载人航天60问（8）

航天员穿的航天服分为舱内航天服和舱外航天服两种。它是载人航天中航天员必备的个人安全防护装备。     

舱外航天服热真空试验技术研究进展

概述舱外航天服热真空试验技术,介绍国内外舱外航天服试验设备,分析中美舱外航天服热真空试验技术差异,结合中国未来载人航天发展特点探讨中国舱外航天服热真空试验技术发展方向。     

舱外航天服便携式生命保障系统研究进展

随着空间探索的发展,舱外航天服便携式生命保障系统必须具有更优良的性能.本文介绍了国外舱外航天服生保系统的研究进展,主要包括CO2去除和H2O去除等方面的新技术.对各种技术进行了分析、比较.探讨了舱外航天服生保系统的发展趋势.我国载人航天应该采用成熟、可靠的生保技术,同时开展再生式生保技术的研制工作.     

航天中压力应急防护措施的发展

载人航天中座舱或舱外航天服应急失压是严重的偶发事件，应急失压的医学要求和生理限值是防护装置设计的基础，防护原则是立即加压供氧，确保航天员生命安全。装备应轻便，具有高度可靠性和操作简单，并需和其他防护措施协调一致，做到防护装备一体化，航天服已由早期舱内救生用发展为出舱活动装备，从低压力制向高压力制发展，出舱活动航天服制做难度大，救生措施更复杂，航天医学工程应重视研究发展舱外活动航天服及其救护措施。     

太空人的特殊衣服——航天服

人类在进行航天飞行和太空探索时,要面对与地球完全不同的特殊环境:在航天器内部,航天员有可能会遭遇由于机械故障或其他紧急情况引发的减压危险;在航天器外部,不但没有大气压和维持生命所需要的氧气,而且还存在对宇航员身体有致命杀伤力的宇宙辐射。为了更好地保护自己,最大限度地减少外界环境的不利影响,航天员必须根据情况和任务的不同,穿着不同类型的航天服。目前的航天服按其用途和使用环境不同,大致可以分为在航天器内部穿着的舱内航天服,以及离开航天器、在外部空间中工作和执行任务时穿着的舱外航天服。舱内航天服在航天器发射和返…     

舱外航天服上肢主动助力外骨骼建模与仿真

目的为消除舱外航天服关节阻尼力矩对航天员舱外作业的影响,设计一种舱外航天服主动助力上肢外骨骼方案。方法上肢外骨骼关节采用串联弹性体(rotary series elastic actuator,RSEA);分别建立人体和航天服间接触力、舱外航天服关节阻尼、上肢外骨骼动力学模型;按照人在回路控制系统原理,提出关节力控制策略和外骨骼力控方法,并进行仿真实验。结果仿真表明:助力外骨骼可将航天服肩关节阻尼力矩从39.5Nm减小到0.45Nm,可将肘关节阻尼力矩从9.8Nm减小到0.1Nm。结论该舱外航天服上肢主动助力外骨骼能够显著减少人体受到的阻尼力矩,有利于降低航天员体力消耗,延长舱外作业时间。     

舱外航天服试验舱紧急复压系统研制

目的 为舱外航天服试验舱研制配套紧急复压系统,以保障载人低压试验的安全.方法 优选了紧急复压方案和快开阀门,对复压有效口径、复压噪声及气流推力进行了计算,对消声器、散流器和过滤器进行了设计和选择,并通过试验验证和仿真验算证明了设计计算的有效性.结果 最终测试表明,复压指标满足要求,并在舱外航天服研制测试试验和航天员低压舱训练中得到了应用.结论 舱外航天服试验舱紧急复压系统设计合理可行,满足工程使用要求.     

舱外航天服动力学模型

目的：根据舱外航天服的实际结构，建立舱外航天服的简化的动力学模型。方法：考虑舱外航天服的各个部分的质量、惯量、各关节活动性能以及航天服施加给航天员的服装力矩，对舱外航天服各部分几何形状进行了简化，并给出了计算航天服各部分惯量的公式。采用经典Preisach模型定量地描述了航天服服装力矩迟滞曲线特性。结果：得到了考虑质量、惯量以及服装力矩的舱外航天服动力学模型。结论：本文建立的模型为进行计算机动态仿真航天员舱外活动提供了一定的基础。     

舱外航天液冷服传热分析

简单介绍了舱外航天液冷服的结构、功能，分析了通风气体与液冷服基础服装间的对流换热、液冷服的传热传质过程，给出了液冷服传热传质数学模型。通过舱外航天服液冷通风系统与人体的联合热生理实验，该模型得到了验证，并为舱外航天服液冷通风系统的设计提供了依据。     

舱外航天服温控系统的研究现状与展望

随着出舱活动时间的增长,对舱外航天服的温控提出了更高的要求,本文综述了舱外航天服温控系统的研究进展,对辐射器,冰盒,金属氢化物热泵,相变储热／辐射器式热沉和升华器等几种热沉方案进行了比较分析。论述了自动温控应满足的要求,并分析了已有的航天服自动温控方案。最后展望了航天服温控系统的发展趋势。     

Physiologic and pathologic calcifications and ossifications in the face and neck

The aim was to give a systematic presentation of physiologic and pathologic calcifications and ossifications in the face and neck with a special emphasis on clinical relevance. In a sometimes subacute setting one should recognize specific calcifications which often lead to important diagnoses such as fungal sinusitis or sclerosing labyrinthitis. In a more chronic situation intraocular calcifications in small children are pathognomonic for retinoblastoma. Juxtatumoral sclerosis of the laryngeal cartilage in laryngopharyngeal carcinoma is usually caused by tumor infiltration of the cartilage resulting in a higher tumor stage and, this way, has a major impact on the therapeutical strategy. Calcified lymph nodes are mainly unspecific but can be the result of tuberculosis or metastases of thyroid cancer. Cross-sectional imaging methods, most of all computed tomography, are ideally suited to reveal head and neck calcifications and ossifications, especially those which are clinically relevant.     

Head and neck infection and inflammation

This article discusses the imaging manifestations of infectious and inflammatory conditions of the head and neck. Special attention is paid to the sites, routes of spread, and complications of neck infections. Because the clinical signs and symptoms and the complications of these conditions are often determined by the precise anatomic site involved, anatomic considerations are stressed. Familiarity with the fascial layers, spaces of the neck, and the contents of each space is helpful for this discussion. The fascial layers of the neck are important barriers to infection, and once infection is established, the fascial layers play a part in directing its spread.     

Staging and surgical management of pancreatic and biliary cancer and inflammation

Management of benign and malignant diseases of the pancreas, liver, and biliary tract has made remarkable progress in the last two decades. Advances in minimally invasive surgery, interventional radiology, and diagnostic and therapeutic endoscopy have changed the treatment of common diseases such as cholelithiasis and more serious diseases such as pancreatic adenocarcinoma. Advances in biliary tract and pancreatic surgery have paralleled the advances in ultrasonographic imaging, CT, and MR imaging. This article outlines the surgeon's perspective on radiologic imaging and preoperative staging of benign and malignant biliary and pancreatic disease.     

The thyroid and parathyroid glands. CT and MR imaging and correlation with pathology and clinical findings

Thyroid imaging approach is based on the preliminary clinical evaluation. Lesions that are smaller than 2 cm should be assessed with US, which is capable of discriminating masses as small as 2 mm and distinguishing solid from cystic nodules. US-guided FNAB provides tissue for cytologic examination of thyroid nodules. CT and MR imaging are indicated for larger tumors (greater than 3 cm diameter) that extend outside the gland to adjoining structures, including the mediastinum, and retropharyngeal region. Metastatic lymph nodes in the neck and invasion of the aerodigestive tract are also in the realm of CT and MR imaging. Thyroid nodules are categorized on scintigraphy as hot or cold nodules. Hot nodules are rarely malignant, whereas cold nodules have an incidence of 10% to 20% of malignancy. Calcifications (amorphous, globular, nodular, and linear) occur in adenomas and carcinomas and have no differential diagnostic features except for psammomatous calcifications, which are a pathognomonic finding in papillary carcinomas and a small percentage of medullary carcinomas. Papillary carcinoma is the most common malignant tumor (80%) followed by follicular (20% to 25%); medullary (5%); undifferentiated; anaplastic carcinomas (< 5%); lymphoma (5%); and metastases. Lymph node metastases are common in papillary carcinoma, 50% at presentation, and less common in follicular carcinomas. The metastatic nodes in papillary carcinoma may enhance markedly (hypervascular); show increased signal intensity on T1-weighted images (increased thyroglobulin content or hemorrhage); and reveal punctate calcifications. Localized invasion of the larynx, trachea, and esophagus occurs predominantly in papillary and follicular carcinomas; the incidence is less than 5%. Ectopic thyroid tissue may be encountered in the tongue (foramen cecum); along the midline between posterior tongue and isthmus of thyroid gland; lateral neck; mediastinum; and oral cavity. Goiter and malignant tumors, notably papillary carcinoma, may develop in ectopic thyroid tissue. Carcinomas may also arise in thyroglossal duct cysts, which develop from duct remnants between the foramen cecum and thyroid isthmus. Infectious disease of the thyroid gland is not common and the CT and MR imaging findings are similar as described under neck infection. Other types of inflammatory disorders including Hashimoto's thyroiditis, granulomatous thyroiditis, and Riedel's struma display no specific imaging features. Imaging studies may, however, be indicated to confirm a suspected clinical diagnosis and assess compromise of the airway (Riedel's struma). HPT is a clinical diagnosis in which hypercalcemia is the most important finding. Parathyroid hyperplasia, adenoma, and carcinoma represent underlying lesions. To relieve the patient's symptoms surgical extirpation is indicated. The surgical success rate without imaging is 95%. The indications for imaging studies vary but it is generally agreed that reoperation after a previous failed surgical attempt and suspicion of an ectopic parathyroid adenoma should be investigated by imaging. These consist of US, nuclear medicine studies, CT and MR imaging. US and technetium sestamibi scanning have the highest accuracy rate for localizing an adenomatous gland at and near the thyroid gland. Ectopic adenomas, particularly if they are located in the mediastinum, are preferrably investigated with CT and MR imaging with gadolinium and fat suppression. Carcinomas and parathyroid cysts are optimally evaluated by CT and MR imaging. On MR imaging adenomas are low in signal intensity on T1-weighted images, high in signal intensity on T2-weighted images, and enhance post introduction of gadolinium.     

细胞自噬与肿瘤发生发展

自噬是真核生物中一种高度保守的胞内降解途径.其主要通过溶酶体或液泡进行饥饿状态下的营养动员,清除受损蛋白质、细胞器和胞内病原体.自噬主要包括巨自噬、分子伴侣介导自噬(CMA)和微自噬.自噬已被证实与多种人类疾病相关,其在肿瘤发生发展中具有重要意义.近年研究中,对于自噬和肿瘤关系有了进一步的认识,该文就自噬分子机制、调控通路以及与肿瘤发生发展关系的研究进展作一综述.