47 research outputs found
ON THE ISSUE OF PLANNING SOWING AGRICULTURAL CROPS WITH THE MINIMUM RISK UNDER THE PRESENCE OF VARIOUS AGROCLIMATIC CONDITIONS
The present paper deals with one problem of quantitative controlling the seeding of the sown area by agricultural crops in different agroclimatic conditions. The considered problem is studied from the standpoint of three strategies: from the seeding planning perspective aiming at minimal risk associated with possible unfavourable agroclimatic conditions (a probabilistic approach is used); from the perspective of obtaining the maximum crops sales profit (a deterministic approach is used); from the perspective of obtaining the maximum crops harvest. For the considered problem, mathematical models are constructed (one probabilistic model and two deterministic models, respectively), their analytical solutions are found, and then, using a specific example, the application of the constructed and solved mathematical models is illustrated as well as the obtained numerical results are analysed.
DKK1 Mediated Inhibition of Wnt Signaling in Postnatal Mice Leads to Loss of TEC Progenitors and Thymic Degeneration
Thymic epithelial cell (TEC) microenvironments are essential for the recruitment of T cell precursors from the bone marrow, as well as the subsequent expansion and selection of thymocytes resulting in a mature self-tolerant T cell repertoire. The molecular mechanisms, which control both the initial development and subsequent maintenance of these critical microenvironments, are poorly defined. Wnt signaling has been shown to be important to the development of several epithelial tissues and organs. Regulation of Wnt signaling has also been shown to impact both early thymocyte and thymic epithelial development. However, early blocks in thymic organogenesis or death of the mice have prevented analysis of a role of canonical Wnt signaling in the maintenance of TECs in the postnatal thymus.Here we demonstrate that tetracycline-regulated expression of the canonical Wnt inhibitor DKK1 in TECs localized in both the cortex and medulla of adult mice, results in rapid thymic degeneration characterized by a loss of DeltaNP63(+) Foxn1(+) and Aire(+) TECs, loss of K5K8DP TECs thought to represent or contain an immature TEC progenitor, decreased TEC proliferation and the development of cystic structures, similar to an aged thymus. Removal of DKK1 from DKK1-involuted mice results in full recovery, suggesting that canonical Wnt signaling is required for the differentiation or proliferation of TEC populations needed for maintenance of properly organized adult thymic epithelial microenvironments.Taken together, the results of this study demonstrate that canonical Wnt signaling within TECs is required for the maintenance of epithelial microenvironments in the postnatal thymus, possibly through effects on TEC progenitor/stem cell populations. Downstream targets of Wnt signaling, which are responsible for maintenance of these TEC progenitors may provide useful targets for therapies aimed at counteracting age associated thymic involution or the premature thymic degeneration associated with cancer therapy and bone marrow transplants
Temperature change in pig rib bone during implant site preparation by low-speed drilling
Rate and causes of lost "gillnets and entangling nets" in the black sea coasts of turkey
In this study, we determined the numbers of gillnets and entangling nets used throughout the Black Sea coasts of Turkey. In addition the number of nets lost over a one year period and principal causes of loss were also calculated. Field studies were carried out at 158 fishing ports in 15 provinces between February 2015 and December 2016. All nets from 3372 fishing boats were counted to determine the total number of gillnets and entangling nets. In order to determine numbers of lost nets, we conducted personal interviews with the skippers of 315 randomly selected fishing boats. Gillnets and entangling nets in the region were divided into 5 categories (Turbot, Whiting, Bonito, Red mullet and Other sp. net) according to target species. Calculations revealed the total number of net panels as 107331 panels. The total number of Turbot, Whiting, Bonito, Red mullet nets and Other sp. net panels were found to be 47144 (43.92%), 22919 (21.35%), 17366 (16.18%), 10461 (9.75%) and 9441 (8.80%) respectively. The average amounts of nets lost per fishing boat were estimated as 2.22±0.74, 1.54±0.47, 0.83±0.43, 1.57±0.57 and 1.56±0.11 panels respectively. The total amount of panels lost throughout the Black Sea was determined as 1626.83 (1.52%) panels/year. © 2018, Central Fisheries Research Inst. All rights reserved.This study was funded by the General Directorate of Agricultural Research and Policies. The data were collected within the framework of TAGEM /HAYSUD/2015/A11/P-09/02?“Investigation?of?Gillnets? and Effects in Black Sea Fisheries" project. The authors are grateful to the anonymous referee for their valuable input on an earlier version of the article and to Alison Kideyş?for?her?linguistic?corrections. Also, we thank Serdar?Sakınan?for?his?contribution
Alkaline sulphite anthraquinone pulping of caucasian spruce (Picea orientalis L.) chips with added sodium borohydride and ethanol
The study determined and compared the yield, viscosity, and chemical and physical properties of the pulps obtained as a result of Alkaline Sulfite–Anthraquinone(AS-AQ) pulping of Caucasian spruce wood with and without the addition of sodium borohydride (ASAB process) and ethanol (ASAE). It was found that the addition of ethanol to the AS-AQ pulping had a favourable influence on the screened yield and kappa number of the pulps. The addition of NaBH4 to the AS-AQ pulping in general also had a favourable influence on these pulps’ indices, provided that the amount added was not higher than 1–2% and the time of pulping was 180 mins. The higher yield of the ASAE pulps resulted from the higher retention of both cellulose and hemicelluloses, while the higher yield of ASAB pulps resulted from the higher retention of hemicelluloses and lignin. Regarding the AS-AQ pulping conditions,a distinct negative effect of modification on the viscosity of the pulps was observed in the case of the NaBH4 a additions to this pulping process. The viscosity reduction was, however, lower with extended pulping time. The static strength properties (tensile index and burst index) of the ASAB and ASAE pulps were in general lower than the AS-AQ pulps. In the case of the tear index, the tendency was similar.The addition of ethanol and especially NaBH4 to the AS-AQ pulping had a distinctly unfavourable influence on the whiteness and brightness of the pulps
Effect of Surgical Drill Guide on Heat Generated From Implant Drilling
Purpose: The purpose of this study was to evaluate the heat generated in bone by 2 implant drill systems in vitro with and without using surgical drill guides. Materials and Methods: Temperature was measured with K type thermocouple in vitro using the bovine femoral cortical bone model. A constant drill load of 2.0 kg was applied throughout the drilling procedures via a drilling rig at a speed of 1,500 rpm. Two different implant drill systems-System A (with external irrigation) and System B (with both external and internal irrigation)-were evaluated. The samples were divided into 4 groups. System A test group 1 (TG1) included the following: 20 samples for drilling with surgical drill guides; control group 1 (CG1): 20 samples for classical implant site preparation. System B test group 2 (TG2) included the following: 20 samples for drilling with surgical drill guides; control group 2 (CG2): 20 samples for classical implant site preparation. Heat was measured at the final drill in the drilling sequence (4.2 and 4.4 mm). Thermocouples were placed at a 1-mm distance from the osteotomy area at depths of 3, 6, and 9 mm. Heat measurements were recorded out to 50 uses by a software program. Data were subjected to the Mann-Whitney U and Kruskal-Wallis tests. The ? level was set a priori at 0.05. Results: The mean maximum temperatures at the depths of 3, 6, and 9 mm using surgical drill guides were 34.2°, 39.7°, and 39.8°C, respectively, although without using surgical drill guides the values were 28.8°, 30.7°, and 31.1°C. A statistically significant difference was found at the depths of 3, 6, and 9 mm between using surgical drill guides and classical drilling procedure. Conclusions: From a heat generation standpoint, we conclude that preparing an implant site with using surgical drill guides generates heat more than classical implant site preparation regardless of the irrigation type. © 2009 American Association of Oral and Maxillofacial Surgeons