Cost-Effectiveness Analysis of Patiromer in Combination with Renin-Angiotensin-Aldosterone System Inhibitors for Chronic Kidney Disease in Sweden.

OBJECTIVES: Patients with chronic kidney disease (CKD) are commonly treated with renin-angiotensin-aldosterone system inhibitors (RAASi) in order to delay progression of renal disease. However, research has shown that RAASi in CKD patients increases hyperkalaemia (HK) prevalence, which leads to RAASi discontinuation or dose reduction with the loss of benefits on the kidney. Patiromer is a novel therapy for HK treatment and may enable patients to remain on their RAASi regimen. This study aimed to assess the cost-effectiveness of patiromer from a Swedish healthcare perspective. METHODS: A Markov model was developed to evaluate the economic outcomes of patiromer versus no patiromer in HK patients with stage 3-4 CKD taking RAASi. The model consisted of six health states reflecting disease progression and hospitalisations. The analysis mainly considered clinical data from the OPAL-HK trial and national costs. The main outcomes of interest were incremental costs (euro [EUR] 2016) and quality-adjusted life years (QALYs), discounted at 3%, and the incremental cost-effectiveness ratio (ICER). Extensive uncertainty analyses were performed. RESULTS: In comparison to no patiromer, a patiromer patient gained 0.14 QALYs and an incremental cost of EUR 6109 (Swedish krona [SEK] 57,850), yielding an ICER of EUR 43,307 (SEK 410,072)/QALY gained. The results were robust to a range of sensitivity analyses. At a willingness-to-pay threshold of EUR 52,804 (SEK 500,000)/QALY, patiromer had a 50% chance of being cost-effective. CONCLUSIONS: The results indicate that patiromer may demonstrate value for money in Swedish patients with stage 3-4 CKD, by enabling RAASi treatment. However, there is a considerable degree of uncertainty.

Investigation and Feasibility of Combined 3D Printed Thermoplastic Filament and Polymeric Foam to Simulate the Cortiocancellous Interface of Human Vertebrae.

Disorders of the spine are among the most common indications for neurosurgical and orthopedic surgical interventions. Spinal fixation in the form of pedicle screw placement is a common form of instrumentation method in the lower cervical, thoracic, and lumbar spine. A vital principle to understand for the safe and accurate placement of pedicle screws is the palpable difference between the cortical and cancellous bone, both of which have different material properties and compositions. Probing and palpation of the hard cortical bone, also known as the "ventral lamina", covering the neural elements of the spinal canal during screw placement provides manual feedback to the surgeon, indicating an impending breach if continued directional force is applied. Generally, this practice is learned at the expense of patients in live operating room scenarios. Currently, there is a paucity of human vertebra simulation designs that have been validated based on the in vivo ultrastructure and physical properties of human cortical and cancellous bone. In this study, we examined the feasibility of combining three-dimensionally printed thermoplastic polymers with polymeric foam to replicate both the vertebral corticocancellous interface and surface anatomy for procedural education.

Inkjet-printed PEDOT:PSS multi-electrode arrays for low-cost in vitro electrophysiology.

Multi-electrode arrays (MEAs) have become a key element in the study of cellular phenomena in vitro. Common modern MEAs are still based on costly microfabrication techniques, making them expensive tools that researchers are pushed to reuse, compromising the reproducibility and the quality of the acquired data. There is a need to develop novel fabrication strategies, able to produce disposable devices that incorporate advanced technologies beyond the standard metal electrodes on rigid substrates. Here we present an innovative fabrication process for the production of polymer-based flexible MEAs. The device fabrication exploited inkjet printing, as this low-cost manufacturing method allows for an easy and reliable patterning of conducting polymers. Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) was used as the sole conductive element of the MEAs. The physical structure and the electrical properties of the plastic/printed MEAs (pMEAs) were characterised, showing a low impedance that is maintained also in the long term. The biocompatibility of the devices was demonstrated, and their capability to successfully establish a tight coupling with cells was proved. Furthermore, the pMEAs were used to monitor the extracellular potentials from cardiac cell cultures and to record high quality electrophysiological signals from them. Our results validate the use of pMEAs as in vitro electrophysiology platforms, pushing for the adoption of innovative fabrication techniques and the use of new materials for the production of MEAs.

The use of polymeric clips in securing the appendiceal stump during laparoscopic appendicectomy: a systematic review.

PURPOSE: A key step during laparoscopic appendicectomy is securing the appendiceal stump. This has traditionally been achieved using vicryl endoloops, but increasing evidence suggests that the use of polymeric clips (Hem-o-lok) may be a safe and viable method. Current evidence for its clinical use in laparoscopic appendicectomy is unknown. We performed a systematic review of the literature examining the clinical outcomes of laparoscopic appendicectomy using polymeric clips compared to other methods of stump closure. METHODS: A systematic literature review based on PRISMA guidelines was performed using MEDLINE, PubMed, EMBASE and Cochrane library databases between 2000 and 2017. All studies analysing appendiceal stump closure during laparoscopic appendicectomy using polymeric clips compared to other methods of stump closure were included. The methodological quality of the included studies was assessed using the Cochrane Handbook for Systematic Reviews. The review was registered with the PROSPERO register of systematic reviews. RESULTS: Ten studies were included, involving 702 patients, 7 of which were prospective studies and 1 a randomised control trial. Polymeric clips were found to be the cheapest method (€20.47 average per patient) and also had the lowest rate of complications (2.7%) compared to other commonly used closure methods. Meanwhile, operative time and duration of in-patient stay were similar between groups. CONCLUSIONS: Current evidence suggests that polymeric clips are an effective and cost-efficient method for stump closure in laparoscopic appendicectomy for acute appendicitis. Further high-quality evidence is required before polymeric clips can be recommended as the gold standard for appendiceal stump closure.

Health Economic Evaluation of an Ultrathin, Bioresorbable-Polymer Sirolimus-Eluting Coronary Stent Compared to a Thin, Durable-Polymer Everolimus-Eluting Stent.

OBJECTIVES: The study estimated the health economic impact of a latest generation coronary stent with ultrathin struts and bioresorbable polymer coating. BACKGROUND: The recent BIOFLOW V trial, an international FDA approval trial (ClinicalTrials.gov: NCT02389946), has shown that an ultrathin, bioresorbable polymer sirolimus-eluting stent had a significantly lower rate of target lesion failure and target vessel-related myocardial infarction than a thin, durable polymer everolimus-eluting stent at 12 months, driven by a lower rate of peri-procedural myocardial infarction (ppMI). METHODS: We used a Markov model to project mortality and cost outcomes of that lower ppMI rate from a U.S. health system perspective over a 12-month horizon. Model parameters were derived from BIOFLOW V trial data, a systematic literature review and expert interviews. RESULTS: Use of the bioresorbable polymer sirolimus-eluting stent compared to durable polymer everolimus-eluting stent is associated with net reductions in medical cost of $124 (Interquartile Range (IQR) $97-154) per patient in 2018 US$, of which $115 (IQR $76-124) accrues to the initial admission and $10 (IQR $7-72) to cost of follow-up. The lower rate of ppMI translates into a gain of 0.000017 (IQR 0.000011-0.000022) quality-adjusted life-years (QALY) per patient. CONCLUSIONS: Lower ppMI rates of bioresorbable polymer sirolimus-eluting stent translate into reductions in direct medical cost, while improving patient outcomes. Most of the cost reduction is attributed to the initial admission with moderate savings up to 12 months post-discharge.

Bioplastics.

The number of newly developed bioplastics has increased sharply in recent years and innovative polymer materials are increasingly present on the plastics market. Bioplastics are not, however, a completely new kind of material, but rather a rediscovered class of materials within the familiar group of materials known as plastics. Therefore, existing knowledge from the plastics sector can and should be transferred to bioplastics in order to further increase their performance, material diversity and market penetration.

Tailoring Hydrocarbon Polymers and All-Hydrocarbon Composites for Circular Economy.

The world population will rapidly grow from 7 to 9 billion by 2050 and this will parallel a surging annual plastics consumption from today's 350 million tons to well beyond 1 billion tons. The switch from a linear economy with its throwaway culture to a circular economy with efficient reuse of waste plastics is therefore mandatory. Hydrocarbon polymers, accounting for more than half the world's plastics production, enable closed-loop recycling and effective product-stewardship systems. High-molar-mass hydrocarbons serve as highly versatile, cost-, resource-, eco- and energy-efficient, durable lightweight materials produced by solvent-free, environmentally benign catalytic olefin polymerization. Nanophase separation and alignment of unentangled hydrocarbon polymers afford 100% recyclable self-reinforcing all-hydrocarbon composites without requiring the addition of either alien fibers or hazardous nanoparticles. Recycling of durable hydrocarbons is far superior to biodegradation. The facile thermal degradation enables liquefaction and quantitative recovery of low molar mass hydrocarbon oil and gas. Teamed up with biomass-to-liquid and carbon dioxide-to-fuel conversions, powered by renewable energy, waste hydrocarbons serve as renewable hydrocarbon feedstocks for the synthesis of high molar mass hydrocarbon materials. Herein, an overview is given on how innovations in catalyst and process technology enable tailoring of advanced recyclable hydrocarbon materials meeting the needs of sustainable development and a circular economy.

Cost-Effective Biochar Produced from Agricultural Residues and Its Application for Preparation of High Performance Form-Stable Phase Change Material via Simple Method.

A new form-stable composite phase change material (PEG/ASB) composed of almond shell biochar (ASB) and polyethylene glycol (PEG) was produced via a simple and easy vacuum impregnation method. The supporting material ASB, which was cost effective, environmentally friendly, renewable and rich in appropriate pore structures, was produced from agricultural residues of almond shells by a simple pyrolysis method, and it was firstly used as the matrix of PEG. Different analysis techniques were applied to investigate the characteristics of PEG/ASB, including structural and thermal properties, and the interaction mechanism between ASB and PEG was studied. The thermogravimetric analysis (TGA) and thermal cycle tests demonstrated that PEG/ASB possessed favorable thermal stability. The differential scanning calorimetry (DSC) curves demonstrated that the capacities for latent heat storage of PEG/ASB were enhanced with increasing PEG weight percentage. Additionally, PEG/ASB had an excellent thermal conductivity of 0.402 W/mK, which was approximately 1.6 times higher than that of the pure PEG due to the addition of ASB. All the study results indicated that PEG/ASB had favorable phase change properties, which could be used for thermal energy storage.

Cost-Effectiveness Analysis of Patiromer and Spironolactone Therapy in Heart Failure Patients with Hyperkalemia.

BACKGROUND AND OBJECTIVE: Certain patients with heart failure (HF) are unable to tolerate spironolactone therapy due to hyperkalemia. Patiromer is a novel agent used to treat hyperkalemia and has been shown to be efficacious, safe, and well-tolerated. The potential clinical outcomes and economic value of using patiromer and spironolactone in patients with HF unable to otherwise tolerate spironolactone due to hyperkalemia are unclear. The objective of this analysis was to model the potential pharmacoeconomic value of using patiromer and spironolactone in patients with a history of hyperkalemia that prevents them from utilizing spironolactone. METHODS: We performed a cost-effectiveness analysis of treatment with patiromer, spironolactone, and an angiotensin-converting enzyme inhibitor (ACEI) in patients with New York Heart Association (NYHA) class III-IV HF compared with ACEI alone. A Markov model was constructed to simulate a cohort of 65-year-old patients diagnosed with HF from the payer perspective across the lifetime horizon. Clinical inputs were derived from the RALES and OPAL-HK randomized trials of spironolactone and patiromer, respectively. Utility estimates and costs were derived from the literature and list prices. Outcomes assessed included hospitalization, life expectancy, and quality-adjusted life-years (QALYs), costs, and the incremental cost-effectiveness ratio (ICER). One-way and probability sensitivity analyses were performed to test the robustness of the model findings. RESULTS: Treatment with patiromer-spironolactone-ACEI was projected to increase longevity compared with ACEI alone (5.29 vs. 4.62 life-years gained, respectively), greater QALYs (2.79 vs. 2.60), and costs (US$28,200 vs. US$18,200), giving an ICER of US$52,700 per QALY gained. The ICERs ranged from US$40,000 to US$85,800 per QALY gained in 1-way sensitivity analyses. CONCLUSION: Our results suggest that the use of spironolactone-patiromer-ACEI may provide clinical benefit and good economic value in patients with NYHA class III-IV HF unable to tolerate spironolactone due to hyperkalemia.

Cost-effectiveness analysis of biodegradable polymer versus durable polymer drug-eluting stents incorporating real-world evidence.

AIM: Compared with second-generation durable polymer drug-eluting stents (DP-DES), the cost-effectiveness of biodegradable polymer drug-eluting stents (BP-DES) remains unclear in the real-world setting. We assessed the cost-effectiveness of BP-DES in patients with coronary artery disease undergoing percutaneous coronary intervention (PCI). METHODS: We developed a decision-analytic model to compare the cost-effectiveness of BP-DES to DP-DES over 1 year and 5 years from healthcare payer perspective. Relative treatment effects during the first year post-PCI were obtained from a real-world population analysis while clinical event risks in the subsequent 4 years were derived from a meta-analysis of published studies. RESULTS: At 1 year, based on the clinical data analysis of 497 propensity-score matched pairs of patients, BP-DES were associated with an incremental cost-effectiveness ratio (ICER) of USD20 503 per quality-adjusted life-year (QALY) gained. At 5 years, BP-DES yielded an ICER of USD4062 per QALY gained. At the willingness-to-pay threshold of USD50 400 (one gross domestic product per capita in Singapore in 2015), BP-DES were cost-effective. Sensitivity analysis showed that the cost of stents had a significant impact on the cost-effectiveness of BP-DES. Threshold analysis demonstrated that if the cost difference between BP-DES and DP-DES exceeded USD493, BP-DES would not be cost-effective in patients with 1 year of follow-up. CONCLUSIONS: Biodegradable polymer drug-eluting stents were cost-effective compared with DP-DES in patients with coronary artery disease at 1 year and 5 years after PCI. It is worth noting that the cost of stents had a significant impact on the findings.

Water-Soluble Polymers with Strong Photoluminescence through an Eco-Friendly and Low-Cost Route.

Photoluminescence (PL) of nonconjugated polymers brings a favorable opportunity for low-cost and nontoxic luminescent materials, while most of them still exhibit relatively weak emission. Strong PL from poly[(maleic anhydride)-alt-(vinyl acetate)] (PMV) from low-cost monomer has been found in organic solvents, yet the necessity of noxious solvents would hinder its practical applications. Herein, through a novel, eco-friendly, and one-step route, PMV-derived PL polymers can be fabricated with the highest quantum yield of 87% among water-soluble nonconjugated PL polymers ever reported. These PMV-derived polymers emit strong blue emission in both solutions and solids, and can be transformed into red-emission agents easily. These PL polymers exhibit application potentials in light-conversion agricultural films. It is assumed that this work not only puts forward a convenient preparation routine for nonconjugated polymers with high PL, but also provides an industrial application possibility for them.

Economic co-production of poly(malic acid) and pullulan from Jerusalem artichoke tuber by Aureobasidium pullulans HA-4D.

BACKGROUND: poly(L-malic acid) (PMA) is a water-soluble polyester with many attractive properties in medicine and food industries, but the high cost of PMA fermentation has restricted its further application for large-scale production. To overcome this problem, PMA production from Jerusalem artichoke tubers was successfully performed. Additionally, a valuable exopolysaccharide, pullulan, was co-produced with PMA by Aureobasidum pullulans HA-4D. RESULTS: The Jerusalem artichoke medium for PMA and pullulan co-production contained only 100 g/L hydrolysate sugar, 30 g/L CaCO3 and 1 g/L NaNO3. Compared with the glucose medium, the Jerusalem artichoke medium resulted in a higher PMA concentration (114.4 g/L) and a lower pullulan concentration (14.3 g/L) in a 5 L bioreactor. Meanwhile, the activity of pyruvate carboxylase and malate dehydrogenas was significantly increased, while the activity of α-phosphoglucose mutase, UDP-glucose pyrophosphorylase and glucosyltransferase was not affected. To assay the economic-feasibility, large-scale production in a 1 t fermentor was performed, yielding 117.5 g/L PMA and 15.2 g/L pullulan. CONCLUSIONS: In this study, an economical co-production system for PMA and pullulan from Jerusalem artichoke was developed. The medium for PMA and pullulan co-production was significantly simplified when Jerusalem artichoke tubers were used. With the simplified medium, PMA production was obviously stimulated, which would be associated with the improved activity of pyruvate carboxylase and malate dehydrogenas.

Production of poly(malic acid) from sugarcane juice in fermentation by Aureobasidium pullulans: Kinetics and process economics.

Poly(ß-l-malic acid) (PMA) is a biodegradable polymer with many potential biomedical applications. PMA can be readily hydrolyzed to malic acid (MA), which is widely used as an acidulant in foods and pharmaceuticals. PMA production from sucrose and sugarcane juice by Aureobasidium pullulans ZX-10 was studied in shake-flasks and bioreactors, confirming that sugarcane juice can be used as an economical substrate without any pretreatment or nutrients supplementation. A high PMA titer of 116.3g/L and yield of 0.41g/g were achieved in fed-batch fermentation. A high productivity of 0.66g/L·h was achieved in repeated-batch fermentation with cell recycle. These results compared favorably with those obtained from glucose and other biomass feedstocks. A process economic analysis showed that PMA could be produced from sugarcane juice at a cost of $1.33/kg, offering a cost-competitive bio-based PMA for industrial applications.

From square to circular polymeric microchannels by spin coating technology: a low cost platform for endothelial cell culture.

Square microchannels are easy to fabricate by means of micromachining or lithographic techniques. However, in vitro vascular microcapillaries--as well as plug production and microparticle alignment--require mainly circular microchannels that can be used also in applications based on open microchannels. Nowadays, a simple, low cost, and versatile method to fabricate circular microchannels is still missing. Here, we report on a fast, inexpensive, flexible and reproducible method to fabricate circular microchannels by coupling spin coating with micromilled square microchannels. The proposed method is based on the balance between the displacement of liquid PDMS induced by centrifugal forces and the surface tension that tends to keep the liquid accumulated especially in the corners, which become therefore rounded. To show the versatility of the described experimental study we prepared a variety of rounded microchannels, including branched and PMMA-PDMS hybrid configuration microchannels. Finally, an endothelial cell layer was formed by culturing brain endothelial bEnd.3 cells inside the proposed circular microchannels. Results demonstrated a more successful adhesion, growth, and homogeneous distribution of the cells along the circular microchannel than those observed in the square microchannel used as a control.

Cost-effective imprinting combining macromolecular crowding and a dummy template for the fast purification of punicalagin from pomegranate husk extract.

The combination of molecular crowding and virtual imprinting was employed to develop a cost-effective method to prepare molecularly imprinted polymers. By using linear polymer polystyrene as a macromolecular crowding agent, an imprinted polymer recognizable to punicalagin had been successfully synthesized with punicalin as the dummy template. The resulting punicalin-imprinted polymer presented a remarkable selectivity to punicalagin with an imprinting factor of 3.17 even at extremely low consumption of the template (template/monomer ratio of 1:782). In contrast, the imprinted polymer synthesized without crowding agent, did not show any imprinting effect at so low template amount. The imprinted polymers made by combination of molecular crowding and virtual imprinting can be utilized for the fast separation of punicalagin from pomegranate husk extract after optimizing the protocol of solid-phase extraction with the recovery of 85.3 ± 1.2%.

A systematic review of filler agents for aesthetic treatment of HIV facial lipoatrophy (FLA).

HIV facial lipoatrophy (FLA) is characterized by facial volume loss. HIV FLA affects the facial contours of the cheeks, temples, and orbits, and is associated with social stigma. Although new highly active antiretroviral therapy medications are associated with less severe FLA, the prevalence of HIV FLA among treated individuals exceeds 50%. The goal of our systematic review is to examine published clinical studies involving the use of filler agents for aesthetic treatment of HIV FLA and to provide evidence-based recommendations based on published efficacy and safety data. A systematic review of the published literature was performed on July 1, 2015, on filler agents for aesthetic treatment of HIV FLA. Based on published studies, poly-L-lactic acid is the only filler agent with grade of recommendation: B. Other reviewed filler agents received grade of recommendation: C or D. Poly-L-lactic acid may be best for treatment over temples and cheeks, whereas calcium hydroxylapatite, with a Food and Drug Administration indication of subdermal implantation, may be best used deeply over bone for focal enhancement. Additional long-term randomized controlled trials are necessary to elucidate the advantages and disadvantages of fillers that have different biophysical properties, in conjunction with cost-effectiveness analysis, for treatment of HIV FLA.

The Influence of Surface Modification on the Photoluminescence of CdTe Quantum Dots: Realization of Bio-Imaging via Cost-Effective Polymer.

To impart biocompatibility, stability, and specificity to quantum dots (QDs)-and to reduce their toxicity-it is essential to carry out surface modification. However, most surface-modification processes are costly, complicated, and time-consuming. In addition, the modified QDs often have a large size, which leads to easy aggregation in biological environments, making it difficult to excrete them from in vivo systems. To solve these problems, three kinds of conventional polymers, namely, polyvinyl alcohol (PVA, neutral), sodium polystyrene sulfonate (PSS, negative charged), and poly(diallyl dimethyl ammonium chloride) (PDDA, positive charged) were selected to modify the surface of QDs at low cost via a simple process in which the size of the QDs was kept small after modification. The effect of polymer modification on the photoluminescence (PL) properties of the QDs was systematically investigated. High quantum yields (QYs) of 65 % were reached, which is important for the realization of bio-imaging. Then, the cytotoxicity of CdTe QD-polymer composites was systematically investigated via MTT assay using the Cal27 and HeLa cell lines, especially for high concentrations of QD-polymer composites in vitro. The experimental results showed that the cytotoxicity decreased in the order CdTe-PDDA>CdTe>CdTe-PSS>CdTe-PVA, indicating that PSS and PVA can reduce the toxicity of the QDs. An obvious cytotoxicity of CdTe-PVA and CdTe-PSS was present until 120 h for the Cal27 cell line and until 168 h for the HeLa cell line. At last, the Cal27 cell line was selected to realize bio-imaging using CdTe-PSS and CdTe-PVA composites with different emission colors under one excitation wavelength.

Cost utility analysis of urethral bulking agents versus midurethral sling in stress urinary incontinence.

OBJECTIVE: The aim of this study was to determine the cost utility of urethral bulking agents (BA) compared with midurethral slings (MUS) in the treatment of stress urinary incontinence (SUI) in patients without urethral hypermobility. METHODS: A decision tree was constructed to compare the cost utility of urethral BA versus MUS in the setting of SUI without urethral hypermobility. Probability estimates for success, failure, and complications were obtained from the published literature. Immediate-term, short-term, and longer-term complications were accounted for over a 1-year time horizon in the model. One-way and 2-way sensitivity analyses and Monte Carlo simulations were performed to assess the robustness of our results. RESULTS: Our model demonstrated that MUS cost $436,465 more than BA for every 100 women treated in 1 year. Using MUS compared with BA leads to an incremental cost-effectiveness ratio of $70,400 per utility gained. Assuming a willingness to pay of $50,000, this makes MUS not cost-effective as a first-line treatment in many situations. When MUS costs less than $5132, it becomes a cost-effective first-line treatment, and when it costs less than $2035, it is cost saving. CONCLUSIONS: Bulking agents are more cost-effective than MUS over a 1-year time horizon in the treatment of SUI in patients without urethral hypermobility. In women who lack urethral hypermobility, BA remain a cost-effective option in this patient population.

Vertebroplasty Using Calcium Triglyceride Bone Cement (Kryptonite™) for Vertebral Compression Fractures. A Single-Centre Preliminary Study of Outcomes at One-Year Follow-up.

This study assessed the one-year clinical and radiographic outcomes, in terms of pain-relief, vertebral re-fracture and complications, after vertebroplasty (VP) using a new osteoconductive cement (calcium triglyceride bone cement - Kryptonite™ bone cement, Doctors Research Group Inc., Southbury, CT, USA) to treat osteoporotic vertebral compression fractures. Sixteen consecutive osteoporotic patients (12 women and four men, mean age 68+/-10.5) were treated with VP using Kryptonite™ bone cement for a total of 20 vertebral fractures. All the patients complained of a pain syndrome resistant to medical therapy and all procedures were performed under fluoroscopy control with neuroleptoanalgesia using a monopedicular approach in 12 patients and bipedicular approach in four patients. All patients were studied by MR and MDCT and were evaluated with the visual analogue scale (VAS) and the Oswestry disability index (ODI) before treatment and at one and 12 months after the procedure. A successful outcome was observed in 80% of patients, with a complete resolution of pain. Differences in pre and post treatment VAS and ODI at one-year follow-up were significant (P<0.0001). We observed a disk and venous leakage in 66% of patients but only in one case did an asymptomatic pulmonary embolism occur during cement injection. Two cases of vertebral re-fractures at distant metamers were observed during follow-up. VP using Kryptonite bone cement is a helpful procedure that allows complete and long-lasting resolution of painful vertebral symptoms. The cost of the material is very high and the rate of disk and venous leakage is too high compared to standard cement.

Cost-effective nanoporous Agar-Agar polymer/Nickel powder composite particle for effective bio-products adsorption by expanded bed chromatography.

In the present work a novel kind of dense nanoporous composite matrix for expanded bed application has been successfully first prepared with Nickel powder as a densifier and was covered with Agar-Agar layer as a skeleton, through the method of water-in-oil emulsification. Agar-Agar is a porous and inexpensive polymer. In order to fabricate cost-effective adsorbent with favorable qualities Agar-Agar polymer was used. Thereafter, the customized composite particle was modified by pseudo-affinity dye-ligand, Reactive Blue 4 (RB4), aimed at preparing a pseudo-affinity adsorbent (RB4-Agar-Ni) for bioprodut adsorption from aqueous solution. Bovine Serum Albumin (BSA) was selected as a model protein to investigate the adsorption behavior in batchwise and expanded bed chromatography, and the obtained results were evaluated with that of Streamline™ (Amersham-Pharmacia Biotech, Sweden). Spherical appearance and porous structure of composite particles were observed by the optical microscope (OM) and scanning electronic microscope (SEM). The results suggested that the matrices followed the logarithmic normal size distribution with the range of 65-300 µm and average diameter of 126.81-151.47 µm, proper wet density of 1.64-2.78 g/ml, water content of 62.74-34%, porosity of 98-90% and pore size of about 38-130 nm. For better comprehension of the impact of solid phase properties on the performance of the expanded bed, the expansion and hydrodynamic properties of a composite matrix with a series of densities was evaluated and estimated by the retention time distribution method (RTD) in an expanded bed and was compared with that of other matrices. According to obtained results the expansion factors under the same fluid velocity decreased by increasing the matrix density. Moreover, the axial dispersion coefficient (Dax) is the most appropriate parameter for evaluating the stability of expanded bed, on various operating conditions, such as different flow velocity, bed expansion degree, viscosity of the liquid phase and the density of adsorbent. It was observed that the application of matrix with high density was proper for high operation, fluid velocity, since the addition of densifier improves the rigidity of the matrix. Three momentous factors, pH, ionic strength and initial concentration of BSA were analyzed. The best results showed that the adsorption equilibrium isotherms seems to follow a typical Langmuir isotherm and also the maximum adsorption capacity (qm) of BSA on RB4-Agar-Ni (64.01 mg/ml adsorbent) was higher than that on RB4-Streamline commercial adsorbent (about 54 mg.ml adsorbent). Additionally kinetic adsorption processes were characterized by the pseudo-first-order and pseudo-second-order kinetics equations. The experimental data followed the pseudo-first-order kinetic equation. Also the breakthrough curves were investigated. It was found that dynamic binding capacity (DBC) decreased with increasing the flow rate and the values of DBC decreased from 21.08 to 11.15 mg/ml adsorbent when the density of composite beads increased from 1.64 to 2.78 g/ml. All results indicate that the prepared composite is promising for efficient bioproduct adsorption with good hydrodynamic characteristics, high stability and it is suitable for expanded bed usage as a cost-effective adsorbent.