Experimental study on a new type citrate anticoagulant hemodialysate in dogs

Objective:  In this study, we initiated a new hemodialysate with citrate buffer, observed the factors that influence the citrate concentration of solution in hollow fibers when using citrate hemodialysate, and observed the anticoagulant effect and safety of the citrate hemodialysate in the experiment in dogs. Methods:  Ten dogs were given intermittent hemodialysis and were divided into 3 groups according to hemodialysis procedures. Group 1 was saline‐flush hemodialysed with bicarbonate hemodialysate; Group 2 was hemodialysed with citrate hemodialysis without any anticoagulant; Group 3 was hemodialysed with bicarbonate hemodialysate and heparin. ACT, Ca⁺⁺, BUN, Cr, ALT, AST, TBIL, DBIL, Na⁺, Cl⁻,     , and venous pressure were monitored in the animals of each group during hemodialysis. Results:  During the hemodialysis in Group 1, venous pressure increased lastingly, resulting in the failure of hemodialysis for 2 hours. Hemodialysis for 2 hours in Group 2 were all finished successfully. ACT was extended and Ca⁺⁺ decreased obviously in the venous end during hemodialysis. And ALT, AST, Ca⁺⁺, K⁺, Na⁺, Cl⁻,     after the hemodialysis in Group 2 were not changed (P > 0.05). Moreover, the clearance rate of the dialyzers with citrate dialysate increased significantly compared with those of saline‐flush and heparin anticoagulation. Conclusions:  The anticoagulant and dialytic effects of the new type citrate hemodialysis are satisfactory and better than that of saline‐flush.     

Thermosensitive bioadhesive gels for the vaginal delivery of sildenafil citrate: in vitro characterization and clinical evaluation in women using clomiphene citrate for induction of ovulation

Objective: The objective of this study is to develop and characterize in situ thermosensitive gels for the vaginal administration of sildenafil as a potential treatment of endometrial thinning occurring as a result of using clomiphene citrate for ovulation induction in women with type II eugonadotrophic anovulation. While sildenafil has shown promising results in the treatment of infertility in women, the lack of vaginal pharmaceutical preparation and the side effects associated with oral sildenafil limit its clinical effectiveness.

Methods: Sildenafil citrate in situ forming gels were prepared using different grades of Pluronic^® (PF-68 and PF-127). Mucoadhesive polymers as sodium alginate and hydroxyethyl cellulose were added to the gels in different concentrations and the effect on gel properties was studied. The formulations were evaluated in terms of viscosity, gelation temperature (T_sol-gel), mucoadhesion properties, and in vitro drug release characteristics. Selected formulations were evaluated in women with clomiphene citrate failure due to thin endometrium (Clinicaltrial.gov identifier NCT02766725).

Results: The T_sol-gel decreased with increasing PF-127 concentration and it was modulated by addition of PF-68 to be within the acceptable range of 28–37?°C. Increasing Pluronic® concentration increased gel viscosity and mucoadhesive force but decreased drug release rate. Clinical results showed that the in situ sildenafil vaginal gel significantly increased endometrial thickness and uterine blood flow with no reported side effects. Further, these results were achieved at lower frequency and duration of drug administration.

Conclusion: Sildenafil thermosensitive vaginal gels might result in improved potential of pregnancy in anovulatory patients with clomiphene citrate failure due to thin endometrium.     

Factors affecting bonding of metals

Abstract

Adhesives have several advantages over mechanical fastening, and the use of bonding is steadily increasing in many applications. Bonding of primary structures in aircraft has been used for many years and much more research has been directed towards aluminium than any other material. Joint performance depends on the alloy, pretreatment, primer, and adhesive. Many studies of these variables have been made, often making use of modern surface analytical techniques. Informative studies have also been carried out on titanium and steel. Hot, humid conditions, especially combined with stress, can be especially damaging to metal joints. A full understanding of the factors that provide the best resistance to this damaging effect has not yet been achieved. However, stable oxide layers with the correct topography appear critical and selection of the correct pretreatment is therefore of paramount importance.

MST/475     

Factors affecting SEA effectiveness in Estonia

This study addresses the key aspects of the Estonian SEA system and the main factors affecting the effectiveness of SEA. Five dimensions of SEA effectiveness (substantive, pluralist, transactive, normative and transformative) have been examined. The study is also complemented by semi-structured interviews of key actors of the SEA systems (public authorities, SEA experts and environmental NGOs), but also on the authors’ own experiences in analysing and participating in the SEA process. The paper concludes that SEA has become a relatively routine process at national government and local government levels, and effectiveness is affected by the level of assessment of cumulative effects (especially those of climate change, biodiversity loss and green area network), consideration of alternatives and extent of public participation. One of the significant impediments to the effectiveness, however, is the missing SEA follow-up.     

Factors affecting air sparging remediation systems using field data and numerical simulations

Field data from five air sparging sites were used to assess the effect of several soil, contaminant, and air sparging system factors on the removal time and associated costs required to reach specified clean-up criteria. Numerical simulations were also performed to better assess the field data and to expand the data sets beyond the five field sites. Ten factors were selected and evaluated individually over a range of values based on information from practitioners and the literature. Trends in removal time and removal cost to reach a specified clean-up criterion were analyzed to ascertain the conditions controlling contaminant removal with variations in each factors' value. A linear sensitivity equation was used to quantify system dynamics controlling the observed contaminant removal trends for each factor. Factors found most critical across all field sites in terms of removal time and/or cost were contaminant type, sparge pulsing schedule, number of wells, maximum biodecay rate, total soil porosity, and aquifer organic carbon content. Factors showing moderate to low effect included the depth of the sparge point below the water table, air injection rate/pressure, horizontal air conductivity, and anisotropy ratio. At each field site, subsurface coverage of sparged air, sparged air residence time, contaminant equilibrium in the system, contaminant phase distribution, oxygen availability to microbes, and contaminant volatility seem to control the system responses and were affected by one or more of the 10 factors evaluated.     

Factors affecting schedule instability in manufacturing companies

Schedule instability is a major issue in many manufacturing companies. It results in a low service level to customers, high inventory levels, and high costs associated with production changeovers. Much has been written on schedule instability in the literature, but most studies have used simulation and mathematical modelling to look at the internal operations of manufacturing companies. While schedule instability has always been very much a practical problem, there have been few empirical studies presented in the literature. The aim of this research was to obtain the opinions of practitioners on schedule instability, and to identify factors that affect the perceived level of instability experienced by manufacturing companies. An e-mail/web-based survey was administered to practitioners working in the planning and scheduling area. The results suggest that the majority of the respondents perceive schedule instability to be either an important or a very important issue in their operations. Analysis of the responses also shows that schedule instability is affected mainly by external factors, notably relationships with buyers and relationships with suppliers; internal operations have a lower impact. The research moves the debate about schedule instability beyond the current concentration on simulation and mathematical modelling, and from a focus on internal operations to a supply-chain context.     

Factors affecting the hygroexpansion of paper

Paper is a widely used packaging material and is nowadays regaining importance, e.g., as bio-based and biodegradable material. Moreover, new technologies such as polymer–fiber composites, printed electronics and the deep drawing of paper are developing. The process stability and also the resulting quality of paper converting processes such as coating, metallization, printing, and the printing of electronics are highly affected by the hygroexpansion of paper. In order to reduce production instability and to choose and develop paper substrates with ideal characteristics, critical parameters need to be known. This paper offers an extensive overview of those parameters, starting at a molecular and microscopic level with the effect of the constituents and morphology of single fibers, before moving on to paper contents, chemical modifications and additives and finally concluding with paper production and fiber network modification. It was found that the major influences are single fiber sorption, inter-fiber contacts, microfibril angle, fiber morphology (length, width, curliness) and fiber orientation. This review gives new ideas and insights for technologists working in research, development and production optimization of paper-based products.     

Factors affecting the carriage of meat in containers

Changes in trading patterns call for some reappraisal of currently accepted design criteria. The effects of packaging, including vacuum packaging, on the required temperature distribution, and its effect on handling and weight loss are discussed. Proposals are made to improve temperature control and air distribution in integral containers. Examples are quoted covering both in-service and controlled test conditions.     

Factors affecting the temporal stability of semipermanent bilayer coatings in capillary electrophoresis prepared using double-chained surfactants

Surfactants such as didodecyldimethylammonium bromide (DDAB) adsorb onto fused-silica capillaries to form semipermanent bilayer coatings. However, such coatings must be regenerated between runs to maintain efficiency and reproducibility. In this paper, chemical and physical factors affecting the stability of DDAB coatings are investigated. Chemical factors such as ionic strength and the nature of the buffer anion (e.g., from acetate to phosphate), which decrease the critical micelle concentration of DDAB, improve the coating stability. Increasing buffer pH also increases the coating stability. Finally, reducing the capillary diameter and reducing the volume of buffer flushed through the capillary enhance the coating stability. Using 50 mM acetate, pH 5.0, in a 25-microm-i.d. capillary, cationic proteins were separated with efficiencies of 1.05 million plates/m and a run-to-run migration time reproducibility of 0.6-0.8% RSD for 10 successive runs without regeneration of the DDAB coating between runs.     

Factors affecting properties of mechanically-formed building units

The physical and mechanical properties of mechanically-pressed clay building units, whether solid or perforated, are largely improved by deairing. Die-laminations are lessened. Moreover, deairing provides always units of developed strengths. Prepugging, using birollers machinery, proves effective only in rubbing and well mixing the clay mixes before extrusion. In solid machine-pressed building units the direction of extrusion shows the relatively highest value when tested for strength. On the other hand, for the perforated equivalents, this depends, among other factors, on the load-bearing area to which the pressure is applied. However, the size and shape of perforations through the perforated units largely affect the mechanical properties of the latter.     

Factors affecting the development of biodeterioration in wooden constructions

Water leakages are the general cause of moisture stress exceeding the moisture tolerances of constructions. Moisture stress causes biodeterioration (mould, rot and insect damage) in wooden constructions. The degree of damage is affected by the severity and duration of moisture exposure and temperature, together with the sensitivity of the wooden construction to environmental stress. The growth of mould fungi on wooden materials depends mainly on the air humidity, temperature and the surface quality of wood. Long term humidity conditions above a relative humidity (RH) of 80% are a risk for mould growth in pine and spruce sapwood when the temperature is between +5°C and +50°C. Between −5°C and +5°C the growth of mould fungi is slow, and possible only when the relative humidity is above 90%. High nutrient content of the surface can stimulate the mould growth. In fluctuating humidity conditions, the severity and cumulative time of conditions suitable for mould growth are critical factors for the development of mould fungi in constructions. Humidity conditions must be above RH 95% (around the fibre saturation point of wood, wood moisture content about 25–30%) for the spore germination and mycelium activation of brown rot fungi. Under unsuitable conditions, fungi are inactive, but they can become active quickly under suitable conditions. The degree of decay in wood depends on the total time the decay organism is active. The natural durability of wood varies with the environmental conditions, wood characteristics (wood species, sapwood or heartwood, etc.) and the decay organisms. The service time of wooden materials can be extended by modification of the wood.

---

Resume Les eaux d'infiltration sont, en général, responsables de la contrainte due à l'humidité dépassant le seuil de tolérance des constructions en bois. Le degré de détérioration est affecté par la sévérité et la durée de l'exposition à l'humidité et la température, ainsi que par la sensibilité de la construction en bois à la contrainte ambiante. Le développment de moisissures sur des matériaux en bois dépend surtout de l'humidité de l'air, de la température et de la qualité de la surface. Dans des conditions d'humidité à long terme supérieure à une humidité relative de 80%, des moisissures risquent de se développer dans le pin et l'aubier de sapin quand la température se situe entre +5°C et +50°C. Entre −5°C et +5°C, la croissance de champignons est lente et possible seulement si l'humidité relative dépasse 90%. Une teneur importante d'éléments nutritifs à la surface peut stimuler le développement de moisissures. Dans des conditions d'humidité fluctuantes, la réunion et l'accumulation dans le temps de conditions favorables à la croissance de champignons constitute un facteur critique de développement de moisissures. Les conditions d'humidité doivent dépasser une humidité relative de 95% (autour du point de saturation de la fibre, une teneur en humidité d'environ 25 à 30%) pour la germination du spore et l'activation du mycélium de champignons brun rouge. Dans des conditions défavorables, les champignons sont inactifs mais ils peuvent devenir rapidement actifs dans des conditions favorables. Le degré de détérioration du bois dépend de la vie active totale de l'organisme de décomposition. La durabilité naturelle du bois varie avec les conditions ambiantes, les caractéristiques du bois (espèce, aubier ou coeur) et les organismes de décomposition. La durée de vie du bois peut être allongée en le traitant.

     

Factors affecting the interfacial adhesion of ultrahigh-modulus polyethylene fibre–vinylester composites using gas plasma treatment

The interfacial adhesion of ultrahigh-modulus polyethylene (UHMPE) fibre–vinylester composites was improved by the oxygen plasma treatment of the UHMPE fibre. The chemical functional group formations on the UHMPE fibre surface by oxygen plasma treatment were analysed using diffuse reflectance Fourier transform infrared spectroscopy and the morphological changes of the UHMPE fibre surface by plasma etching were observed by scanning electron microscopy. The wettability enhancement by the chemical functional group formation and the mechanical interlocking due to the micropits were important factors in improving the interfacial adhesion of the UHMPE fibre–vinylester composites by oxygen plasma treatment. In order to investigate the relative importance of the two factors, wettability enhancement and mechanical interlocking, in the improved interfacial adhesion of the UHMPE fibre–vinylester composites, nitrogen plasma treatment was also performed. Nitrogen plasma treatment of the UHMPE fibre was proved to be effective in the formation of the micropittings and ineffective in the chemical functional group formation in comparison with the oxygen plasma treatment. The interlaminar shear strengths of the nitrogen-plasma-treated UHMPE fibre–vinylester composites showed almost the same value as those of the oxygen-plasma-treated UHMPE fibre–vinylester composites. The wettability enhancement and mechanical interlocking are important in the improvement of interfacial adhesion of UHMPE fibre–vinylester composites by plasma treatment and mechanical interlocking seems to be more important.     

Factors affecting work of fracture of uPVC film

Essential work of fracture (EWF) approach was used to evaluate the fracture toughness of uPVC film. It was found that the specific essential work of fracture, (w_e) is independent of specimen width, specimen gauge length, loading rate and test temperature, but dependent on the geometry of the test specimens. Test temperature and geometry were the only testing parameters affecting the specific non-essential work of fracture (w_p) in a very significant way. The plastic zone shape factor () was found to be very sensitive to both the geometry and temperature. It was established that both w_e and w_p could be partitioned into components that are linked to yielding (i.e. w_e,y and _yw_p,y) and necking/tearing (i.e. w_e,nt and _ntw_p,nt) processes. The only testing parameter that affected w_e,y was test temperature, whereas w_e,nt was affected by test temperature as well as geometry. All testing parameters used in this study affected the values of _yw_p,y and _ntw_p,nt.     

Citrate anticoagulant hemodialysate in renal failure patients at high risk of bleeding

Objective: The aim of this study was to observe the anticoagulant effect of the new type of citrate anticoagulant hemodialysate in renal failure patients at high risk of bleeding. Methods: 57 patients at high risk of bleeding were given hemodialysis for 4 hours and were divided into 3 groups according to hemodialysis procedures: Group 1 was saline‐flush hemodialysed with bicarbonate hemodialysate. Group 2 was hemodialysed with citrate hemodialysate and with no anticoagulant. Group 3 was hemodialysed with bicarbonate hemodialysate and with nadroparin calcium (a low molecular weight heparin, LMWH) as anticoagulant. Bleeding complication, coagulation of extracorporeal circuit, venous blood pressure, heart rate, QT_C, activated coagulation time (ACT), ionized‐calcium (iCa⁺⁺), total calcium and pH, , Na⁺, K⁺, Cl^?, BUN, Cr, GPT, GST, TBIL, DBIL, as well as the blood cell counts were monitored during hemodialysis, and a scanning electron microscopic (SEM) analysis was used to investigate the morphology of thrombus formation and cellular aggregation on the interior surface of hemodialysis membranes. Results: During the hemodialysis in Group 1, venous blood pressure increased continuously, resulting in the failure of hemodialysis for 4 out of 19 patients. Hemodialysis for 4 hours in Group 2 were all successfully fulfilled. No bleeding episodes occurred. No severe clotting of dialyzers and blood accesses was observed. ACT was extended and iCa⁺⁺ decreased obviously in the venous line, but ACT and iCa⁺⁺ in vivo were normal. pH, tended to increase but not to metabolic alkalosis levels. Na⁺, K⁺, Cl^?, GPT, GST, TBIL, DBIL, as well as the counts of blood cells were all within the normal range. There was no severe thrombus observed by SEM in the hollow fibers. In Group 3, severe bleeding complication happened to 3 out of 19 patients, and one of them died. ACT was extended obviously at the arterial end. Conclusions: The citrate anticoagulant hemodialysate was proved to be practical, safe and effective. So it is indicated for patients with an active or recently active bleeding focus.     

影响一体式平板膜生物反应器临界通量的因素

利用阶梯式通量递增法测定了一体式平板膜-生物反应器中的临界通量,对不同操作条件下测定值的差异进行了考察.通过正交试验设计,研究了曝气强度、污泥浓度(MLSS)和滤液COD(SCOD)三个因素分别在0.8,1.2,1.5 m3/h;10,20,30 g/L和50,100和150 mg/L水平下对临界通量测得值的影响.研究发现,污泥浓度和SCOD均对临界通量测得值呈负影响作用,而曝气强度则起正作用.随着污泥浓度和SCOD的增大,临界通量测得值是逐步减小的;而曝气强度的增大在一定程度上可以提高临界通量值.其中,临界通量测定值受SCOD的影响最大,MLSS次之,曝气强度最小.     

Factors affecting recovery stress in Fe-Mn-Si-Cr-Ni-C shape memory alloys

The effects of the heating temperature, the carbon content, the amount of pre-strain, the annealing temperature, and the conventional training on the recovery stresses at room temperature of cold-drawn Fe-Mn-Si-Cr-Ni-C shape memory alloys were studied. The results showed that the addition of carbon or the refining of grains could more significantly enhance the recovery stress than the conventional training. The recovery stress of a cold-drawn Fe-Mn-Si-Cr-Ni alloy with 0.18%C could reach 565 MPa only after annealed at 1023 K. Its recovery stress was only improved to 452 MPa after it was subjected to annealing at conventional temperature 1373 K and then four cycles of the conventional training. The dominating factors affecting the recovery stress were the amount of the plastic deformation and that of the martensitic transformation induced by the recovery stress in cooling, not the recovery strain under no constraints.     

Factors affecting the sensitivity of gamma-level ring-core magnetometers

A theoretical and experimental analysis has been made of the geometrical and magnetic factors affecting the sensitivity of the ring-core magnetometer first introduced by Geyger in 1961. Using a drive-to-pickup transfer function derived from an assumed dynamic hysteresis loop and a given dc input signal, the second-harmonic output voltage was derived for both current-source and voltage-source driving conditions. Results of the analysis, which were confirmed by experiment, show the following. 1) When a single, diametrically wound (solenoid-type) pickup winding is used with a ring-core sensor, simultaneous minimization of both fundamental and second-harmonic feedthrough can be achieved by a simple rotational adjustment. This optimization is possible only with a circular core. 2) Sensitivity can be increased by increasing frequency, number of pickup turns, dynamic differential permeability, cross-sectional area, and effective sensor length, and by decreasing the dc initial permeability (μ0). 3) The dominant factor affecting the sensitivity is the demagnetizing termmu_{0}K = mu_{0}l^{-1.72} (4A/pi)^{0.86}, which determines the entrance attenuation of the dc signal to be measured. Highest sensitivity is obtained whenmu_{0}Kis small, which requires a low initial permeability, since a large dimensional ratiol/A^{1/2}is usually not attainable. When the demagnetizing term is not small, the sensitivity advantages of the other factors are negated by the input signal attenuation. Power considerations show that increasing sensitivity by raising area, length, or frequency results in increased power consumption. However, increasing sensitivity by using a pickup coil with a larger number of turns or by a sensor core with lower initial permeability can be achieved without additional power.     

Factors affecting dynamic recrystallization of metals and alloys

Abstract

The high-temperature mechanical behaviour of copper, Cu–Al alloys, and nickel has been examined using torsional testing with hollow testpieces in conjunction with microstructural observations on deformed and quenched specimens using both optical and electron microscopy. Dynamic recrystallization occurred in these materials as the restoration process during high-temperature deformation. The factors influencing dynamic recrystallization have been considered, including materials of high stacking fault energy. It was found that the regime of dynamic recrystallization and the transition in flow stress behaviour could be reasonably represented in terms of the Zener–Hollomon parameter. In Cu–Al solid solution alloys, although the addition of the solute aluminium into copper lowered the stacking fault energy, dynamic recrystallization was retarded to higher strains due to the reduced mobility of the grain boundary. By mechanical and microstructural analysis of the behaviour of various single phase metals and alloys during dynamic recrystallization, the factors influencing the behaviour (i.e. stacking fault energy (solute elements), Zener–Hollomon parameter (deformation condition), and strain) can be summarized on a three dimensional schematic.

MST/587