Isolation and identification of a polyester-polyurethane degrading bacterium Bacillus altitudinis YX8-1 / 生物工程学报

Although polyurethane (PUR) plastics play important roles in daily life, its wastes bring serious environmental pollutions. Biological (enzymatic) degradation is considered as an environmentally friendly and low-cost method for PUR waste recycling, in which the efficient PUR-degrading strains or enzymes are crucial. In this work, a polyester PUR-degrading strain YX8-1 was isolated from the surface of PUR waste collected from a landfill. Based on colony morphology and micromorphology observation, phylogenetic analysis of 16S rDNA and gyrA gene, as well as genome sequence comparison, strain YX8-1 was identified as Bacillus altitudinis. The results of high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed that strain YX8-1 was able to depolymerize self-synthesized polyester PUR oligomer (PBA-PU) to produce a monomeric compound 4, 4'-methylene diphenylamine. Furthermore, strain YX8-1 was able to degrade 32% of the commercialized polyester PUR sponges within 30 days. This study thus provides a strain capable of biodegradation of PUR waste, which may facilitate the mining of related degrading enzymes.

Screening and identification of a polyurethane-degrading bacterium G-11 and its plastic degradation characteristics / 生物工程学报

Polyurethane (PUR) plastics is widely used because of its unique physical and chemical properties. However, unreasonable disposal of the vast amount of used PUR plastics has caused serious environmental pollution. The efficient degradation and utilization of used PUR plastics by means of microorganisms has become one of the current research hotspots, and efficient PUR degrading microbes are the key to the biological treatment of PUR plastics. In this study, an Impranil DLN-degrading bacteria G-11 was isolated from used PUR plastic samples collected from landfill, and its PUR-degrading characteristics were studied. Strain G-11 was identified as Amycolatopsis sp. through 16S rRNA gene sequence alignment. PUR degradation experiment showed that the weight loss rate of the commercial PUR plastics upon treatment of strain G-11 was 4.67%. Scanning electron microscope (SEM) showed that the surface structure of G-11-treated PUR plastics was destroyed with an eroded morphology. Contact angle and thermogravimetry analysis (TGA) showed that the hydrophilicity of PUR plastics increased along with decreased thermal stability upon treatment by strain G-11, which were consistent with the weight loss and morphological observation. These results indicated that strain G-11 isolated from landfill has potential application in biodegradation of waste PUR plastics.

Selective Separation and Preconcentration of Caffeine from Natural and Pharmaceutical Products using New Polyurethane Foams

Abstract Two polyurethane foam-based sorbents (PUF) were synthesized by imprinting and grafting techniques and examined for selective separation and preconcentration of caffeine (CAF) in some pharmaceutical products and in black tea. Molecularly imprinted PUF was synthesized based on hydrogen-bonding interactions between CAF and alizarin yellow G (AYG) and subsequent polymerization into PUF. The static experiments indicated optimum sorption conditions at pH=6.5 and 5.5 for imprinted PUF (AY-IPUF) and grafted PUF (AY-GPUF), respectively. In the online experiments, the suitable preconcentration time was found to be 40 and 20s for (AY-IPUF) and (AY-GPUF), respectively, at a flow rate of 1.75 mL.min-1. Desorption of CAF has been affected by passing 500 µL of 0.05, 0.01 mol.L−1 HCl eluent onto (AY-IPUF) and (AY-GPUF), respectively. The online methods have provided satisfactory enrichment factors of 8.4 and 10.5 for (AY-IPUF) and (AY-GPUF), respectively. The time consumed for preconcentartion, elution and determination steps was 1.48 and 1.05 min, thus, the throughput was 42 and 57 h-1, for (AY-IPUF) and (AY-GPUF), respectively. The developed sorbents were studied for the determination of CAF in pharmaceutical samples which will be helpful to minimize caffeinism. Finally, in silico bioactivity, ADMET and drug-likeness predictive computational studies of caffeine were also carried out

Application of different posture fixation methods in radiotherapy of breast cancer / 中华放射医学与防护杂志

Objective:To study the inter-fraction setup errors, intra-fraction movement of patients and its influence on dosimetry, position repeatability of the supraclavicular area, and the plastic stability of the vacuum cushion and styrofoam when one of the three fixation method are applied in the clinical radiotherapy of breast cancer. The three fixation method include acuum negative pressure pad (VP), acuum negative pressure pad combined with a breast bracket (VB), and polyurethane styrofoam combined with a breast bracket (PB).Methods:A total of 96 breast cancer patients who received radiotherapy at Jiangsu Cancer Hospital during 2019-2021 were collected prospectively for study. They were randomly divided into three groups (VP, VB, and PB). Cone-Beam CT and a planning system were used to obtain inter-fraction setup errors, intra-fraction movement of patients and its influence on dosimetry, position repeatability of supraclavicular area, and the plastic stability of vacuum pad and polyurethane tyrofoam.Results:In the left-right (LR) direction, there were no statistical differences in the inter-fraction setup errors among the three groups. In the superior-inferior (SI) direction, inter-fraction setup errors of the PB group were smaller than those of the VB group (3.02 ± 2.04, 3.65 ± 2.64, t=2.35, P=0.031). In the anterior-posterior (AP) direction, the inter-fraction setup errors of both the VB and PB groups were smaller than those of the VP group (3.36 ± 2.93, 3.14 ± 0.98, 4.03 ± 2.55, t=2.29, 3.11, P< 0.05). In the AP direction, the intra-fraction movement of patients of the VP and PB groups were less than that of the VB group (1.31 ± 0.95, 1.24 ± 0.89, 1.88 ± 1.33, t=-2.04, -2.31, P< 0.05). Moreover, the intra-fraction movement of patients had no statistical effect on the dosimetric distribution ( P> 0.05), and the breast bracket did not improve the position repeatability of the supraclavicular region ( P>0.05). In addition, the plastic stability of polyurethane styrofoam was significantly better than that of the acuum negative pressure pad ( t=2.43-5.63, P< 0.05). Conclusions:The inter-fraction setup errors and intra-fraction movement of patients with breast cancer can be reduced by using PB. Compared to an acuum negative pressure pad, polyurethane styrofoam can keep plastic stability throughout the treatment of the patients.

Avaliação do tratamento recorrente de fístulas anais com plasma rico em plaquetas / Assessment of recurrent anal fistulas treatment with platelet-rich plasma

ABSTRACT BACKGROUND: Surgical treatment of recurrent anal fistulas can lead to numerous complications, including fecal incontinence. Therefore, sphincter preserving techniques are gaining more popularity. OBJECTIVE: The aim of the study was to assess effectiveness of platelet-rich plasma (PRP) therapy in the patients with recurrent cryptoglandular anal fistulas. METHODS: A cohort of 18 patients with anal fistulas was enrolled into a preliminary and prospective trial. They were divided into two groups consisting of eight and ten patients respectively. PRP was injected locally in all patients, however in the group II it was applied after 7 days drainage of fistulas with polyurethane foam or negative pressure wound therapy. On average, three doses of PRP were administered, but with the opportunity to double the number of applications if it was clinically justified. The patients were evaluated in an out-patient department after fortnight and then in 1, 6, and 12 months following the last PRP application. RESULTS: Anal fistulas were closed in 4 (50%) patients from the group I and in 7 (70%) patients form the group II. Although, the difference between both groups was not statistically significant, PRP therapy should be preceded with fistulous tract drainage in all patients. Summarizing, that successful result was achieved in 11 (60%) patients from the entire group of 18 participants. CONCLUSION: The rate of recurrent cryptoglandular anal fistulas closure reaching 60%, after topical treatment with PRP, exceeds the results of other sphincter-saving methods of treatment. Therefore, it might become a novel method of anal fistulas therapy.

RESUMO CONTEXTO: O tratamento cirúrgico de fístulas anais recorrentes pode levar a inúmeras complicações, incluindo incontinência fecal. Portanto, as técnicas de preservação do esfíncter estão ganhando mais popularidade. OBJETIVO: O objetivo do estudo foi avaliar a eficácia da terapia de plasma rico em plaquetas (PRP) nos pacientes com fístulas anais criptoglandulares recorrentes. MÉTODOS: Uma coorte de 18 pacientes com fístulas anais foi inscrita em ensaio preliminar e prospectivo. Eles foram divididos em dois grupos compostos por 8 e 10 pacientes, respectivamente. PRP foi injetado localmente em todos os pacientes, porém no grupo II foi aplicado espuma de poliuretano ou terapia de feridas por pressão negativa após 7 dias de drenagem de fístulas. Em média, foram administradas três doses de PRP, mas com a oportunidade de dobrar o número de aplicações se fosse clinicamente justificado. Os pacientes foram avaliados em ambulatório após quinze dias e depois em 1, 6 e 12 meses após a última aplicação do PRP. RESULTADOS: As fístulas anais foram fechadas em 4 (50%) pacientes do grupo I e em 7 (70%) pacientes do grupo II. Embora a diferença entre ambos os grupos não tenha sido estatisticamente significante, a terapia PRP deve ser precedida de drenagem do trato fístulo em todos os pacientes. Resumindo, esse resultado bem-sucedido foi alcançado em 11 (60%) pacientes de todo o grupo de 18 participantes. CONCLUSÃO: A taxa de fechamento recorrente de fístulas anais criptoglandulares chegando a 60%, após tratamento tópico com PRP, excede os resultados de outros métodos de tratamento que preservam o esfíncter. Portanto, pode se tornar um novo método de terapia das fístulas anais.

Craft Brewery Wastewater Treatment: a Fixed-Bed Single-Batch Reactor with Intermittent Aeration to Remove COD and TN

Abstract This study evaluated an intermittently aerated, fixed-bed, single-batch reactor, with mini BioBob© as biofilm media support, as an alternative treatment of craft brewery wastewater. In order to remove chemical oxygen demand (COD) and total nitrogen (TN), seven conditions were performed in a central composite experimental design (CCD) with different aeration times (1, 2 and 3 h in a 4 h cycle) and hydraulic retention times (HRT) (12, 16 and 20 h). The results showed that the removal of COD and TN were positively affected by increased aeration time and HRT. The condition that presented the best quality effluent was Condition No. 1 (20 h HRT and 3 h aeration), with 209 ± 28 mg COD L-1; 3.00 ± 0.15 mg TKN L-1 ; and 0.67 ± 0.11 mg NO3-N L-1. Kinetic assays showed that the highest values for the substrate removal rate constant, kCOD = 0.1774 h-1 were obtained with the longest aeration time (3 h). The most probable number (MPN) test showed a higher concentration of denitrifying bacteria (heterotrophic), 3.3 x 106, than for AOB and NOB bacteria (autotrophic), which were 4.9 x 103 and 2.7 x 103, respectively. Moreover, it was possible to verify that correcting the influent alkalinity with 7.14 mg CaCO3 for each 1 mg of TKN resulted in better process efficiency. It was concluded that COD and TN can be removed from craft brewery wastewater using an intermittently aerated, fixed-bed, single-batch reactor with mini Biobob© as biofilm media support.

Biomechanical modeling and experimental research of peripherally inserted venous catheter / 国际生物医学工程杂志

Objective:To conduct theoretical analysis and experimental research on peripherally inserted venous catheters, establish theoretical models of interaction between different materials catheters and simulated skin tissues, and test different catheters at the same time to provide theoretical basis and experimental basis for the optimization design.Methods:According to the mechanical properties of the catheter at 25 ℃ and 37 ℃, a finite element model of the catheter and simulate skin tissue was established. The relationship between catheter folds and material and structure during puncture was analyzed, and the stiffness, radiographic properties, etc. were tested experimentally.Results:The performance of the catheter at different temperatures is closely related to its material. The wrinkle situation of the catheter is related to the catheter material and the inclination of the wedge surface. The elastic modulus of the polyurethane (PU) catheter is about 500 MPa and 250 MPa, respectively at room temperature (25 ℃) and body temperature (37 ℃), which meets the clinical needs of high rigidity during puncture and soft material during indwelling. When the catheter structure is the same, the PU catheter is less prone to wrinkles than the fluorinated ethylene propylene copolymer (FEP) catheter. When the catheter material is the same, the smaller the inclination of the wedge surface, the less likely the catheter to wrinkle.Conclusions:Appropriately reducing the inclination of the wedge-shaped surface of the needle of peripherally inserted venous catheters can improve the success rate of puncture. The PU catheters have good mechanical properties, they are not prone to wrinkles during puncture, and their stiffness can be reduced at body temperature, which can not only increase the success rate of puncture, but also reduce the occurrence of complications. Therefore, PU catheters have a better clinical application prospect.

Advances in microbial degradation of plastics / 生物工程学报

Plastics are widely used in daily life. Due to poor management and disposal, about 80% of plastic wastes were buried in landfills and eventually became land and ocean waste, causing serious environmental pollution. Recycling plastics is a desirable approach, but not applicable for most of the plastic waste. Microbial degradation offers an environmentally friendly way to degrade the plastic wastes, and this review summarizes the potential microbes, enzymes, and the underpinning mechanisms for degrading six most commonly used plastics including polyethylene terephthalate, polyethylene, polyvinyl chloride, polypropylene, polystyrene and polyurethane. The challenges and future perspectives on microbial degradation of plastics were proposed.

Isolation and characterization of a polyurethane-degrading bacterium / 生物工程学报

Biodegradation of polyurethane (PUR) pollutants by microorganisms has received widespread attention currently. Identification of microorganisms capable of efficiently degrading PUR plastics is a key point. In this study, a strain P10 capable of degrading PUR was isolated from the plastic wastes, and identified as a bacterium belonging to the genus of Brevibacillus based on colony morphology and 16S rDNA phylogenetic analysis. Brevibacillus sp. P10 was capable of degrading 71.4% of waterborne polyurethane (Impranil DLN) after 6 days growth in MSM medium with DLN as a sole carbon source. In addition, strain P10 can use commercial PUR foam as the sole carbon source for growth. Brevibacillus sp. P10 can degrade 50 mg PUR foam after 6 days growth in MSM medium supplemented with 5% (V/V) LB after optimization of degradation conditions. This indicates that Brevibacillus sp. P10 has potential to be used in biodegradation of PUR waste.

Corrosion Cast- Comparison of Different Techniques and Materials Used in Corrosion Casting

In medical terms, cast refers to the replica obtained after filling a luminal structure with resin to reproduce its morphology. It can be accomplished by removing the soft tissue around it, termed corrosion or maceration. Corrosion casts form very important material in learning morphology of various structures like- vascular tree, tracheobronchial tree, luminal casts of various organs. Vascular casts have been studied using scanning electron microscopy, which has contributed to understanding the biological processes. If the specimen is fixed after resin injection, it can be used for surgical training, medical teaching etc. In the present review, the authors have tried to analyse the technical aspects of corrosion casting. We have also added note on polyurethane foam cast of coronary vessels, which was carried out in our laboratory.

Inhalation risk assessment of naphthalene emitted from deodorant balls in public toilets

The inhalation of naphthalene used as deodorant balls in public toilets could be an important cancer risk factor. The atmospheric concentration of naphthalene in public toilets (C(in)) was estimated both by a polyurethane foam passive air sampler (PUF-PAS) deployed in nine public toilets in Seoul, Korea and by a steady-state indoor air quality model, including emission estimation using Monte-Carlo simulation. Based on the estimated C(in), cancer risk was also assessed for cleaning workers and the general population. The steady-state C(in) estimated using the estimated emission rate, which assumed that air exchange was the only process by which naphthalene was removed, was much greater than the C(in) value measured using PUF-PAS in nine public toilets, implying the importance of other removal processes, such as sorption to walls and the garments of visitors, as well as decreased emission rate owing to wetting of the naphthalene ball surface. The 95 percentile values of cancer risk for workers based on the estimation by PUF-PAS was 1.6×10⁻⁶, whereas those for the general public were lower than 1×10⁻⁶. The results suggested that naphthalene deodorant balls in public toilets may be an important cancer risk factor especially for the cleaning workers.

Inhalation risk assessment of naphthalene emitted from deodorant balls in public toilets

The inhalation of naphthalene used as deodorant balls in public toilets could be an important cancer risk factor. The atmospheric concentration of naphthalene in public toilets (C(in)) was estimated both by a polyurethane foam passive air sampler (PUF-PAS) deployed in nine public toilets in Seoul, Korea and by a steady-state indoor air quality model, including emission estimation using Monte-Carlo simulation. Based on the estimated C(in), cancer risk was also assessed for cleaning workers and the general population. The steady-state C(in) estimated using the estimated emission rate, which assumed that air exchange was the only process by which naphthalene was removed, was much greater than the C(in) value measured using PUF-PAS in nine public toilets, implying the importance of other removal processes, such as sorption to walls and the garments of visitors, as well as decreased emission rate owing to wetting of the naphthalene ball surface. The 95 percentile values of cancer risk for workers based on the estimation by PUF-PAS was 1.6×10⁻⁶, whereas those for the general public were lower than 1×10⁻⁶. The results suggested that naphthalene deodorant balls in public toilets may be an important cancer risk factor especially for the cleaning workers.

Pullout Strength Predictor: A Machine Learning Approach

STUDY DESIGN: A biomechanical study. PURPOSE: To develop a predictive model for pullout strength. OVERVIEW OF LITERATURE: Spine fusion surgeries are performed to correct joint deformities by restricting motion between two or more unstable vertebrae. The pedicle screw provides a corrective force to the unstable spinal segment and arrests motions at the unit that are being fused. To determine the hold of a screw, surgeons depend on a subjective perioperative feeling of insertion torque. The objective of the paper was to develop a machine learning based model using density of foam, insertion angle, insertion depth, and reinsertion to predict the pullout strength of pedicle screw. METHODS: To predict the pullout strength of pedicle screw, an experimental dataset of 48 data points was used as training data to construct a model based on different machine learning algorithms. A total of five algorithms were tested in the Weka environment and the performance was evaluated based on correlation coefficient and error matrix. A sensitive study of various parameters for obtaining the best combination of parameters for predicting the pullout strength was also preformed using the L9 orthogonal array of Taguchi Design of Experiments. RESULTS: Random forest performed the best with a correlation coefficient of 0.96, relative absolute error of 0.28, and root relative squared error of 0.29. The difference between the experimental and predicted value for the six test cases was not significant (p >0.05). CONCLUSIONS: This model can be used clinically for understanding the failure of pedicle screw pullout and pre-surgical planning for spine surgeon.

Mechanical study of polyurethane elastomer and Medpor as the material of artificial auricular scaffold / 中国修复重建外科杂志

Objective: By comparing the mechanics of human auricular cartilage, polyurethane elastic material, and high density polyethylene material (Medpor), to produce theoretical proof on choosing optimal artificial auricular scaffold materials. Methods: The experimental materials were divided into 3 groups with 6 samples in each: the auricular cartilage group (group A), the polyurethane elastic material group (group B), and the Medpor group (group C). With an Instron5967 mechanical testing machine, compression and tensile testing were performed to respectively measure values of compression parameters (including yield stress, yield load, elastic modulus, yield compressibility, compressibility within 2 MPa, and compression stress within 10% strain) and values of tensile parameters (including yield stress, yield load, elastic modulus, yield elongation, elongation within 2 MPa, tensile stress within 1% strain) for comparison. Results: Compression testing: no obvious yield points were observed in the whole process in samples of group B, while obvious yield points were observed in samples of groups A and C. There was no significant difference between groups A and C with respect to yield stress and yield load ( P>0.05); while the yield compressibility in group C was significantly lower than that in group A ( P0.05). Tensile testing: the materials in group B had extremely high tensile strength. The yield stress in groups A and B was significantly higher than that in group C ( P0.05). There was no significant difference with respect to yield load among the 3 groups ( P>0.05); but there was significant difference with respect to yield elongation among the 3 groups ( P0.05). Conclusion: Compared with the Medpor, the polyurethane elastic material is a more ideal artificial auricular scaffold material.

Effect of shaped polyurethane foam dressing on healing of scalp donor sites in the patients with extensive burn / 上海交通大学学报（医学版）

Objective • To evaluate shaped polyurethane foam dressing applied on scalp donor sites in the patients with extensive burn. Methods • The extensively burned adult patients without chronic diseases before injury, who were hospitalized in the Department of Burns and Plastic Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from October, 2017 to October, 2018 were selected. Their scalps as skin donor sites during all past grafting surgeries were divided into two groups by different treatments, i.e. control group and research group. The scalps in control group were covered by gauze clipped by the skulls. Those in research group were covered by shaped polyurethane foam dressing. Afterwards, the wound healing time for the scalps, the intervals between the two adjacent grafting operations, the post-operation pain assessed by visual analogue scale (VAS), and the workload of medical staffs were analyzed and compared between the two groups. Results • The mean time of wound healing for scalp donor sites in research group was (6.77±0.10) d, whereas it was (9.73±0.17) d in control group. For the intervals between the two contiguous operations, they were (9.33±0.16) d in research group and (11.90±0.22) d in control group, respectively. The differences in these two indexes between the two groups were statistically significant (P=0.000). Also, the VAS scores were significantly lower in research group compared with those in control group at all the points after operations (P=0.000). The application of shaped polyurethane foam dressing evidently reduced the treatment time for turning bed and had no need of lamp-aid treatment, so it reduced the workload for medical staffs. Conclusion • The application of shaped polyurethane foam dressing on extensively burned patients' scalp may significantly accelerate its wound healing, shorten the intervals between two grafting operations, which will be beneficial in closing the wounds of these patients earlier eventually. Meanwhile, its application may also alleviate pains of the patients and reduce the burdens of post-operation nursing.

Evaluation of a polyurethane foam dressing impregnated with 3% povidone-iodine (Betafoam) in a rat wound model

PURPOSE: The purpose of this study was to evaluate the efficacy of Betafoam in terms of wound healing and safety. METHODS: Fifty-four male adult Sprague-Dawley rats (weight, 200–250 g) were used in the study. Full-thickness skin defects were created on the back of each rats. The rats were assigned to 6 groups according to the type of wound dressing used (n = 9 for each group): Betafoam, Allevyn-Ag, Mepilex-Ag, Medifoam silver, Polymem-Ag, and gauze. The wound size, histological findings, and amount of DNA on the changed dressings for each group were analyzed and compared. RESULTS: All groups showed an effective decrease in wound size. However, the differences between Betafoam and the other dressings were statistically significant on day 14 (P < 0.05). The number of newly generated blood vessels in the Betafoam group was significantly higher than in the gauze, Allevyn-Ag, and Medifoam silver groups (P < 0.001). In the Betafoam group, the proportion of collagen deposition was highest and showed a significantly superior arrangement of collagen fibers compared with the gauze, Allevyn-Ag, Mepilex-Ag, and Medifoam silver groups. The total content of the remaining DNA counts of the exchanged dressings were significantly lower in the Betafoam group than the others. CONCLUSION: Betafoam is effective in wound healing and provides the best performance amongst the various types of dressing materials in terms of re-epithelialization, angiogenesis, collagen deposition, and tissue invasion.

Comparison of positioning accuracy between personalized polyurethane foam with wing boards and negative pressure vacuum bag in radiotherapy for lung cancer / 中华放射肿瘤学杂志

Objective To compare the positioning accuracy between personalized polyurethane foam with wing boards and negative pressure vacuum bag in radiotherapy for lung cancer using kilovoltage cone beam computed tomography(CBCT). Methods Thirty-nine patients with lung cancer who received chest radiotherapy in our hospital from 2015 to 2016 were enrolled as subjects. In those patients, 20 were immobilized by negative pressure vacuum bags(VB group)and the others by personalized polyurethane foam with wing boards(PF group).CBCT images were acquired weekly and registered with planning CT images. Setup errors in the left-right, superior-inferior, and anterior-posterior directions, three-dimensional(3D) displacement vector,and setup time were recorded. The margin of the planning target volume(PTV)was calculated using the Van Herk formula(2.5∑+0.7σ). Between-group comparison was made by paired t test. Results The PF group had a significant smaller setup error in the y-direction than the VB group (2.54±1.79 vs.3.19±2.14 mm,P=0.03),while there were no significant differences in setup errors in the x-or z-direction between the two groups(1.80± 1.48 vs. 1.90± 1.41 mm, P=0.46;2.14± 1.75 vs. 2.25± 1.75 mm,P=0.35). There were no significant differences in rotational setup errors in the Rx-,Ry-,or Rz-direction between the two groups(1.15°±0.76°vs. 1.15°±0.85°, P=0.50;0.71°±0.60°vs. 0.72°±0.43°, P=0.45;0.62°±0.54° vs. 0.46°±0.30°,P=0.06). The PTV margins in the x?,y?,and z?directions were expanded by 5.56, 8.57, and 7.02 mm, respectively, in the PF group, and by 5.62, 9.27, and 7.23 mm,respectively,in the VB group. The proportion of patients with 3D displacement vectors larger than 5 mm was 40% in the PF group and 45% in the VB group.Conclusions For patients undergoing radiotherapy for lung cancer,personalized polyurethane foam with wing boards can,to a certain extent,reduce the setup error in the superior-inferior direction and PTV margin expansion.[Key words] Lung neoplasms/radiotherapy; Polyurethane foam; Vacuum bag; Setup errors;Margin

Two Cases of Corneal Edema Due to Vaporized Amine

PURPOSE: We report two cases of corneal edema in patients who presented with bilateral blurry vision due to vaporized amines while working in a polyurethane processing plant. CASE SUMMARY: A 28-year-old male presented with bilateral blurred vision. His work involved solidifying polyurethane liquid and he often found himself exposed to polyurethane heat and gas. On examination, the patient's uncorrected visual acuity (UCVA) was 20/40 (right) and 30/50 (left). A slit lamp examination revealed subepithelial microbullae in both eyes. The central corneal thickness (CCT) was also increased in both eyes, measuring 698 µm (right) and 672 µm (left). After prescribing 0.5% moxifloxacin and, 1% fluorometholone eye drops for 3 days in both eyes, the UCVA recovered to 20/40 (right) and 20/20 (left). The CCT decreased to 644 µm (right) and 651 µm (left), and the microbullae improved significantly in the left eye. The second patient was a 34-year-old female who presented with bilateral decreased visual acuity while at work. She worked in a factory that produced car seat filling. Her UCVA was 20/25 (right) and 20/20 (left). The CCT by specular microscopy was 537 µm (right) and 541 µm (left). On slit lamp examination, both eyes demonstrated bilateral central subepithelial edema. The patient did not attend any follow-up outpatient appointments after the initial presentation. CONCLUSIONS: Exposure to vaporized amines such as polyurethane may causereversible corneal toxicityeven without direct contact. Further consideration should be given to ocular safety and protection from amine compounds in the industrial field.

Microbial degradation of polyurethane plastics / 生物工程学报

Plastic pollution has become a global environmental issue, making it necessary to explore the environmental disposal technology for plastic waste. Recently, we and other researchers have individually found microorganisms or enzymes from nature that can degrade synthetic plastic. These findings indicated that the capability of these microorganisms or enzymes to degrade plastic could be used for the disposal of plastic waste. Polyurethane (PUR) was one of the most used general plastic and its plastic waste occupied 30% of the total volume of different plastic waste. This review tried to provide a comprehensive summary of the researches on microbial degradation of PUR plastic in the past 70 years since its invention, and focused on the PUR-degrading fungi, bacteria, genes or enzymes, degradation products and the corresponding biological disposal technologies. We finally proposed the key scientific challenges on the development of high efficient biological disposal for PUR waste in the perspective researches.

Aplicação de resina poliuretânica derivada do óleo de mamona em formas farmacêuticas gastrorretentivas de liberação controlada / Application of polyurethane resin from castor oil in controlled release gastroretentive dosage forms

Polímeros naturais têm sido amplamente utilizados como excipientes farmacêuticos, principalmente por serem biocompatíveis e renováveis. O objetivo deste estudo foi investigar a aplicação da resina poliuretânica derivada do óleo de mamona (RPDOM) em formas farmacêuticas gastrorretentivas de liberação controlada. O trabalho aqui apresentado está dividido em quatro capítulos. O capítulo 1 trata-se de uma visão geral sobre a aplicação dos poliuretanos como sistemas de liberação de fármacos, enfatizando os estudos contendo poliuretanos do óleo de mamona. O capítulo 2 trata-se de uma revisão sistemática sobre sistemas gastrorretentivos de liberação de fármacos. O capítulo 3 trata do desenvolvimento e da caracterização da RPDOM contendo fármaco na sua matriz. Domperidona e cloridrato de verapamil foram escolhidos como fármacos modelos devido ao potencial uso desses em formulações gastrorretentivas. Os estudos físico-químicos mostraram que parte da domperidona interagiu quimicamente com a RPDOM. Visto que não é possível a quebra dessa ligação química durante o estudo de dissolução, parte do fármaco ficou indisponível para liberação. Por outro lado, o verapamil foi incorporado com sucesso na RPDOM pelo método de evaporação do solvente. O verapamil interagiu através de forças intermoleculares com o polímero e esse sistema mostrou um promissor perfil de dissolução. O capítulo 4 trata do desenvolvimento de matrizes monolíticas flutuantes, contendo verapamil como fármaco modelo, espuma de polipropileno como excipiente de baixa densidade e um blend da RPDOM e da celulose microcristalina como sistema matricial. A capacidade de flutuação in vitro das matrizes e o controle da liberação do fármaco foram demonstrados. Por fim, a RPDOM mostrou-se um polímero promissor para o uso em sistemas de liberação controlada de fármacos devido a sua hidrofobicidade e para o uso em sistemas gastrorretentivos flutuantes devido à sua baixa densidade

Natural polymers have been extensively used as pharmaceutical excipients mainly due to their biocompatibility and renewability. The aim of this study was to investigate the application of polyurethane resin from castor oil (PU) in controlled release gastroretentive dosage forms. The work presented herein is divided in four chapters. Chapter 1 is an overview of the application of polyurethanes as drug delivery systems, emphasizing studies containing castor oil-based polyurethanes. Chapter 2 is a systematic review of gastroretentive drug delivery systems. Chapter 3 is about the development and characterization of the PU containing drug in its matrix. Domperidone and verapamil hydrochloride were chosen as model drugs due to their potential use in gastroretentive formulations. Physicochemical studies showed that part of domperidone interacted chemically with PU. Since it is not possible a cleavage of the chemical bond between domperidone and the polyurethane during the dissolution study, part of the drug was not available for release. On the other hand, verapamil was successfully incorporated into PU by solvent evaporation method. Verapamil interacted by intermolecular forces with the polymer and this system showed a promising drug dissolution profile. Chapter 4 shows the development of floating monolithic matrices, containing verapamil as model drug, polypropylene foam as low-density excipient and a blend of PU and microcrystalline cellulose as matrix-forming polymers. The in vitro buoyancy capability of the matrices and the ability to control drug release were demonstrated. Finally, PU proved to be a potential polymer to be used in controlled drug delivery systems due to its hydrophobicity and in gastroretentive floating systems due to its low density