Crohn's disease (CD) is an autoimmune disease with an unclear pathogenesis, primarily affecting the digestive tract. Perianal involvement represents a complex form of CD. Refractory proctoanal CD is a major cause of rectal resection and permanent anal sphincter dysfunction in patients. The colon pull-through with delayed anastomosis of the anal canal involves the resection of the diseased rectum and the management of the dentate line and anal canal. After the pulled-through colon has adhered to the anal canal, a revision and anastomosis are performed, aiming to preserve anal function and enhance the patients' quality of life. The specific criteria and timing for selecting this surgical approach for refractory proctoanal CD merit further discussion and investigation.

Crohn's disease (CD) is an autoimmune disease with an unclear pathogenesis, primarily affecting the digestive tract. Perianal involvement represents a complex form of CD. Refractory proctoanal CD is a major cause of rectal resection and permanent anal sphincter dysfunction in patients. The colon pull-through with delayed anastomosis of the anal canal involves the resection of the diseased rectum and the management of the dentate line and anal canal. After the pulled-through colon has adhered to the anal canal, a revision and anastomosis are performed, aiming to preserve anal function and enhance the patients' quality of life. The specific criteria and timing for selecting this surgical approach for refractory proctoanal CD merit further discussion and investigation.

As an important functional material for water treatment,ion exchange resin is widely used in medicine,chemical industry,nuclear industry and other fields.Due to its high efficiency and reliability,it is also widely used in the water circulation system of China Space Station,such as urine treatment subsystem,water treatment subsystem,and electrolytic oxygen production subsystem,which effectively guarantees the normal operation of the equipment and the safe use of water resources.Considering its renewability,the development of ion exchange resin regeneration technology for manned space missions can further reduce the supply demand of long-term missions,which is of great significance for the development of manned space flight to deep space.This paper focuses on the application characteristics and research progress of three kinds of ion exchange resin electro-regeneration technology,and the potential auxiliary regeneration technologies such as thermal regeneration,biological regeneration,ultrasonic regeneration and carbon dioxide regeneration are introduced,and the application prospect analysis of ion exchange regeneration technology is given according to the application characteristics of manned spaceflight.

The polyfoliate perforator flap is a new type of flap that was developed on the basis of the traditional polyfoliate myocutaneous flap, polyfoliate fascial flap and perforator flap. It overturns the traditional idea that the deep fascial vascular network is the fundamental for a survival of the flap, and enables the flaps to achieve the best profile and function of the recipient areas with minimal damage to the donor area. In order to improve the understanding of the polyfoliate perforator flap and further standardise its clinical application, this paper forms a consensus on the definition, classification, indications, operative points and precautions of the polyfoliate perforator flap, so as to provide references in diagnosis and treatment process and practical application for the surgeons.

In response to the challenge of sintering silicon carbide ceramic into complex part,which limits it application in certain mechanical seal,a design was developed that integrates silicon carbide ring with metal component to create a mechanical sealed with intricate structure.Type tests and durability tests were designed and conducted in the context of urine processor assembly for space stations,the test results indicate that the static liquid leakage rate of mosaic type mechanical seal did not exceed 0.88 mL/h under a pressure differential of 50 kPa,and the dynamic liquid leakage rate did not exceed 0.47 mL/h at a rotational speed of 400 r/min.The vibration and impact qualification tests of dynamic environment were conducted under the conditions of mechanical seals installed.There was no change in sealing performance observed before and after the tests.Following that,a 4 500-hour durability test was performed in pretreated urine.The results showed good sealing performance.After the test,the mechanical seals were disassembled and checked.the installation and appearance of ceramic rings were found to be in good condition,with no visible corrosion or wear.The results suggest that this integrated structure meets the requirements for complex mechanical structures and can operate stably over extended periods under acidic and corrosive liquid conditions.

When conducting long-term experimental verification of urine regeneration using ground equipment of manned space water regeneration system,it was found that the ion exchange removal ability of the water regeneration system is also affected when the pre-treatment agent changes.Therefore,the influence behavior and mechanism of pre-treatment agent changes on the ion exchange removal capacity of water regeneration systems were studied through small sample experiments,water quality composition analysis,and other means.The results showed that with the increase of CrO3 content in the pre-treatment agent,the organic acid content in distilled water increased,leading to an increase in the conductivity,an increase in the organic carbon content,and a decrease in pH value of distilled water.Organic acids have low degree of dissociation in water,and their selectivity coefficients are low when exchanging with strong alkaline anion exchange resins.This results in a slow ion exchange rate of the acid ion.As the organic acid content in distilled water increases,the ion exchange band of acid ion widens and shifts backwards,causing resin penetration,resulting in a decrease in the ion exchange removal ability of the water regeneration system.

Crohn′s disease (CD) is an autoimmune disease that mainly affects the digestive tract. Rectal and perianal involvement is a complex manifestation of CD. Refractory proctoanal type CD is the main cause of rectal resection and permanent anal dysfunction. Recently, our center performed modified Bacon surgery in two CD patients with complex rectoperineal and rectovaginal fistulas who were about to undergo rectotomy and enterostomy. The data of these two cases are summarized and reported.

Crohn′s disease (CD) is an autoimmune disease that mainly affects the digestive tract. Rectal and perianal involvement is a complex manifestation of CD. Refractory proctoanal type CD is the main cause of rectal resection and permanent anal dysfunction. Recently, our center performed modified Bacon surgery in two CD patients with complex rectoperineal and rectovaginal fistulas who were about to undergo rectotomy and enterostomy. The data of these two cases are summarized and reported.

The polyfoliate perforator flap is a new type of flap that was developed on the basis of the traditional polyfoliate myocutaneous flap, polyfoliate fascial flap and perforator flap. It overturns the traditional idea that the deep fascial vascular network is the fundamental for a survival of the flap, and enables the flaps to achieve the best profile and function of the recipient areas with minimal damage to the donor area. In order to improve the understanding of the polyfoliate perforator flap and further standardise its clinical application, this paper forms a consensus on the definition, classification, indications, operative points and precautions of the polyfoliate perforator flap, so as to provide references in diagnosis and treatment process and practical application for the surgeons.

Short bowel syndrome (SBS) is a disabling malabsorptive disease in which patients are incapable of maintaining proper nutrition and hydration through normal oral intake alone because of extensive resection of the small intestine.The incidence, which has been increasing in recent years, is relatively low, but patients with SBS are seriously affected in their everyday life. The severity and prognosis of SBS are largely decided by the etiology and the length of remaining small intestine. The key strategy to prevent and reduce SBS is to fully understand the etiology.This paper summarizes the common etiologies of SBS, in order to provide references for clinical work.