A novel thermo-sensitive superabsorbent hydrogel with salt- and pH-responsiveness properties was obtained by grafting of mixtures of acrylic acid （AA） and N-isopropylacrylamide （N1PAM） monomers onto kappa-carragee...A novel thermo-sensitive superabsorbent hydrogel with salt- and pH-responsiveness properties was obtained by grafting of mixtures of acrylic acid （AA） and N-isopropylacrylamide （N1PAM） monomers onto kappa-carrageenan, kC, using ammonium persulfate （APS） as a free radical initiator in the presence of methylene bisacrylamide （MBA） as a crosslinker. Infrared spectroscopy was carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy （SEM）. The effect of MBA concentration and AA/NIPAM weight ratio on the water absorbency capacity has been investigated. The swelling variations of hydrogels were explained according to swelling theory based on the hydrogel chemical structure. The hydrogels exhibited salt-sensitivity and cation exchange properties. The temperature- and pH-reversibility properties of the hydrogels make the intelligent polymers as good candidates for considering as potential carriers for bioactive agents, e.g. drugs.展开更多
Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Lin...Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Line (VDSL) systems which use higher frequencies for data transmission than the other DSL systems, this effect is more considerable in Bit Error Rate (BER) degradation. This paper considers a complete adaptive iterative water-filling (IWF) algorithm for Resolving Upstream Near-Far Problem in VDSL Systems. The new distributed dynamic spectrum management algorithm is proposed, which improve achievable bit rate of iterative water-filling algorithm. The paper proffers a new power back-off strategy of the spectral mask at the near-end users, in order to protect the far-end users. Simulation of the proposed algorithm indicates that the bit rate is increased considerably rather the IWF and adaptive water-filling (AIWF) algorithms by keeping their low complexity. Furthermore, by adding the number of users in network, the new algorithm achieves performance gains over the AIWF, completely adaptive.展开更多
In this work, synthesis and swelling behavior of a superabsorbent hydrogel based on Pectin (Pc) and polyacrylonitrile (PAN) were investigated. A mechanism for hydrogel formation was proposed and the structure of the p...In this work, synthesis and swelling behavior of a superabsorbent hydrogel based on Pectin (Pc) and polyacrylonitrile (PAN) were investigated. A mechanism for hydrogel formation was proposed and the structure of the product was es-tablished using FTIR spectroscopy. The Pc-poly (sodium acrylate-co-acrylamide) hydrogel exhibited a pH-responsive swelling-deswelling behavior at pH’s 2 and 8. This on-off switching behavior provides the hydrogel with the potential to control delivery of bioactive agents. Release profiles of ibuprofen (IBU), a poor water-soluble drug, from the hydro-gels were studied under both simulated gastric and intestinal pH conditions.展开更多
In this article, we synthesize of a novel starch-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and 2-Hydroxy ethyl methacrylate (HEMA) onto starch backbones. The polymerizat...In this article, we synthesize of a novel starch-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and 2-Hydroxy ethyl methacrylate (HEMA) onto starch backbones. The polymerization reaction was carried out in an aqueous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N’-methylene bisacrylamide (MBA) as a crosslinker. The hydrogel structures were confirmed by FTIR spectroscopy. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1 and 13. It showed a reversible pH-responsive behavior at pHs 2 and 8. This on-off switching behavior makes the synthesized hydrogels as an excellent candidate for controlled delivery of bioactive agents. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR and SEM spectroscopies.展开更多
Background: Over the years, an optimal surgical method for septorhinoplasty in deviated nose as a challenging problem was the one of common interest of plastic surgeon;the purpose of this study is to compare outcomes ...Background: Over the years, an optimal surgical method for septorhinoplasty in deviated nose as a challenging problem was the one of common interest of plastic surgeon;the purpose of this study is to compare outcomes of open and closed methods of septorhinoplasty in patients with deviated noses. Methods: Through a prospective study, we selected seventy patients with deviated nose. Based on their deviation severity, they underwent open or closed septorhinoplasty. Patients were evaluated for deviation angles of nasal bony and cartilage components, nasal projection, nasolabial angle, nasofacial angle, and nasofrontal angle;for which three standard photos were captured pre and postoperatively. Finally the outcomes were analyzed according to their surgical methods. Results: Closed septorhinoplasty could grant a mean 11 degrees correction to nasal bony component and a mean 8.6 degrees correction to cartilage component. That’s while open septorhinoplasty could bring a mean 19.5 degrees deviation correction to the bony component and a mean 12.5 degrees deviation correction to the cartilage component. Cosmetic angles were not improved significantly after the surgery, maybe because of complicated deformities our series of patients had. Conclusion: Open septorhinoplasty resulted in better cosmetic and functional outcomes than the closed method.展开更多
文摘A novel thermo-sensitive superabsorbent hydrogel with salt- and pH-responsiveness properties was obtained by grafting of mixtures of acrylic acid （AA） and N-isopropylacrylamide （N1PAM） monomers onto kappa-carrageenan, kC, using ammonium persulfate （APS） as a free radical initiator in the presence of methylene bisacrylamide （MBA） as a crosslinker. Infrared spectroscopy was carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy （SEM）. The effect of MBA concentration and AA/NIPAM weight ratio on the water absorbency capacity has been investigated. The swelling variations of hydrogels were explained according to swelling theory based on the hydrogel chemical structure. The hydrogels exhibited salt-sensitivity and cation exchange properties. The temperature- and pH-reversibility properties of the hydrogels make the intelligent polymers as good candidates for considering as potential carriers for bioactive agents, e.g. drugs.
文摘Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Line (VDSL) systems which use higher frequencies for data transmission than the other DSL systems, this effect is more considerable in Bit Error Rate (BER) degradation. This paper considers a complete adaptive iterative water-filling (IWF) algorithm for Resolving Upstream Near-Far Problem in VDSL Systems. The new distributed dynamic spectrum management algorithm is proposed, which improve achievable bit rate of iterative water-filling algorithm. The paper proffers a new power back-off strategy of the spectral mask at the near-end users, in order to protect the far-end users. Simulation of the proposed algorithm indicates that the bit rate is increased considerably rather the IWF and adaptive water-filling (AIWF) algorithms by keeping their low complexity. Furthermore, by adding the number of users in network, the new algorithm achieves performance gains over the AIWF, completely adaptive.
文摘In this work, synthesis and swelling behavior of a superabsorbent hydrogel based on Pectin (Pc) and polyacrylonitrile (PAN) were investigated. A mechanism for hydrogel formation was proposed and the structure of the product was es-tablished using FTIR spectroscopy. The Pc-poly (sodium acrylate-co-acrylamide) hydrogel exhibited a pH-responsive swelling-deswelling behavior at pH’s 2 and 8. This on-off switching behavior provides the hydrogel with the potential to control delivery of bioactive agents. Release profiles of ibuprofen (IBU), a poor water-soluble drug, from the hydro-gels were studied under both simulated gastric and intestinal pH conditions.
文摘In this article, we synthesize of a novel starch-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and 2-Hydroxy ethyl methacrylate (HEMA) onto starch backbones. The polymerization reaction was carried out in an aqueous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N’-methylene bisacrylamide (MBA) as a crosslinker. The hydrogel structures were confirmed by FTIR spectroscopy. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1 and 13. It showed a reversible pH-responsive behavior at pHs 2 and 8. This on-off switching behavior makes the synthesized hydrogels as an excellent candidate for controlled delivery of bioactive agents. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR and SEM spectroscopies.
文摘Background: Over the years, an optimal surgical method for septorhinoplasty in deviated nose as a challenging problem was the one of common interest of plastic surgeon;the purpose of this study is to compare outcomes of open and closed methods of septorhinoplasty in patients with deviated noses. Methods: Through a prospective study, we selected seventy patients with deviated nose. Based on their deviation severity, they underwent open or closed septorhinoplasty. Patients were evaluated for deviation angles of nasal bony and cartilage components, nasal projection, nasolabial angle, nasofacial angle, and nasofrontal angle;for which three standard photos were captured pre and postoperatively. Finally the outcomes were analyzed according to their surgical methods. Results: Closed septorhinoplasty could grant a mean 11 degrees correction to nasal bony component and a mean 8.6 degrees correction to cartilage component. That’s while open septorhinoplasty could bring a mean 19.5 degrees deviation correction to the bony component and a mean 12.5 degrees deviation correction to the cartilage component. Cosmetic angles were not improved significantly after the surgery, maybe because of complicated deformities our series of patients had. Conclusion: Open septorhinoplasty resulted in better cosmetic and functional outcomes than the closed method.
