The formation process and composition of the acrylonitrile/urea inclusion compounds （AN/UIC） with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry （DSC） and X-ra...The formation process and composition of the acrylonitrile/urea inclusion compounds （AN/UIC） with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. It is suggested that DSC can determine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of decomposition are obtained, which are 1.17 and 5361.53 J/mol, respec- tively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN.展开更多
Three yearling lambs with a rumen cannula were used to investigate the effects of supplementation with an urea-minerals lick block （ULB） on the kinetics of ruminal fibre digestion, nutrient digestibility and nitrog...Three yearling lambs with a rumen cannula were used to investigate the effects of supplementation with an urea-minerals lick block （ULB） on the kinetics of ruminal fibre digestion, nutrient digestibility and nitrogen （N） utilization office straw （RS）, ammonia bicarbonate （AB）-treated RS （ABRS） and hay prepared from natural pasture. The digestibility of dry matter and organic matter of RS increased by 13.1% and 12.7% （P〈0.05） when the diet was supplemented with ULB, and approached to that of ABRS, indicating that the effect of ULB on digestibility of RS is similar to that of AB treatment. The digestibility of ABRS was slightly improved by the ULB feeding. Nitrogen retention was highest in lambs fed on ABRS alone, followed by hay with ULB, and was lowest in animals fed on RS with ULB. However, both the amount and proportion of N retention to N intake were enhanced by ULB supplementation to lambs fed on hay. The proportion of N retained to N digested decreased due to ULB supplementation to lambs fed on RS or ABRS. Supplementing ULB did not greatly influence the rumen degradation of either dry matter or crude protein in each of the three diets. RS and hay had similar values in the potential extent of digestion （PED） and digestion rate of PED （kd） of fibrous materials, but the discrete lag time for RS was lower than that for hay. The AB treatment significantly increased the PED （P〈0.05） and kd （P〈0.05） of RS. Neither the PED nor kd for RS and ABRS was influenced by ULB supplementation, but the kd for hay significantly increased due to ULB. The lag time for hay was also shortened by the ULB feeding. The ULB improved the digestion of fibre in the rumen of lambs fed on low quality roughage. It is inferred that while ULB is effective in increasing nutrient digestibility of low quality roughages by improving ruminal fibre digestion. A synchronized supply of N and energy to rumen microbes should be considered to improve the efficiency of N utilization when the basal diet is ammoniated straw.展开更多
1,3-disubstituted ureas of adamantine series are potent for hypertension and inflammatory treatment. The most valuable parameters of these compounds are melting point and solubility. Higher melting point leads to lowe...1,3-disubstituted ureas of adamantine series are potent for hypertension and inflammatory treatment. The most valuable parameters of these compounds are melting point and solubility. Higher melting point leads to lower bioavailability and for most of the compounds investigated before it was very high. Usage of isocyanates containing 1,3-dimethyladamantane fragment will significantly decrease the melting point, improve solubility and therefore improve bioavailability of 1,3-disubstituted ureas and other biologically active compounds produced on its base. This article presents new 1,3-disubstituted ureas and biureas synthesized by the authors.展开更多
文摘The formation process and composition of the acrylonitrile/urea inclusion compounds （AN/UIC） with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. It is suggested that DSC can determine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of decomposition are obtained, which are 1.17 and 5361.53 J/mol, respec- tively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN.
基金Project (No. 011102193) supported by the Foundation of the Science and Technology Commission of Zhejiang Provincethe Foundation for Excellent Youth Teachers from the State Commission of Education, China
文摘Three yearling lambs with a rumen cannula were used to investigate the effects of supplementation with an urea-minerals lick block （ULB） on the kinetics of ruminal fibre digestion, nutrient digestibility and nitrogen （N） utilization office straw （RS）, ammonia bicarbonate （AB）-treated RS （ABRS） and hay prepared from natural pasture. The digestibility of dry matter and organic matter of RS increased by 13.1% and 12.7% （P〈0.05） when the diet was supplemented with ULB, and approached to that of ABRS, indicating that the effect of ULB on digestibility of RS is similar to that of AB treatment. The digestibility of ABRS was slightly improved by the ULB feeding. Nitrogen retention was highest in lambs fed on ABRS alone, followed by hay with ULB, and was lowest in animals fed on RS with ULB. However, both the amount and proportion of N retention to N intake were enhanced by ULB supplementation to lambs fed on hay. The proportion of N retained to N digested decreased due to ULB supplementation to lambs fed on RS or ABRS. Supplementing ULB did not greatly influence the rumen degradation of either dry matter or crude protein in each of the three diets. RS and hay had similar values in the potential extent of digestion （PED） and digestion rate of PED （kd） of fibrous materials, but the discrete lag time for RS was lower than that for hay. The AB treatment significantly increased the PED （P〈0.05） and kd （P〈0.05） of RS. Neither the PED nor kd for RS and ABRS was influenced by ULB supplementation, but the kd for hay significantly increased due to ULB. The lag time for hay was also shortened by the ULB feeding. The ULB improved the digestion of fibre in the rumen of lambs fed on low quality roughage. It is inferred that while ULB is effective in increasing nutrient digestibility of low quality roughages by improving ruminal fibre digestion. A synchronized supply of N and energy to rumen microbes should be considered to improve the efficiency of N utilization when the basal diet is ammoniated straw.
文摘1,3-disubstituted ureas of adamantine series are potent for hypertension and inflammatory treatment. The most valuable parameters of these compounds are melting point and solubility. Higher melting point leads to lower bioavailability and for most of the compounds investigated before it was very high. Usage of isocyanates containing 1,3-dimethyladamantane fragment will significantly decrease the melting point, improve solubility and therefore improve bioavailability of 1,3-disubstituted ureas and other biologically active compounds produced on its base. This article presents new 1,3-disubstituted ureas and biureas synthesized by the authors.
