Packing triangles in weighted graphs

Tuza conjectured that for every graph $G$, the maximum size $\nu$ of a set of edge-disjoint triangles and minimum size $\tau$ of a set of edges meeting all triangles satisfy $\tau \leq 2\nu$. We consider an edge-weighted version of this conjecture, which amounts to packing and covering triangles in multigraphs. Several known results about the original problem are shown to be true in this context, and some are improved. In particular, we answer a question of Krivelevich who proved that $\tau \leq 2\nu^*$ (where $\nu^*$ is the fractional version of $\nu$), and asked if this is tight. We prove that $\tau \leq 2\nu^*-\frac{1}{\sqrt{6}}\sqrt{\nu^*}$ and show that this bound is essentially best possible.Comment: v2: 20 pages, corrected version (from 2013) following referee report

Teratozoospermia: spotlight on the main genetic actors in the human

BACKGROUND Male infertility affects >20 million men worldwide and represents a major health concern. Although multifactorial, male infertility has a strong genetic basis which has so far not been extensively studied. Recent studies of consanguineous families and of small cohorts of phenotypically homogeneous patients have however allowed the identification of a number of autosomal recessive causes of teratozoospermia. Homozygous mutations of aurora kinase C (AURKC) were first described to be responsible for most cases of macrozoospermia. Other genes defects have later been identified in spermatogenesis associated 16 (SPATA16) and dpy-19-like 2 (DPY19L2) in patients with globozoospermia and more recently in dynein, axonemal, heavy chain 1 (DNAH1) in a heterogeneous group of patients presenting with flagellar abnormalities previously described as dysplasia of the fibrous sheath or short/stump tail syndromes, which we propose to call multiple morphological abnormalities of the flagella (MMAF). METHODS A comprehensive review of the scientific literature available in PubMed/Medline was conducted for studies on human genetics, experimental models and physiopathology related to teratozoospermia in particular globozoospermia, large headed spermatozoa and flagellar abnormalities. The search included all articles with an English abstract available online before September 2014. RESULTS Molecular studies of numerous unrelated patients with globozoospermia and large-headed spermatozoa confirmed that mutations in DPY19L2 and AURKC are mainly responsible for their respective pathological phenotype. In globozoospermia, the deletion of the totality of the DPY19L2 gene represents ∼81% of the pathological alleles but point mutations affecting the protein function have also been described. In macrozoospermia only two recurrent mutations were identified in AURKC, accounting for almost all the pathological alleles, raising the possibility of a putative positive selection of heterozygous individuals. The recent identification of DNAH1 mutations in a proportion of patients with MMAF is promising but emphasizes that this phenotype is genetically heterogeneous. Moreover, the identification of mutations in a dynein strengthens the emerging point of view that MMAF may be a phenotypic variation of the classical forms of primary ciliary dyskinesia. Based on data from human and animal models, the MMAF phenotype seems to be favored by defects directly or indirectly affecting the central pair of axonemal microtubules of the sperm flagella. CONCLUSIONS The studies described here provide valuable information regarding the genetic and molecular defects causing infertility, to improve our understanding of the physiopathology of teratozoospermia while giving a detailed characterization of specific features of spermatogenesis. Furthermore, these findings have a significant influence on the diagnostic strategy for teratozoospermic patients allowing the clinician to provide the patient with informed genetic counseling, to adopt the best course of treatment and to develop personalized medicine directly targeting the defective gene product

Integrated systems research for sustainable smallholder agriculture in the Central Mekong: Achievements and challenges of implementing integrated systems research

Internal Revie

Nurses’ judgments of patient risk of deterioration at change-of-shift handoff : agreement between nurses and comparison with early warning scores

Background Nurses begin forming judgments regarding patients’ clinical stability during change-of-shift handoffs. Objectives To examine the agreement between incoming and outgoing nurses’ judgments of deterioration risk following handoff and compare these judgments to commonly used early warning scores (MEWS, NEWS, ViEWS). Methods Following handoffs on three medical/surgical units, nurses completed the Patient Acuity Rating. Nurse ratings were compared with computed early warning scores based on clinical data. In follow-up interviews, nurses were invited to describe their experiences of using the rating scale. Results Sixty-two nurses carried out 444 handoffs for 158 patients. While the agreement between incoming and outgoing nurses was fair, correlations with early warning scores were low. Nurses struggled with predicting risk and used their impressions of differential risk across all the patients to whom they had been assigned to arrive at their ratings. Conclusion Nurses shared information that influenced their clinical judgments at handoff; not all of these cues may necessarily be captured in early warning scores

Advances in the deposition of ceramics by soft chemistry process : example of rare- earth silicate coatings

The dip-coating process consists in immersing a sample to be coated in the liquid medium and then removing it at a controlled speed in order to obtain a film of regular thickness, as shown in Figure 1a). Dip-coating technique is now used in many industrial fields (biomedical, transportation, optics…). It is a very simple, and easy process to implement for the deposition and shaping of different natures of coatings (ceramic, metallic and polymer). In the case of ceramic coatings, after the dip-coating operation, the layers undergo a sintering post-treatment leading to the consolidation and/or the densification of the deposit. The corresponding mechanisms need a rigorous control of many parameters. The parameters involved in the dip-coating process are related to the medium and to the process. Concerning the medium, the dispersion medium nature, the particles concentration, viscosity, and stability are the main ones. The stability of the suspension is a first-order parameter and a preliminary formulation work has been carried out to cope with it. Moreover, parameters relative to the fabrication process such as the number of layers and the thermal profile (intermediary and final temperatures), will also be key factors to be taken into account in the formation of homogeneous and reproducible coatings by dip-coating.This work highlights the influence of these various parameters in the case of rare earth silicates based coatings. The various experiments were carried out in correlation to the coatings quality and microstructure. Homogeneous and conformal ceramic coatings of few tens of micrometers thick, as shown in Figure 1b), were obtained. A multi-layers deposit in a sol loaded at 40% mass generally allows to reach the desired thickness. With these experiments relationship between dip-coating parameters and coatings microstructure and morphology can be established. Please click Additional Files below to see the full abstract

C-terminal amino acids are essential for human heat shock protein 70 dimerization

The human inducible heat shock protein 70 (hHsp70), which is involved in several major pathologies, including neurodegenerative disorders and cancer, is a key molecular chaperone and contributes to the proper protein folding and maintenance of a large number of protein structures. Despite its role in disease, the current structural knowledge of hHsp70 is almost exclusively based on its Escherichia coli homolog, DnaK, even though these two proteins only share ~50 % amino acid identity. For the first time, we describe a complete heterologous production and purification strategy that allowed us to obtain a large amount of soluble, full-length, and non-tagged hHsp70. The protein displayed both an ATPase and a refolding activity when combined to the human Hsp40. Multi-angle light scattering and bio-layer interferometry analyses demonstrated the ability of hHsp70 to homodimerize. The role of the C-terminal part of hHsp70 was identified and confirmed by a study of a truncated version of hHsp70 that could neither dimerize nor present refolding activity

Control of lateral composition distribution in graded films of soluble solid systems A1-xBx by partitioned dual-beam pulsed laser deposition

Altres ajuts: AGAUR agency (project 2017SGR)Lateral compositionally-graded thin films are powerful media for the observation of phase boundaries aswell as for high-throughputmaterials exploration.We herein propose amethod to prepare epitaxial lateral compositionally-graded films using a dual-beampulsed laser deposition (PLD)method with two targets separated by a partition. Tuning the ambient pressure and the partition-substrate gap makes it possible to control of the gradient length of the deposits at the small sizes (≤ 10 mm) suitable for commercial oxide single crystal substrates. A simple Monte Carlo simulation qualitatively reproduced the characteristic features of the lateral thickness distribution. To demonstrate this method, we prepared (1-x)PbTiO-xPbZrO and (1-x)LaMnOLaSrMnO films with lateral composition gradient widths of 10 and 1 mm, respectively, with the partitioned dual PLD

Distinct profiles of impaired associative memory and underlying cerebral networks in Alzheimer's disease

peer reviewe

Evaluation of total body weight and body mass index cut-offs for increased cefazolin dose for surgical prophylaxis

AbstractFrench and American guidelines recommend increased dosage regimens of cefazolin (CFZ) for surgical prophylaxis in patients with a body mass index (BMI) ≥ 35 kg/m2 or with a total body weight (TBW) ≥ 120 kg. The objective of this study was to evaluate the accuracy of these cut-offs in identifying patients who require CFZ dose adjustment. A pharmacokinetic study was conducted in patients of varying TBW and BMI who received 2 g of CFZ intravenously for prophylaxis prior to digestive surgery. Adequacy of therapy, defined as a serum concentration of unbound CFZ (fCFZ) ≥ 4 mg/L, was evaluated 180 min (T180) and 240 min (T240) after the start of CFZ infusion. Possible factors associated with insufficient fCFZ levels were also assessed. A P-value of <0.05 was considered statistically significant. A total of 63 patients were included in the study, categorised according to BMI (<35 kg/m2, 20 patients; and ≥35 kg/m2, 43 patients) and TBW (<120 kg, 41 patients; and ≥120 kg, 22 patients). All patients had adequate drug levels at T180 but only 40/63 patients (63%) had adequate levels at T240. At T240, therapy was adequate in 15/20 patients (75%) and 25/43 patients (58%) with BMI <35 kg/m2 and ≥35 kg/m2, respectively (P = 0.20), and in 28/41 patients (68%) and 12/22 patients (55%) with TBW <120 kg and ≥120 kg, respectively (P = 0.28). No factor associated with insufficient fCFZ was identified. In conclusion, current BMI and TBW cut-offs are poor indicators of which patients could benefit from increased CFZ dosage regimens