A Scenario-Based Functional Testing Approach to Improving DNN Performance

This paper proposes a scenario-based functional testing approach for enhancing the performance of machine learning (ML) applications. The proposed method is an iterative process that starts with testing the ML model on various scenarios to identify areas of weakness. It follows by a further testing on the suspected weak scenarios and statistically evaluate the model's performance on the scenarios to confirm the diagnosis. Once the diagnosis of weak scenarios is confirmed by test results, the treatment of the model is performed by retraining the model using a transfer learning technique with the original model as the base and applying a set of training data specifically targeting the treated scenarios plus a subset of training data selected at random from the original train dataset to prevent the so-call catastrophic forgetting effect. Finally, after the treatment, the model is assessed and evaluated again by testing on the treated scenarios as well as other scenarios to check if the treatment is effective and no side effect caused. The paper reports a case study with a real ML deep neural network (DNN) model, which is the perception system of an autonomous racing car. It is demonstrated that the method is effective in the sense that DNN model's performance can be improved. It provides an efficient method of enhancing ML model's performance with much less human and compute resource than retrain from scratch.Comment: The paper is accepted to appear in the proceedings of IEEE 17th International Conference on Service-oriented Systems Engineering (IEEE SOSE 2023) as an invited paper of 2023 IEEE CISOSE Congres

Transformation Chlorophyll a of Spirulina platensis to Chlorin e6 Derivatives and Several Applications

BACKGROUND: Spirulina platensis contains a large amount of chlorophylls, chlorophyll a, that are starting materials to synthesize functionalized chlorins. Chlorin e6 (Ce6) as well as its derivatives are second generation sensitizers using in photodynamic therapy (PDT) of various cancers. In this study, we transfer chlorophyll a of S. platensis to Ce6derivatives and determine their several applications. AIM: to evaluate the effects of Ce6 derivatives to treat cancer cells. METHODS: Ce6 trimethylester was created from methyl pheophorbide a2 in S. platensis provided by the Hidumi Company, Nghe An province, Viet Nam. Hela cells were incubated with Ce6 trimethylester and the irradiated with the diode laser dose of 1.2 J/cm2/min through the system of filters £ 650 nm. MTT assay and clonogenic assay were used to determine survival rate and cloning efficiency of cells. Antimicrobial effect of Ce6 trimethylester with halogen light were studied with Propionibacterium acnes VTCC 0218 and Staphylococcus aureus VTCC 0173. RESULTS: From dry biomass (700 g) of S. platensis, after extracting chlorophyll a and methanolysis, 4.2 g of methyl pheophorbide a was obtained. The reaction to give Ce6 trimethylester with 82% yield was performed with potassium hydroxide (KOH) in MeOH/THF/CHCl3. After irradiation with a 650 nm laser at 1.2 J, the cell viability in all samples decreased with Ce6 trimethylester treatment, the survival declining trend of Hela cells treated with Ce6 trimethylester were proportional when concentration of Ce6 trimethylester increased. The rate of colony formation was declined as the concentration of Ce6 trimethylester treated was increased. The growth of both S. aureus and P. acnes can be inactivated by Ce6 trimethylester PDT. The MIC99 value against P. acnes VTCC 0218 and S. aureus VTCC 0173 of Ce6 trimethylester with halogen light was 1.25 μg/ml. CONCLUSION: The Ce6 trimethylester from S. platensis cultivated in Viet Nam could be used as a potential photosentizer for photodynamic therapy for treatment of cancer and acne

Chemical composition and antibacterial activities of essential oils from fruits of Melicope pteleifolia (Champ. Ex Benth.) T.G. Hartley grown in Lam Dong Province, Vietnam

In the present study, chemical composition and antibacterial properties of essential oil obtained from the aerial parts of the Melicope pteleifolia (Champ. ex Benth.) T.G Hartley in Dalat were evaluated. Essential oil was isolated through hydro-distillation. Twenty-nine constituents comprising 100% of the essential oil were characterized by gas chromatography/mass spectrometry (GC-MS) techniques. The major compounds in the essential oil were (+)-Sabinene (34.73%), Cis-α-bergamotene (13.15%), Z-α-trans-bergamotol (5.28%), β-mycrene (4.98%), and 1,3,6-octatriene, 3,7-dimethyl-(4.71%). Antibacterial activities of Melicope pteleifolia essential oil were investigated against Gram-positive and-negative bacteria. Results showed significant activities against Streptococcus pyogenes and Escherichia coli using an agar well diffusion method. The application of this essential oil in preventing and eliminating bacteria could be useful in fields as medicine and cosmetics.

Genetic variation and outcrossing rate of Dipterocarpus dyeri in the Tan Phu tropical rain forest (Dong Nai), Vietnam

Dipterocarpus dyeri (Dipterocarpaceae) is widely distributed in lowland rainforests in southeastern Vietnam. Due to over- exploitation and habitat destruction in the 1980s and 1990s, this species is listed as threatened. Understanding the genetic variation and mating rate among D. dyeri population that occurs in forest patches is necessary to establish effectively conservation strategies for this species. To conserve the species in tropical forests, genetic diversity and mating rate were investigated using eight microsatellites (single sequence repeat, SSR) as markers. All of the eight loci were polymorphic. A total of 36 different alleles were observed across the loci screened. The SSR data indicated high genetic diversity (NA = 4.5; HO = 0.542 and HE = 0.667) and high inbreeding value, FIS= 0,182. The mating system parameters were determined using the mixed mating model and the results indicated high outcrossing rate (tm=0.81 and ts=0.675) and lowselfing rate (0.19). Difference of tm-ts value indicated that inbreeding contributed to selfing rate for this species in the Tan Phu tropical rain forest. The results reflected that D. dyeri habitat in this area has been restored and the number of individuals was high, about 500 individuals. However, seedlings were not found so far in this study. These results indicated the importance of conserving of the genetic resources of Dipterocarpus dyeri species in the Tan Phu rain forest. The conservation strategy should include an establishment of an ex-situ conservation site with new big population for this species from all genetic groups, which might improve its fitness under different environmental stresses. 

Mental health and its determinants among adolescents living in families with separated or divorced parents in an urban area of Vietnam

Objectives We assessed the prevalence of stress, anxiety, and depression among adolescents living in families with separated or divorced parents in Hue City, Vietnam and identified factors associated with these conditions. Methods This cross-sectional study enrolled 309 adolescents, aged 12 to 17 years, living in families with separated or divorced parents in Hue City, Vietnam. The depression anxiety stress scale-21 (DASS-21) was used to measure stress, anxiety, and depression. Predictors of overall and individual mental health problems were identified using ordered and binary logistic regression, respectively. Results The DASS-21 scale revealed a 49.2% prevalence of stress, while anxiety and depression had s prevalence rates of 61.5%. Among participants, 42.4% experienced all 3 mental health issues. Several factors were identified as significant predictors of mental health problems, including poor to average economic status (adjusted odds ratio [aOR], 2.00; 95% confidence interval [CI], 1.21–3.31; p=0.007); being in high school (aOR, 5.02; 95% CI, 2.93–8.60; p<0.001); maternal occupation of teacher, healthcare professional, or official (aOR, 2.39; 95% CI, 1.13–5.03; p=0.022); longer duration of family separation or divorce (aOR, 1.24; 95% CI, 1.05–1.45; p=0.009); living with one’s mother (aOR, 1.69; 95% CI, 1.03–2.76; p=0.04); alcohol consumption (aOR, 1.70; 95% CI, 0.99–2.92; p=0.050); and being bullied (aOR, 5.33; 95% CI, 1.10–25.69; p=0.037). Most of these factors were associated with stress, anxiety, and depression. Additionally, smoking was associated with stress. Conclusion Adolescents with separated or divorced parents were at increased risk of stress, anxiety, and depression. The findings of this study provide important implications for prevention programs

Enzimatska obrada iskorištenih listića zelenog čaja i njihova primjena u proizvodnji čajnog peciva s velikim udjelom prehrambenih vlakana

Research background. By-products of food industry have been studied as sources of high fibre and antioxidant ingredients for healthy food products, because of their economic and environmental benefits. However, the soluble dietary fibre content of these materials is usually lower than the recommended value that is claimed to bring positive health effects. Enzymatic treatment could be an efficient method for modifying insoluble and soluble dietary fibre contents of these materials. The purpose of this study is to investigate the effects of enzymatic treatment conditions on soluble, insoluble and total dietary fibre mass fractions in spent green tea leaves, and evaluate the quality of dough and cookies when different mass fractions of untreated and treated leaves were added to the recipe. Experimental approach. The mass fractions of soluble, insoluble and total dietary fibre in spent tea leaf powder was evaluated after the leaves were treated with cellulase amount of 0−25 U/g for 0 to 2 h. Wheat flour was replaced by untreated and treated spent tea leaf powder at 0, 10, 20, 30 and 40% in cookie formulation. Textural properties of dough, proximate composition, physical properties and overall acceptability of cookies were analysed. Results and conclusions. The appropriate conditions for enzymatic treatment were enzyme loading of 20 U/g and biocatalytic time of 1.5 h, under which the mass fraction of soluble dietary fibre in spent tea leaves increased by 144.5% compared to that of the control sample. The addition of spent tea leaves led to the increase in dough hardness. Increase in the spent tea leaf amount also enhanced fibre mass fraction, antioxidant activity and hardness of cookies but reduced their overall acceptability. Moreover, the enzymatic treatment of spent tea leaves improved the soluble to total dietary fibre ratio of the cookies, which influenced their textural properties and health benefits. The cookies with added 20% untreated or treated spent tea leaves were overall accepted by the panel. Novelty and scientific contribution. For the first time, spent tea leaves have been treated with enzymes to improve their soluble to total dietary fibre ratio. The treated spent tea leaves are a new promising high-fibre antioxidant ingredient for cookie preparation.Pozadina istraživanja. Nusproizvodi prehrambene industrije ispituju se iz ekonomskih i ekoloških razloga kao izvori sastojaka s velikim udjelom prehrambenih vlakana i antioksidacijskim učinkom koji se mogu upotrijebiti u proizvodnji zdrave hrane. Međutim, udjel topljivih prehrambenih vlakana u nusproizvodima je obično manji od preporučenih vrijednosti koje mogu imati pozitivan učinak na zdravlje. Enzimatska obrada bi mogla biti učinkovita metoda modificiranja netopljivih i topljivih prehrambenih vlakana iz otpada prehrambene industrije. Svrha je ovog rada bila ispitati utjecaj različitih uvjeta enzimatske obrade na masene udjele topljivih, netopljivih i ukupnih prehrambenih vlakana u iskorištenim listićima zelenog čaja, te procijeniti kakvoću tijesta i čajnog peciva s dodatkom različitih masenih udjela obrađenih i neobrađenih listića. Eksperimentalni pristup. Maseni udjeli topljivih, netopljivih i ukupnih prehrambenih vlakana u prahu od iskorištenih listića zelenog čaja mjereni su nakon njihove obrade s 0–25 U/g celulaze tijekom 0 do 2 h. U smjesi za čajno pecivo je pšenično brašno zamijenjeno s 0, 10, 20, 30 i 40 % obrađenog ili neobrađenog praha iskorištenih listića zelenog čaja. Ispitani su tekstura tijesta te kemijski sastav, fizikalna svojstva i ukupna prihvatljivost dobivenog čajnog peciva. Rezultati i zaključci. Pri povoljnim uvjetima enzimatske obrade, a to su 20 U/g enzima i vrijeme trajanja biokatalitičkog procesa od 1,5 sata, maseni udjel topljivih prehrambenih vlakana u iskorištenim listićima zelenog čaja porastao je za 144,5 % u usporedbi s kontrolnim uzorkom. Dodatkom iskorištenih listića zelenog čaja povećala se tvrdoća tijesta. Povećanjem količine listića čaja povećali su se i maseni udjel vlakana, antioksidacijska svojstva i tvrdoća čajnog peciva, ali se smanjila njihova prihvatljivost. Osim toga, enzimatskom se obradom iskorištenih listića zelenog čaja poboljšao omjer topljivih i ukupnih vlakana u čajnom pecivu, što je utjecalo na njegovu teksturu i pozitivan učinak na zdravlje. Panel ocjenjivača je okarakterizirao čajno pecivo s dodatkom 20 % obrađenih ili neobrađenih iskorištenih listića čaja kao prihvatljive. Novina i znanstveni doprinos. Prvi put je enzimatskom obradom iskorištenih listića zelenog čaja poboljšan njihov omjer topljivih i ukupnih prehrambenih vlakana. Obrađeni iskorišteni listići zelenog čaja novi su obećavajući sastojak s antioksidacijskim svojstvima koji se može upotrijebiti u pripremi čajnog peciva

Selective breeding of saline-tolerant striped catfish (Pangasianodon hypophthalmus) for sustainable catfish farming in climate vulnerable Mekong Delta, Vietnam

peer reviewedStriped catfish (Pangasianodon hypophthalmus), a freshwater species cultured mainly in the Mekong Delta region in Southern Vietnam, is facing a significant challenge due to salinity intrusion as a result of climatic changes. Given these evolving environmental conditions, selecting new strains with a higher salinity tolerance could make production of striped catfish economically feasible in brackish environments. In this study, we carried out a selection program aimed at developing a striped catfish strain able to survive and grow fast in a saline environment. To implement the selection program, we first collected males and females from different provinces in the Mekong delta. We next performed a factorial cross of these breeders to produce half- and full-sib families. When fish reached fry stage (47 dph), we put them in a saline environment (10 ppt) and subsequently kept 50 % of the fastest-growing fish after 143 days post hatching (dph). We repeated this mass selection procedure after 237 dph and 340 dph. We maintained in parallel a randomly selected group in saline conditions and a group of fish reared in freshwater to serve as controls. After crossing the selected individuals, we performed several tests on the next generation of fish to evaluate the effectiveness of selection after one generation in saline conditions. Average direct responses to selection were 18.0 % for growth and 11.4 % for survival rate after one generation of selection. We estimated a moderate realized heritability (0.29) for body weight. The genetic gains obtained in our study for body weight and survival rate after one generation of selection under saline conditions suggest that selection can be effective to improve ability of striped catfish to cope with saline stress. We conclude that our selection program has succeeded in developing a productive strain of striped catfish with better tolerance to salinity. © 2022 The Author

Chemical composition and antimicrobial activity of the essential oil from twigs and leaves of Magnolia macclurei (Dandy) Figlar from Ha Giang Province, Vietnam

The chemical composition of the essential oil obtained by hydrodistillation of the twigs and leaves of Magnolia macclurei collected in Hoang Su Phi, Ha Giang Province, Vietnam was analyzed using GC/MS. A total of 38 compounds were detected in essential oil, accounting for 94.49% of the oil, in which 37 compounds were identified accounting for 93.33%. cis-β-Elemene (14,30%), bicyclogermacrene (18,57%), and 10-epi-ᵧ-eudesmol (16,86%) were the main components of essential oil. The minor components present with rather high amount were: Germacrene D (2,12%), guaiol (8,52%), hinesol (2,34%), valerianol (6,76%), and bulnesol (2,93%). Antibiotic activity of the essential oil sample was tested against a Gram positive bacteria Staphylococcus aureus, a Gram negative bacteria Escherichia coli, and a yeast Candida albicans using an agar disk diffusion method. All three microorganisms tested are resistant to the oil from twigs and leaves of M. macclurei. That is exhibited through the inhibitory zone diameters ranging from 4 to 12 mm

A universal genome sequencing method for rotavirus A from human fecal samples which identifies segment reassortment and multi-genotype mixed infection.

BACKGROUND: Genomic characterization of rotavirus (RoV) has not been adopted at large-scale due to the complexity of obtaining sequences for all 11 segments, particularly when feces are used as starting material. METHODS: To overcome these limitations, we developed a novel RoV capture and genome sequencing method combining commercial enzyme immunoassay plates and a set of routinely used reagents. RESULTS: Our approach had a 100% success rate, producing >90% genome coverage for diverse RoV present in fecal samples (Ct < 30). CONCLUSIONS: This method provides a novel, reproducible and comparatively simple approach for genomic RoV characterization and could be scaled-up for use in global RoV surveillance systems. TRIAL REGISTRATION (PROSPECTIVELY REGISTERED): Current Controlled Trials ISRCTN88101063 . Date of registration: 14/06/2012