Dregea cuneifolia Tsiang & P. T. Li - a new record for flora of Vietnam

The genus Dregea comprises approximately 12 species and is distributed in Asia, Africa. In Vietnam, a species of Dregea has been recognized (Pham Hoang Ho, 1993, 2000; Tran The Bach, 2005): Dregea volubilis (L. f.) Benth. Hook.. We have confirmed the distribution of Dregea cuneifolia Tsiang P. T. Li in Vietnam. The species is found in Lam Dong province (Da Lat), the specimens are preserved in HN herbarium - Institute of Ecology and Biological Resources. Therefore, the genus Dregea with 2 species has been recognized in Vietnam. In Vietnam, genus Dregea is distinguished from other genera of Asclepiadaceae by characters of pollinarium, corolla and corona. Some main characters of D. cuneifolia: Lianas. Leaf blade oblong. Corolla greenish white, ca. 9 mm in diam.; tube ca. 2 mm, glabrous; lobes ovate-triangular, ca. 4 ´ 4 mm, margin ciliate. Corona lobes globose. Pollinia spatulate, 0.6 ´ 0.16 mm; caudicles 0.13 mm; corpusculum 0.45 mm. Ovaries glabrous, ca. l mm. Loc. class.: China: Guangxi: Damiao Shan, bushland, 500-800 m, 7 Sept. 1958. Typus: S. H. Chun 15587 (HT: SCBI). Ecology and Biology: Flowering april-september. In bushland, light place. Distribution: Lam Dong province (Da Lat). Also in China. Studied specimens: Lam Dong (Da Lat), 12/04/84, LX-VN 1470 (HN). Dregea cuneifolia is distinguished from Dregea volubilis by some characters: Dregea cuneifolia: Leave oblong. Pollinium 0.6 mm. Ovaries glabrous; Dregea volubilis: Leave broad ovate or cordate. Pollinium 0.5 mm. Ovaries pubescent

Pollen and seed morphology of cleome species (Cleomaceae) in Vietnam

Cleomaceae is a family that includes 18 genera distributed worldwide in tropical and temperate regions. Cleome L. is the largest genus having 207 species, widely distributed in tropical and subtropical regions (POWO 2019). In Vietnam, the genus is represented by four species Cleome rutidosperma DC., C. houtteana Schltdl., C. viscosa L. and C. gynandra L. The present study documents the pollen and seed characteristics of all four species of Cleome in Vietnam, and the data obtained using light microscope and scanning electron microscope are analyzed considering their importance in taxonomic delimitation and understanding their phylogenetic relationship. The results indicated a close relationship between different pollen and aperture types. The striking differences between the pollen shapes among different species of Cleome could be useful in taxonomic and evolutionary studies. Similarly, seed shape and surface characters provided important clues for their delimitation. Based on the pollen and seed morphological characteristics, a taxonomic key has been provided for easy identification of the Cleome species in Vietnam

An Outbreak of Severe Infections with Community-Acquired MRSA Carrying the Panton-Valentine Leukocidin Following Vaccination

Background: Infections with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination. Methods and Findings: We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mec type V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, althoughthey belong to the same lineage. Conclusions. We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

Observation of Associated Near-Side and Away-Side Long-Range Correlations in sqrt[s_{NN}]=5.02 TeV Proton-Lead Collisions with the ATLAS Detector.

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in sqrt[s_{NN}]=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb^{-1} of data as a function of transverse momentum (p_{T}) and the transverse energy (ΣE_{T}^{Pb}) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) "near-side" (Δϕ∼0) correlation that grows rapidly with increasing ΣE_{T}^{Pb}. A long-range "away-side" (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣE_{T}^{Pb}, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣE_{T}^{Pb} dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣE_{T}^{Pb} ranges and particle p_{T}

A New Species of Heterostemma (Apocynaceae, Asclepiadoideae) from Vietnam

Volume: 20Start Page: 367End Page: 37

Jasminanthes xuanlienensis (Apocynaceae, Asclepiadoideae), a new species from Vietnam

Jasminanthes xuanlienensis (Apocynaceae, Asclepiadoideae), a new species from Vietnam is described, illustrated and compared with its five congeners. Jasminanthes xuanlienensis differs distinctly from congeners by the longer peduncles (14–18 cm vs. 4 cm at most in J. pilosa and J. saxatilis, salmon-pink color of the inner corolla lobes (white or greenish in the other species), and corolla tube length (12.0–14.5 mm vs. shorter or longer in congeners)

Tribochemical insights into the carbon film formation induced by metallic species derived from layered double hydroxide nanoadditives

Layered double hydroxides (LDHs) have demonstrated excellent tribological performance in various studies. However, there remains a fundamental knowledge gap concerning the chemical composition of tribofilms across the cross-section. In this study, we seek to elucidate this question by tribologically testing various binary LDHs. It was found that five out of eight LDHs, denoted as CoAl-, CoFe-, MgAl-, NiFe-, and ZnAl-LDHs could induce hierarchical protective tribofilms due to the formation of rigid oxide layers and in situ carbon-based films. The five tribofilms helped to reduce wear loss and friction by approximately 90% and 20%, respectively. Remarkably, the Co-based tribofilms showed the best antiwear performance because of the thick carbon tribofilm formation and the strong bonding at the metallic/tribo-oxide interfaces. The formation mechanisms of the carbon tribofilm and its characteristic nature were evaluated and revealed by scanning transmission electron microscopy and electron energy loss spectroscopy. Meanwhile, the intriguing nano-scale mechanical properties, i.e., the hardness and reduced elastic modulus of different tribofilms, were well-demonstrated by nanoindentation and nanoscratch experiments. The correlation between chemical structures and mechanical properties of the tribofilms derived from LDH lubricant additives was first conducted and discussed, unveiling the tribochemical and lubrication mechanisms between the LDHs and sliding surfaces