161 research outputs found
Modeling power grids
We present a method to construct random model power grids that closely match
statistical properties of a real power grid. The model grids are more difficult
to partition than a real grid.Comment: 9 pages, 5 figure
Post partum haemorrhage secondary to uterine atony, complicated by platelet storage pool disease and partial placenta diffusa: a case report
Diblock copolymers at a homopolymer-homopolymer-interface: a Monte Carlo simulation
The properties of diluted symmetric A-B diblock copolymers at the interface
between A and B homopolymer phases are studied by means of Monte Carlo (MC)
simulations of the bond fluctuation model. We calculate segment density
profiles as well as orientational properties of segments, of A and B blocks,
and of the whole chain. Our data support the picture of oriented ``dumbbells'',
which consist of mildly perturbed A and B Gaussian coils. The results are
compared to a self consistent field theory (SCFT) for single copolymer chains
at a homopolymer interface. We also discuss the number of interaction contacts
between monomers, which provide a measure for the ``active surface'' of
copolymers or homopolymers close to the interface
Governors and directors: Competing models of corporate governance
Why do we use the term âcorporate governanceâ rather than âcorporate directionâ? Early British joint stock companies were normally managed by a single âgovernorâ. The âcourt of governorsâ or âboard of directorsâ emerged slowly as the ruling body for companies. By the nineteenth century, however, companies were typically run by directors while not-for-profit entities such as hospitals, schools and charitable bodies had governors. The nineteenth century saw steady refinement of the roles of company directors, often in response to corporate scandals, with a gradual change from the notion of the director as a ârepresentative shareholderâ to the directors being seen collectively as ârepresentatives of the shareholdersâ. Governors in not-for-profit entities, however, were regarded as having broader responsibilities. The term âgovernanceâ itself suggests that corporate boards should be studied as âpoliticalâ entities rather than merely through economic lenses such as agency theory
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SIOPâPODC adapted risk stratification and treatment guidelines: Recommendations for neuroblastoma in lowâ and middleâincome settings
Neuroblastoma is the most common extracranial solid tumor in childhood in highâincome countries (HIC), where consistent treatment approaches based on clinical and tumor biological risk stratification have steadily improved outcomes. However, in lowâ and middleâ income countries (LMIC), suboptimal diagnosis, risk stratification, and treatment may occur due to limited resources and unavailable infrastructure. The clinical practice guidelines outlined in this manuscript are based on current published evidence and expert opinions. Standard risk stratification and treatment explicitly adapted to graduated resource settings can improve outcomes for children with neuroblastoma by reducing preventable toxic death and relapse. Pediatr Blood Cancer 2015;62:1305â1316. © 2015 The Authors. Pediatric Blood & Cancer, published by Wiley Periodicals, Inc
Self-consistent field theory for the interactions between keratin intermediate filaments
Background: Keratins are important structural proteins found in skin, hair and nails. Keratin Intermediate Filaments are major components of corneocytes, nonviable horny cells of the Stratum Corneum, the outermost layer of skin. It is considered that interactions between unstructured domains of Keratin Intermediate Filaments are the key factor in maintaining the elasticity of the skin.
Results: We have developed a model for the interactions between keratin intermediate filaments based on self-consistent field theory. The intermediate filaments are represented by charged surfaces, and the disordered terminal domains of the keratins are represented by charged heteropolymers grafted to these surfaces. We estimate the system is close to a charge compensation point where the heteropolymer grafting density is matched to the
surface charge density. Using a protein model with amino acid resolution for the terminal domains, we find that the terminal chains can mediate a weak attraction between the keratin surfaces. The origin of the attraction is a combination of bridging and electrostatics. The attraction disappears when the system moves away from the charge compensation point, or when excess small ions and/or NMF-representing free amino acids are added.
Conclusions: These results are in concordance with experimental observations, and support the idea that the interaction between keratin filaments, and ultimately in part the elastic properties of the keratin-containing tissue, is controlled by a combination of the physico-chemical properties of the disordered terminal domains and the composition of the medium in the inter-filament region.
Keywords: Stratum corneum, Skin keratins, Intermediate filaments, Unstructured terminal domains, Bridging attractio
High incidence of vertebral fractures in children with acute lymphoblastic leukemia 12 months after the initiation of therapy
Purpose: Vertebral fractures due to osteoporosis are a potential complication of childhood acute lymphoblastic leukemia (ALL). To date, the incidence of vertebral fractures during ALL treatment has not been reported. Patient and Methods: We prospectively evaluated 155 children with ALL during the first 12 months of leukemia therapy. Lateral thoracolumbar spine radiographs were obtained at baseline and 12 months. Vertebral bodies were assessed for incident vertebral fractures using the Genant semiquantitative method, and relevant clinical indices such as spine bone mineral density (BMD), back pain, and the presence of vertebral fractures at baseline were analyzed for association with incident vertebral fractures. Results: Of the 155 children, 25 (16%; 95% CI, 11% to 23%) had a total of 61 incident vertebral fractures, of which 32 (52%) were moderate or severe. Thirteen (52%) of the 25 children with incident vertebral fractures also had fractures at baseline. Vertebral fractures at baseline increased the odds of an incident fracture at 12 months by an odds ratio of 7.3 (95% CI, 2.3 to 23.1; P = .001). In addition, for every one standard deviation reduction in spine BMD Z-score at baseline, there was 1.8-fold increased odds of incident vertebral fracture at 12 months (95% CI, 1.2 to 2.7; P = .006). Conclusion: Children with ALL have a high incidence of vertebral fractures after 12 months of chemotherapy, and the presence of vertebral fractures and reductions in spine BMD Z-scores at baseline are highly associated clinical features. © 2012 by American Society of Clinical Oncology
Thrombin-induced lysosomal exocytosis in human platelets is dependent on secondary activation by ADP and regulated by endothelial-derived substances
Pharmacological development of target-specific delocalized lipophilic cation-functionalized carboranes for cancer therapy
PURPOSE:
Tumor cell heterogeneity and microenvironment represent major hindering factors in the clinical setting toward achieving the desired selectivity and specificity to malignant tissues for molecularly targeted cancer therapeutics. In this study, the cellular and molecular evaluation of several delocalized lipophilic cation (DLC)-functionalized carborane compounds as innovative anticancer agents is presented.
METHODS:
The anticancer potential assessment of the DLC-carboranes was performed in established normal (MRC-5, Vero), cancer (U-87 MG, HSC-3) and primary glioblastoma cancer stem (EGFRpos, EGFRneg) cultures. Moreover, the molecular mechanism of action underlying their pharmacological response is also analyzed.
RESULTS:
The pharmacological anticancer profile of DLC-functionalized carboranes is characterized by: a) a marked in vitro selectivity, due to lower concentration range needed (ca. 10 fold) to exert their cell growth-arrest effect on U-87 MG and HSC-3, as compared with that on MRC-5 and Vero; b) a similar selective growth inhibition behavior towards EGFRpos and EGFRneg cultures (>10 fold difference in potency) without, however, the activation of apoptosis in cultures; c) notably, in marked contrast to cancer cells, normal cells are capable of recapitulating their full proliferation potential following exposure to DLC-carboranes; and, d) such pharmacological effects of DLC-carboranes has been unveiled to be elicited at the molecular level through activation of the p53/p21 axis.
CONCLUSIONS:
Overall, the data presented in this work indicates the potential of the DLC-functionalized carboranes to act as new selective anticancer therapeutics that may be used autonomously or in therapies involving radiation with thermal neutrons. Importantly, such bifunctional capacity may be beneficial in cancer therapy
Building an immune-mediated coagulopathy consensus: early recognition and evaluation to enhance post-surgical patient safety
Topical hemostats, fibrin sealants, and surgical adhesives are regularly used in a variety of surgical procedures involving multiple disciplines. Generally, these adjuncts to surgical hemostasis are valuable means for improving wound visualization, reducing blood loss or adding tissue adherence; however, some of these agents are responsible for under-recognized adverse reactions and outcomes. Bovine thrombin, for example, is a topical hemostat with a long history of clinical application that is widely used alone or in combination with other hemostatic agents. Hematologists and coagulation experts are aware that these agents can lead to development of an immune-mediated coagulopathy (IMC). A paucity of data on the incidence of IMC contributes to under-recognition and leaves many surgeons unaware that this clinical entity, originating from normal immune responses to foreign antigen exposure, requires enhanced post-operative vigilance and judicious clinical judgment to achieve best outcomes
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