Standard Polyethylene Research Articles

Design of biobased poly(butylene succinate) foams by single‐screw extrusion: Identification of relevant rheological parameters controlling foam morphologies

Key relationships between foam morphologies and melt‐state rheological parameters are here exposed for biobased poly(butylene‐succinate) (PBS) and standard petrobased polyethylene (PE) foams processed by single‐screw extrusion. Scanning electron microscopy followed by image analysis revealed cell diameters and densities in the range of 250–700 µm and 3–4.104 cells/cm3, respectively. PBS and PE have similar morphologies except for cell diameters which are slightly higher for PBS foams. The melt index roughly controls foam microstructures but deeper insights are obtained through correlations with shear/extensional rheology experiments. In particular, the melt strength and the strain hardening control the cell growth mechanisms. Concerning the cell density, the shear viscosity in the die plays a key role and agreements with nucleation theories can be discussed based on simulated pressure–velocity profiles using finite element software. In our extrusion conditions, the residence time comes out to have a crucial role with distinct behaviors between PE and PBS indicating a potential modification of the polymer/CO2 interfacial tension. Consequently, an accurate control of the foam morphology seems achievable via a careful selection of the polymer grades and PBS represents a promising alternative to PE for further developments of biobased foams. POLYM. ENG. SCI., 58:503–512, 2018. © 2017 Society of Plastics Engineers

Experimental development of natural convection heat transfer correlations for spiral-helical surface water heat exchangers (1385-RP)

Surface water heat pump systems utilize surface water bodies, such as lakes, reservoirs, and rivers, as heat sources and heat sinks. Closed-loop surface water heat pumps use submerged heat exchangers to extract or reject heat from the surface water body. Heat transfer between the heat exchanger and the lake is generally governed by buoyancy driven natural convection. One form of surface water heat exchanger is the spiral-helical heat exchanger, which is usually fabricated from high-density polyethylene tubing. Though the exterior convective resistance is an important part of the design calculation, convection correlations suitable for spiral-helical surface water heat exchangers are not available. In the current article, the authors cover an experimental study involving heat rejection experiments and heat extraction experiments on nine different spiral-helical configurations with three different high-density polyethylene tube sizes. Standard high-density polyethylene and thermally enhanced high-density polyethylene heat exchangers were also tested and compared. Convection correlations for spiral-helical heat exchangers were developed for heat extraction and heat rejection conditions. Heat transfer rate predicted with the correlations is compared against experimental data.

Revision Total Hip Arthroplasty in the Setting of a Well-Fixed Cup: Early Report on the Cup-in-Cup Technique

AbstractWhen faced with a well-fixed acetabular component during revision total hip arthroplasty (THA) in the setting of recurrent instability, reconstructive options are limited, and consequences can prove dire if removal leads to severe bone loss or pelvic discontinuity. Our aims are to report the surgical technique, early survivorship, radiographic improvements, and complications on a consecutive, retrospective series of 13 hips in 12 patients who were treated with a cup-in-cup surgical technique to address multiply recurrent dislocations in the setting of a well-fixed cup. If determined to be stable and acceptably positioned upon intraoperative assessment, the acetabular component is retained, a second shell is cemented into the preexisting cup, and a dual mobility or standard polyethylene liner bearing is utilized. At 2-year minimum follow-up, the cup-in-cup arthroplasty exhibited an overall 85% survivorship. Two subjects required subsequent revisions: one for infection and one for ongoing instability in the setting of general noncompliance. No revisions were performed for loosening of the cup-in-cup interface. The median affected leg length was increased by 2.8 mm (p = 0.04) and horizontal offset improved by an average of 6.9 mm (p < 0.001). There were a total of four dislocations in two subjects after cup-in-cup revision arthroplasty with no failures at the cup–cup cement interface. Our series demonstrates acceptable early outcomes in terms of improved stability and decreasing the need for further revision surgery while utilizing the cup-in-cup revision arthroplasty technique in situations of recurrent dislocations.

Modeling the effect of biodegradable paper and plastic mulch on soil moisture dynamics

Plastic mulch films are often used in agriculture to conserve soil moisture. Most of the plastic mulch currently used worldwide is made of non-biodegradable polyethylene, which has to be removed and disposed after harvest, incurring significant environmental costs. Biodegradable paper or plastic mulch could offer a valuable alternative to polyethylene. The objective of this study was to compare the effects of biodegradable mulches and standard polyethylene mulch on soil moisture dynamics during a growing season. A field experiment was carried out with pumpkin (Cucurbita pepo), which were irrigated and grown on raised beds covered with the following mulch treatments: no mulch, biodegradable paper, biodegradable plastic, and polyethylene. Soil moisture was measured at 10- and 20-cm depths. A numerical model (HYDRUS-2D) was used to simulate the moisture dynamics under the different mulch treatments, each represented by different boundary conditions at the soil surface. Polyethylene mulch, which created an impermeable surface layer, effectively reduced evaporation and maintained highest water content among the treatments. Biodegradable paper mulch, which was partially permeable to evaporation and rainfall throughout the growing season, resulted in soil moisture that was intermediate between that obtained for no mulch and polyethylene. Biodegradable plastic mulch, which was similar to that of polyethylene mulch initially in terms of effects on soil moisture, disintegrated during the growing season and allowed rainfall to penetrate and water to evaporate from the soil surface. Field data and model simulations both indicate that the biodegradable paper and plastic mulches provide comparable soil moisture dynamics as polyethylene mulch.

A classification-based approach to the patella in revision total knee arthroplasty.

BackgroundThere is a paucity of data to guide management of the patella in revision total knee arthroplasty (RTKA). The purpose of this study was to review our experience with patellar management in RTKA.MethodsWe retrospectively reviewed 422 consecutive RTKAs at a minimum of 2 years (mean, 42 months). Patellar management was guided by a classification that considered stability, size, and position of the implanted patellar component, thickness/quality of remaining bone stock, and extensor mechanism competence.ResultsManagement in 304 aseptic revisions included retention of a well-fixed component in 212 (69.7%) and revision using an all-polyethylene component in 46 (15.1%). Patella-related complications included 5 extensor mechanism ruptures (1.6%), 3 cases of patellar maltracking (1.0%), and 2 periprosthetic patellar fractures (0.7%). Of 118 2-stage revisions for infection, an all-polyethylene component was used in 88 (74.6%), patelloplasty in 20 (16.9%), and patellectomy in 7 (5.9%). Patella-related complications included 4 cases of patellar maltracking (3.4%), 3 extensor mechanism ruptures (2.5%), and 1 periprosthetic patellar fracture (0.8%).ConclusionsSeptic revisions required concomitant lateral releases more frequently (38.1% vs 10.9%; P < .02) but had a similar rate of patellar complications (6.8% vs 3.3%; P = .40). No cases required rerevision specifically for failure of the patellar component. Patients who had a patelloplasty had worse postoperative Knee Society functional scores than those with a retained or revised patellar component. In most aseptic RTKAs, a well-fixed patellar component can be retained. If revision is required, a standard polyethylene component is sufficient in most septic and aseptic revisions. Rerevisions related to the patellar component are infrequent.

Pancreatic and Intestinal Function Post Roux-en-Y Gastric Bypass Surgery for Obesity.

Objectives:Despite the fact that the most effective treatment for morbid obesity today is gastric bypass surgery, some patients develop life-threatening nutritional complications associated with their weight loss.Methods:Here we examine the influence of the altered anatomy and digestive physiology on pancreatic secretion and fat absorption. Thirteen post Roux-en-Y gastric bypass (RYGB) patients who had lost >100 lbs in the first year following surgery and who gave variable histories of gastrointestinal (GI) dysfunction, were selected for study. Food-stimulated pancreatic enzyme secretion and GI hormone responses were measured during 2 h perfusions of the Roux limb with a standard polymeric liquid formula diet and polyethylene glycol marker, with collections of secretions from the common channel distal to the anastomosis and blood testing. Fat absorption was then measured during a 72 h balance study when a normal diet was given containing ~100 g fat/d.Results:Result showed that all patients had some fat malabsorption, but eight had coefficients of fat absorption <80%, indicative of steatorrhea. This was associated with significantly lower feed-stimulated secretion rates of trypsin, amylase, and lipase, and higher plasma peptide-YY concentrations compared with healthy controls. Five steatorrhea patients were subsequently treated with low quantities of pancreatic enzyme supplements for 3 months, and then retested. The supplements were well tolerated, and fat absorption improved in four of five patients accompanied by an increase in lipase secretion, but body weight increased in only three. Postprandial breath hydrogen concentrations were elevated with some improvement following enzyme supplementation suggesting persistent bacterial overgrowth and decreased colonic fermentation.Conclusions:Our investigations revealed a wide spectrum of gastrointestinal abnormalities, including fat malabsorption, impaired food stimulated pancreatic secretion, ileal brake stimulation, and bacterial overgrowth, in patients following RYGB which could be attributed to the breakdown of the normally highly orchestrated digestive anatomy and physiology.

Off-tarp emissions, distribution, and efficacy of carbonated fumigants in a low permeability film tarped field

Carbonated fumigants have been shown to distribute quickly and uniformly in sandy soils and improve pest control efficacy for annual crops. Low permeability films, such as VaporSafe® (TIF), could further improve fumigant dispersion by effectively retaining the fumigant in soil; however, there is a concern that the TIF can lead to higher off-tarp edge emissions. An orchard field trial was conducted to determine the off-tarp emissions, distribution, efficacy, and fate of carbonated Telone® C35 [63.4% 1,3-dichloropropene (1,3-D), 34.7% chloropicrin (CP)] that was shank-injected at 46cm soil depth. Treatments included carbonated fumigants at full- or 2/3 rates and a full rate of regular (nitrogen-pressurized) fumigants covered with standard polyethylene (PE) film, TIF, or no surface seal. Fumigant emissions at the regular tarp edge (25cm from the shank line) peaked at 3.98μgm−2s−1 for 1,3-D and 0.05μgm−2s−1 for CP. The addition of a TIF tarp extension (to 85cm from the shank line) reduce peak off-tarp emissions to <1 and <0.03μgm−2s−1 for 1,3-D and CP, respectively. Fumigant concentration under TIF was usually at least twice that under PE regardless of carbonation. Carbonation at 345KPa with 1.5% of dissolved CO2 did not significantly improve fumigant dispersion in soil profile compared to the conventional nitrogen pressurization. In a citrus nematode bioassay, only the 2/3 rate of carbonated fumigation treatment sealed with PE failed to control nematodes at 25cm away from shank line. This research indicates that a 60-cm TIF extension can effectively reduce off-tarp edge emissions in strip fumigation treatments. While the adaptability of carbonation of fumigants is still questionable, further research efforts are needed in finding effective solutions to control plant parasitic nematodes, which remain a challenge in orchard fumigation.

Engineering and catching performance of five netting materials in commercial prawn-trawl systems

High-strength netting trawls have less drag due to the opportunity to use thinner twine. In prawn/shrimp trawl systems, where large otter boards spread the trawls to high spread ratios, further substantial drag reduction should occur due to the reduced size of otter boards required. Here we conducted two comparative experiments with commercial prawn trawls made from five respective netting materials including standard polyethylene (PE), high tenacity PE and three examples of Ultra High Molecular Weight (UHMW) PE. In the first experiment, a sequence of paired comparisons of engineering performance (drag and spread) was undertaken across all trawls individually connected to one of three pair of different size otter boards; in all cases codends were left open to avoid catch size confounding the measurements. In the second experiment, catch and selectivity performances were assessed by towing the five trawls simultaneously in a five-rig system, with location in the system randomly varied. The trawl-board combination with the best engineering performance for each high-strength material produced a range of drag reduction compared to the best combination for the standard PE trawl: ∼12% for high tenacity PE and ∼19–21% for the three UHMW PE trawls. The high-strength netting trawls caught larger prawns compared to the standard PE trawl, possibly due to (i) increased twine flexibility allowing smaller prawns to escape, and (ii) greater flow of water through the trawl causing increased catch efficiency for larger, more mobile prawns. A strong negative result was the large amount of bycatch for most high-strength netting trawls—it was concluded that this was driven in part by low fishing line tension, exacerbated by higher operating spread ratio. Some evidence was obtained that this could be mitigated by applying layback to the headline.

Ultrathin Alumina Membranes as Scaffold for Epithelial Cell Culture from the Intestine of Rainbow Trout.

Permeable membranes are indispensable for in vitro epithelial barrier models. However, currently available polymer-based membranes are low in porosity and relatively thick, resulting in a limited permeability and unrealistic culture conditions. In this study, we developed an ultrathin, nanoporous alumina membrane as novel cell culture interface for vertebrate cells, with focus on the rainbow trout (Onchorynchus mykiss) intestinal cell line RTgutGC. The new type of membrane is framed in a silicon chip for physical support and has a thickness of only 1 μm, with a porosity of 15% and homogeneous nanopores (Ø = 73 ± 21 nm). Permeability rates for small molecules, namely lucifer yellow, dextran 40, and bovine serum albumin, exceeded those of standard polyethylene terephthalate (PET) membranes by up to 27 fold. With the final goal to establish a representative model of the fish intestine for environmental toxicology, we engineered a simple culture setup, capable of testing the cellular response toward chemical exposure. Herein, cells were cultured in a monolayer on the alumina membranes and formed a polarized epithelium with apical expression of the tight junction protein ZO-1 within 14 days. Impedance spectroscopy, a noninvasive and real time electrical measurement, was used to determine cellular resistance during epithelial layer formation and chemical exposure to evaluate barrier functionality. Resistance values during epithelial development revealed different stages of epithelial maturity and were comparable with the in vivo situation. During chemical exposure, cellular resistance changed immediately when barrier tightness or cell viability was affected. Thus, our study demonstrates nanoporous alumina membranes as promising novel interface for alternative in vitro approaches, capable of allowing cell culture in a physiologically realistic manner and enabling high quality microscopy and sensitive measurement of cellular resistance.

Micro X-Ray Computed Tomography Mass Loss Assessment of Different UHMWPE: A Hip Joint Simulator Study on Standard vs. Cross-Linked Polyethylene.

More than 60.000 hip arthroplasty are performed every year in Italy. Although Ultra-High-Molecular-Weight-Polyethylene remains the most used material as acetabular cup, wear of this material induces over time in vivo a foreign-body response and consequently osteolysis, pain, and the need of implant revision. Furthermore, oxidative wear of the polyethylene provoke several and severe failures. To solve these problems, highly cross-linked polyethylene and Vitamin-E-stabilized polyethylene were introduced in the last years. In in vitro experiments, various efforts have been made to compare the wear behavior of standard PE and vitamin-E infused liners. In this study we compared the in vitro wear behavior of two different configurations of cross-linked polyethylene (with and without the add of Vitamin E) vs. the standard polyethylene acetabular cups. The aim of the present study was to validate a micro X-ray computed tomography technique to assess the wear of different commercially available, polyethylene’s acetabular cups after wear simulation; in particular, the gravimetric method was used to provide reference wear values. The agreement between the two methods is documented in this paper.

A randomised feasibility study comparing total hip arthroplasty with and without dual mobility acetabular component in the treatment of displaced intracapsular fractures of the proximal femur : The Warwick Hip Trauma Evaluation Two : WHiTE Two.

The optimal treatment for independent patients with a displaced intracapsular fracture of the hip remains controversial. The recognised alternatives are hemiarthroplasty and total hip arthroplasty. At present there is no established standard of care, with both types of arthroplasty being used in many centres. We conducted a feasibility study comparing the clinical effectiveness of a dual mobility acetabular component compared with standard polyethylene component in total hip arthroplasty for independent patients with a displaced intracapsular fracture of the hip, for a 12-month period beginning in June 2013. The primary outcome was the risk of dislocation one year post-operatively. Secondary outcome measures were EuroQol 5 Dimensions, ICEpop CAPability measure for Older people, Oxford hip score, mortality and re-operation. Only 20 patients were recruited during this time. The baseline demographics were similar in the two groups and no patient suffered a dislocation. Differences in secondary outcomes were not analysed due to the small sample. This feasibility study suggests that any trial investigating the effectiveness of total hip arthroplasty for fracture of the hip might not be deliverable within the constraints of current systems of care in the United Kingdom. Cite this article: Bone Joint J 2016;98-B:1431-5.

Vitamin E stabilised polyethylene for total knee arthroplasty evaluated under highly demanding activities wear simulation

As total knee arthroplasty patients are getting more active, heavier and younger and structural material fatigue and delamination of polyethylene tibial inserts becomes more likely in the second decade of good clinical performance, it appears desirable to establish advanced pre-clinical test methods better characterizing the longterm clinical material behaviour. Various studies reported in literature attempted to artificially create delamination during in vitro knee wear simulation. We combined artificial ageing to clinically observed oxidation of gamma inert and vitamin E stabilised polyethylene inserts and highly demanding patient activities knee wear simulation based on in vivo load data. With this new method we were able to create clinically relevant subsurface delamination and structural material fatigue on standard polyethylene inserts in vitro.

Tribological characterisation of UHMWPE used in dual mobility total hip prosthesis

Total hip arthroplasty represents an effective solution for bone and joint diseases. Nevertheless, the hip prosthesis has a limited lifetime, in the average around fifteen years. Their improvement, especially their dual mobility is the objective of this study. Therefore, our strategy is focused on improving the material by comparing three types of polyethylene to determine the best one from a friction mechanism and wear rate minimization standpoint. A dual mobility hip prosthesis, containing a two-sided steel and cobalt chrome cup, was tested with a TORNIER hip joint simulator in calf serum. The rubbed surfaces were characterized using scanning electron microscopy (SEM), contact angle measurements, atomic force microscopy (AFM) and confocal fluorescence microscopy. All these multiscale characterization techniques (from nanoscale to millimeter and micro- scale) showed that the velocity accommodation mechanism is different from one type of polyethylene to another. The wear in the case of standard polyethylene was noticeable and the particles were large and scattered between the surface of polyethylene, the surface of the cup and in the calf serum. For the crosslinked polyethylene, the particles coming from the wear, were not as large, but they were spread the same way as the first case. Even though it shares the same accommodation principle on the detachment of the material with the crosslinked polyethylene the wear particles for the crosslinked vitaminized polyethylene were large and they were only found on the surface of the polyethylene.

Visual Assessments of Biodegradable Mulch Deterioration Are Not Indicative of Changes in Mechanical Properties

The functionality of biodegradable mulch can be evaluated in agricultural field settings by visually assessing mulch intactness over time (a measure of deterioration), but it is unclear if mulch deterioration is indicative of mulch degradation as measured by mechanical properties (like breaking force and elongation). This 3-year study (2010–12) examined mulch percent visual deterioration (PVD) during the summer growing season in open-field and high tunnel production systems, and compared these to mulch mechanical properties at mulch installation (12–30 May), midseason (22 July–9 Aug.), and season end (6–25 Oct.), to determine if the field-based measures reliably predict degradation as revealed by changes in mulch mechanical properties. Four different types of biodegradable mulches [two plastic film mulches marketed as biodegradable (BioAgri and BioTelo); one fully biodegradable paper mulch (WeedGuardPlus); and, one experimental spunbonded plastic mulch designed to biodegrade (SBPLA)] were evaluated against a standard nonbiodegradable polyethylene (PE) mulch where tomato (Solanum lycopersicum L. cv. Celebrity) was planted as the model crop. Each year for the 3 years, PVD increased earlier for WeedGuardPlus than the other mulches in both the high tunnel and open field, and WeedGuardPlus had the greatest PVD in both high tunnels and the open field (6% and 48%, respectively). Mechanical strength of WeedGuardPlus also declined by the end of the season both in the high tunnel (up to 46% reduction) and in the open field (up to 81% reduction). PVD of BioAgri and BioTelo reached a maximum of 3% in the high tunnel and 28% in the open field by the end of the season. Mechanical strength of BioAgri and BioTelo did not change over the course of the season in either the open field or high tunnel, even though the ability of these mulches to elongate or stretch declined 89% in the open field and 82% in the high tunnel. SBPLA and PE mulches did not show a change in PVD or mechanical properties in either the high tunnel or the open field. Overall, PVD was three to six times greater by midseason in the open field than in the high tunnels. Although there were significant relationships between visual assessments and various mechanical properties for each mulch except SBPLA, the relationships differed for each mulch when evaluated separately and had coefficients of determination (R2) below 30%. Furthermore, PVD overestimated mechanical deterioration of BioAgri and BioTelo. Results of this study indicate that mulch visual assessments may reflect general trends in changes in certain mechanical properties of the mulch; however, visual assessment and mechanical properties provide different information on deterioration. Each should be used as needed, but not as a substitute for each other.

Highly Cross-linked Polyethylene Provides Decreased Osteolysis and Reoperation at Minimum 10-Year Follow-Up

BackgroundHighly cross-linked polyethylene was introduced to decrease periprosthetic osteolysis and reoperation, but this has not been conclusively proven. MethodsOne surgeon performed 513 consecutive primary total hip arthroplasties (450 patients) using 1 modern, cementless, titanium-mesh acetabular component with screw fixation. This study analyzed the differences in the rate of reoperation and incidence of osteolysis between 133 hips with standard and 112 hips with highly cross-linked polyethylene at minimum 10-year follow-up time. ResultsOf the entire cohort of 513 hips, no acetabular component was removed or revised for aseptic loosening. There were significantly more reoperations in the cohort with standard polyethylene (11 of 133, 8%) than highly cross-linked polyethylene (1 of 112, 1%; P = .03). Osteolysis was seen in 24% (32 of 133 hips) with standard polyethylene, compared with 13% (15 of 112 hips) with highly cross-linked polyethylene (P = .02). These differences occurred despite the presence of patients with greater BMI and higher activity in the cohort with highly cross-linked polyethylene. ConclusionWe continue to use this acetabular component with highly cross-linked polyethylene. Longer follow-up is required to determine the progression of osteolysis.

Dendrimer Dipole Excitation: A New Mechanism for Terahertz Generation

An electro-optic dendrimer (EO dendrimer) material has been designed for high power terahertz generation. An ordinary poly (amidoamine organosilicon) (PAMAMOS) dendrimer was modified via doping and poling to generate a high electro-optic coefficient nanomaterial. Measured EO coefficient varied from ~130 pm/V at 633 nm to ~90 pm/V at 1553 nm. An emitter designed from this EO dendrimer generates milliwatts of continuous wave (CW) terahertz radiation (T-ray) when pumped by a CW laser of suitable wavelength. The mechanism termed as the dendrimer dipole excitation (DDE) works via excitation of the dipole population generated by the doping process. The doping protocol also generates a distribution of dipole moments, as opposed to fixed dipoles in the lattice of a crystalline material; thus, when excited by a suitable pump laser, these dipoles radiate a broadband frequency that range from 0.1 THz to ~ 30 THz. A terahertz time-domain spectrometer (TeraSpectra) was designed with this DDE terahertz source. As a test of the spectrometer functionality, a standard polyethylene calibration was conducted. It was found that TeraSpectra reproduces several known absorbance peaks of polyethylene. It also produces additional absorbance peaks not observed before. It is surmised that the ultra-high sensitivity of T-ray enables observation and discovery of additional absorbance peaks that are not visible via other spectroscopy such as visible, UV, FTIR or Raman.

Processing Temperature of Sustainable Polymer with Thermoplastics by Injection Moulding (Part 1)

This research is started by mixing in-house produced sustainable polymers (SP) from waste cooking oil with the standard low density polyethylene (LDPE) via melt-mixing at low ratios. These mixtures are then compounded via injection molding to produce tensile samples according to ISO 527 (5A). The parameters used in injection molding were initially set to follow the parameters of neat LDPE. Fortunately, by using the quality of individual compounds injected, the parameters obtained for all ratios were the same with neat LDPE. The corresponding mechanical behaviors of each ratio were also examined and the results showed that both tensile strength and strain of the LDPE/SP were better than neat LDPE. Therefore, not only does the presence of SP provide biodegradable properties, but it also improves the mechanical properties. It was concluded that the processing temperature and composition of SP will both influence the quality and mechanical behavior of the product made. This study may aid any intention on processing these in-house produced polymers by injection molding.

Recycling of Cooking Oil Waste into Reactive Polyurethane for Blending with Thermoplastic Polyethylene

Driven by the need of growing to a more sustainable and environmentally friendly future, this research is started by mixing in-house produced biorenewable polymers (BP) from waste cooking oil with the standard low density polyethylene (LDPE) and high density polyethylene (HDPE) via melt-mixing at low ratios. These mixtures are then compounded via injection molding to produce tensile samples. By using the quality of individual compounds injected, the parameters obtained for all ratios of LDPE/BP were the same with neat LDPE whereas some adjustments were required for the HDPE/BP compounds. The corresponding mechanical behaviors of each ratio were also examined and the results showed that both tensile strength and strain of the LDPE/BP were better than neat LDPE. On the other hand, increasing the BP content in HDPE/BP will increase the toughness of the compound if compared to neat HDPE. Therefore, not only does the presence of BP provide renewable properties, but it also improves the mechanical properties. Moreover, the processing temperature and composition of BP will both influence the quality and mechanical behavior of the product made. Thus, this study may aid any intention on processing these in-house produced polymers by injection molding.

A randomized, prospective trial on efficacy and tolerability of low-volume bowel preparation methods for colonoscopy

BackgroundLow-volume bowel preparations have been shown to provide an equivalent cleansing effect as that of a standard 4L polyethylene glycol. However, studies comparing the efficacy of low-volume bowel preparations are few, and the results have been controversial. This study aimed to compare the bowel cleansing quality and tolerability between sodium picosulfate/magnesium citrate and polyethylene glycol with ascorbic acid. MethodsA randomized study was performed with two hundred outpatients who were prospectively enrolled. The Boston Bowel Preparation Scale and the Aronchick scale were used to evaluate the bowel cleansing quality, and bubble scoring was also performed to back up both results. To investigate patients’ preferences and tolerability, a questionnaire was administered. ResultsSodium picosulfate/magnesium citrate was not inferior to polyethylene glycol with ascorbic acid in terms of successful bowel preparation (≥6 Boston scale score: 80% vs. 82%; p=0.718, adequate Aronchick grade: 93% vs. 96%; p=0.352). In addition, sodium picosulfate/magnesium citrate caused fewer gastrointestinal symptoms, and tasted better than polyethylene glycol with ascorbic acid. ConclusionsSodium picosulfate/magnesium citrate was not inferior to polyethylene glycol with ascorbic acid in cleansing efficacy, and was found to have higher tolerability.

Cementless total hip replacement without femoral osteotomy in patients with severe developmental dysplasia of the hip: minimum 15-year clinical and radiological results.

We describe the clinical and radiological results of cementless primary total hip replacement (THR) in 25 patients (18 women and seven men; 30 THRs) with severe developmental dysplasia of the hip (DDH). Their mean age at surgery was 47 years (23 to 89). In all, 21 hips had Crowe type III dysplasia and nine had Crowe type IV. Cementless acetabular components with standard polyethylene liners were introduced as close to the level of the true acetabulum as possible. The modular cementless S-ROM femoral component was used with a low resection of the femoral neck. A total of 21 patients (25 THRs) were available for review at a mean follow-up of 18.7 years (15.8 to 21.8). The mean modified Harris hip score improved from 46 points pre-operatively to 90 at final follow up (p < 0.001). A total of 15 patients (17 THRs; 57%) underwent revision of the acetabular component at a mean of 14.6 years (7 to 20.8), all for osteolysis. Two patients (two THRs) had symptomatic loosening. No patient underwent femoral revision. Survival with revision of either component for any indication was 81% at 15 years (95% CI 60.1 to 92.3), with 21 patients at risk. This technique may reduce the need for femoral osteotomy in severe DDH, while providing a good long-term functional result.