Improved Algorithm for Degree Bounded Survivable Network Design Problem

We consider the Degree-Bounded Survivable Network Design Problem: the objective is to find a minimum cost subgraph satisfying the given connectivity requirements as well as the degree bounds on the vertices. If we denote the upper bound on the degree of a vertex v by b(v), then we present an algorithm that finds a solution whose cost is at most twice the cost of the optimal solution while the degree of a degree constrained vertex v is at most 2b(v) + 2. This improves upon the results of Lau and Singh and that of Lau, Naor, Salavatipour and Singh

Thermal injury healing in the context of neocollagenogenesis induction: preclinical randomized experimental study

Background. The healing of skin wounds having various etiologies is known to involve a multistep process characterized by certain intercellular interactions affecting dermal cells, their attachment, migration, and differentiation. Here, recovery is interpreted as the return of dermis to its original state. The fact is, however, that the dermal extracellular matrix (ECM) is structurally impaired, which suppresses the regulatory and repository functions of the dermis, leading to the formation of a scar that inhibits several biological functions in the affected area and causes aesthetic problems associated with mobility.Objectives. To evaluate the structural features of dermis during wound healing using a calcium-containing biodegradable implant.Methods. The study used 60 rats that were inflicted with a third-degree burn injury (partially damaged dermis). The selected animals were divided into two groups: experimental and control. On post-burn day 14, a calcium-containing biodegradable implant was administered to rats from the experimental group, while a sterile saline solution was used in the control group. Material was sampled at two months (74 days) and four months (134 days). In order to assess the morphological state of the burn area, its sections were stained with hematoxylin and eosin, according to Mallory and Van-Gieson. For the selective detection of collagens, immunohistochemical tests using antibodies to collagen types I and III (Abcam, England) were employed. To characterize dermal cells, the authors used antibodies to vimentin (LabVision, USA), as well as to СD-68 (cluster of differentiation 68), α-SMA (alpha-smooth muscle actin), CD-105 (cluster of differentiation 105), and VEGF (vascular endothelial growth factor) receptors (Abcam, England). The obtained results were processed using the Statistica 6 software (StatSoft, USA).Results. The administration of a calcium-containing biodegradable filler during the burn healing process was found to ensure local fibroblast activation with the formation of collagen types I and III. When the implant residence time was prolonged up to four months, an increase in the number of macrophages expressing CD-68 receptors was observed. Of note is that these cells retained their localization, while α-SMA-expressing cells were localized in both the superficial and deep dermal compartments. The number of cells expressing CD-105 and VEGF rose as well.Conclusion. The use of the biodegradable filler is found to be promising in terms of post-burn dermal regeneration, as well as providing a dermal ECM, whose collagen network composition and assembly are similar to the original. Here, macrophages act as the primary synthesis regulators of the dermal ECM and stimulate fibroblasts, which ensures re-epithelialization and angiogenesis of the inflicted area

Constraints on new interactions from neutron scattering experiments

Constraints for the constants of hypothetical Yukawa-type corrections to the Newtonian gravitational potential are obtained from analysis of neutron scattering experiments. Restrictions are obtained for the interaction range between 10^{-12} and 10^{-7} cm, where Casimir force experiments and atomic force microscopy are not sensitive. Experimental limits are obtained also for non-electromagnetic inverse power law neutron-nucleus potential. Some possibilities are discussed to strengthen these constraints.Comment: 18 pages, 3 figure

Construction of Special Solutions for Nonintegrable Systems

The Painleve test is very useful to construct not only the Laurent series solutions of systems of nonlinear ordinary differential equations but also the elliptic and trigonometric ones. The standard methods for constructing the elliptic solutions consist of two independent steps: transformation of a nonlinear polynomial differential equation into a nonlinear algebraic system and a search for solutions of the obtained system. It has been demonstrated by the example of the generalized Henon-Heiles system that the use of the Laurent series solutions of the initial differential equation assists to solve the obtained algebraic system. This procedure has been automatized and generalized on some type of multivalued solutions. To find solutions of the initial differential equation in the form of the Laurent or Puiseux series we use the Painleve test. This test can also assist to solve the inverse problem: to find the form of a polynomial potential, which corresponds to the required type of solutions. We consider the five-dimensional gravitational model with a scalar field to demonstrate this.Comment: LaTeX, 14 pages, the paper has been published in the Journal of Nonlinear Mathematical Physics (http://www.sm.luth.se/math/JNMP/

Analysis of Value Dimensions in Public Satisfaction with Primary Health Care: Prospective Observational Study

Background. Artificial neural network models can be used to analyze and predict structural components within the value dimension of the main processes in an outpatient clinic as indicators of patient satisfaction.Objective — to form and test the methodology for analyzing and predicting structural components within the value dimension of the main processes in an outpatient clinic, as indicators of patient satisfaction with availability and quality of medical care, using artificial intelligence.Methods. The results of questionnaires administered to 525 patients were used to analyze their satisfaction with GP appointments. A network ensemble consisting of radial basis network and multilayer perceptron was chosen as the basis for a neural network model. The model testing involved five outpatient clinics in Kirov. The total number of respondents comprised 217 patients. Statistical processing included data description and analysis. Qualitative attributes were represented by relative values (P, %). The statistical significance of differences in qualitative data was assessed using the Chi-square test. The correlation between the observed and predicted data was assessed by means of nonparametric Spearman correlation analysis. The value of p <0.05 was chosen as the significance level ( p). Statistical data processing was performed using Statistica 13.0.Results. Analysis of the value dimensions of satisfaction showed a predominance of “pre-appointment” stage: work of a registrar (85.29% significance in the receiving medical services), waiting time for an appointment with a doctor (66.76% respondents noted its significance), duration of waiting directly at the office (important for 69.11% of respondents). “Appointment” stage was formed according to the common procedure of a GP appointment (interview, examination, recommendations) and was assessed from the value perspective of the patient. The priority components included sufficiency of appointment duration (significant in 88.27% of cases), satisfaction with examination (significant in 85.14% of cases), as well as completeness and informativeness of consultation (significant in 89.9% of cases). A strong direct correlation between the observed and predicted data (ρxy = 0.9; p < 0.05) was found out. Statistically significant differences between the observed and predicted levels of general patient satisfaction were not revealed in all medical organizations.Conclusion. The suggested neural network models can be used as the basis when creating information management systems that monitor meeting the effectiveness criteria for a new model of a medical organization; as well as an essential support for administrative decisions related to organizing the optimal patient management

10KP: A phylodiverse genome sequencing plan.

Understanding plant evolution and diversity in a phylogenomic context is an enormous challenge due, in part, to limited availability of genome-scale data across phylodiverse species. The 10KP (10,000 Plants) Genome Sequencing Project will sequence and characterize representative genomes from every major clade of embryophytes, green algae, and protists (excluding fungi) within the next 5 years. By implementing and continuously improving leading-edge sequencing technologies and bioinformatics tools, 10KP will catalogue the genome content of plant and protist diversity and make these data freely available as an enduring foundation for future scientific discoveries and applications. 10KP is structured as an international consortium, open to the global community, including botanical gardens, plant research institutes, universities, and private industry. Our immediate goal is to establish a policy framework for this endeavor, the principles of which are outlined here

On the issue of obtaining platelet-rich plasma

Objective: To determine the optimal technological modes for the preparation of platelet-rich plasma (PRP) using standard laboratory equipment.Material and methods: Blood for the research was taken from 25 healthy volunteers. Its centrifugation was performed on a standard CM-6M laboratory centrifuge using various modes and two types of vacuum tubes with lithium heparin containing separation gel and without it. The number of platelets and leukocytes was calculated in the upper, lower and middle layers of the obtained plasma sample.Results: Plasma samples obtained during centrifugation modes from 415 to 1660 g for 10 minutes using test tubes that do not contain separation gel are optimal in terms of the number of platelets. Plasma intake from the lower layer of the obtained sample after centrifugation is always accompanied by the inclusion of leukocytes in its composition, which can lead to undesirable tissue reactions when it is used.Conclusion: To obtain PRP, it is possible to use standard laboratory equipment in the centrifugation mode from 415 to 1660 g for 10 minutes using test tubes that do not contain separation gel. Plasma sampling for clinical use should be carried out from the middle layer of the obtained sample

Comparative Evaluation of Biomechanical Characteristics of Acellular Dermal Matrix for Hernioplasty

Background. With the introduction of synthetic mesh implants into clinical practice, the recurrence rate of postoperative ventral hernias was signifi cantly reduced. The extensive use of synthetic implants led to the development of specifi c complications. The development of biological implants, based on extensively purifi ed decellularized collagen matrix of xenogeneic origin is highly relevant due to the fact that, unlike synthetic analogues, they have a biological origin and biodegrade in a natural way, gradually being replaced with newly formed connective tissue. The use of bioprostheses reduces the risk of complications.Objectives. To conduct a comparative evaluation of the biomechanical characteristics of acellular dermal matrix, obtained by detergent-enzymatic decellularization, and commercially distributed Permacol™ matrix.Methods. Acellular dermal matrix (ADM) was created by using samples of native skin of pig of Landras breed aged 4 months. The dermis was processed by means of detergent-enzymatic method. In order to evaluate and compare the mechanical properties of acellular dermal matrix, the biological samples were divided into 2 groups of 15 samples each. The fi rst group included acellular dermal matrix samples, the second group — native samples of pigs unprocessed dermis. The control group consisted of samples of PermacolTM Surgical Implant, xenotransplant for hernioplasty approved for use in the Russian Federation (Covidien, France). All samples were tested wet using universal testing instrument Instron 1122. MedCalc Statistical Software (Belgium) was used for statistical processing of the study results.Results. In the present study, pig dermis was processed using a detergent-enzymatic method to produce ADM. Routine histological examination confi rmed the removal of all cellular elements, and at the same time it was proven that the native structure of the dermis remained intact during its processing. The mechanical characteristics of xenogenic ADM were further determined. Its tensile strength was 9.1 ± 0.6 MPa (910 N/cm2 ), elongation to break was 21.1 ± 2.3%, and elastic modulus was 50.0 ± 1.6 MPa. These characteristics largely corresponded to the strength characteristics of native pig dermis and far exceeded the necessary physiological parameters. PermacolTM control was tested in two directions (longitudinal and transverse). In the longitudinal direction, the sample had higher mechanical characteristics: strength — 12.0 ± 1.7 MPa, elongation to break — 29.7 ± 2.4%, stiffness modulus — 47.2 ± 6.5 MPa. In the transverse direction, all indicators were 1.5–2 times lower.Conclusion. The developed xenogeneic biological implant in the form of ADM demonstrates rather good characteristics of plasticity, tensile strength and elasticity, to be used as a biological endoprosthesis for plasty of hernia defects of the abdominal wall of any size and shape