Ab initio insights into the interaction mechanisms between H2_2, H2_2O, and O2_2 molecules with diamond surfaces

Diamond displays outstanding chemical, physical, and tribological properties, making it attractive for numerous applications ranging from biomedicine to tribology. However, the reaction of the materials with molecules present in the air, such as oxygen, hydrogen, and water, could significantly change the electronic and tribological properties of the films. In this study, we performed several density functional theory calculations to construct a database for the adsorption energies and dissociation barriers of these molecules on the most relevant diamond surfaces, including C(111), C(001), and C(110). The adsorption configurations, reaction paths, activation energies, and their influence on the structure of diamond surfaces are discussed. The results indicate that there is a strong correlation between adsorption energy and surface energy. Moreover, we found that the dissociation processes of oxygen molecules on these diamond surfaces can significantly alter the surface morphology and may affect the tribological properties of diamond films. These findings can help to advance the development and optimization of devices and antiwear coatings based on diamond

Tournament-Based Incentives and Mergers and Acquisitions

This research examines the relation between tournament-based incentives, which are proxied by the difference between a firm’s CEO pay and the median pay of the senior managers, and mergers and acquisitions (M&As). We find that tournament-based incentives are positively related to firm acquisitiveness and acquiring firms’ stock and operating performance. Further analysis indicates that positive acquisition performance increases the likelihood of the CEO being promoted from inside the acquiring firm. Our evidence is consistent with the view that tournament-based incentives motivate acquiring firms’ managers to make greater efforts and take more risk that result in superior acquisition performance

Inverse velocity statistics in two dimensional turbulence

We present a numerical study of two-dimensional turbulent flows in the enstrophy cascade regime, with different large-scale forcings and energy sinks. In particular, we study the statistics of more-than-differentiable velocity fluctuations by means of two recently introduced sets of statistical estimators, namely {\it inverse statistics} and {\it second order differences}. We show that the 2D turbulent velocity field, $\bm u$, cannot be simply characterized by its spectrum behavior, $E(k) \propto k^{-\alpha}$. There exists a whole set of exponents associated to the non-trivial smooth fluctuations of the velocity field at all scales. We also present a numerical investigation of the temporal properties of $\bm u$ measured in different spatial locations.Comment: 9 pages, 12 figure

Required flows for aquatic ecosystems in Ma River, Vietnam

Ecological flow requirements for the Ma River in dry season were assessed in three reaches of Ma – Buoi, Ma – Len and Ma – Chu. 5 indictor fish species was chosen based on biodiversity survey and roles of those species in aquatic ecosystem as well as local communities. Biological and hydrological data (dry season of 2016- 2017) and 35 year recorded hydrological data were collected and analyzed as input data for a physical habitat model River HYdraulic and HABitat SImulation Model – RHYHABSIM. Model results shown that the optimal flows of the reaches were very much higher compare with the minimum annual low flow - MALF. In this study, MALF7day were applied to calculate the recommended minimum flows of the three reaches. The recommended required minimum flows for Ma – Buoi, Ma – Len and Ma – Chu reaches were 51 m3/s, 49 m3/s and 61 m3/s, respectively. It must be stressed that this study only assessed whether or not there is enough habitat available for the river to sustain a healthy ecosystem

Survey of synthesis processes for N-doped carbon dots assessed by green chemistry and circular and ecoscale metrics

Six of the most promising lab-scale synthesis process methodologies for N-doped carbon dots (NCDs) are selected and compared in terms of green chemistry and circular and EcoScale/Good-Manufacturing-Practice metrics. We compare a new innovative route, the low-temperature plasma-enabled synthesis of carbon dots, e.g., from citric acid and monoethanolamine, to more-established literature processes, such as thermochemical processes, from the same or other materials. Along with this study, the advantages and disadvantages of each method are depicted in manifold sustainability facets. It is shown how recycling/reuse of nonconverted starting materials and solvents can improve the sustainability profile. In addition, safety constraints, cost analysis, and energy consumption are considered. The analysis showed that the thermal process from citric acid and monoethanolamine gives the best performance with regard to the sustainability assessment chosen here. It has a material circularity indicator of 0.971, with an EcoScale factor of 56% and an E-factor of 5.56. In continuation of those results, the paper shows how the low-temperature plasma using the same materials and the same recycling strategy can be improved to come closer to the performance of its thermal counterpart. It has the best energy efficiency, while lacking so far in mass efficiency. From this study, we learned more about which of these methods are most promising for scaling-up and industrial manufacturing of N-doped carbon dots

The clinical features of osteogenesis imperfecta in Vietnam

Purpose Osteogenesis imperfecta (OI) has not been studied in a Vietnamese population before. The aim of this study was to systematically collect epidemiological information, investigate clinical features and create a clinical database of OI patients in Vietnam for future research and treatment strategy development. Method Participants underwent clinical and physical examinations; also medical records were reviewed. Genealogical information was collected and family members’ phenotypical manifestations recorded. Cases were classified according to the Sillence classification. Results In total, 146 OI patients from 120 families were studied: 46 with OI Type I, 46 with Type III and 54 with Type IV. Almost patients had skeletal deformations. One hundred and forty-two had a history of fractures, 117 blue sclera, 89 dentinogenesis imperfecta and 26 hearing loss. The total number of fractures was 1,932. Thirty-four patients had intra-uterine fractures and nine had perinatal fractures. Surgery was performed 163 times in 58 patients; 100 osteosyntheses and 63 osteotomies. Bisphosphonate treatment was used in 37 patients. The number of affected individuals and predominance of severe forms of OI indicate that the disease is under diagnosed in Vietnam, especially in cases without a family history or with mild form of OI. Deformities appeared in all patients with different severity and localisation, affecting mostly the lower limbs. OI medical and surgical treatment rates are low and in most cases surgery was performed due to fractures. Conclusions Compared to previous studies, our results indicate a lower OI prevalence and greater severity of symptoms in the Vietnamese population when compared with other areas. Further investigation, improved diagnosis and treatment are needed to increase the patients’ quality of life

Additive biocomponents from catfish by-products enhance the growth of shrimp Litopenaeus vannamei

The rapid expansion of shrimp production requires a huge amount of protein sources from soybeans and wild-caught fishmeal; both are becoming a shortage. Meanwhile, catfish production and processing is a giant industry in Vietnam, which produce hundred thousand tonnes of protein- and lipid-rich by-products, annually. Using catfish by-products to gradually replace the traditional protein sources in shrimp aquaculture may bring triple benefits: 1) reducing pressure on wild fish exploitation for fishmeal, 2) reducing the environmental impacts of catfish by-products, and 3) increasing the value and sustainability of aquaculture production. In this study, we used catfish by-products to produce fish protein hydrolysate (FPH) and nano-hydroxyapatite (HA) as additives in feed for Pacific white shrimp (Litopenaeus vannamei). The supplement mixture of FPH and HA was added into the commercial diet (Charoen Pokphand Group [CP], 38% protein, and 6.5% lipid) to reach 38%, 38.5%, 40%, 43%, and 44% of the crude protein content. The survival and growth of shrimps were weekly assessed to day 55. The results showed that the shrimp growth was highest at 43% crude protein content in the feed as indicated by an increase of 124% and 112% in shrimp weight and length, respectively, compared to the commercial reference diet. No negative effects of adding the mixture of FPH and HA on the water quality were observed. Vibrio density was lower than 6.5 × 103 CFU/mL, which is the lowest Vibrio density negatively affecting the shrimp growth and development. These findings indicate that the mixture of FPH and HA are promising additive components in feed for post-larval shrimp L. vannamei diets