AIM: To investigate the impact of titanium dioxide nanoparticles(Ti O2NPs) on embryonic development and retinal neurogenesis.METHODS: The agglomeration and sedimentation of Ti O2 NPs solutions at different dilutions w...AIM: To investigate the impact of titanium dioxide nanoparticles(Ti O2NPs) on embryonic development and retinal neurogenesis.METHODS: The agglomeration and sedimentation of Ti O2 NPs solutions at different dilutions were observed,and the ultraviolet-visible spectra of their supernatants were measured. Zebrafish embryos were experimentally exposed to Ti O2 NPs until 72 h postfertilization(hpf). The retinal neurogenesis and distribution of the microglia were analyzed by immunohistochemistry and whole mount in situ hybridization.RESULTS: The 1 mg/L was determined to be an appropriate exposure dose. Embryos exposed to Ti O2 NPs had a normal phenotype. The neurogenesis was initiated on time, and ganglion cells, cones and rods were well differentiated at 72 hpf. The expression of fms m RNA and the 4C4 antibody, which were specific to microglia in the central nervous system(CNS), closely resembled their endogenous profile.CONCLUSION: These data demonstrate that short-term exposure to Ti O2 NPs at a low dose does not lead to delayed embryonic development or retinal neurotoxicity.展开更多
An unsteady, two-dimensional, explicitly solved fmite difference heat transfer model of a billet caster was presented to clarify the influence of the thermal conductivity of steel on model accuracy. Different approach...An unsteady, two-dimensional, explicitly solved fmite difference heat transfer model of a billet caster was presented to clarify the influence of the thermal conductivity of steel on model accuracy. Different approaches were utilized for calculating the thermal conductivity of solid, mushy and liquid steels. Model results predicted by these approaches were compared, and the advantages of advocated approaches were discussed. It is found that the approach for calculating the thermal conductivity of solid steel notably influences model predictions. Convection effects of liquid steel should be considered properly while calculating the thermal conductivity of mushy steel. Different values of the effective thermal conductivity of liquid steel adopted could partly be explained by the fact that different models adopted dissimilar ap- proaches for calculating the thermal conductivity of solid and mushy steels.展开更多
AIM: To investigate the effect of pituitary homeobox 1 (PITX1) expression in cases of human gastric cancer on cancer differentiation and progression, and carcinogenesis. METHODS: Using polyclonal PITX1 antibodies, we ...AIM: To investigate the effect of pituitary homeobox 1 (PITX1) expression in cases of human gastric cancer on cancer differentiation and progression, and carcinogenesis. METHODS: Using polyclonal PITX1 antibodies, we studied the expression of PITX1 in normal gastric mucosa, atypical hyperplasia, intestinal metaplasia, and cancer tissue samples from 83 gastric cancer patients by immunohistochemistry. Moreover, semi-reverse transcription polymerase chain reaction (semi-RT-PCR) was performed to detect the mRNA level of PITX1 in three gastric cancer cell lines and a normal gastric epithelial cell line. Subsequently, somatic mutations of the PITX1 gene in 71 gastric cancer patients were analyzed by a combination of denaturing high performance liquid chromatography (DHPLC) and DNA sequencing. RESULTS: Immunohistochemistry showed that PITX1 was strongly or moderately expressed in the parietal cells of normal gastric mucosa (100%), while 55 (66.3%) out of 83 samples of gastric cancers showed decreased PITX1 expression. Moreover, PITX1 expression was reduced in 20 out of 28 cases (71.5%) of intestinal metaplasia, but in only 1 out of 9 cases (11%) of atypical hyperplasia. More importantly, PITX1 expression was significantly associated with the differentiation, position and invasion depth of gastric cancers (r = -0.316, P < 0.01; r = 0.213, P < 0.05; r = -0.259, P < 0.05, respectively). Similarly, levels of PITX1 mRNA were significantly decreased in 2 gastric cancer cell lines, BGC-823 and SGC-7901, compared with the normal gastric epithelial cell line GES-1 (0.306 ± 0.060 vs 0.722 ± 0.102, P < 0.05; 0.356 ± 0.081 vs 0.722 ± 0.102, P < 0.05, respectively). Nevertheless, no somatic mutation of PITX1 gene was found in 71 samples of gastric cancer by DHPLC analysis followed by sequencing. CONCLUSION: Down-regulation of PITX1 may be a frequent molecular event in gastric carcinogenesis. Aberrant levels of PITX1 expression may be closely correlated with the progression and differentiation of gastric cancer.展开更多
The strategy that replacing part of MnS with BN was proposed in order to decrease the sulfur content in sulfur based free-cutting steel. The effects of BN and MnS inclusions on the microstructure and machinability of ...The strategy that replacing part of MnS with BN was proposed in order to decrease the sulfur content in sulfur based free-cutting steel. The effects of BN and MnS inclusions on the microstructure and machinability of the steel were systematically investigated. The results show that most of the BN and MnS inclusions exist individually in the steel and only a small amount of them are in a composite state form- ing either isolated particles or clusters of particles. In the case of multi-phased steel, the theoretical calculation predicts that the volume of large BN particles should be 0.7 times of the volume of large MnS particles. The machinability of this type of BN and MnS alloy steel over a wide range of cutting speeds ranging from a low speed appropriate for drilling to a high speed appropriate for turning is confirmed as being equal to or superior to that of an MnS reference steel, even though the sulfur content in the composite steel is only half that of the MnS steel. The aptitude for cutting effect of 240 ppm nitrogen and 115 ppm boron in the composite steel is demonstrated to be equivalent or even better than 1000 ppm sulfur in MnS free-cutting steel.展开更多
By simplifying the r-bridge unit,a nonfused ring electron acceptor(NFREA)BM-2F was designed and synthesized with several high-yield steps.The specific molecular structure features of BM-2F are planar molecular backbon...By simplifying the r-bridge unit,a nonfused ring electron acceptor(NFREA)BM-2F was designed and synthesized with several high-yield steps.The specific molecular structure features of BM-2F are planar molecular backbone and out-of-plane side chain,which is favorable for charge transport and can suppress the over-aggregation.BM-2F based neat and blend films display obvious face-on molecular orientation.Specially,D18:BM-2F based blend film can form good bicontinuous interpenetrating network.More excitingly,a power conversion efficiency of 16.15%was achieved with D18:BM-2F based photovoltaic devices,which is the highest one based on NFREAs.Our researches manifest that NFREA is a promising direction for low-cost and high-performance organic solar cells.展开更多
Advanced cathode materials have been considered as the key to significantly improve the energy density of lithium-ion batteries(LIBs).High-Ni layer-structured cathodes,especially with Ni atomic content above 0.9(LiN1_...Advanced cathode materials have been considered as the key to significantly improve the energy density of lithium-ion batteries(LIBs).High-Ni layer-structured cathodes,especially with Ni atomic content above 0.9(LiN1_(x)M_(1-x)O_(2),x≥0.9),exhibit high capacity to be commercially available in electric vehicles(EVs).However,the intrinsic structure instability of high-Ni materials and the negative impacts severely restrict their further applic ation.In addition,Co has various effective efforts to stabilize the layered structure.Nevertheless,due to the high cost of Co,it is required to be replaced.Therefore,modification methods on increasing the stability of high-Ni cathode with the reduction of Co content have been widely investigated.In this review,we summarized various effective research progresses and several potential modification strategies of Cofree/Co-poor layered c athodes with Ni content over 0.9.The challenges and development opportunities of high-Ni,Cofree/Co-poor cathodes are further overviewed to meet the future commercial energy demands.展开更多
Background: It is important to choose an appropriate antiepileptic drug (AED) to manage partial epilepsy. Traditional AEDs, such as carbamazepine (CBZ) and valproate (VPA), have been proven to have good therape...Background: It is important to choose an appropriate antiepileptic drug (AED) to manage partial epilepsy. Traditional AEDs, such as carbamazepine (CBZ) and valproate (VPA), have been proven to have good therapeutic effects. However, in recent years, a variety of new AEDs have increasingly been used as first-line treatments for partial epilepsy. As the studies regarding the effectiveness of new drugs and comparisons between new AEDs and traditional AEDs are few, it is determined that these are areas in need of further research. Accordingly, this study investigated the long-term effectiveness of six AEDs used as monotherapy in patients with partial epilepsy. Methods: This is a retrospective, long-term observational study. Patients with partial epilepsy who received monotherapy with one of six AEDs, namely, CBZ, VPA, topiramate (TPM), oxcarbazepine (OXC), lamotrigine (LTG), or levetiracetam (LEV), were identified and followed up from May 2007 to October 2014, and time to first seizure after treatment, 12-month remission rate, retention rate, reasons for treatment discontinuation, and adverse effects were evaluated. Results: A total of 789 patients were enrolled. The median time of follow-up was 56.95 months. CBZ exhibited the best time to first seizure, with a median time to first seizure of 36.06 months (95% confidential interval: 30.64~4.07). CBZ exhibited the highest 12-month remission rate (85.55%), which was significantly higher than those of TPM (69.38%, P = 0.006), LTG (70.79%, P= 0.001), LEV (72.54%, P = 0.005), and VPA (73.33%, P = 0.002). CBZ, OXC, and LEV had the best retention rate, followed by LTG, TPM, and VPA. Overall, adverse effects occurred in 45.87% of patients, and the most common adverse effects were memory problems (8.09%), rashes (7.76%), abnormal hepatic function (6.24%), and drowsiness (6.24%). Conclusion: This study demonstrated that CBZ, OXC, and LEV are relatively effective in managing tbcal epilepsy as measured by time to first seizure, 12-month remission rate, and retention rate.展开更多
As the earliest commercial cathode material for lithium-ion batteries,lithium cobalt oxide(LiCoO_(2)) shows various advantages,including high theoretical capacity,excellent rate capability,compressed electrode density...As the earliest commercial cathode material for lithium-ion batteries,lithium cobalt oxide(LiCoO_(2)) shows various advantages,including high theoretical capacity,excellent rate capability,compressed electrode density,etc.Until now,it still plays an important role in the lithium-ion battery market.Due to these advantages,further increasing the charging cutoff voltage of LiCoO_(2)to guarantee higher energy density is an irresistible development trend of LiCoO_(2)cathode materials in the future.However,using high charging cutoff voltage may induce a lot of negative effects,especially the rapid decay of cycle capacity.These are mainly caused by rapid destruction of crystal structure and aggravation of interface side reaction at high voltage during the cycle.Therefore,how to maintain a stable crystal structure of LiCoO_(2)to ensure the excellent long cycle performance at high voltage is a hot research issue in the further application of LiCoO_(2).In this review,we summarized the failure causes and extensive solutions of LiCoO_(2)at high voltage and promoted some new modification strategies.Moreover,the development trend of solving the failure problem of high-voltage LiCoO_(2)in the future such as defect engineering and high-temperature shock technique is also discussed.展开更多
Three nonfused ring electron acceptors (NFREAs) TTC6,TT-C8T and TT-TC8 were purposefully designed and synthesized.The molecular geometry can be adjusted by the steric hindrance of lateral substituents.According to the...Three nonfused ring electron acceptors (NFREAs) TTC6,TT-C8T and TT-TC8 were purposefully designed and synthesized.The molecular geometry can be adjusted by the steric hindrance of lateral substituents.According to the DFT calculations,from TTC6 to TT-C8T and TT-TC8,planarity of the molecular backbone is gradually improved,accompanying with the enhancing of intramolecular charge transfer effect.As for TT-TC8,the two phenyl substituents are almost perpendicular to the molecular backbone,which endues the acceptor with good solubility and suppresses it to form over-aggregation.Multidirectional regular molecular orientation and closer molecular stacking are formed in TT-TC8 film.As a result,TT-TC8 based devices afford the highest PCE of 13.13%,which is much higher than that of TTC6 (4.41%) and TT-C8T (10.42%) and among the highest PCE values based on NFREAs.展开更多
In this work,regio-regular and random polymers(reg-PTF and ran-PTF)comprising benzodithiophene and 3-fluorothiophene units are developed to investigate the influence of polymer chain regularity on the photovoltaic per...In this work,regio-regular and random polymers(reg-PTF and ran-PTF)comprising benzodithiophene and 3-fluorothiophene units are developed to investigate the influence of polymer chain regularity on the photovoltaic performance.Interestingly,reg-PTF exhibits higher HOMO energy level(∼0.2 eV)than that of ran-PTF due to the more ordered molecular structure and higher crystallization.As the result,the HOMO energy level offset between donor and acceptor can be well controlled by selecting different acceptors.Using BTP-ec9-4F with a much deep HOMO energy level as acceptor,reg-PTF-based devices display an inferior PCE of 7.66%compared with ran-PTF based ones(11.78%)due to the too large HOMO energy levels offset.When blending with Y18-1F,the PCE of reg-PTF-based devices is increased to 13.23%due to the appropriate energy level.In comparison,the ran-PTF-based devices nearly do not work because of the negative HOMO energy levels offset.This work indicates that both the polymer chain regularity and the energy level offset between the donor and acceptor material are important to the performance of organic solar cells.展开更多
基金Supported by the National Natural Science Foundation of China (No.81301080)the National Key Technology R&D Program of China (2012BAI08B06)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
文摘AIM: To investigate the impact of titanium dioxide nanoparticles(Ti O2NPs) on embryonic development and retinal neurogenesis.METHODS: The agglomeration and sedimentation of Ti O2 NPs solutions at different dilutions were observed,and the ultraviolet-visible spectra of their supernatants were measured. Zebrafish embryos were experimentally exposed to Ti O2 NPs until 72 h postfertilization(hpf). The retinal neurogenesis and distribution of the microglia were analyzed by immunohistochemistry and whole mount in situ hybridization.RESULTS: The 1 mg/L was determined to be an appropriate exposure dose. Embryos exposed to Ti O2 NPs had a normal phenotype. The neurogenesis was initiated on time, and ganglion cells, cones and rods were well differentiated at 72 hpf. The expression of fms m RNA and the 4C4 antibody, which were specific to microglia in the central nervous system(CNS), closely resembled their endogenous profile.CONCLUSION: These data demonstrate that short-term exposure to Ti O2 NPs at a low dose does not lead to delayed embryonic development or retinal neurotoxicity.
基金financially supported by the National Natural Science Foundation of China(No.51074019)
文摘An unsteady, two-dimensional, explicitly solved fmite difference heat transfer model of a billet caster was presented to clarify the influence of the thermal conductivity of steel on model accuracy. Different approaches were utilized for calculating the thermal conductivity of solid, mushy and liquid steels. Model results predicted by these approaches were compared, and the advantages of advocated approaches were discussed. It is found that the approach for calculating the thermal conductivity of solid steel notably influences model predictions. Convection effects of liquid steel should be considered properly while calculating the thermal conductivity of mushy steel. Different values of the effective thermal conductivity of liquid steel adopted could partly be explained by the fact that different models adopted dissimilar ap- proaches for calculating the thermal conductivity of solid and mushy steels.
基金The National Science Fund for Distinguished Young Scholars, No. 30125017The Major State Basic Research Development Program of China (973 Program), No. 2002CB513100
文摘AIM: To investigate the effect of pituitary homeobox 1 (PITX1) expression in cases of human gastric cancer on cancer differentiation and progression, and carcinogenesis. METHODS: Using polyclonal PITX1 antibodies, we studied the expression of PITX1 in normal gastric mucosa, atypical hyperplasia, intestinal metaplasia, and cancer tissue samples from 83 gastric cancer patients by immunohistochemistry. Moreover, semi-reverse transcription polymerase chain reaction (semi-RT-PCR) was performed to detect the mRNA level of PITX1 in three gastric cancer cell lines and a normal gastric epithelial cell line. Subsequently, somatic mutations of the PITX1 gene in 71 gastric cancer patients were analyzed by a combination of denaturing high performance liquid chromatography (DHPLC) and DNA sequencing. RESULTS: Immunohistochemistry showed that PITX1 was strongly or moderately expressed in the parietal cells of normal gastric mucosa (100%), while 55 (66.3%) out of 83 samples of gastric cancers showed decreased PITX1 expression. Moreover, PITX1 expression was reduced in 20 out of 28 cases (71.5%) of intestinal metaplasia, but in only 1 out of 9 cases (11%) of atypical hyperplasia. More importantly, PITX1 expression was significantly associated with the differentiation, position and invasion depth of gastric cancers (r = -0.316, P < 0.01; r = 0.213, P < 0.05; r = -0.259, P < 0.05, respectively). Similarly, levels of PITX1 mRNA were significantly decreased in 2 gastric cancer cell lines, BGC-823 and SGC-7901, compared with the normal gastric epithelial cell line GES-1 (0.306 ± 0.060 vs 0.722 ± 0.102, P < 0.05; 0.356 ± 0.081 vs 0.722 ± 0.102, P < 0.05, respectively). Nevertheless, no somatic mutation of PITX1 gene was found in 71 samples of gastric cancer by DHPLC analysis followed by sequencing. CONCLUSION: Down-regulation of PITX1 may be a frequent molecular event in gastric carcinogenesis. Aberrant levels of PITX1 expression may be closely correlated with the progression and differentiation of gastric cancer.
基金financially supported by the National Natural Science Foundation of China(No.51274029)the China Postdoctoral Science Foundation(No.2012M 510319)the State Key Laboratory of Advanced Metallurgy Foundation(No.41602014)
文摘The strategy that replacing part of MnS with BN was proposed in order to decrease the sulfur content in sulfur based free-cutting steel. The effects of BN and MnS inclusions on the microstructure and machinability of the steel were systematically investigated. The results show that most of the BN and MnS inclusions exist individually in the steel and only a small amount of them are in a composite state form- ing either isolated particles or clusters of particles. In the case of multi-phased steel, the theoretical calculation predicts that the volume of large BN particles should be 0.7 times of the volume of large MnS particles. The machinability of this type of BN and MnS alloy steel over a wide range of cutting speeds ranging from a low speed appropriate for drilling to a high speed appropriate for turning is confirmed as being equal to or superior to that of an MnS reference steel, even though the sulfur content in the composite steel is only half that of the MnS steel. The aptitude for cutting effect of 240 ppm nitrogen and 115 ppm boron in the composite steel is demonstrated to be equivalent or even better than 1000 ppm sulfur in MnS free-cutting steel.
基金This research was made possible thanks to the financial support from the National Natural Science Foundation of China(51933001,52173174,22109080,21734009).
文摘By simplifying the r-bridge unit,a nonfused ring electron acceptor(NFREA)BM-2F was designed and synthesized with several high-yield steps.The specific molecular structure features of BM-2F are planar molecular backbone and out-of-plane side chain,which is favorable for charge transport and can suppress the over-aggregation.BM-2F based neat and blend films display obvious face-on molecular orientation.Specially,D18:BM-2F based blend film can form good bicontinuous interpenetrating network.More excitingly,a power conversion efficiency of 16.15%was achieved with D18:BM-2F based photovoltaic devices,which is the highest one based on NFREAs.Our researches manifest that NFREA is a promising direction for low-cost and high-performance organic solar cells.
基金financially supported by the National Natural Science Foundation of China(Nos.22109091 and 91963113)。
文摘Advanced cathode materials have been considered as the key to significantly improve the energy density of lithium-ion batteries(LIBs).High-Ni layer-structured cathodes,especially with Ni atomic content above 0.9(LiN1_(x)M_(1-x)O_(2),x≥0.9),exhibit high capacity to be commercially available in electric vehicles(EVs).However,the intrinsic structure instability of high-Ni materials and the negative impacts severely restrict their further applic ation.In addition,Co has various effective efforts to stabilize the layered structure.Nevertheless,due to the high cost of Co,it is required to be replaced.Therefore,modification methods on increasing the stability of high-Ni cathode with the reduction of Co content have been widely investigated.In this review,we summarized various effective research progresses and several potential modification strategies of Cofree/Co-poor layered c athodes with Ni content over 0.9.The challenges and development opportunities of high-Ni,Cofree/Co-poor cathodes are further overviewed to meet the future commercial energy demands.
文摘Background: It is important to choose an appropriate antiepileptic drug (AED) to manage partial epilepsy. Traditional AEDs, such as carbamazepine (CBZ) and valproate (VPA), have been proven to have good therapeutic effects. However, in recent years, a variety of new AEDs have increasingly been used as first-line treatments for partial epilepsy. As the studies regarding the effectiveness of new drugs and comparisons between new AEDs and traditional AEDs are few, it is determined that these are areas in need of further research. Accordingly, this study investigated the long-term effectiveness of six AEDs used as monotherapy in patients with partial epilepsy. Methods: This is a retrospective, long-term observational study. Patients with partial epilepsy who received monotherapy with one of six AEDs, namely, CBZ, VPA, topiramate (TPM), oxcarbazepine (OXC), lamotrigine (LTG), or levetiracetam (LEV), were identified and followed up from May 2007 to October 2014, and time to first seizure after treatment, 12-month remission rate, retention rate, reasons for treatment discontinuation, and adverse effects were evaluated. Results: A total of 789 patients were enrolled. The median time of follow-up was 56.95 months. CBZ exhibited the best time to first seizure, with a median time to first seizure of 36.06 months (95% confidential interval: 30.64~4.07). CBZ exhibited the highest 12-month remission rate (85.55%), which was significantly higher than those of TPM (69.38%, P = 0.006), LTG (70.79%, P= 0.001), LEV (72.54%, P = 0.005), and VPA (73.33%, P = 0.002). CBZ, OXC, and LEV had the best retention rate, followed by LTG, TPM, and VPA. Overall, adverse effects occurred in 45.87% of patients, and the most common adverse effects were memory problems (8.09%), rashes (7.76%), abnormal hepatic function (6.24%), and drowsiness (6.24%). Conclusion: This study demonstrated that CBZ, OXC, and LEV are relatively effective in managing tbcal epilepsy as measured by time to first seizure, 12-month remission rate, and retention rate.
基金financially supported by the National Natural Science Foundation of China(Nos.52171219 and 91963113)
文摘As the earliest commercial cathode material for lithium-ion batteries,lithium cobalt oxide(LiCoO_(2)) shows various advantages,including high theoretical capacity,excellent rate capability,compressed electrode density,etc.Until now,it still plays an important role in the lithium-ion battery market.Due to these advantages,further increasing the charging cutoff voltage of LiCoO_(2)to guarantee higher energy density is an irresistible development trend of LiCoO_(2)cathode materials in the future.However,using high charging cutoff voltage may induce a lot of negative effects,especially the rapid decay of cycle capacity.These are mainly caused by rapid destruction of crystal structure and aggravation of interface side reaction at high voltage during the cycle.Therefore,how to maintain a stable crystal structure of LiCoO_(2)to ensure the excellent long cycle performance at high voltage is a hot research issue in the further application of LiCoO_(2).In this review,we summarized the failure causes and extensive solutions of LiCoO_(2)at high voltage and promoted some new modification strategies.Moreover,the development trend of solving the failure problem of high-voltage LiCoO_(2)in the future such as defect engineering and high-temperature shock technique is also discussed.
基金supported by the National Natural Science Foundation of China (51933001, 21734009)。
文摘Three nonfused ring electron acceptors (NFREAs) TTC6,TT-C8T and TT-TC8 were purposefully designed and synthesized.The molecular geometry can be adjusted by the steric hindrance of lateral substituents.According to the DFT calculations,from TTC6 to TT-C8T and TT-TC8,planarity of the molecular backbone is gradually improved,accompanying with the enhancing of intramolecular charge transfer effect.As for TT-TC8,the two phenyl substituents are almost perpendicular to the molecular backbone,which endues the acceptor with good solubility and suppresses it to form over-aggregation.Multidirectional regular molecular orientation and closer molecular stacking are formed in TT-TC8 film.As a result,TT-TC8 based devices afford the highest PCE of 13.13%,which is much higher than that of TTC6 (4.41%) and TT-C8T (10.42%) and among the highest PCE values based on NFREAs.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51933001 and 22109080).
文摘In this work,regio-regular and random polymers(reg-PTF and ran-PTF)comprising benzodithiophene and 3-fluorothiophene units are developed to investigate the influence of polymer chain regularity on the photovoltaic performance.Interestingly,reg-PTF exhibits higher HOMO energy level(∼0.2 eV)than that of ran-PTF due to the more ordered molecular structure and higher crystallization.As the result,the HOMO energy level offset between donor and acceptor can be well controlled by selecting different acceptors.Using BTP-ec9-4F with a much deep HOMO energy level as acceptor,reg-PTF-based devices display an inferior PCE of 7.66%compared with ran-PTF based ones(11.78%)due to the too large HOMO energy levels offset.When blending with Y18-1F,the PCE of reg-PTF-based devices is increased to 13.23%due to the appropriate energy level.In comparison,the ran-PTF-based devices nearly do not work because of the negative HOMO energy levels offset.This work indicates that both the polymer chain regularity and the energy level offset between the donor and acceptor material are important to the performance of organic solar cells.