Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to hab...Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to habitat destruction.In China,these most-at-risk species are described as 'plant species with extremely small populations'(PSESP).Implementing conservation action for such listed species is urgent.Storing seeds is one of the main means of ex situ conservation for flowering plants.Spore storage could provide a simple and economical method for fern ex situ conservation.Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation.But what is known about the seed and spore biology(storage and germination) of at-risk species? We have used China's PSESP(the first group listing) as a case study to understand the gaps in knowledge on propagule biology of threatened plant species.We found that whilst germination information is available for 28 species(23%of PSESP),storage characteristics are only known for 8%of PSESP(10 species).Moreover,we estimate that 60%of the listed species may require cryopreservation for long-term storage.We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.展开更多
“Be Silly.Be honest.Be kind.” -Ralph Waldo Emerson “The first of April is the day we remember what we are the other 364 days of the year.” -American humorist Mark Twain 愚人节有时也被称为“All Fool’s Day”,...“Be Silly.Be honest.Be kind.” -Ralph Waldo Emerson “The first of April is the day we remember what we are the other 364 days of the year.” -American humorist Mark Twain 愚人节有时也被称为“All Fool’s Day”,它不像大多数其它非愚人性质的节日,其历史并不完全明晰。现在真的无法查明第一个愚人节的具体日期。展开更多
Inorganic carbon utilization in the non calcifying marine microalgae, Nannochloropsis oculata, Phaeodactylum tricornutum and Porphyridium purpureum was compared with high and low calcifying strains of Emiliania huxley...Inorganic carbon utilization in the non calcifying marine microalgae, Nannochloropsis oculata, Phaeodactylum tricornutum and Porphyridium purpureum was compared with high and low calcifying strains of Emiliania huxleyi grown in artificial seawater medium aerated with either air (0.03% V/V CO 2) or CO 2 free air. For high calcifying strain of E. oculata and P. tricornutem , similar growth patterns were observed in air and CO 2 free air grown cultures. P. purpureum showed a less final cell density in CO 2 free air than in air grown culture. However, low calcifying strain of E. huxleyi was able to grow only in air grown culture, but not in CO 2 free air grown culture. Measurements of alkalinity, pH, concentration of dissolved inorganic carbon (DIC) and free CO 2 showed different patterns of DIC utilization. With N. oculata, P. tricornutum and P. purpureum the pattern of DIC utilization was characterized by an increase of pH and a decrease of DIC but a constant alkalinity in the cultures aerated with air or CO 2 free air, suggesting that bicarbonate utilization was concomitant with an efflux of OH -. Both alkalinity and pH were maintained rather constant in air grown culture of low calcifying strain of E. huxleyi, suggesting that diffusive entry of CO 2 could meet the requirement of DIC for its photosynthesis and growth. High calcifying strain of E.huxleyi , however, showed a pattern of decrease of alkalinity and DIC but an almost constant pH , indicating that bicarbonate was the major form of inorganic carbon utilised by this organism and bicarbonate uptake is unlikely to be accompanied by an efflux of OH -. The final pH values reached by N. oculata, P. tricornutum and P. purpureum in a closed system were 10.75, 10.60 and 9.85 respectively, showing that bicarbonate utilisation is concomitant with an efflux of OH . While the final pH of 8.4 in high calcifying E. huxleyi suggests that bicarbonate utilization was not accompanied by an efflux of OH -.展开更多
Periampullary cancers include pancreatic, ampullary, biliary and duodenal cancers. At presentation, the majority of periampullary tumours have grown to involve the pancreas, bile duct, ampulla and duodenum. This can r...Periampullary cancers include pancreatic, ampullary, biliary and duodenal cancers. At presentation, the majority of periampullary tumours have grown to involve the pancreas, bile duct, ampulla and duodenum. This can result in difficulty in defining the primary site of origin in all but the smallest tumors due to anatomical proximity and architectural distortion. This has led to variation in the reported proportions of resected periampullary cancers. Pancreatic cancer is the most common cancer resected with a pancreaticoduodenectomy followed by ampullary(16%-50%), bile duct(5%-39%), and duodenal cancer(3%-17%). Patients with resected duodenal and ampullary cancers have a better reported median survival(29-47 mo and 22-54 mo) compared to pancreatic cancer(13-19 mo). The poorer survival with pancreatic cancer relates to differences in tumour characteristics such as a higher incidence of nodal, neural and vascular invasion. While small ampullary cancers can present early with biliary obstruction, pancreatic cancers need to reach a certain size before biliary obstruction ensues. This larger size at presentation contributes to a higher incidence of resection margin involvement in pancreatic cancer. Ampullary cancers can be subdivided into intestinal or pancreatobiliary subtype cancers with histomolecular staining. This avoids relying on histomorphology alone, as even some poorly differentiated cancers preserve the histomolecular profile of their mucosa of origin. Histomolecular profiling is superior to anatomic location in prognosticating survival. Ampullary cancers of intestinal subtype and duodenal cancers are similar in their intestinal origin and form a logical clinical and therapeutic subgroup of periampullary cancers. They respond to 5-FU based chemotherapeutic regimens such as capecitabine-oxaliplatin. Unlike pancreatic cancers, KRAS mutation occurs in only approximately a third of ampullary and duodenal cancers. Future clinical trials should group ampullary cancers of intestinal origin and duodenal cancers toge展开更多
After much controversy, multimodality therapy is now accepted worldwide as the gold standard for treatment of resectable bulky localized gastric cancer. There is significant regional variation in the style of multimod...After much controversy, multimodality therapy is now accepted worldwide as the gold standard for treatment of resectable bulky localized gastric cancer. There is significant regional variation in the style of multimodality treatment with adjuvant chemoradiation the North American standard, neoadjuvant chemotherapy preferred in Europe and Australasia, whilst adjuvant chemotherapy is preferred in Asia. With further standardization of surgery and D1+/D2 resections increasingly accepted world wide, and in particular in the West, as the surgical standard of care for potentially curable disease, it is timely to reassess the multimodality regimes being used. The challenge in the use of multimodality therapy is how current outcomes can be standardized and improved further. Recent studies indicate that mere intensification of the regime in time, dosage or addition of further agents does not improve localized gastric cancer outcomes. More novel strategies including early commencement of adjuvant therapies, intra-peritoneal chemotherapy or assessing neoadjuvant response with positron emission tomography scanning may give improvements in outcomes. The introduction of targeted therapies means that the adjuvant use of biological agents needs to be explored. By proper assessment of the patient’s co-morbidities, full tumour staging, and a better understanding of the tumour’s molecular pathology, multimodality therapy for gastric adenocarcinoma may be individualized to optimize the likelihood of cure.展开更多
Background:The sterilization of corneal implants composed of carbodiimide crosslinked recombinant human collagen type III(RHCIII)and phosphorylcholine polymers(RHCIII-MPC)is constrained by the biochemical properties o...Background:The sterilization of corneal implants composed of carbodiimide crosslinked recombinant human collagen type III(RHCIII)and phosphorylcholine polymers(RHCIII-MPC)is constrained by the biochemical properties of RHCIII.Early human trials used 1%chloroform in 0.1 M phosphate buffered saline(C-PBS),but require a stringent wash procedure with antibiotics to remove the chloroform.Irradiation with gamma or electron-beam(e-beam)allows a chemical-free sterilization method,but may result in crosslinking or denaturation.Here,electron-beam irradiation is evaluated as a sterilization method for RHCIII-MPC implants.Methods:Dose-finding study:RHCIII-MPC were cast in round,350µm thick,12 mm diameter molds for corneal implants and 0.5 mm thick dumbbell-shaped molds for mechanical testing.The hydrogels received an irradiation dose of 17,19,or 21 kGy and unirradiated controls were stored in C-PBS,n=3 per group.The hydrogels were tested for sterility and endotoxin,optical and mechanical properties,biodegradation,free radicals,and cell compatibility.Clinical evaluation in rabbits:RHCIII-MPC implants were e-beamed at 17 kGy or kept in C-PBS.One implant from each group was implanted into the right cornea of each rabbit by deep anterior lamellar keratoplasty,n=4 animals per group.Animals underwent preoperative and 6-month post-operative in vivo confocal microscopy(IVCM)to check nerve count and ingrowth of keratocytes.Corneal grafts and controls were assessed via histology and immunohistochemistry.Results:Dose finding study:hydrogels were sterile at all irradiation doses with no evidence of free radicals.There were no significant differences in optical or mechanical properties between the treatment groups and controls.All hydrogels supported cell growth.The 19 and 21 kGy implants had high collagenase degradation for 21 hours until they stabilized,whereas the 17 kGy and C-PBS implants had gradual degradation until 48 hours.Clinical results:the rabbits did not experience post-surgical inflammatory reactions and full epithelial co展开更多
基金Funding (No. U1302262) to W.B. Sun from the NSFC-Yunnan joint fund on key projects is gratefully acknowledgedThe Royal Botanic Gardens, Kew receives grant-in-aid from Defra+1 种基金This joint work was undertaken under the Memorandum of Agreement (2014e24) on Plant and Fungal Science between the Chinese Academy of Sciences and the Trustees of the Royal Botanic Gardens, KewHWP thanks Darwin Initiative Project 21-003 on cycads for funding
文摘Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to habitat destruction.In China,these most-at-risk species are described as 'plant species with extremely small populations'(PSESP).Implementing conservation action for such listed species is urgent.Storing seeds is one of the main means of ex situ conservation for flowering plants.Spore storage could provide a simple and economical method for fern ex situ conservation.Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation.But what is known about the seed and spore biology(storage and germination) of at-risk species? We have used China's PSESP(the first group listing) as a case study to understand the gaps in knowledge on propagule biology of threatened plant species.We found that whilst germination information is available for 28 species(23%of PSESP),storage characteristics are only known for 8%of PSESP(10 species).Moreover,we estimate that 60%of the listed species may require cryopreservation for long-term storage.We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.
文摘“Be Silly.Be honest.Be kind.” -Ralph Waldo Emerson “The first of April is the day we remember what we are the other 364 days of the year.” -American humorist Mark Twain 愚人节有时也被称为“All Fool’s Day”,它不像大多数其它非愚人性质的节日,其历史并不完全明晰。现在真的无法查明第一个愚人节的具体日期。
文摘Inorganic carbon utilization in the non calcifying marine microalgae, Nannochloropsis oculata, Phaeodactylum tricornutum and Porphyridium purpureum was compared with high and low calcifying strains of Emiliania huxleyi grown in artificial seawater medium aerated with either air (0.03% V/V CO 2) or CO 2 free air. For high calcifying strain of E. oculata and P. tricornutem , similar growth patterns were observed in air and CO 2 free air grown cultures. P. purpureum showed a less final cell density in CO 2 free air than in air grown culture. However, low calcifying strain of E. huxleyi was able to grow only in air grown culture, but not in CO 2 free air grown culture. Measurements of alkalinity, pH, concentration of dissolved inorganic carbon (DIC) and free CO 2 showed different patterns of DIC utilization. With N. oculata, P. tricornutum and P. purpureum the pattern of DIC utilization was characterized by an increase of pH and a decrease of DIC but a constant alkalinity in the cultures aerated with air or CO 2 free air, suggesting that bicarbonate utilization was concomitant with an efflux of OH -. Both alkalinity and pH were maintained rather constant in air grown culture of low calcifying strain of E. huxleyi, suggesting that diffusive entry of CO 2 could meet the requirement of DIC for its photosynthesis and growth. High calcifying strain of E.huxleyi , however, showed a pattern of decrease of alkalinity and DIC but an almost constant pH , indicating that bicarbonate was the major form of inorganic carbon utilised by this organism and bicarbonate uptake is unlikely to be accompanied by an efflux of OH -. The final pH values reached by N. oculata, P. tricornutum and P. purpureum in a closed system were 10.75, 10.60 and 9.85 respectively, showing that bicarbonate utilisation is concomitant with an efflux of OH . While the final pH of 8.4 in high calcifying E. huxleyi suggests that bicarbonate utilization was not accompanied by an efflux of OH -.
文摘一、引言
澳大利亚银行业吸收外国直接投资的历史比较长,但其对外直接投资的历史则相对较短.本文对澳大利亚银行业的讨论增加了世界银行业FDI国别案例研究的数量,从而使现有的国别案例不仅仅局限于英国,美国,日本,而且还有一些较小的欧洲国家(Engwall and Wallenstal, 1988;Huertas, 1990;Jones, 1990,1993;Ozawa and Hine, 1993;Hellman, 1994;Guillen and Tschoegl,2000;Boldt-Christmas etal.,2001 ).
文摘Periampullary cancers include pancreatic, ampullary, biliary and duodenal cancers. At presentation, the majority of periampullary tumours have grown to involve the pancreas, bile duct, ampulla and duodenum. This can result in difficulty in defining the primary site of origin in all but the smallest tumors due to anatomical proximity and architectural distortion. This has led to variation in the reported proportions of resected periampullary cancers. Pancreatic cancer is the most common cancer resected with a pancreaticoduodenectomy followed by ampullary(16%-50%), bile duct(5%-39%), and duodenal cancer(3%-17%). Patients with resected duodenal and ampullary cancers have a better reported median survival(29-47 mo and 22-54 mo) compared to pancreatic cancer(13-19 mo). The poorer survival with pancreatic cancer relates to differences in tumour characteristics such as a higher incidence of nodal, neural and vascular invasion. While small ampullary cancers can present early with biliary obstruction, pancreatic cancers need to reach a certain size before biliary obstruction ensues. This larger size at presentation contributes to a higher incidence of resection margin involvement in pancreatic cancer. Ampullary cancers can be subdivided into intestinal or pancreatobiliary subtype cancers with histomolecular staining. This avoids relying on histomorphology alone, as even some poorly differentiated cancers preserve the histomolecular profile of their mucosa of origin. Histomolecular profiling is superior to anatomic location in prognosticating survival. Ampullary cancers of intestinal subtype and duodenal cancers are similar in their intestinal origin and form a logical clinical and therapeutic subgroup of periampullary cancers. They respond to 5-FU based chemotherapeutic regimens such as capecitabine-oxaliplatin. Unlike pancreatic cancers, KRAS mutation occurs in only approximately a third of ampullary and duodenal cancers. Future clinical trials should group ampullary cancers of intestinal origin and duodenal cancers toge
文摘After much controversy, multimodality therapy is now accepted worldwide as the gold standard for treatment of resectable bulky localized gastric cancer. There is significant regional variation in the style of multimodality treatment with adjuvant chemoradiation the North American standard, neoadjuvant chemotherapy preferred in Europe and Australasia, whilst adjuvant chemotherapy is preferred in Asia. With further standardization of surgery and D1+/D2 resections increasingly accepted world wide, and in particular in the West, as the surgical standard of care for potentially curable disease, it is timely to reassess the multimodality regimes being used. The challenge in the use of multimodality therapy is how current outcomes can be standardized and improved further. Recent studies indicate that mere intensification of the regime in time, dosage or addition of further agents does not improve localized gastric cancer outcomes. More novel strategies including early commencement of adjuvant therapies, intra-peritoneal chemotherapy or assessing neoadjuvant response with positron emission tomography scanning may give improvements in outcomes. The introduction of targeted therapies means that the adjuvant use of biological agents needs to be explored. By proper assessment of the patient’s co-morbidities, full tumour staging, and a better understanding of the tumour’s molecular pathology, multimodality therapy for gastric adenocarcinoma may be individualized to optimize the likelihood of cure.
文摘Background:The sterilization of corneal implants composed of carbodiimide crosslinked recombinant human collagen type III(RHCIII)and phosphorylcholine polymers(RHCIII-MPC)is constrained by the biochemical properties of RHCIII.Early human trials used 1%chloroform in 0.1 M phosphate buffered saline(C-PBS),but require a stringent wash procedure with antibiotics to remove the chloroform.Irradiation with gamma or electron-beam(e-beam)allows a chemical-free sterilization method,but may result in crosslinking or denaturation.Here,electron-beam irradiation is evaluated as a sterilization method for RHCIII-MPC implants.Methods:Dose-finding study:RHCIII-MPC were cast in round,350µm thick,12 mm diameter molds for corneal implants and 0.5 mm thick dumbbell-shaped molds for mechanical testing.The hydrogels received an irradiation dose of 17,19,or 21 kGy and unirradiated controls were stored in C-PBS,n=3 per group.The hydrogels were tested for sterility and endotoxin,optical and mechanical properties,biodegradation,free radicals,and cell compatibility.Clinical evaluation in rabbits:RHCIII-MPC implants were e-beamed at 17 kGy or kept in C-PBS.One implant from each group was implanted into the right cornea of each rabbit by deep anterior lamellar keratoplasty,n=4 animals per group.Animals underwent preoperative and 6-month post-operative in vivo confocal microscopy(IVCM)to check nerve count and ingrowth of keratocytes.Corneal grafts and controls were assessed via histology and immunohistochemistry.Results:Dose finding study:hydrogels were sterile at all irradiation doses with no evidence of free radicals.There were no significant differences in optical or mechanical properties between the treatment groups and controls.All hydrogels supported cell growth.The 19 and 21 kGy implants had high collagenase degradation for 21 hours until they stabilized,whereas the 17 kGy and C-PBS implants had gradual degradation until 48 hours.Clinical results:the rabbits did not experience post-surgical inflammatory reactions and full epithelial co