-wrapped beef meat. The overall agreement between the experimental and simulation results shows the potential of this technique for real-world applications in food traceability

Novel design of RFID UHF passive tag for wideband applications by direct and contactless chip connection

International audienceIn this paper, we present two different designs for Ultra High Frequency (UHF) Radio Frequency Identification (RFID) passive tags. The first proposed design has been mounted on AK3 Tagsys® loop, which is a small loop antenna already connected to the chip while the second approach is connected directly with RFID chip. The optimized designs have compact size and bandwidth for worldwide UHF RFID applications (860MHz to 960 MHz). The advantages and disadvantages of each approach will be also discussed. From the experimental results, these designs have the acceptable read-range for ETSI regulations of RFID (9.6m and 5.97m) and can be applied for real-world applications. However, the calibration between the simulation and the characterization in order to remove the tolerance of fabrication process should be executed in future steps to obtain the best performance by improving the proposed designs

RFID beefs up

International audienceA low-cost wireless sensor for the real-time detection of food contamination and quality has been developed by collaborating researchers from the Vietnam National University, and CEA-LETI and Université Grenoble Alpes in France. In their approach, RFID passive tags are transformed into sensors that show potential to create a non-invasive, robust and cheap alternative that could be used by small companies and individuals in the food industry and agriculture

Antioxidant Motifs in Flavonoids: O–H versus C–H Bond Dissociation

Flavonoids provide potential health benefits due to their antioxidant properties. The antioxidant activity of natural flavonoids is primarily exerted by phenolic hydroxyl groups; however, C–H bonds also contribute to these properties. In this study, the contributions of phenolic groups and C–H bonds to the antioxidant properties of 13 flavonoids were investigated by using the (RO)­B3LYP/6-311++G­(2df,2p)//B3LYP/6-311G­(d,p) model chemistry in the gas phase and water and ethanol solvents. It was found that the C–H bonds have lower bond dissociation energies than O–H bonds in the 4-carbonyl and/or 3-hydroxyl group containing flavonoids and hence define antioxidant activity. The HOO· radical scavenging of the selected flavonoids is also investigated in detail through the potential energy surface, natural bond orbitals, and kinetic calculations. It was found that the favored radical scavenging mechanism of the flavonoids is hydrogen atom transfer, with the gas phase rate constants in the range of 7.23 × 103–2.07 × 109 L·mol–1·s–1. The results suggest that the flavonoids, isomelacacidin, isoteracacidin, melacacidin, and teracacidin, have antioxidant properties as high as typical phenolic compounds such as quercetin, trans-resveratrol, trolox, and ascorbic acid

Development and Identification of Working Parameters for a Lychee Peeling Machine Combining Rollers and a Pressing Belt

This work describes the development, design, and parameter identification of a lychee peeling machine. The working principle of the machine combines two rollers with a pressing belt to separate the peel from the fruits. It was designed and its operational parameters identified on the basis of experimental data on the Thieu lychee, which currently covers about 80% of the plantation area in Vietnam. To this end, the first step was to measure the physical characteristics of the fruits, such as size, shape, and density. Moreover, the coefficient of static friction between lychees and rubber rollers, and the critical peeling force, were identified, with a view to optimizing the operational parameters later on. Results showed that a minimum tangential force of 10.5 N is needed to break the peel and separate it from the pulp. Based on the balanced force principle, various optimal machine parameters such as roller rotation speed, roller diameter, roller length, gap size between the two rollers, belt velocity, and minimum pressure of the belt were calibrated. In addition, spiral grooves were created on the roller surface to facilitate the motion of the fruits. The optimal results were roller size 900 &times; 100 mm (length &times; diameter), rotation speed 159 RPM, gap size between rollers 4 mm, belt size 850 &times; 60 mm (length &times; width), belt pressure 13.5 N, and belt velocity 140 mm/s. Using the design and operational parameters mentioned above, the machine was able to perform regularly at a throughput of 100 kg/h, as demanded by the current market. Moreover, it would be easily feasible to combine multiple pairs of rollers and pressing belts in order to increase throughput. The methodology for the design of this peeling machine and identification of working parameters with respect to experimental data could be applied in many other post-harvesting configurations

Hybrid Artificial Intelligence Approaches for Predicting Critical Buckling Load of Structural Members under Compression Considering the Influence of Initial Geometric Imperfections

The main aim of this study is to develop different hybrid artificial intelligence (AI) approaches, such as an adaptive neuro-fuzzy inference system (ANFIS) and two ANFISs optimized by metaheuristic techniques, namely simulated annealing (SA) and biogeography-based optimization (BBO) for predicting the critical buckling load of structural members under compression, taking into account the influence of initial geometric imperfections. With this aim, the existing results of compression tests on steel columns were collected and used as a dataset. Eleven input parameters, representing the slenderness ratios and initial geometric imperfections, were considered. The predicted target was the critical buckling load of columns. Statistical criteria, namely the correlation coefficient (R), the root mean squared error (RMSE), and the mean absolute error (MAE) were used to evaluate and validate the three proposed AI models. The results showed that SA and BBO were able to improve the prediction performance of the original ANFIS. Excellent results using the BBO optimization technique were achieved (i.e., an increase in R by 7.15%, RMSE by 40.48%, and MAE by 38.45%), and those using the SA technique were not much different (i.e., an increase in R by 5.03%, RMSE by 26.68%, and MAE by 20.40%). Finally, sensitivity analysis was performed, and the most important imperfections affecting column buckling capacity was found to be the initial in-plane loading eccentricity at the top and bottom ends of the columns. The methodology and the developed AI models herein could pave the way to establishing an advanced approach to forecasting damages of columns under compression