Ngô Minh Đức - Academia.edu (original) (raw)

Papers by Ngô Minh Đức

International Journal of Heat and Technology

Drying is one of the most important steps in tobacco processing because it determines the color, ... more Drying is one of the most important steps in tobacco processing because it determines the color, taste, and micronutrients in tobacco. The loading density and the arrangement of tobacco leaves in the drying chamber affect the temperature and humidity distribution of the air, thereby affecting the drying quality. In this paper, three drying cases with different tobacco weights were studied by computational fluid dynamics (CFD) simulation as well as experimental. The results show that when the loading density of the tobacco drying chamber increases, the local resistance of tobacco leaves increases sharply, and the velocity difference and temperature difference of the air in the tobacco drying chamber increases. The maximum temperature difference in the highest loading density reaches 10 K. The uneven temperature distribution of the air reduces the quality of the dried tobacco.

Journal of Theoretical and Applied Mechanics

Hue University Journal of Science: Agriculture and Rural Development, 2014

Kết quả phân loại đã xác định được 107 loài thuộc 92 chi và 55 họ thực vật hoang dại được người d... more Kết quả phân loại đã xác định được 107 loài thuộc 92 chi và 55 họ thực vật hoang dại được người dân sử dụng làm rau ăn. Nguồn tài nguyên rau rừng được xác định theo tính đa dạng bao gồm (i) dạng sống: dạng thân gỗ (29,9%), dạng dây leo (15%), dạng cây bụi nhỏ (9,3%), dạng thân củ (6,5%) và dạng thân thảo hay cỏ (39,3%); (ii) nhóm sử dụng: gia vị (27 loài), rau ăn (73 loài) và rau vị chua (15 loài); (iii) bộ phận sử dụng: lá và ngọn non (58,7%); quả và hạt (19,0%), toàn thân (11,1%) và sử dụng các bộ phận từ cuống lá, thân non, hoa và thân củ (11,2%).Từ khóa: Rau rừng, thành phần loài, tính đa dạng, A Lưới.

The International journal of biological markers

Human chorionic gonadotropin (hCG) is widely used in the management of hydatidiform mole and pers... more Human chorionic gonadotropin (hCG) is widely used in the management of hydatidiform mole and persistent rophoblastic disease (PTD). Studies on hyperglycosylated human chorionic gonadotropin (invasive trophoblast antigen, ITA) in PTD are limited. In serum samples taken before evacuation of molar pregnancies we measured the concentrations of free hCG -subunit (free hCG ), "total" hCG (hCG+hCG ) and ITA, and determined whether ITA, the two other hCG analytes, or the calculated ratios of hCG /hCG+hCG , hCG /ITA and hCG+hCG /ITA could predict the later development of PTD. A retrospective study based on blood specimens collected in the Dutch Central Registry for Hydatidiform Moles. The study group comprised 97 patients with hydatidiform moles who did not develop PTD after mole evacuation and 33 patients who did develop PTD. Serum samples from 130 patients with hydatidiform mole with or without PTD were assayed using specific (radio) immunoassays for free hCG , total hCG, and ITA...

公共経営研究e, Dec 12, 2013

Based on Kugler and Tammen (2012) theoretical framework and their recommendation for developing c... more Based on Kugler and Tammen (2012) theoretical framework and their recommendation for developing countries, a statistical model to estimate 2 indices: Relative Political Extraction (RPE) and Relative Political Reach (RPR) was developed to take into account Vietnamese socioeconomic structure and development level. Using this model, an estimation for 30 provinces from 5 regions of Vietnam was carried out with 3 purposes: i) To evaluate the applicability of theoretical model in Vietnam; ii) To identify the usefulness of the indices for Vietnam, especially through a comparison with exsisting performance measures such as PAPI and PCI; iii) To identify conditions for further application. Our result show that: i) The theoretical model can be applied for Vietnam as availability and access to statistical data are satisfactory, although we will need more time and resources to gather from many sources to have a better quality. ii) The indices RPE and RPR for 30 provinces show some counter-intuitive ranking, compared with two popular measures (PAPI and PCI), and also compared with level of economic development in each provinces. The 2 indices help to understand some aspects of political leadership that other indices might miss due to the fact that all of them are perception indices. iii) In the future, if an estimate for all provinces is carried out, a careful effort should be paid to : i) Improvement of statistical model as our test statistics were not strong; ii) Improvement of data quality. An single intergrate index should be developed for the indices have more practical impacts.

ChemInform, 2011

Review: ca. 100 refs.

Chemistry (Weinheim an der Bergstrasse, Germany), Jan 18, 2014

Bicyclogermacrene is a strained bicyclic and common sesquiterpene found in several essential oils... more Bicyclogermacrene is a strained bicyclic and common sesquiterpene found in several essential oils. A short and good yielding synthesis of bicyclogermacrene proceeding in seven steps is reported. This terpene is used as key platform intermediate for a biomimetic access to several aromadendrene sesquiterpenoids, such as ledene, viridiflorol, palestrol, and spathulenol. Furthermore, bicyclogermacrene is shown to be the terpene component in the synthesis of the meroterpenoids psiguadial A, C, and D.

Physical Review E, 2011

We study the dynamic response of a one-dimensional chain of ellipsoidal particles excited by a si... more We study the dynamic response of a one-dimensional chain of ellipsoidal particles excited by a single compressive impulse. We detail the Hertzian contact theory describing the interaction between two ellipsoidal particles under compression, and use it to model the dynamic response of the system. We observe the formation of highly nonlinear solitary wave in the chain, and we also study their propagation properties. We measure experimentally the traveling pulse amplitude (force), the solitary wave speed and the solitary wave width. We compare these results with theoretical predictions in the long wavelength approximation, and with numerical results obtained with a discrete particle model and with finite element simulations. We also study the propagation of highly nonlinear solitary waves in the chain with particles arranged in different configurations to show the effects of the particle's geometry on the wave propagation characteristics and dissipation. We find very good agreement between experiment, theory and simulations for all the ranges of impact velocity and particles' arrangement investigated.

Ultramicroscopy, 2011

We illustrate an approach which allows determining the out-of-plane component of the vortex core ... more We illustrate an approach which allows determining the out-of-plane component of the vortex core (polarity) in NiFe nanodots using Fresnel imaging in Lorentz electron microscopy. Using tilted Fresnel images, contribution of the polarity is introduced into the Fresnel image. However, this contribution is relatively small and a difference image from two symmetrically tilted Fresnel images must be used to eliminate the strong contribution from the in-plane curling magnetization and non-magnetic contrast. The sense of the polarity appears as a bipolar white-black contrast in the difference image on the tilt axis. A vortex core with a diameter of 16.5 7 2.5 nm is experimentally measured. Image tilting, displacement and geometrical distortion may disturb the difference image, and hence subtraction of the difference image must be aligned by cross-correlation. The method is also justified by a study of the observed contrast characteristic due to misalignment. The method is confirmed to be superior to similar approach with direct interpretation of information and more information subtracted.

Resuscitation, 2005

To study the effects of mild hypothermia on the 24h concentration of serum astroglial of S-100 be... more To study the effects of mild hypothermia on the 24h concentration of serum astroglial of S-100 beta protein in patients who survived cardiac arrest (CA). A prospective, randomised, clinical study in a university teaching hospital. Sixty-one resuscitated patients were randomised into two prospective studies, known as the short study period (SSP) (n = 33 patients) and the long study period (LSP) (n = 28 patients). In the SSP study, patients older than 18 years of age and surviving asystole or pulseless electrical activity were included. In the LSP study, patients with ventricular fibrillation (VF) or non-perfusing ventricular tachycardia (VT) aged between 18 and 75 years were included. In each of the study groups, the patients were further randomised into either normothermic or hypothermic subgroups. The standard supportive therapy was similar, only the devices used to reduce the body temperature and the period of hypothermia were different. Serum samples for the measurement of astroglial S-100 beta protein were collected at admission and 24h later. During the first 24h after the cardiac arrest, the concentration of astroglial serum S-100 beta protein decreased significantly in the hypothermic cohort. In the normothermic cohort, the decrease of serum astroglial S-100 beta protein was less pronounced and even increased in the normothermic LSP group. Induced mild hypothermia reduced the 24h astroglial serum S-100 beta protein concentration and might play a neuroprotective effect after cardiac arrest.

New Phytologist, 2005

• Here we analyzed the shape of the central vacuole of Acetabularia acetabulum by visualizing its... more • Here we analyzed the shape of the central vacuole of Acetabularia acetabulum by visualizing its development during diplophase (from juvenility through reproduction) and haplophase (from meiosis through mating). • Light microscopy and whole-organism applications of a pH-sensitive dye, neutral red, were used to visualize the anatomy of the central vacuole. We studied connectivity within the thallus by locally applying dye to morphologically distinct regions (rhizoid, stalk, apex, hairs) and observing dye movements. • In vegetative thalli most of the rhizoid, stalk and young hairs stained with dye. In reproductive structures (caps, gametangia) dye also stained the majority of the interiors. When applied to small areas, dye moved at different rates through each region of the thallus (e.g. within the stalk). Dye moved from younger hairs, but not from older hairs, into the stalk. Errors in incorporation of central vacuole into gametangia occurred at <10 − 5. • These data indicate that the central vacuole of A. acetabulum is a ramified polar organelle with, potentially, a gel-like sap that actively remodels its morphology during development.

NeuroImage, 2006

Obesity is accompanied by damage to several tissues. Overweight is a risk factor for Alzheimer's ... more Obesity is accompanied by damage to several tissues. Overweight is a risk factor for Alzheimer's disease and other neurodegenerative disorders. Whether structural abnormalities associated with excess body fat may also occur in the brain is unknown. We sought to determine to what extent excess body fat is associated with regional alterations in brain structure using voxel-based morphometry (VBM), a whole-brain unbiased technique based upon high-definition 3D magnetic resonance imaging (MRI) scans normalized into a common standard space and allowing for an objective assessment of neuroanatomical differences throughout the brain. We studied 24 obese (11 male, 13 female; age: 32 T 8 years; body mass index [BMI]: 39.4 T 4.7 kg/m 2) and 36 lean (25 male, 11 female; mean age: 33 T 9 years; BMI: 22.7 T 2.2 kg/m 2) non-diabetic Caucasians. In comparison with the group of lean subjects, the group of obese individuals had significantly lower gray matter density in the post-central gyrus, frontal operculum, putamen, and middle frontal gyrus (P < 0.01 after adjustment for sex, age, handedness, global tissue density, and multiple comparisons). BMI was negatively associated with GM density of the left post-central gyrus in obese but not lean subjects. This study identified structural brain differences in human obesity in several brain areas previously involved in the regulation of taste, reward, and behavioral control. These alterations may either precede obesity, representing a neural marker of increased propensity to gaining weight, or occur as a consequence of obesity, indicating that also the brain is affected by increased adiposity.

Nanotechnology, 2009

In this paper, a systematic investigation of the microstructure, high performance magnetic hardne... more In this paper, a systematic investigation of the microstructure, high performance magnetic hardness as well as novel magnetic memory effect of the Pr 4 Fe 76 Co 10 B 6 Nb 3 Cu 1 nanocomposite magnet fabricated by conventional melt-spinning followed by annealing at temperatures ranging from 600 to 700 °C in Ar gas for nanocrystallization are presented and discussed. Transmission electron microscopy (TEM)

Metabolism, 2009

The objective of the study was to evaluate the reproducibility and repeatability of the combined ... more The objective of the study was to evaluate the reproducibility and repeatability of the combined use of the hyperinsulinemic-euglycemic (H-E) clamp and tracer dilution techniques. Ten nondiabetic men underwent a low-dose (40 mU/[m 2 min]) HE clamp that was repeated within 3 to 4 days using porcine or human insulin in a double-blinded, randomized, crossover design. Coefficients of variation (CVs) for intraindividual differences and repeatability coefficient were calculated to evaluate reproducibility and repeatability. The Bland and Altman method was used to quantify repeatability. The CVs for intraindividual differences were 5.7% ± 3.5% for steady-state (SS) insulin; 6.7% ± 6.2% and 54.2 ± 38.3% for basal and SS endogenous glucose product (EGP), respectively; and 10.3% ± 8.5% for total insulin-stimulated glucose disposal (M) values. Basal EGP, SS EGP, and SS glucose and insulin concentrations were similar for the 2 clamps; but glucose infusion rate (P = .02) and M (borderline significant, P = .06) were higher in the first clamp than the second clamp. No significant correlations between mean of differences and average of basal and SS EGP, SS insulin concentration, and M between the 2 clamps were observed. We also found that the different values were less than the repeatability coefficients of these parameters and that the 95% limits of agreement and the interval of repeatability coefficient of these parameters were similar. There were no differences in metabolic responses between clamps when compared by the type of insulin (porcine vs human) infused. Our findings indicate that, although SS EGP has a high CV, the clamp, which measures insulin action (ie, SS insulin, M), and the tracer dilution technique for assessing basal EGP are repeatable and reproducible. Decreased glucose infusion rate and M over a short period in the second clamp may reflect an accumulative effect of continued physical inactivity.

The Journal of Organic Chemistry, 2004

Amide formation Amide formation O 0325 Amidations Using N,N'-Carbonyldiimidazole: Remarkable Rate... more Amide formation Amide formation O 0325 Amidations Using N,N'-Carbonyldiimidazole: Remarkable Rate Enhancement by Carbon Dioxide.-A significant rate enhancement is observed for the amidation reaction of several benzoic acids and pyrrole carboxylic acids with amines in the presence of CO 2 compared to the CO 2-free reactions. A very high rate enhancement is observed for the formation of amide (Va). While the CO 2-catalyzed reaction reaches 50% completion in less than 3 h, the CO 2-free reaction is only 11% complete after 8.5 h. When either the acid or the amine is highly sterically encumbered, the reaction fails to appear at all.

International Journal of Gynecologic Cancer, 2008

The objective of the present study was to assess the diagnostic potential of serum human chorioni... more The objective of the present study was to assess the diagnostic potential of serum human chorionic gonadotropin (hCG) ratios obtained at different intervals after evacuation of hydatidiform mole to diagnose persistent trophoblastic disease (PTD) and to compare its diagnostic accuracy with the current FIGO 2000 criteria as a gold standard. We calculated hCG ratios from serum hCG concentrations of 204 patients (86 with and 118 without PTD) registered with the Dutch Central Registry for Hydatidiform Moles between 1977–2004. The hCG ratios obtained in week 1, 3, and 5 after evacuation identified, respectively, 20%, 52%, and 79% of patients with PTD (median: 3.0 weeks) at the 95% specificity level, while FIGO 2000 criteria identified, respectively, 0%, 16%, and 66% (median: 4.7 weeks). It is concluded that a serum hCG ratio identifies patients with PTD approximately 2 weeks earlier than the internationally accepted FIGO 2000 criteria and identifies more than 75% of patients who develop P...

Granular Matter, 2011

We study the dynamic response of uniform granular chains composed of short cylindrical particles ... more We study the dynamic response of uniform granular chains composed of short cylindrical particles excited by an impulse. The particles in the chains are arranged with their axes orthogonal to the chain's axis, and the particles maintain a constant relative orientation angle. We study the formation and propagation of solitary waves in the chains varying the orientation angle (α) between particles, and show tunability of the stress transfer as a function of α. We use the general Hertzian contact theory to model the interaction between particles. We compare experimental findings with theoretical predictions based on the long wavelength approximation, and with numerical predictions based on a one-dimensional discrete particle model, and on a three-dimensional finite element approach, finding good agreement.

European Journal of Epidemiology, 2009

The objective of this study is to conduct a metaanalysis of published and unpublished studies tha... more The objective of this study is to conduct a metaanalysis of published and unpublished studies that examine the association between Agent Orange (AO) exposure and the risk of spina bifida. Relevant studies were identified through a computerized literature search of Medline and Embase from 1966 to 2008; a review of the reference list of retrieved articles and conference proceedings; and by contacting researchers for unpublished studies. Both fixedeffects and random-effects models were used to pool the results of individual studies. The Cochrane Q test and index of heterogeneity (I 2) were used to evaluate heterogeneity, and a funnel plot and Egger's test were used to evaluate publication bias. Seven studies, including two Vietnamese and five non-Vietnamese studies, involving 330 cases and 134,884 non-cases were included in the meta-analysis. The overall relative risk (RR) for spina bifida associated with paternal exposure to AO was 2.02 (95% confidence interval [CI]: 1.48-2.74), with no statistical evidence of heterogeneity across studies. Non-Vietnamese studies showed a slightly higher summary RR (RR = 2.22; 95% CI: 1.38-3.56) than Vietnamese studies (RR = 1.92 95% CI: 1.29-2.86). When analyzed separately, the overall association was statistically significant for the three case-control studies (Summary Odds Ratio = 2.25, 95% CI: 1.31-3.86) and the cross sectional study (RR = 1.97, 95% CI: 1.31-2.96), but not for the three cohort studies (RR: 2.11; 95% CI: 0.78-5.73). Paternal exposure to AO appears to be associated with a statistically increased risk of spina bifida.

European Journal of Clinical Nutrition, 2005

Background: The prevalence of allergic diseases has remarkably increased in the last decades in t... more Background: The prevalence of allergic diseases has remarkably increased in the last decades in tandem with the number of obese individuals. Results of studies on obesity and allergic diseases are controversial, and most of them are related to asthma and asthma-like symptoms. Objective: In our study, we evaluated the association of several obesity indices and the prevalence of allergic diseases, including bronchial asthma, allergic rhino-conjunctivitis, atopic dermatitis and food allergy. Design: Cross-sectional study. Results: From a total of 1185 adolescents (49.3% boys) aged 12 to 17 y old, 19.3% reported a physician-diagnosed allergic disease, and 35.3% reported undiagnosed allergic symptoms. Logistic regression analysis revealed a higher risk of allergy in children of middle (OR ¼ 2.02, CI: 1.12-3.64) and high (OR ¼ 2.40, CI: 1.25-4.61) compared to low socioeconomic status, in subjects reporting industrial emissions in the neighborhood (OR ¼ 2.19, CI: 1.40-3.41), and in adolescents with parental history of allergy (OR ¼ 1.92, CI: 1.26-2.92). Body mass index (BMI) and percentage of body fat (%BF) were significantly related to allergy (OR ¼ 1.16, CI: 1.01-1.34 for BMI; OR ¼ 1.03, CI: 1.01-1.06 for %BF). After controlling for socioeconomic status, industrial emissions and parental history of allergy, only %BF remained statistically significant (OR ¼ 1.03, CI: 1.01-1.06). Food allergy was not related to obesity in our study population, and when adolescents with food allergy were excluded from the analysis, the odds of having allergy increased 28% with each increase in SD of BMI (OR ¼ 1.28, CI: 1.05-1.57) and 5% for each unit increase in the percentage of body fat (OR ¼ 1.05, CI: 1.01-1.08). Conclusion: In conclusion, being overweight was associated with an increased risk of allergy in our study population. Our results point towards an association between being overweight and rhino-conjunctivitis, but not food allergy. No association was observed with other allergic diseases.

Diabetes Research and Clinical Practice, 2008