Biodegradable Polymeric Materials Research Articles

Maleic Anhydride-Derived Copolymers Conjugated with Beta-Lactam Antibiotics: Synthesis, Characterization, In Vitro Activity/Stability Tests with Antibacterial Studies

The synthesis and characterization of biocompatible three different maleic anhydride co-polymer conjugated with two different beta-lactam antibiotics at in vitro conditions were conducted. The polymer–drug conjugates were synthesized by coupling β-lactam antibiotics via amide bonds to the copolymer. In this work, six different drug-functionalized maleic anhydride copolymers (DFMACs) were synthesized by the chemical conjugation method. This method is based on the ring-opening reaction of the anhydride ring of the copolymer to form an amide bond linking the drug. The synthesized DFMACs were characterized by 1H NMR and FTIR/ATR spectroscopies and analyses were carried out by UV/VIS spectroscopy and Zeta-sizer instrument in detail with consecutive antibacterial tests. The existence of a newly formed amide covalent bond between the drug and the copolymer chains was confirmed by 1H NMR and FTIR/ATR studies. This is the first report on the application of the selected branched biodegradable polymeric matrices for the covalent conjugation of ampicillin and cefalexin. Optimum stability and activity conditions for the synthesized DFMACs were determined. Analyses were conducted under in vitro conditions including varying pH values and simulated body fluids as a function of time to obtain new drug delivery system candidates for the two different antibiotics.

Novel DNA-Binding Activity Exhibited by Poly(aspartic acid) Hydrolase-1 Inhibits Poly(aspartic acid) Hydrolase Activity.

Significant attention has been shifted toward the use and development of biodegradable polymeric materials to mitigate environmental accumulation and potential health impacts. One such material, poly(aspartic acid) (PAA), is a biodegradable alternative to superabsorbent poly(carboxylates), like poly(acrylate). Three enzymes are known to hydrolyze PAA: PahZ1KT-1 and PahZ2KT-1 from Sphingomonas sp. KT-1 and PahZ1KP-2 from Pedobacter sp. KP-2. We previously reported the X-ray crystal structure for PahZ1KT-1, which revealed a homodimer complex with a strongly cationic surface spanning one side of each monomer. Here, we report the first characterization of any polymer hydrolase binding to DNA, where modeling data predict binding of the polyanionic DNA near the cationic substrate binding surface. Our data reveal that PahZ1 homologues from Sphingomonas sp. KT-1 and Pedobacter sp. KP-2 bind ssDNA and dsDNA with nanomolar binding affinities. PahZ1KT-1 binds ssDNA and dsDNA with an apparent dissociation constant, KD,app = 81 ± 14 and 19 ± 1 nM, respectively, and these estimates are similar to the same behaviors exhibited by PahZ1KP-2. Gel permeation chromatography data reveal that dsDNA binding promotes inhibition of PahZ1-catalyzed PAA biodegradation for each homologue. We propose a working model wherein binding of PahZ1 to extracellular biofilm DNA aids in the localization of the hydrolase to the environment in which PAA would first be encountered, thereby providing a mechanism to degrade extracellular PAA and potentially harvest aspartic acid for nutritional uptake.

Immobilization of EPS-modified sodium alginate microcapsule by co-polymerization for methylene blue dye adsorption and kinetics

Exopolysaccharide (EPS) was extracted from Bacillus sp. and purified by ethanol precipitation method. This work mainly examines the dye removal efficiency of biopolymer beads (sodium alginate microcapsules) encapsulated with EPS extracted from Bacillus sp. Encapsulation of EPS-modified sodium alginate microcapsule was done by co-polymerization method. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the co-polymerization of sodium alginate and EPS in the microcapsule. The adsorption capacity of the microcapsule was found to be 0.58682 mg/mL which can be attributed to the larger surface area and increased surface sites in the microcapsule adsorbent. Increased dye removal efficiency of 83% was observed for the microcapsule with 50 mg/mL of EPS. The results of the methylene blue dye adsorption experiment show that the adsorption fitted into the Freundlich isotherm and followed pseudo-second-order reaction with correlation coefficients of 0.939 and 0.9673, respectively. The prepared sodium alginate biopolymer is biodegradable, and numerous studies have documented its biodegradability. Overall, these results evidenced that dye adsorption from textile effluent can be easily managed using the biodegradable polymer materials. Hence, this immobilization approach can be effectively used in textile dye removal process.

Genetic Algorithms for Optimized Selection of Biodegradable Polymers in Sustainable Manufacturing Processes

Sustainable Manufacturing Practices (SMP), particularly in the selection of materials, have become essential due to environmental issues caused by the expansion of industry. Compared to conventional polymers, biodegradable Polymer Materials (BPM) are growing more commonly as an approach to reducing trash pollution. Suitable materials can be challenging due to numerous considerations, like ecological impact, expenditure, and material properties. When addressing sophisticated trade-offs, standard approaches drop. To compete with such challenges, employing Genetic Algorithms (GA) may be more successful, as they have their foundation in the basic concepts of biological development and the natural selection process. With a focus on BPM, this study provides a GA model for optimal packaging substance selection. Out of the four algorithms for computation used for practical testing—PSO, ACO, and SA—the GA model is the most effective. The findings demonstrate that GA can be used to enhance SMP and performs well in enormous search spaces that contain numerous different combinations of materials.

Application Analysis of Biodegradable Polymer Materials in Food Packaging

With the rapid development of biotechnology, the society pays more attention than in the past to the production and development of environmental protection. Choosing materials has always been a more important part of environmental protection work, among them, the degradable polymer materials are also professional research topics, it can be self-degradation under certain conditions, with far-reaching environmental protection value and social significance. Food packaging is a kind of carrier that plays a protective role in packaging, preservation and sales of food, the application of degradable polymer materials in food packaging can play a positive role in environmental protection, reducing environmental pollution and building an ecological society. In this paper, the active application of biodegradable polymer materials for food packaging is elaborated, hoping to provide theoretical reference.

Application Analysis of Biodegradable Polymer Materials in Food Packaging

With the rapid development of biotechnology, the society pays more attention than in the past to the production and development of environmental protection. Choosing materials has always been a more important part of environmental protection work, among them, the degradable polymer materials are also professional research topics, it can be self-degradation under certain conditions, with far-reaching environmental protection value and social significance. Food packaging is a kind of carrier that plays a protective role in packaging, preservation and sales of food, the application of degradable polymer materials in food packaging can play a positive role in environmental protection, reducing environmental pollution and building an ecological society. In this paper, the active application of biodegradable polymer materials for food packaging is elaborated, hoping to provide theoretical reference.

Significantly enhanced crystallization of poly(L‐lactide) by incorporation of poly(D‐lactide) grafted cellulose nanocrystals

AbstractPoly(L‐lactic acid) (PLLA), as a green, biodegradable polymer material, has garnered considerable attention due to its ease of processing and exceptional properties. However, the inherent slow crystallization rate and brittleness of PLLA substantially restrict its extensive applications across various domains. In present work, PLLA and poly(D‐lactide) (PDLA)‐modified cellulose nanocrystals (CNCs), referred as CNC‐g‐L and CNC‐g‐D, are serving as nano‐fillers to enhance the crystallization rate of PLLA. Our findings demonstrate that both nano‐fillers could enhance the crystallization rate of PLLA, but the CNC‐g‐D shows a more efficient nucleation agent compared with its counterpart, CNC‐g‐L. Isothermal crystallization analysis indicates that CNC‐g‐D substantially increases nucleation density of PLLA, with pronounced crystallization at an elevated temperature of 155°C as confirmed by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Wide‐angle x‐ray diffraction (WAXD) analysis shows the preformation of stereocomplex crystals on the CNC‐g‐D surface may result in a fast crystallization rate. Meanwhile, after incorporation of different nano‐fillers, the toughness property of PLLA has also been significantly enhanced. Our result has shown the CNC‐g‐D could serve as an efficient nucleation agent toward PLLA and also facilitate to aiding in establishing comprehensive structure–property relationships of polymer materials.

Screening and safety assessment of migrating substances released from biodegradable packaging materials into milk

Biodegradable polymeric packaging materials are being studied for their potential to replace traditional petroleum-based ones for food contact applications. However, potential safety concerns associated with the utilization of these biodegradable polymers have not been studied in detail. In this study, we conducted non-targeted screening and migration studies on two types of biodegradable milk packaging materials, which were composed of a mixture of polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS), and cellulose. In particular, we monitored the transfer of migrating substances from the packaging materials into a food simulant (50% ethanol) and into a real food (fat free and whole milk). A screening study identified seven compounds in the biodegradable packaging bags, including degradation products of antioxidants, lubricants, and plasticizers such as triethylene glycol, diethyl succinate, glycerin, 2,4-di-tert-butylphenol, and 13-docosenamide were identified. The migration studies indicated that the types and amounts of migrating substances transferred into the real food were appreciably lower than those transferred into the food simulant. Most of the detected migrating substances were below the levels established in the European Union regulations. However, the triethylene glycol levels (68-144 mg/kg) in the food simulant exceeded the limits (60 mg/kg) for one of the packaging materials tested. A safety assessment suggested that there is a low level of safety risk associated with one of the biodegradable packaging materials. This study provides important insights into the safety of biodegradable packaging materials that might be used in the food industry.

Preparation and performance exploration of 2,5‐furandicarboxylic acid‐based copolyester bioplastics: Controlling thermal properties, tensile properties, and surface hydrophilicity through composition

AbstractTo improve the comprehensive properties of polybutylene furandicarboxylate (PBF), 2,5‐furandicarboxylic acid (2,5‐FDCA), and aliphatic chain diol 1,8‐octanediol and 1,4‐butanediol were used as monomers to synthesize a series of bio‐based polybutylene glycol‐octanediol 2,5‐furandicarboxylate (PBOF). The results showed that the chemical composition of PBOF could be controlled through the molar ratio of monomers. Compared with PBF, as the proportion of octanediol segments gradually increased, PBOF could gradually transform from semi‐crystalline thermoplastic to amorphous form, and the glass transition temperature (Tg) gradually decreased. The crystallization ability reduced but a part of the crystal area was still retained. The copolyesters still has a decomposition temperature above 370°C, indicating excellent thermal stability. The introduction of the octanediol segment significantly improved the tensile mechanical properties and flexibility of the POBF copolyester. These meet the requirements for the preparation of bio‐based engineering plastics. The water absorption rate of PBOF showed that it may have certain degradable potential. PBOF copolyesters have potential application prospects in bio‐based medical plastics and biodegradable packaging polymer materials after copolymerization modification.

Facile Green Synthesis of Zingerone Based Tissue‐Like Biodegradable Polyester with Shape‐Memory Features for Regenerative Medicine

AbstractThe abundance of plants as a renewable bioresource has captured the significant attention of researchers, driving them to explore new biodegradable polymeric materials. However, there are still many biobased materials with untapped potential, offering opportunities to synthesize novel biodegradable polymers with multifunctional properties. This work provides a unique solvent and catalyst‐free melt polycondensation process to prepare a series of polyesters using zingerol (Zing‐OH), a reduced form of zingerone, as a primary component for the first time. Briefly, Zing‐OH (a ginger‐based component) is employed in conjunction with a variety of renewable resources, such as citric acid (CA), sebacic acid (SA), and xylitol (Xy), to synthesize multifunctional soft tissue‐like ZCSX polyesters. Fourier‐transform infrared (FTIR) and 1H‐nuclear magnetic resonance (NMR) spectroscopy are used to validate the synthesis of the polyesters, while thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and universal testing machine (UTM) are employed to investigate their physicochemical properties. Moreover, the synthesized polyester's thermal, mechanical, and biodegradation properties can be fine‐tuned by simply varying the Zing‐OH feed ratio. The mechanical properties of the synthesized polymer resemble various human tissues, including the liver, uterus, bladder, breast, and temporal and nasal cartilage. This suggests that the synthesized polyesters can potentially be useful in tissue engineering applications. Furthermore, the polyester demonstrated exceptional recovery responses and good shape memory behavior at ambient body temperature. Additionally, as observed from Alamar blue, live/dead assays, and time‐dependent in vitro wound images, the synthesized polyester demonstrated antibacterial activity, good in vitro cytocompatibility, cell proliferation, and wound healing capabilities against mouse fibroblast cells (NIH/3T3). The developed biocompatible polyester also exhibits excellent hemocompatibility for human blood, indicating its potential use in the field of regenerative medicine.

Crystalline Transformation of Glycolide Induced by Organic Solvents and Relative Humidity

AbstractAs a biodegradable and biocompatible polymer material, polyglycolic acid is attracting more and more attention in the field of polymeric and biomedical materials. Consequently, the study of the transformation between different crystal forms of glycolide, the monomer of polyglycolic acid, is of great importance, because crystal forms of glycolide determine the stabilities and properties of polyglycolic acid products polymerized under different conditions in industry. Herein, this article reports the synthesis and crystallization of α‐ and β‐glycolide controlled by the type of organic solvents and/or temperatures, during which an intermediate crystal form of β′‐glycolide is newly observed. The transformation between α‐, β‐, and β′‐glycolide is investigated in detail, and the stabilities of different crystal forms are illustrated via the controlled experiments under different relative humidity (RH) as well as the theoretical calculations, which should provide fundamental concepts and guidance for the industrial production of glycolide and optimization of polyglycolic acid products.

Machine Learning Analysis of Enhanced Biodegradable Phoenix dactylifera L./HDPE Composite Thermograms.

Worldwide, environmental groups and policymakers are focusing on waste recycling to create economic value and on the decomposition of waste by leveraging on scarce resources. This work, therefore, explores the thermal decomposition of enhanced biodegradable polymer matrices made from a mixture of discarded Phoenix dactylifera L./high-density polyethylene (PD/HDPE) using the machine learning analysis of experimental data. The experimental results of these samples were obtained via thermogravimetric (TGA) analysis under an oxidation-free environment, with heating rates of 10, 20, and 40 °C·min-1 and a degradation temperature range from 25 to 600 °C. The TGA analyses revealed the continued dependence of the actual percentage weight loss by these materials as a test function of the degradation temperature, shifting thermograms to temperature maxima consistent with increasing heating rates. Although high-density polyethylene (HDPE) materials were found to be thermally more stable than Phoenix dactylifera L. (PD) materials, PD/HDPE composite materials contained a significant amount of residual ash. Using a machine learning deep neural network approach for this process, significantly improved learning algorithms have been developed, which reduces the overall cost function (residual error) to almost zero (0.025) after just over a million iterations (epochs) and provides predictions that overlap with the experimental results (R2~1). Learning algorithms, along with optimized synaptic weights and biases, were employed to predict the behaviour of PD materials based on experimental thermograms conducted at higher degradation temperatures, typically ranging between 600 and 1000 °C. Predicted data using the enhanced learning algorithms completely overlapped the experiments (R2~1) for these higher degradation temperatures with near unity correlation if the decomposition of the materials continued until the residue was attained. With this approach, it is possible to predict and optimize the thermal characteristics of PD and HDPE with greater efficiency, which reduces the need for multiple design iterations and experimentation.

Multifunctional 3D-printed composites based on biopolymeric matrices and tomato plant (Solanum lycopersicum) waste for contextual fertilizer release and Cu(II) ions removal

The production of tomatoes faces significant challenges, including the high amount of waste generated during the harvest stage and copper-contaminated soil due to pesticide use. To address these issues and to promote a more sustainable agriculture, innovative biodegradable green composites for contextual controlled soil fertilization and Cu removal were produced by 3D-printing technology. These composites were made by incorporating NPK fertilizer flour and tomato plant waste particles (SLP) into three different biodegradable polymeric matrices: polylactic acid (PLA); a commercial blend of biodegradable co-polyesters (Mater-Bi®, MB) and their blend (MB/PLA, 50:50). Rheological characterization suggested the potential processability of all of the composites by FDM. Morphological analysis of printed samples confirmed the good dispersion of both filler and fertilizer, which also acted as reinforcement for MB and MB/PLA composites. SLP and NPK moduli were evaluated by powder nanoindentation and, for almost composites, the theoretical Halpin-Tsai model satisfactorily fitted the actual tensile moduli. The decrease in NPK fertilizer release rate and the increase in Cu(II) removal efficiency were achieved using whole 3D-printed composites. By selecting the appropriate matrix and incorporating SLP particles, it was possible to tune the NPK release rate and achieve copper absorption efficiency. Notably, MB samples containing SLP particles displayed the fastest release and the highest Cu(II) removal efficiency.Graphical abstract

Ultrasonic welding of Cork Wood/PLA composites: effect of welding factors on lap shear strength performance

Ultrasonic welding of Cork Wood/PLA composites: effect of welding factors on lap shear strength performance

Development of highly bacterial filtration efficient and antibacterial cellulose acetate/gum rosin composite nanofibers for facemask application

Cellulose acetate (CA) is a non-toxic, renewable, and biodegradable polymeric material that can be effectively electrospuned into bacterial filtration efficient nanofiber membrane for face mask application. However, its fragile and non-antibacterial nature influenced its scalability. In this context, natural antibacterial gum rosin (GR) additive can be explored. Therefore, the present study aimed to produce a CA/GR composite nanofibers membrane for the finest bacterial filtration, excellent antibacterial moiety, and improved tensile properties for facemask application. Hence, in this work, we have studied the effect of GR concentrations (0–15 g) on the needleless electrospinning behavior and fibers' morphology through rheology, electrical conductivity, and SEM analysis. These analyses revealed that GR significantly affects the fibers' spinning behavior, morphology, and diameter of the produced fibers. Later, ATR-FTIR spectroscopy mapped the functional changes in the produced nanofibers that affirmed the integration of GR with CA polymer. This modification resulted in a 3-fold rise in tensile strength and an 11-fold decline in elongation% in 15 g CA/GR composite nanofibers membrane than the control sample. Furthermore, it has shown 98.79 ± 0.10% bacterial filtration efficiency and ∼ 93 % reduction in Staphylococcus Aureus and Klebsiella Pneumoniae bacterial growth, elucidating a high-efficiency level for potential facemask application.

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives.

The last few decades have witnessed significant advances in the development of polymeric-based foam materials. These materials find several practical applications in our daily lives due to their characteristic properties such as low density, thermal insulation, and porosity, which are important in packaging, in building construction, and in biomedical applications, respectively. The first foams with practical applications used polymeric materials of petrochemical origin. However, due to growing environmental concerns, considerable efforts have been made to replace some of these materials with biodegradable polymers. Foam processing has evolved greatly in recent years due to improvements in existing techniques, such as the use of supercritical fluids in extrusion foaming and foam injection moulding, as well as the advent or adaptation of existing techniques to produce foams, as in the case of the combination between additive manufacturing and foam technology. The use of supercritical CO2 is especially advantageous in the production of porous structures for biomedical applications, as CO2 is chemically inert and non-toxic; in addition, it allows for an easy tailoring of the pore structure through processing conditions. Biodegradable polymeric materials, despite their enormous advantages over petroleum-based materials, present some difficulties regarding their potential use in foaming, such as poor melt strength, slow crystallization rate, poor processability, low service temperature, low toughness, and high brittleness, which limits their field of application. Several strategies were developed to improve the melt strength, including the change in monomer composition and the use of chemical modifiers and chain extenders to extend the chain length or create a branched molecular structure, to increase the molecular weight and the viscosity of the polymer. The use of additives or fillers is also commonly used, as fillers can improve crystallization kinetics by acting as crystal-nucleating agents. Alternatively, biodegradable polymers can be blended with other biodegradable polymers to combine certain properties and to counteract certain limitations. This work therefore aims to provide the latest advances regarding the foaming of biodegradable polymers. It covers the main foaming techniques and their advances and reviews the uses of biodegradable polymers in foaming, focusing on the chemical changes of polymers that improve their foaming ability. Finally, the challenges as well as the main opportunities presented reinforce the market potential of the biodegradable polymer foam materials.

Overview of biodegradable polymers: synthesis, modification and application

Biodegradable polymeric represents a growing field. Owing to their wide-ranging properties, both synthetic and natural polymeric materials perform a vital and ubiquitous role in everyday life. Amended natural polymeric materials such as starch, cellulose, lignin, chitosan, cottonseed shell (CTS), and cotton gin trash (CGT) have enhanced properties, while synthetic Biodegradable polymeric materials such as poly (vinyl alcohol) (PVA), biodegradable plastics, biodegradable foams. Bioplastics are a kind of polymers able to be degraded by different microorganisms to small molecules (e.g., H2O, CO2, and CH4). Bioplastics are observed to solve waste materials and biodegradability is just a new material to be exploited at the end of its life in specific terms. They should be used for applications that require cheap methods to dispose of items after it has fulfilled their job (e.g., for food packaging, agriculture, or medical products).

Application of PLGA in Tumor Immunotherapy.

Biodegradable polymers have been extensively researched in the field of biomedicine. Polylactic-co-glycolic acid (PLGA), a biodegradable polymer material, has been widely used in drug delivery systems and has shown great potential in various medical fields, including vaccines, tissue engineering such as bone regeneration and wound healing, and 3D printing. Cancer, a group of diseases with high mortality rates worldwide, has recently garnered significant attention in the field of immune therapy research. In recent years, there has been growing interest in the delivery function of PLGA in tumor immunotherapy. In tumor immunotherapy, PLGA can serve as a carrier to load antigens on its surface, thereby enhancing the immune system's ability to attack tumor cells. Additionally, PLGA can be used to formulate tumor vaccines and immunoadjuvants, thereby enhancing the efficacy of tumor immunotherapy. PLGA nanoparticles (NPs) can also enhance the effectiveness of tumor immunotherapy by regulating the activity and differentiation of immune cells, and by improving the expression and presentation of tumor antigens. Furthermore, due to the diverse physical properties and surface modifications of PLGA, it has a wider range of potential applications in tumor immunotherapy through the loading of various types of drugs or other innovative substances. We aim to highlight the recent advances and challenges of plga in the field of oncology therapy to stimulate further research and development of innovative PLGA-based approaches, and more effective and personalized cancer therapies.

Fabrication of biodegradable Poly(butylene adipate-co-butylene terephthalate) bead foams through solid utilization of chitin and controllable incorporation of porous structure

The pollution caused by waste plastics is becoming increasingly serious, and utilizing the biodegradable materials, that can be completely degraded in nature, is considered to be one of the most promising ways to solve this problem. Poly(butylene adipate-co-butylene terephthalate) (PBAT), as the commonly used biodegradable polymer material, is subjected to the problem of high cost, poor mechanical performance, and low melt strength at high temperatures. Herein, a novel strategy combining solid utilization of biomass material chitin and incorporation of porous structure was developed to fabricate the PBAT bead foams, relying on the solid-state shear milling (S3M) and supercritical carbon dioxide (scCO2) foaming technologies. Chitin scraps were super finely pulverized and uniformly combined with PBAT, and the PBAT-based bead foams with controllable cell structure, improved mechanical performance, and low cost after foaming the composite. When the content of chitin was 20%, the tensile strength and Young’s modulus of PBAT/chitin bead foam were 0.72 MPa and 2.14 MPa, respectively, much higher than that of neat PBAT bead foam, expressing the great significance to broadening the application field of degradable plastics.

Preparation, structure, and properties of biodegradable core‐sheath composite fibers derived from poly (butylene adipate‐co‐terephthalate) and polylactic acid

AbstractThe non‐biodegradability of Ethylene‐Propylene Side‐by‐Side (ES) fibers has led to significant environmental pollution from waste sanitary products, thereby posing a severe challenge to the environment. Replacing traditional non‐biodegradable materials with biodegradable polymeric materials is the most effective method to achieve a green environment. In this study, core‐sheath fibers composed of biodegradable poly (butylene adipate‐co‐terephthalate) (PBAT) as the sheath layer and polylactic acid (PLA) as the core layer were fabricated. The effects of different viscosity ratios and the composite ratios of sheath and core on the structure and performance of the resultant core‐sheath fibers were investigated in detail. The results showed that when the PBAT/PLA composite ratio is 50:50 and the viscosity ratio range from 0.8 to 1.43, the PBAT/PLA core‐sheath composite fibers exhibit good spinnability and a complete core‐sheath structure, with their tensile properties comparable to those of PP/PE core‐sheath composite fibers. Further research found that when the viscosity ratio was 1.00 and the PLA component content in the PBAT/PLA composite fibers increased from 40% to 60%, the fibers still maintained good spinnability and a complete core‐sheath structure. In addition, when the PBAT/PLA composite ratio was 60:40, after 120 days of biodegradation, its strength retention rate was only 35.2%.