Phosphorus Groups Research Articles

Functionalization of graphene oxide coatings with phosphorus atoms and their corrosion resistance in sodium chloride environment

In this work, we compared corrosion resistance of graphene oxide, and phosphorus functionalized reduced graphene oxide coatings obtained as a result of electrophoretic deposition on the copper substrate. Doping graphene oxide with phosphorus atoms was performed by a hydrothermal method in the presence of different amounts of phosphoric acid. Structural studies confirmed the insertion of phosphorus atoms into the graphene oxide structure. FTIR spectra showed peaks at 1020 cm−1 and 1131–1450 cm−1 which can be assigned to phosphorus groups. XPS analysis indicated that phosphorus atoms were inserted in an amount of around 5%. The stable and uniform suspension of functionalized graphene precursors of coatings allowed electrodeposition. These coatings show good protective properties due to hydrophobic and intact surfaces without significant damages.

Study on the Synergies of Nanoclay and MWCNTs to the Flame Retardant and Mechanical Properties of Epoxy Nanocomposites

Modern flame retardants are organic compounds containing halogen or phosphorus groups and are not always well dispersed in polymers. Thus, by using a small amount of nanoclay and multiwalled carbon nanotubes (MWCNTs), they can significantly reduce the number of conventional flame retardant additives, making the material with optimal flame retardant properties. Conventional flame retardants always have some negative effects on the mechanical properties of the polymer substrate, so by using nanoclay and MWCNTs, those adverse effects can be minimized and overcome. In this work, in order to improve the mechanical properties and flame retardant of nanocomposite materials, nanoclay I.30E and MWCNTs are mixed into epoxy, with the selected percentage of 2% and 0.02% by weight, respectively, stirring mechanically for 7, 8, and 9 hours at 3000 rpm at 80°C, then performing ultrasonic vibration for 6 hours at 65°C.

MO593CONTROLLING DIETARY PHOSPHORUS IN CHRONIC KIDNEY DISEASE STAGES 1 AND 2 DECREASES PROTEINURIA AND PREVENTS DECLINE IN RENAL FUNCTION

Abstract Background and Aims High phosphorus intake is known to cause renal and vascular calcification and renal tubular injury and albuminuria. Dietary phosphorus restriction is therapeutic for controlling disordered phosphorus homeostasis and for improving cardiovascular outcomes in CKD. However, early restriction of dietary phosphorus is not advocated Aim: To evaluate if early control of dietary phosphorus ameliorates proteinuria, prevents decline in glomerular filtration rate and prevents increase in FGF-23 Method One year longitudinal study on 79 CKD patients in stages 1 and 2. eGFR, serum creatinine , phosphorus, calcium, FGF-23, soluble α-Klotho iPTH FGF 23, blood pressure, were evaluated and compared with 35 controls. 3 days dietary intake was taken using standard methodology on first visit, 6 and 12 months. CKD patients were grouped based on dietary phosphorus intake: Group 1 (n 42): normal phosphorous intake (<1000mg/day) and Group 2 (n=37; 17 in CKD 1; 20 CKD 2): high phosphorous intake (>1000mg/d). Patients in Group 2 were educated on high and low phosphorus foods and counselled to avoid fresh and frozen and processed meat, eggs, nuts and seeds, chocolates, packaged food, phosphorus-containing food additives and counselled to adopt a plant-based diet, for low phosphorus availability/absorption diet with directed diet plan. Lentils and pulses, milk and milk products (hard cheese, ice-creams, custards, cottage cheese, pudding, yoghurt), bran and whole wheat cereals were restricted up to 1-2 servings a day Data were analysed using SPSS. Results At baseline there was no significant difference in the GFR (group1 85.00±18.64 ml/min vs group 2 82.53±16.30ml/min), serum creatinine between groups. In group2 ; GFR, sKlotho, serum phosphorus and FGF-23 correlated significantly with dietary phosphorus intake. In group 2, FGF-23, Serum phosphorus, dietary protein and phosphorus intake were significantly higher and sKlotho was significantly lower than group 1. There was significant difference in serum phosphorus (p 0.000), iPTH, (p 0.004), FGF23 (p0.000), Klotho (p0.000), urinary protein (p0.000), dietary protein (Group 1 37.57±3.40; Group 248.79±5.86 p 0.000) and phosphorus (Group 1868.96±69.99 mg/d and Group 2 1312.26±137.57 mg/d p 0.000) intake and dietary phosphorous to protein ratio (p 0.000) between groups 1 and 2.. After dietary intervention in group 2 GFR increased from 80.93±15.34 to 84.11±15.38 in six months and to 87.43±18.27 ml/min at 12 months p 0.012, and urinary protein declined to 22.01±3.39 mg/mL. FGF 23 declined from 60.67±6.26 to 58.00±7.07 to 53.29±9.48 pg/mL at 12 months. Urinary phosphorus excretion increased from 574.37±214.22 to 624.64±137.67 at 12 months. Dietary phosphorus protein to ratio reduced from 27.16±4.35 to24.75±4.34 p 0.000 at 12 months Conclusion CKD patients should be cautioned and counselled on their first visit on the impact of dietary phosphorus intake on the progression of CKD and development of CVD.

Pyrroloquinoline quinone-dependent glucose dehydrogenase bioelectrodes based on one-step electrochemical entrapment over single-wall carbon nanotubes

Development of effective direct electron transfer is considered an interesting platform to obtain high performance bioelectrodes. Therefore, designing of scalable and cost-effective immobilization routes that promotes correct direct electrical contacting between the electrode material and the redox enzyme is still required. As we present here, electrochemical entrapment of pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) on single-wall carbon nanotube (SWCNT)-modified electrodes was carried out in a single step during electrooxidation of para-aminophenyl phosphonic acid (4-APPA) to obtain active bioelectrodes. The adequate interaction between SWCNTs and the enzyme can be achieved by making use of phosphorus groups introduced during the electrochemical co-deposition of films, improving the electrocatalytic activity towards glucose oxidation. Two different procedures were investigated for electrode fabrication, namely the entrapment of reconstituted holoenzyme (PQQ-GDH) and the entrapment of apoenzyme (apo-GDH) followed by subsequent in situ reconstitution with the redox cofactor PQQ. In both cases, PQQ-GDH preserves its electrocatalytic activity towards glucose oxidation. Moreover, in comparison with a conventional drop-casting method, an important enhancement in sensitivity was obtained for glucose oxidation (981.7 ± 3.5 nA mM−1) using substantially lower amounts of enzyme and cofactor (PQQ). The single step electrochemical entrapment in presence of 4-APPA provides a simple method for the fabrication of enzymatic bioelectrodes.

Cadmium removal from diluted wastewater by using high-phosphorus-culture modified microalgae

In this study, living algae Didymogenes palatina XR was cultured in high-phosphorus medium for efficient Cd2+ immobilization from diluted wastewater solution. Algae cultivated from different phosphorus concentration medium was used to investigate its production and adsorption performances of Cd2+. This study showed that microalgae is sensitive to low concentration of heavy metal Cd, and different concentrations of phosphorus culture could regulate the surface phosphorus loading of microalgae to enhance its adsorption ability of Cd2+. The Cd2+ was further immobilized with the algae surface phosphorus group, such as PO43−, HPO4−, forming metallic mineral Cd-phosphate.

Study on the morphological and metabolic changes of femur in laying hens with hypophosphatemia

Layer fatigue syndrome caused by the lack of calcium and phosphorus can cause fracture in laying hens. The effect of phosphorus deficiency on the femur of laying hens with layer fatigue syndrome has not been studied. In this study, sixty 22-week-old Roman white layers were randomly divided into control group (group C) and low phosphorus group (group P), 30 individuals in each group. The available phosphorus content of group P was 0.18%. At the age of 26, 30 and 34 weeks, the production performance, biomechanical index, protein expression, histopathological change of femur and serological index were detected. The results showed that the laying rate, egg quality and body weight of laying hens, bone density, cortical bone thickness, rigidity, flexural modulus, flexural rigidity, the maximum load of femur and expression of osteocalcin (OCN), receptor activator of nuclear factor kappa-Β (RANK) and receptor activator of nuclear factor kappa-Β ligand (RANKL) decreased of group P. The number of osteocytes was decreased, and the voids was increased. However, cell lacunae were not obvious. The levels of phosphorus, calcium and OCN were increased, and the content of estradiol (E2), OPG and calcitonin (CT) were decreased in serum. In conclusion, the low phosphorus diet can induce layer fatigue syndrome and affect the content of OPG and E2 in serum and the expression of OCN, OPG, RANK and RANKL in femur protein, which leads to the imbalance of bone homeostasis, the thinning of femur cortex bone and the decrease of bone density.

Renewable epoxy thermosets with extremely high biomass content from furan derivatives and their flame retardancy

As renewable thermosets, a furan-based epoxy resin, 2,5-bis[(2-oxiranylmethoxy)methyl] furan (BOF), and a furan-based amine curing agent, difurfuryl diamine (DFDA), were synthesized using 5-hydroxymethyl-2-furfural (HMF) and furfurylamine (FFAM), respectively. A novel phosphorus-containing, furan-based, flame-retardant epoxy (PFFE) was also synthesized using HMF, FFAM and diethylphosphite to improve the flame retardancy of BOF. PFFE had high biomass content and improved the flame retardancy of BOF because PFFE had both furan and phosphorous groups in its molecular structure. To observe the changes in the physical properties following the addition of PFFE, BOF and PFFE mixtures (BOF/PFFE), BOF, and a diglycidyl ether of bisphenol-A (DGEBA) were cured with DFDA, and their thermal, mechanical, and flame retardancy properties were measured and compared. The glass transition temperature, crosslinking density, and tensile strength of the (BOF/PFFE)-DFDA system were enhanced with increased amounts of PFFE. The BOF/PFFE mixture resin (1:1 by wt.) showed comparable tensile strength to DGEBA and had a higher tensile modulus due to the effect of increased crosslinking density and intermolecular hydrogen bonding. Owing to the furan and phosphorus groups, (BOF/PFFE)-DFDA showed remarkably improved flame retardancy by reducing the release of total heat, the rate of heat release, and the spread of fire.

Understanding enhanced charge storage of phosphorus-functionalized graphene in aqueous acidic electrolytes

ABSTRACT The mechanisms behind enhanced charge storage of P-functionalized carbons are unraveled for the first time using non-porous graphene oxide treated with phosphoric acid and annealed at either 400 or 800 °C. The electrochemical study in 1 M H2SO4 reveals that phosphorus groups boost charge storage and electrochemical stability, with more effect for the higher annealing temperature. Annealing at 800 °C also leads to the material withstanding 60,000 charge-discharge cycles with no capacitance loss at 1.5 V. The improvement in the electrochemical performance is shown to be mainly governed by the change in surface chemistry comprehensively studied with NMR, FTIR and XPS characterization techniques. The collective analysis of electrochemical response and surface chemistry demonstrates that enhanced charge storage by phosphorus-functionalized graphene materials is made possible due to the following synergistic mechanisms: i) non-Faradaic charging; ii) nascent hydrogen storage in the interlayer; iii) benzoquinone-to-hydroquinone redox processes; iv) phosphate-to-phosphonate like transformation. From the practical perspective, the stored charge can be boosted due to the higher capacitance upon prior electrochemical activation in the vicinity of oxygen evolution potential and the wider usable electrochemical window enabled by phosphorus-related groups.

A novel P–N-based flame retardant with multi-reactive groups for treatment of cotton fabrics

A novel P–N based, flame retardant ammonium salt of pentaethylenehexamine octa (methylene-phosphoric acid) (APHOMPA) was synthesized in this study. The structure of the prepared material flame retardant contains eight reactive ammonium phosphorus groups and was characterized by 1H NMR, 13C NMR, 31P NMR, and (Fourier-transform infrared) FT-IR. The results showed that cotton fabrics finished with this flame retardant exhibited excellent flame retardancy and durability. The cotton fabrics finished with 30% APHOMPA solution had limiting oxygen index value 40.5%, and maintained 28.8% even after 50 laundering cycles. The FT-IR results showed that APHOMPA could be grafted on cellulose through P–O–C covalent bond. Vertical flammability, cone calorimetry, thermogravimetric (TG), and TG-IR results revealed the excellent flame retardancy of the finished cotton fabrics and suggested that the flame retardant mechanism of APHOMPA is a condensed phase process. Scanning electron microscopy results suggested the flame retardant entered the inner space of the cotton fabrics, and the X-ray diffraction results showed slight changes to the cotton crystal structure in the finishing process. The breaking strength, softness, and whiteness of finished cotton fabrics were sufficient, suggesting this retardant can be used to prepare treated cotton for multiple applications.

Natural Polymeric Compound Based on High Thermal Stability Catechin from Green Tea.

Catechin is a plant polyphenol with valuable antioxidant and health-promoting properties. Polymerization is one way to stabilize flavonoids and may cause changes in their specific properties. The aim of this study is to obtain a polymeric complex catechin compound with high thermal stability. As a result of polymerization, a condensed and cross-linked catechin structure was obtained, which guaranteed high thermal resistance and, moreover, the phosphorus groups added in the second step of polymerization ensured that the compound obtained had thermal stability higher than natural condensed tannins. The first step of self-polymerization of (+)-catechin may be an easy way to obtain proanthocyanidins with greater antioxidant activity. The second step of the polymerization obtained a polymeric complex catechin compound that showed better thermal stability than catechin. This compound can potentially be used as a new pro-ecological thermal stabilizer.

An inherently flame-retardant polyamide 6 containing a phosphorus group prepared by transesterification polymerization

During the hydrolysis polymerization of caprolactam, melt polycondensation requires that the stoichiometry of the carboxyl-terminal and amine-terminal groups be kept in balance, which greatly limits the copolymerization modification of polyamide 6 (PA6). In this paper, we designed a PA6 prepolymer and modified 9,10-dihydro-10-[2,3-di(hydroxycarbonyl)propyl]-10-phosphaphenanthrene-10-oxide (DDP) monomers so that they have the same ethylene glycol ester end groups. Based on the principle of transesterification to achieve chain growth, an intrinsic flame-retardant polyamide 6 (FR-PA6) is prepared. Our research results show that the FR-PA6 prepared by the synthetic route outlined in this article not only maintains the excellent performance of polyamide 6 but also allows the molecular weight growth of the polyamide 6 polymer to behave independently of the stoichiometric balance of the terminal groups. This method breaks the limitation of the copolymerization reaction caused by hetero end groups after the hydrolysis of caprolactam and ensures a stable degree of polymerization when a high proportion of modifier is added. When the EDE content is increased to 8%, the phosphorus content in the polymer reaches 4640 ppm, the limiting oxygen index reaches 29.5%, and the vertical combustion reaches V-0. The flame-retardant mechanism is analysed by cone calorimetry and pyrolysis gas chromatography-mass spectrometry. This method can prepare flame-retardant PA6 on traditional polyester equipment and can be widely used in the fields of plastics and fibres.

Phosphorylated kraft lignin with improved thermal stability

The low cost, environmental friendliness, and reproducibility of kraft lignin (KL) make it a potential candidate for the development of new green material. The phosphorylation of KL can extend its application as a flame-retardant material. Herein, the phosphorylated kraft lignin (PKL) was systematically fabricated in a sustainable process by utilizing a green phosphating reagent, NH4H2PO4, in the presence of urea. The influence of the reaction parameters, i.e., reaction time and temperature, and NH4H2PO4/lignin ratio on the phosphorylation process were investigated. Advanced characterization techniques including 1H NMR, 31P NMR, and XPS confirmed that the phosphorus groups were successfully introduced to lignin molecules. The active phenolic and aliphatic hydroxy groups of kraft lignin underwent a nucleophilic substitution reaction with the phosphate group to generate phosphorylated lignin. Compared with KL, PKL showed excellent thermal stability, and its maximum decomposition temperature was 620 °C compared with 541 °C for KL.

Ru/P-Containing Porous Biochar-Efficiently Catalyzed Cascade Conversion of Cellulose to Sorbitol in Water under Medium-Pressure H2 Atmosphere

Abstract This paper discloses a simple and productive strategy for the preparation of biochar-based bifunctional catalysts. In this strategy, very cheap bamboo powder is thermally carbonized to yield P-containing porous biochars (PBCs) by the activation of concentrated phosphoric acid (H3PO4), and the latter can be transformed into the target catalysts via loading Ru nanometer particles (NPs) on them (marked as Ru/PBCs). A series of characterizations and measurements support that PBCs have stable and rich micro-meso pores and small strong acidic protons (0.10–0.28 mmol·g−1) attributable to the grafted and/or skeleton phosphorus groups, as well as a strong affinity to β-1,4-glycosidic bonds, thus exhibiting a good acid catalytic activity for the hydrolysis of cellulose to glucose. More importantly, they are excellent acidic supports for the loading of Ru NPs owing to high BET surface area, which can give the loaded Ru NPs uniform and narrow distribution (1–6 nm). The resulting bifunctional Ru/PBCs catalysts possess excellent hydrolytic hydrogenating activity for the one-pot cascade conversion of cellulose and the optimized conditions can achieve ca. 89% hexitol yield with 98% sorbitol selectivity under relatively mild conditions. This work provides a good example for the preparation of biomass-derived bifunctional catalysts and their applications in biorefinery.

Influence of Structure of Chemically Grafted onto Polyethylene Surface Two-Component Titanium-Phosphoroxide Nanostructures on the Properties of Composite Material

Nanostructures with different mutual arrangement of phosphorus and titanium oxide groups were synthesized on the surface of low-density polyethylene (LDPE) films using the molecular layering technology by treatment in a different predetermined sequence with TiCl4, POCl3 and H2O vapors. Based on the data of atomic force microscopy, differential thermal analysis, as well as the assessment of the energy characteristics of the surface by the value of the contact angle, it is shown that the sequence of formation of elemental oxide structures has a significant effect both on the chemical composition of surface nanostructures and on the surface morphology and thermal oxidation resistance of polyethylene. Depending on the sequence of introduction of additives, their concentration and ratio in grafted nanostructures change, surface energy increases by 30–50%, and the amounts of polar and dispersion components in its composition largely depend on the moisture content of the environment. It has been found that chemical modification with elemental oxide groups results in a smoothing of the matrix surface, and local destruction of the polymer is observed during the synthesis of two-component nanostructures. The presence of modifiers leads to an increase in the thermal-oxidative resistance of the composition by 50–110°, depending on its structure and composition, in comparison with the original LDPE. Therewith titanium is the most active inhibitor of polymer oxidation.

Metabonomic analysis of hypophosphatemic laying fatigue syndrome in laying hens

Laying fatigue syndrome (LFS) is a common disease in poultry, which is characterized by low egg laying rate, increased broken and soft shell egg rate and osteoporosis, and even death of poultry. Insufficient phosphorus content in feed is one of the major causes of LFS. In this study, a total of 22-week-old Roman white shell hens were randomly divided into two groups, including control (group C) and low dietary phosphorus (group P) groups. The hens of groups C and P were fed with a full mixed diet and a mixed diet containing 0.18% available phosphorus content, respectively. At 25, 29 and 34 weeks, the production performance of hens was detected and the serum samples of hens were collected to detect the changes of serum phosphorus, calcium, osteopelectin (OPG), parathyroid hormone (PTH), estradiol (E2), tartaric acid-resistant phosphatase (TRACP) and alkaline phosphatase (ALP). The keels were removed and x-rayed. In addition, all serum samples were tested by LC-MS metabolomics. Our results showed that low dietary phosphorus decreased the production performance, phosphorus content, and E2 and OPG levels, while increased calcium and PTH levels, and ALP and TRACP activities in laying hens. The hens of group P had bent keels. Besides, small molecular metabolites in serum were enriched in 10 pathways and 17 metabolites were significantly different according to the area under the receiver operating characteristic curve (AUC) analysis. Our results showed that low phosphorus diet could induce LFS. Also, 17 metabolites detected by metabonomics can be used as biomarkers for clinical diagnosis and early warning of hypophosphatemic laying fatigue syndrome (HLFS). This study provides a scientific basis for the early prevention and treatment of HLFS.

Transition-Metal-Catalyzed Synthesis of Organophosphorus Compounds Involving P–P Bond Cleavage

Organophosphorus compounds are used as drugs, pesticides, detergents, food additives, flame retardants, synthetic reagents, and catalysts, and their efficient synthesis is an important task in organic synthesis. To synthesize novel functional organophosphorus compounds, transition-metal-catalyzed methods have been developed, which were previously considered difficult because of the strong bonding that occurs between transition metals and phosphorus. Addition reactions of triphenylphosphine and sulfonic acids to unsaturated compounds in the presence of a rhodium or palladium catalyst lead to phosphonium salts, in direct contrast to the conventional synthesis involving substitution reactions of organohalogen compounds. Rhodium and palladium complexes catalyze the cleavage of P–P bonds in diphosphines and polyphosphines and can transfer organophosphorus groups to various organic compounds. Subsequent substitution and addition reactions proceed effectively, without using a base, to provide various novel organophosphorus compounds.1 Introduction2 Transition-Metal-Catalyzed Synthesis of Phosphonium Salts by Addition Reactions of Triphenylphosphine and Sulfonic Acids3 Rhodium-Catalyzed P–P Bond Cleavage and Exchange Reactions4 Transition-Metal-Catalyzed Substitution Reactions Using Diphosphines4.1 Reactions Involving Substitution of a Phosphorus Group by P–P Bond Cleavage4.2 Related Substitution Reactions of Organophosphorus Compounds4.3 Substitution Reactions of Acid Fluorides Involving P–P Bond Cleavage of Diphosphines5 Rhodium-Catalyzed P–P Bond Cleavage and Addition Reactions6 Rhodium-Catalyzed P–P Bond Cleavage and Insertion Reactions Using Polyphosphines7 Conclusions

Effects of low dietary phosphorus on tibia quality and metabolism in caged laying hens

Osteoporosis is a common bone metabolic disease in caged laying hens. This disease affects animal welfare and economic costs. In this study, a model of osteoporosis induced by low dietary phosphorus was established. A total of sixty 22-week-old Roman white laying hens were randomly divided into two groups, including a control group (group C) and a low dietary phosphorus group (group P). The effects of low dietary phosphorus on the endocrine and tibial osteoprotegerin (OPG)/nuclear factor kappa B receptor activating factor ligand (RANKL) signaling pathways of osteoporosis in caged laying hens were analyzed by serology, bone biomechanics, molecular biology and histopathology. The results showed that low dietary phosphorus decreased the production performance, and egg quality of laying hens and increased the contents of serum calcium (Ca), osteocalcin (OCN), alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRACP). The contents of serum phosphorus, calcitonin (CT), OPG and tibial biomechanics index decreased. The bone mineral density (BMD), cortical bone thickness and the expression level of OPG protein in tibia decreased. The expression of OCN, nuclear factor kappa B receptor activating factor (RANK) and RANKL protein increased. Low dietary phosphorus caused thinning and fracture of the bone trabeculae and enlargement of the bone marrow cavity of tibia. Our results suggest that phosphorus may affect bone metabolism by regulating the OPG/RANKL signaling pathway.

One-pot green hydrothermal synthesis of bio-derived nitrogen-doped carbon sheets embedded with zirconia nanoparticles for electrochemical sensing of methyl parathion

We report a simple, economical and green one-pot hydrothermal strategy to synthesize the bio-derived nitrogen-doped carbon sheets (ONCSs) embedded with zirconia nanoparticles (ZrO2NPs) with orange juice as carbon source and solvent. The ONCSs-ZrO2NPs composite was further applied in the decoration of glassy carbon electrode (GCE) for electrochemical sensing of methyl parathion. The orange juice-derived ONCSs with graphene-like micromorphology showed good electrical conductivity, large specific surface area, and nitrogen functional groups. They could accelerate the electron transport, provide sufficient electrolyte-electrode interface, and improve the surface wettability, thus forming a suitable microenvironment for the redox reaction of MP. The embedded ZrO2NPs in graphene-like ONCSs possessed a strong affinity toward the phosphorus groups on MP molecules, which could promote the preconcentration of MP in the interface of the fabricated sensor and electrolyte. Benefitting from the synergistic effect of ONCSs and ZrO2NPs/GCE, the ONCSs-ZrO2NPs/GCE sensor exhibited excellent peak current response towards MP with a linear detection range of 0.01–15 μg mL−1 and a low detection limit of 0.115 ng mL−1. Furthermore, the ONCSs-ZrO2NPs/GCE sensor presented good capability to investigate the MP levels in romaine and kiwifruit juices with satisfactory recoveries. This work provides a novel and green one-step approach in the development of carbon-based composite materials for high-performance MP electrochemical sensors.

Effect of caloric restriction on phosphate metabolism and uremic vascular calcification.

Caloric restriction (CR) is known to have multiple beneficial effects on health and longevity. To study the effect of CR on phosphorus metabolism and vascular calcification (VC), rats were fed normal or restricted calories (67% of normal). The phosphorus content of the diets was adjusted to provide equal phosphorus intake independent of the calories ingested. After 50 days of CR, rats had negative phosphorus balance, lower plasma phosphorus, glucose, triglycerides, and leptin, and higher adiponectin than rats fed normal calories. Uremia was induced by 5/6 nephrectomy (Nx). After Nx, rats were treated with calcitriol (80 ng/kg ip every other day) and high-phosphorus diets (1.2% and 1.8%). No differences in aortic calcium content were observed between rats that ate normal or restricted calories before Nx in either rats that received 1.2% phosphorus (11.5 ± 1.7 vs. 10.9 ± 2.1 mg/g tissue) or in rats that received 1.8% phosphorus (12.5 ± 2.3 vs. 12.0 ± 2.9 mg/g of tissue). However, mortality was significantly increased in rats subjected to CR before Nx in both the 1.2% phosphorus groups (75% vs. 25%, P = 0.019) and 1.8% phosphorus groups (100% vs. 45%, P < 0.001). After calcitriol administration was stopped and phosphorus intake was normalized, VC regressed rapidly, but no significant differences in aortic calcium were detected between rats that ate normal or restricted calories during the regression phase (5.7 ± 2.7 and 5.2 ± 1.5 mg/g tissue). In conclusion, CR did not prevent or ameliorate VC and increased mortality in uremic rats.

Synthesis of Novel Polymeric Acrylate-Based Flame Retardants Containing Two Phosphorus Groups in Different Chemical Environments and Their Influence on the Flammability of Poly (Lactic Acid).

Novel polymeric acrylate-based flame retardants (FR 1–4) containing two phosphorus groups in different chemical environments were synthesized in three steps and characterized via nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mass spectrometry (MS). Polylactic acid (PLA) formulations with the synthesized compounds were investigated to evaluate the efficiency of these flame retardants and their mode of action by using TGA, UL94, and cone calorimetry. In order to compare the results a flame retardant polyester containing only one phosphorus group (ItaP) was also investigated in PLA regarding its flame inhibiting effect. Since the fire behavior depends not only on the mode of action of the flame retardants but also strongly on physical phenomena like melt dripping, the flame retardants were also incorporated into PLA with higher viscosity. In the UL94 vertical burning test setup, 10% of the novel flame retardants (FR 1–4) is sufficient to reach a V-0 rating in both PLA types, while a loading of 15% of ItaP is not enough to reach the same classification. Despite their different structure, TGA and cone calorimetry results confirmed a gas phase mechanism mainly responsible for the highly efficient flame retardancy for all compounds. Finally, cone calorimetry tests of the flame retardant PLA with two heat fluxes showed different flame inhibiting efficiencies for different fire scenarios.