Preparation of co-electrospinning membrane loaded with simvastatin and substance P to accelerate bone regeneration by promoting cell homing, angiogenesis and osteogenesis.

Bone regeneration is a complex process that requires the coordination of various biological events. Developing a tissue regeneration membrane that can regulate this cascade of events is challenging. In this study, we aimed to fabricate a membrane that can enrich the damaged area with mesenchymal stem cells, improve angiogenesis, and continuously induce osteogenesis. Our approach involved creating a hierarchical polycaprolactone/gelatin (PCL/GEL) co-electrospinning membrane that incorporated substance P (SP)-loaded GEL fibers and simvastatin (SIM)-loaded PCL fibers. The membrane could initiate a burst release of SP and a slow/sustained release of SIM for over a month. In vitro experiments, including those related to angiogenesis and osteogenesis (e.g., migration, endothelial network formation, alkaline phosphatase activity, mineralization, and gene expression), clearly demonstrated the membrane's superior ability to improve cell homing, revascularization, and osteogenic differentiation. Furthermore, a series of in vivo studies, including immunofluorescence of CD29+/CD90+ double-positive cells and immunohistochemical staining for CD34 and vWF, confirmed the co-electrospinning membrane's ability to enhance MSC migration and revascularization response after five days of implantation. After one month, the Micro-CT and histological (Masson and H&E) results showed accelerated bone regeneration. Our findings suggest that a co-electrospinning membrane with time-tunable drug delivery could advance the development of tissue engineering therapeutic strategies and potentially improve patient outcomes.

Laparoscopic versus robot-assisted pyeloplasty in infants and young children.

OBJECTIVE: To compare the characteristics of conventional laparoscopic pyeloplasty (LP) and robotic-assisted laparoscopic pyeloplasty (RALP) in infants and young children with ureteropelvic junction obstruction (UPJO). METHODS: We performed a retrospective study of patients (age: 0-36 months) who underwent dismembered pyeloplasty (Anderson-Hynes) with the fourth-generation RALP or traditional LP between April 2020 and December 2020. RESULTS: A total of 33 patients with UPJO were enrolled: 12 underwent RALP (9 left side; 3 right side) and 21 underwent LP (18 left side; 3 right side). In the RALP group, the median patient age was 17 months (range: 5-36 months). In the LP group, the median patient age was 9 months (range: 2-36 months) (P = 0.182). The mean operation times were 120.25 ± 37.54 min (RALP) and 156.10 ± 51.11 min (LP) (P = 0.042), and the mean lengths of hospital stay were 6.42 ± 1.62 days (RALP) and 8.19 ± 2.25 days (LP) (P = 0.023). Removal of the drainage tube was performed after 3.08 ± 0.69 days (RALP) and after 4.76 ± 1.81 days (LP) (P = 0.001). The postoperative pain showed no significant difference. The mean hospitalization costs were 61464.75 ± 2800.53 yuan (RALP) and 22169.52 ± 3442.15 yuan (LP) (P < 0.001). The mean follow-up time was 10-18 months. Significant improvements in the anteroposterior diameter and parenchymal thickness were observed after surgery. Conversion to laparotomy was not performed. No short-term complications occurred during postoperative hospitalization and follow-up. CONCLUSION: RALP has the advantages of less trauma and faster recovery. It can be safely and effectively performed in infants and young children, and its effectiveness is similar to that of traditional LP.

Improvement in osteogenesis, vascularization, and corrosion resistance of titanium with silicon-nitride doped micro-arc oxidation coatings.

Titanium (Ti) implants have been widely used for the treatment of tooth loss due to their excellent biocompatibility and mechanical properties. However, modifying the biological properties of these implants to increase osteointegration remains a research challenge. Additionally, the continuous release of various metal ions in the oral microenvironment due to fluid corrosion can also lead to implant failure. Therefore, simultaneously improving the bioactivity and corrosion resistance of Ti-based materials is an urgent need. In recent decades, micro-arc oxidation (MAO) has been proposed as a surface modification technology to form a surface protective oxide layer and improve the comprehensive properties of Ti. The present study doped nano silicon nitride (Si3N4) particles into the Ti surface by MAO treatment to improve its corrosion resistance and provide excellent osteoinduction by enhancing alkaline phosphatase activity and osteogenic-related gene expression. In addition, due to the presence of silicon, the Si3N4-doped materials showed excellent angiogenesis properties, including the promotion of cell migration and tubule formation, which play essential roles in early recovery after implantation.

Congenital vaginal obstruction in a female with Cornelia de Lange syndrome: A case report.

Cornelia de Lange syndrome (CdLS) is a rare genetic disease involving multiorgan systems that varies in clinical manifestations. Female genital abnormalities in patients with CdLS are rarely reported, and current guidelines for CdLS contain little information related to female genital abnormalities. We report a case of classic CdLS with an NIPBL gene pathogenic variant in a 4.5-year-old girl who experienced recurrent urinary tract infections (UTIs) with vesical tenesmus. Urogenital physical and imaging examinations revealed external vaginal orifice obstruction and bilateral vesicoureteral reflux (VUR). Vaginal diaphragm-like tissue resection and vaginal orifice plasty were performed on this patient. The symptoms of urination disorders and recurrent UTIs, as well as VUR grading, improved after relieving the vaginal obstruction during the operation. For female CdLS patients, especially those with VUR, it is necessary to check for genital abnormalities and perform timely treatment, which is of great significance in improving urination disorder symptoms, reducing resistance during voiding, decreasing the occurrence of secondary VUR, and controlling recurrent UTIs.

Vitamin D and curcumin-loaded PCL nanofibrous for engineering osteogenesis and immunomodulatory scaffold.

The accelerating bone healing process is still a major challenge in clinical orthopedics, especially in critical-sized bone defects. Recently, Nanofiber membranes are showing increasing attention in the biomedical field due to their good biocompatibility, mechanical stability, and the ability to work as a drug carrier to achieve localized and sustained drug delivery. Herein, a multifunction nanofiber membrane loaded with vitamin D (Vit D) and curcumin (Cur) was successfully fabricated using electrospinning technology. In addition, we innovatively modified Vit D with PEG to improve the hydrophilicity of PCL nanofibers. The vitro results of CCK-8, alkaline phosphatase (ALP) and mineralization demonstrated that the PCL/Vit D-Cur membrane had great potential for enhancing the proliferation/differentiation of osteoblasts. Moreover, the synergistic effect of Vit D-Cur loaded PCL nanofiber membrane showed a superior ability to improve the anti-inflammatory activity through M2 polarization. Furthermore, in vivo results confirmed that the defect treated with PCL/Vit D-Cur nanofiber membrane was filled with the newly formed bone after 1 month. These results indicate that the Vit D/Cur loaded membrane can be applied for potential bone regeneration therapy.

Enhancing ink adhesion of specialty paper using an interpenetrating polyvinyl alcohol-blocked polyurethane polymer network sizing system.

The printing quality and strength of specialty papers such as money, maps, newspapers and bank notes have been a significance challenge in recent years. The adhesive effect between ink and paper is depend on both the secondary binding force between the molecules and the mechanical anchoring effect of the ink on the paper. Also, the porous and fibrous structures of base paper restrain its application in printed products because of the strong capillary effect leading to the diffusion of ink particles. To address the problems involved in ink diffusion and mechanical reinforcement, surface sizing is an attractive choice from the perspective of paper handling. Herein, the surface sizing system of specialty paper with an interpenetrating polyvinyl alcohol-blocked polyurethane polymer network was applied to fabricate paper of high ink adhesive properties. In the case of the same external factors (gluing temperature, drying time, etc.), the surface sizing effect of paper samples (sizing with TBPU, polyvinyl alcohol and TBPU/PVA system) were evaluated by infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle measurements and scanning electron microscopy. Some of the pure cotton pulp paper with surface sizing treatment was treated via adhering inks to paper by spraying, smearing and soaking. The bonding strength was tested by peel-off tape tests, soaking tests, and simulated washing tests. The results showed that the water contact angle of the sized-paper increased from 67.6° to 89.7°. The mechanical properties had been greatly improved after treatment and SEM, AFM and XPS analyses indicated an increase in surface roughness and the oxygen-containing polar groups (C[double bond, length as m-dash]O, C-OH, -NH-COO- and COOH) enhanced the fixation of ink particles on the fiber surface. These tests indicated that the novel composite system of TBPU/PVA could endow specialty paper with superb mechanical properties and more than 90% ink retention rate. All these advantages of this composite system may contribute to its wide application in the fields of papermaking and printing.

High proportion strontium-doped micro-arc oxidation coatings enhance early osseointegration of titanium in osteoporosis by anti-oxidative stress pathway.

The excessive accumulation of reactive oxygen species (ROS) under osteoporosis precipitates a microenvironment with high levels of oxidative stress (OS). This could significantly interfere with the bioactivity of conventional titanium implants, impeding their early osseointegration with bone. We have prepared a series of strontium (Sr)-doped titanium implants via micro-arc oxidation (MAO) to verify their efficacy and differences in osteoinduction capabilities under normal and osteoporotic (high OS levels) conditions. Apart from the chemical composition, all groups exhibited similar physicochemical properties (morphology, roughness, crystal structure, and wettability). Among the groups, the low Sr group (Sr25%) was more conducive to osteogenesis under normal conditions. In contrast, by increasing the catalase (CAT)/superoxide dismutase (SOD) activity and decreasing ROS levels, the high Sr-doped samples (Sr75% and Sr100%) were superior to Sr25% in inducing osteogenic differentiation of MC3T3-E1 cells and the M2 phenotype polarization of RAW264.7 cells, thus enhancing early osseointegration. Furthermore, the results of both in vitro cell co-culture and in vivo studies also showed that the high Sr-doped samples (especially Sr100%) had positive effects on osteoimmunomodulation under the OS microenvironment. Ultimately, the collated findings indicated that the high proportion Sr-doped MAO coatings were more favorable for osteoporosis patients in implant restorations.

JK-2 loaded electrospun membrane for promoting bone regeneration.

Hydrogen sulfide (H2S) has been as an essential gasotransmitter and a potential therapeutic approach for several biomedical treatments such as cardiovascular disorders, hypertension, and other diseases. The endogenous and exogenous H2S also plays a crucial role in the bone anabolic process and a protective mechanism in cell signalling. In this study, we have utilized two types of polymers, polycaprolactone (PCL) and gelatin (Gel), for the fabrication of JK-2 (H2S donor) loaded nanofibrous scaffold via electrospinning process for bone healing and bone tissue engineering. Comparing the PCL/Gel and PCL/Gel-JK-2 scaffolds, the latter demonstrated enhanced cell adhesion and proliferation capabilities. Furthermore, both experimental scaffolds have been subjected to an in vivo experiment for 4 and 8 weeks in a bone-defect model of a rabbit to determine their biological responses under physiological conditions. There was an obvious increase in bone regeneration in the PCL/Gel-JK-2 group compared to the control and PCL/Gel groups. These results indicate the use of PCL/Gel scaffolds loaded with JK-2 should be considered for possible bone regeneration.

Asymptomatic obstructive hydronephrosis associated with diabetes insipidus: a case report and review.

The treatment of asymptomatic hydronephrosis due to ureteropelvic junction obstruction (UPJO), as well as the timing and indications for surgical intervention, remain controversial. Diabetes insipidus (DI) is a rare disease in infants that is known to cause non-obstructive hydronephrosis, while its association with obstructive hydronephrosis has not been reported. Some studies have found that increased water intake is a predisposing risk factor of developing hydronephrosis. However, there are no studies or guidelines that indicate the specific follow-up intervals and surgical indications for mild hydronephrosis if predisposing risk factors persist. A 46-month-old boy was admitted to our Urology Department with a history of Society of Fetal Urology (SFU) Grade 2 prenatal left hydronephrosis, which was stable at SFU Grade 1-2 at regular postnatal follow-ups. The patient developed polydipsia and polyuria three months prior to admission, then he was considered as primary polydipsia by endocrinology and was treated with fluid restriction while the examination was negative. Renal ultrasound at follow-up demonstrated severe left hydronephrosis with an anterior-posterior diameter (APD) of 6.25 cm three months after symptom onset. Diuretic renography (DR) revealed a renal function of 13.7% with a glomerular filtration rate (GFR) of 11.25 mL/min. The patient was otherwise asymptomatic without any abdominal pain or vomiting. He underwent left pyelostomy immediately as well as laparoscopic left dismembered ureteropelvioplasty after three months, and a diagnosis of UPJO was confirmed. The patient had an uncomplicated postoperative recovery and the result of follow-up renal ultrasound was stable. However, the symptoms of polydipsia and polyuria did not improve significantly. He underwent pituitary magnetic resonance imaging (MRI) and pathological examination, the results of which were consistent with central DI caused by Langerhans cell hyperplasia four months postoperatively. This case indicates the need to pay attention to children with mild hydronephrosis undergoing regular observation and conservative treatment, as a sudden aggravation of the hydronephrosis and a rapid decline of renal function may occur if DI persists.

Preparation of Zirconium Hydrogen Phosphate Coatings on Sandblasted/Acid-Etched Titanium for Enhancing Its Osteoinductivity and Friction/Corrosion Resistance.

BACKGROUND: Sandblasted/acid-etched titanium (SLA-Ti) implants are widely used for dental implant restoration in edentulous patients. However, the poor osteoinductivity and the large amount of Ti particles/ions released due to friction or corrosion will affect its long-term success rate. PURPOSE: Various zirconium hydrogen phosphate (ZrP) coatings were prepared on SLA-Ti surface to enhance its friction/corrosion resistance and osteoinduction. METHODS: The mixture of ZrCl4 and H3PO4 was first coated on SLA-Ti and then calcined at 450°C for 5 min to form ZrP coatings. In addition to a series of physiochemical characterization such as morphology, roughness, wettability, and chemical composition, their capability of anti-friction and anti-corrosion were further evaluated by friction-wear test and by potential scanning. The viability and osteogenic differentiation of MC3T3-E1 cells on different substrates were investigated via MTT, mineralization and PCR assays. RESULTS: The characterization results showed that there were no significant changes in the morphology, roughness and wettability of ZrP-modified samples (SLA-ZrP0.5 and SLA-ZrP0.7) compared with SLA group. The results of electrochemical corrosion displayed that both SLA-ZrP0.5 and SLA-ZrP0.7 (especially the latter) had better corrosion resistance than SLA in normal saline and serum-containing medium. SLA-ZrP0.7 also exhibited the best friction resistance and great potential to enhance the spreading, proliferation and osteogenic differentiation of MC3T3-E1 cells. CONCLUSION: We determined that SLA-ZrP0.7 had excellent comprehensive properties including anti-corrosion, anti-friction and osteoinduction, which made it have a promising clinical application in dental implant restoration.

Infantile synchronous primary bilateral testicular germ cell tumor: a case report and review of the literature.

Testicular tumors are uncommon in adults, accounting for <1% of all cancers, with testicular germ cell tumors (TGCTs) representing the majority (>95%) of reported cases. Adult and prepubertal TGCTs are fundamentally distinct and the latter is extremely rare, representing 1% of all pediatric solid tumors and having an annual incidence rate of 0.5-2/100,000 boys. Bilateral TGCTs (BTGCTs) account for 0.5-5% of all testicular tumors; the majority are metachronous, while the synchronous account for approximately 0.5-1%. A 16-month-old boy was admitted to our Urology Department with a 2-week history of a painless scrotal mass. Ultrasonography revealed a homogeneous hyperechoic solid mass with rich blood supply in the right testis, and no discernable testicular tissue. A well-delineated heterogeneous echo mass was found within the left testis. Contrast-enhanced computed tomography (CT) scan showed a significantly enhanced mass in the right testis and a mildly enhanced mass in the left testis. Serum alpha-fetoprotein (AFP) was 12,567 ng/mL, while ß-human chorionic gonadotrophin (HCG) and total testosterone levels were normal. Accordingly, bilateral testicular tumors were the primary consideration. The patient underwent right radical inguinal orchiectomy with high ligation of the spermatic cord and left testicle-sparing surgery. Final pathology confirmed a pure yolk sac tumor (YST) from the right testis and a cystic mature teratoma from the left. The follow-up ultrasonography showed no recurrence, with serum AFP returned to normal by postoperative day 44. Synchronous primary BTGCT with teratoma and YST respectively can occur coincidently and successfully treated by testicle-sparing surgery.

PCR effects of melting temperature adjustment of individual primers in degenerate primer pools.

Deep sequencing of small subunit ribosomal RNA (SSU rRNA) gene amplicons continues to be the most common approach for characterization of complex microbial communities. PCR amplifications of conserved regions of SSU rRNA genes often employ degenerate pools of primers to enable targeting of a broad spectrum of organisms. One little noticed feature of such degenerate primer sets is the potential for a wide range of melting temperatures between the primer variants. The melting temperature variation of primers in a degenerate pool could lead to variable amplification efficiencies and PCR bias. Thus, we sought to adjust the melting temperature of each primer variant individually. Individual primer modifications were used to reduce theoretical melting temperature variation between primers, as well as to introduce inter-cluster nucleotide diversity during Illumina sequencing of primer regions. We demonstrate here the suitability of such primers for microbial community analysis. However, no substantial differences in microbial community structure were revealed when using primers with adjusted melting temperatures, though the optimal annealing temperature decreased.

Rheological and fracturing characteristics of a novel sulfonated hydroxypropyl guar gum.

A series of sulfonated hydroxypropyl guar gum (SHG) samples with different degrees of substitution (DSs) were prepared, and the SHG solution and SHG fracturing fluid were prepared and analyzed. The SHG aqueous solutions with different DSs all exhibit shear thinning behavior, which is well correlated with the Ostwald-deWaele model. Owing to the electrostatic repulsion of SHG molecular chains, SHG solutions with a higher DS will exhibit weaker thixotropic performance and strong anti-salinity ability. In addition, the SHG fracturing fluids, which were formed by interactions between SHG and organic zirconium, exhibit good temperature- and shear-resistant properties, proppant suspension properties, and salt tolerance. Furthermore, SHG gel-breaking fluids show low interfacial and surface tensions, with low residue content and small core permeability damage. These results provide useful indicators for the applications of SHG in the oil field industry.

Width proportion of the urethral plate to the glans can serve as an appraisal index of the urethral plate in hypospadias repair.

OBJECTIVES: To find a new appropriate evaluation for urethral plate quality in hypospadias repair, with particular interest in the width proportion of the urethral plate to the glans, serving as an appraisal index. METHODS: Data were prospectively collected from prepubertal boys who underwent primary tubularized incised plate hypospadias repair between January 2014 and April 2016 in one center. Intrinsic parameters of the penis (meatal location, glans width, urethral plate width and curvature degree) were measured during the operation. Urethroplasty complications were recorded during follow up. The correlation between width proportion of the urethral plate to the glans and urethroplasty complications was analyzed. RESULTS: Primary tubularized incised plate repair was carried out in 442 patients (mean age 2.8 years, range 0.5-12 years). At mean follow up of 26 months (range 12-38 months), urethroplasty complications occurred in 59 (13.3%) patients. The width proportion of the urethral plate to the glans was weakly correlated to both the glans width and meatal location. The width proportion of the urethral plate to the glans ranged from 0.18 to 0.73, with a mean of 0.39. The cut-off value of width proportion of the urethral plate to the glans was determined to be 0.36 by the receiver operating characteristic curve. Urethroplasty complications occurred in 17 out of 254 patients (6.7%) with width proportion of the urethral plate to the glans >0.36, and 42 out of 188 patients (22.3%) with width proportion of the urethral plate to the glans ≤0.36. The width proportion of the urethral plate to the glans ≤0.36 showed an increased odds of 4.819-fold (95% confidence interval 2.548-9.112, P < 0.001) risk of urethroplasty complications compared with width proportion of the urethral plate to the glans >0.36. Midshaft and proximal meatal location also increased the risk of urethroplasty complications. CONCLUSIONS: The present study highlights the value of the width proportion of the urethral plate to the glans for objectivity and accuracy in urethral plate evaluation, which in turn serves as an independent factor influencing outcomes in tubularized incised plate repair.

Carboxymethyl fenugreek gum: Rheological characterization and as a novel binder for silicon anode of lithium-ion batteries.

The rheology of carboxymethyl fenugreek gum (CFG) is characterized and applied it as a binder for the silicon anode of lithium-ion batteries (LIBs). First, a series of carboxymethyl fenugreek gum (namely CFG-1, CFG-2 and CFG-3) was prepared and characterized by Fourier transform infrared spectrophotometer and hydrogen nuclear magnetic resonance spectrometry studies. In rheological measurements, the CFG solutions show higher flowability, weaker viscoelastic behavior and better thixotropy than that of fenugreek gum (FG) solution. Furthermore, the higher degrees of substitution (DS) of CFG solutions lead to lower apparent viscosity and higher flow index, weaker elastic effect and smaller relaxation time, and higher viscosity recoverability than those obtained for lower DS of CFG solutions. In electrochemical measurements, the polar hydroxyl and carboxyl groups in the CFG skeleton chain provide bonding points between the CFG binders and the silicon electrode to produce binder-silicon bonds, which cause strong hydrogen bonding, and resulted in excellent electrochemical stability and specific capacity. The electrochemical performances were measured via the silicon electrodes with FG and CFG at 5 wt% content. As the DS is increased, the initial Coulombic efficiency can increase from 88.74% to 91.3%. When the electrode undergoes a volume change, the CFG binder with silicon electrodes can hold high capacity of above 1500 mAh/g after 200 charge-discharge cycles. Therefore, the carboxymethyl fenugreek gum as a binder may also be a novel extended binder-design, with applications for silicon anodes of LIBs.

Facile approach to fabricate waterborne polyaniline nanocomposites with environmental benignity and high physical properties.

Waterborne polyaniline (PANI) dispersion has got extensive attention due to its environmental friendliness and good processability, whereas the storage stability and mechanical property have been the challenge for the waterborne PANI composites. Here we prepare for waterborne PANI dispersion through the chemical graft polymerisation of PANI into epichlorohydrin modified poly (vinyl alcohol) (EPVA). In comparison with waterborne PANI dispersion prepared through physical blend and in situ polymerisation, the storage stability of PANI-g-EPVA dispersion is greatly improved and the dispersion keeps stable for one year. In addition, the as-prepared PANI-g-EPVA film displays more uniform and smooth morphology, as well as enhanced phase compatibility. PANI is homogeneously distributed in the EPVA matrix on the nanoscale. PANI-g-EPVA displays different morphology at different aniline content. The electrical conductivity corresponds to 7.3 S/cm when only 30% PANI is incorporated into the composites, and then increases up to 20.83 S/cm with further increase in the aniline content. Simultaneously, the tensile strength increases from 35 MPa to 64 MPa. The as-prepared PANI-g-EPVA dispersion can be directly used as the conductive ink or coatings for cellulose fibre paper to prepare flexible conductive paper with high conductivity and mechanical property, which is also suitable for large scalable production.

Synthesis of 2-alkenyl-3-butoxypropyl guar gum with enhanced rheological properties.

A new guar gum derivative was synthesized though the nucleophilic substitution of sodium hydroxide-activated guar gum with n-butyl glycidyl (BGE) ether. The physicochemical properties of 2-alkenyl-3-butoxypropyl guar gum (ABPG) were characterized by attenuated total reflection Fourier transform infrared spectrometry (ATR-FTIR), X-ray diffraction (XRD) and thermal gravimetric analyses (TGA). The results showed that sodium hydroxide can be effectively substituted with BGE to form the ABPG. The steady and dynamic rheological properties of the aqueous solution and ABPG gel were determined using an RS6000 rheometer. Compared with the guar gum, ABPG enhanced the thickening property and improved the solution stability. The ABPG gel exhibited good temperature resistance and shear stability properties.

Micromorphology and phase behavior of cationic polyurethane segmented copolymer modified with hydroxysilane.

A series of cationic waterborne polyurethane dispersions (SiPU) modified with hydroxysilane (HPMS) were successfully synthesized based on poly(oxytetramethylene) glycols (PTMG) and isophorone isocyanate (IPDI), and the films were obtained by casting the dispersions on tetrafluoroethylene (TFE) plates. Effects of HPMS content on micromorphology, particle size of the dispersions were studied, as well as thermal properties, phase behavior and surface structure of the films. The particles had the morphology of a solid sphere, with particle size varying from 17.1 nm to 114.4 nm corresponding to the increase of HPMS concentration, which can be attributed to the increase of interfacial tension. XPS spectra indicated the surface migration of Si element in the process of film forming, and the SiPU surface was mainly composed of soft segments. DSC analysis, together with TG-DTG-DTA results demonstrated the HPMS soft segment merged with the transition region of PU matrix, forming part of polyurethane backbone, but an improved microphase separation was observed when HPMS concentration greater than 15%. It was also found that incorporation of flexible HPMS prevented the degradation of polyurethane backbone, resulting in the increase of thermal stability in ultimate copolymer.