Stabilization of a Highly Concentrated Colloidal Suspension of Pristine Metallic Nanoparticles

A colloidal suspension containing a high concentration of metallic nanoparticles (NPs) finds potential applications in flexible electronic printing, nanofluids, healthcare, antifouling coating, and so on. Here, we demonstrate a generic, easily scalable, simple, and contamination-free cryogenic temperature grinding method, which can effectively be used to prepare pristine NPs that can be stabilized in polar liquids in high concentrations. These surfactant-free pristine NPs have been found to remain dispersed in different polar liquids (CH3OH, C2H5OH, glycol, etc.) for weeks. The long-term stability of the NPs in these liquids has been investigated using zeta potential, in situ Fourier transform infrared spectroscopy, indicating electrostatic stabilization for ultrapure, surfactant-free NPs. Furthermore, stabilization of the NPs has been probed with detailed calculations using the Derjaguin Landau Verwey Overbeek theory as well as atomistic molecular dynamics simulation (MD). Experimental measurements along with theoretical calculations categorically indicate that the electrostatic energy is helping these NPs to be stabilized in a polar liquid

Comprometimentos cognitivos em pacientes com gliomas de baixo grau e gliomas de alto grau

OBJECTIVE: The relationship between brain tumors and cognitive deficits is well established in the literature. However, studies investigating the cognitive status in low and high-grade gliomas patients are scarce, particularly in patients with average or lower educational level. This study aimed at investigating the cognitive functioning in a sample of patients with low and high-grade gliomas before surgical intervention. METHOD: The low-grade (G1, n=19) and high-grade glioma (G2, n=8) patients underwent a detailed neuropsychological assessment of memory, executive functions, visuo-perceptive and visuo-spatial abilities, intellectual level and language. RESULTS: There was a significant impairment on verbal and visual episodic memory, executive functions including mental flexibility, nominal and categorical verbal fluency and speed of information processing in G2. G1 showed only specific deficits on verbal and visual memory recall, mental flexibility and processing speed. CONCLUSION: These findings demonstrated different levels of impairments in the executive and memory domains in patients with low and high grade gliomas.OBJETIVO: A associação entre tumores cerebrais e déficits cognitivos é bem estabelecida na literatura. No entanto, estudos sobre a cognição de pacientes com gliomas de baixo e alto grau são escassos, especialmente, em sujeitos com baixa escolaridade. Este estudo investigou o funcionamento cognitivo de uma amostra de pacientes com gliomas de baixo e alto grau antes da intervenção cirúrgica. MÉTODO: Os pacientes com glioma de baixo grau (G1, n=19) e alto grau (G2, n=8) foram avaliados quanto à memória, funções executivas, habilidades visuo-perceptivas e visuo-espaciais, nível intelectual e linguagem. RESULTADOS: Houve prejuízo significativo em G2 na memória episódica verbal e visual, funções executivas incluindo flexibilidade mental, fluência verbal nominal e categórica e velocidade de processamento de informações. G1 demonstrou apenas déficits específicos de evocação verbal e visual, flexibilidade mental e velocidade de processamento. CONCLUSÃO: Estes achados demonstraram níveis diferenciados de comprometimento nos domínios executivos e mnésticos de pacientes com gliomas de baixo e alto grau

On star and biclique edge-colorings

A biclique of G is a maximal set of vertices that induces a complete bipartite subgraph Kp,q of G with at least one edge, and a star of a graph G is a maximal set of vertices that induces a complete bipartite graph K1,q. A biclique (resp. star) edge-coloring is a coloring of the edges of a graph with no monochromatic bicliques (resp. stars). We prove that the problem of determining whether a graph G has a biclique (resp. star) edgecoloring using two colors is NP-hard. Furthermore, we describe polynomial time algorithms for the problem in restricted classes: K3-free graphs, chordal bipartite graphs, powers of paths, and powers of cycles

A prospective cohort study of digital cushion and corium thickness, Part 1: associations with body condition, lesion incidence and proximity to calving

Claw horn disruption lesions (CHDL) are a major cause of lameness in dairy cattle and are likely a result of excessive forces being applied to the germinal epithelium that produces claw horn. The digital cushion is a connective tissue structure, containing depots of adipose tissue, that sits beneath the distal phalanx and has been shown to be thicker in fatter cows. Body condition score (BCS) loss is a risk factor for CHDL, and one possible explanation is that fat is mobilised from the digital cushion during negative energy balance, causing the digital cushion to thin and lose force dissipating capacity, leading to disruption of claw horn growth. This prospective cohort study investigated the association between measures of body fat and sole soft tissues (SST) thickness (a combined measure of the corium and digital cushion beneath the distal phalanx) in a longitudinal manner. SST of 179 cows in two high yielding dairy herds were measured at five assessment points between 8 weeks prior to and 35 weeks post calving. BCS, back fat thickness (BFT) and lesion incidence were recorded. Data were analysed in a 4-level mixed effects regression model, with the outcome being SST thickness beneath the flexor tuberosity of the distal phalanx. Data from 827 assessment points were available for analysis. The overall mean of SST was 4.99 mm (SD: 0.95). SST was thickest 8 weeks prior to calving (5.22 mm, SD: 0.91) and thinnest one week post-calving (4.68 mm, SD: 0.87), suggesting that there was an effect of calving on SST. BFT was positively correlated with SST in the model with a small effect size (a 10 mm decrease in BFT corresponded with a 0.13 mm decrease in SST), yet the nadir of BFT was 11.0 mm at 9-17 weeks post calving (when SST was ~4.95 mm), rather than occurring with the nadir of SST immediately after calving. SST also varied with other variables, e.g. cows that developed a sole ulcer or severe sole haemorrhage during the study had thinner SST (-0.24 mm), except when a sole ulcer was present, when it was thicker (+0.53 mm). Cows that developed lesions had a thinner digital cushion prior to the lesion occurrence, which became thickened with sole ulcer presence, perhaps representing inflammation. Further, whilst BFT was correlated with SST over time, SST may also have been influenced by other factors such as integrity of the suspensory apparatus, which could have a major effect on CHDL. Measures of body fat likely contributed to having thin SST, but other factors including calving, herd and lesion presence also had an effec