Maximum principle for optimal control of anticipated forward–backward stochastic differential delayed systems with regime switching

This paper is concerned with a Pontryagin maximum principle for optimal control problem of stochastic system, which is described by an anticipated forward–backward stochastic differential delayed equation and modulated by a continuous‐time finite‐state Markov chain. We establish a necessary maximum principle and sufficient verification theorem for the optimal control by virtue of the duality method and convex analysis. To illustrate the theoretical results, we apply them to a recursive utility investment‐consumption problem, and the optimal consumption rate is derived explicitly. Copyright © 2015 John Wiley & Sons, Ltd.     

Characterization of the interaction forces in a drug carrier complex of doxorubicin with a drug‐binding peptide

Polypeptide‐based materials are used as building blocks for drug delivery systems aimed at toxicity decrease in chemotherapeutics. A molecular‐level approach is adopted for investigating the non‐covalent interactions between doxorubicin and a recently synthesized drug‐binging peptide as a key part of a system for delivery to neoplastic cells. Molecular dynamics simulations in aqueous solution at room and body temperature are applied to investigate the structure and the binding modes within the drug–peptide complex. The tryptophans are outlined as the main chemotherapeutic adsorption sites, and the importance of their placement in the peptide sequence is highlighted. The drug–peptide binging energy is evaluated by density functional theory calculations. Principal component analysis reveals comparable importance of several types of interaction for the binding strength. π‐Stacking is dominant, but other factors are also significant: intercalation, peptide backbone stacking, electrostatics, dispersion, and solvation. Intra‐ and intermolecular H‐bonding also stabilizes the complexes. The influence of solvent molecules on the binding energy is mild. The obtained data characterize the drug‐to‐peptide attachment as a mainly attractive collective process with interactions spanning a broad range of values. These results explain with atomistic detail the experimentally registered doxorubicin‐binging ability of the peptide and outline the complex as a prospective carrying unit that can be employed in design of drug delivery systems.     

“水象”视阈下肿瘤“瘀毒互结”病机探微

[目的] 从“水象”视阈探讨肿瘤“瘀毒互结”病机,发挥中医药原创优势,为中医药治疗肿瘤提供具有中医原创特色的理论支撑。[方法] 通过象思维,从“水象”视阈,谈人体之血象于自然之水,人体经脉象于自然水系,探讨肿瘤“瘀毒”之“瘀”象于河道之“淤”,“瘀毒”之“毒”象于水体污染,并以河道淤泥堵塞及水体污染的治理方法归纳演绎出肿瘤“瘀毒互结”的治则治法。[结果] 以“水象”视阈观之,肿瘤“瘀毒互结”与河道淤堵、水体污染的发生发展过程,肿瘤治疗后机体正气的亏损与水系治理后生态环境的退化,均存在共同之“象”。水系治理的方针法则亦可类比运用于肿瘤“瘀毒”的治疗:河道之“淤”需顺水清淤,肿瘤“瘀毒”之“瘀”需化瘀通脉;水系污染需清污澄源,“瘀毒”之“毒”在解毒寻根;水系治理需重培土,“瘀毒”同治必重扶正;治水当按需制宜,治“瘀毒”应分期论治。[结论] “瘀毒互结”是肿瘤的一大核心病机,象思维是中医的原创思维,从“水象”视阈论证“瘀毒互结”病机,具有中医的原创特色。     

护理工作中引入护理哲理

介绍了哲理、护理哲理及重要性,提出在护理教育和临床护理工作中引入护理哲理可促进护理人员护理价值观与信念的形成。     

白涩症源流浅析

本文通过对历史相关古籍文献的整理研究,梳理白涩症发展沿革,探讨历代医家对其病因病机及治疗方法的认识,以期为白涩症的研究提供理论基础,并为临床治疗开拓思路。中医对白涩症的相关记载,最早可追溯至晋代《针灸甲乙经》中有关目涩的论述,其对于自觉眼部干涩不适的症状有了初步的认识。“白涩症”之名首见于《证治准绳》,后沿用至今。其基本病因病机主要归责于津液亏少,眼目不得濡养,外感邪气、脏腑内伤、情志失常、饮食劳倦等因素均可致病,内治法治疗主要分为祛邪、泻实、补虚三个方面,外治法包括点眼法及针灸疗法,临床上当审察病因,随证治之。现代医学对该病的治疗主要以缓解症状为主,寻找有效的中医治疗手段在现代临床应用中意义重大。     

Optimal control analysis of a tuberculosis model with exogenous re-infection and incomplete treatment

A new mathematical model of tuberculosis (TB) featuring exogenous re-infection and incomplete treatment is presented and analyzed. The model divides total population into susceptible, latently infected, actively infected (uninformed and enlightened), and treatment classes. The model with or without incomplete treatment exhibits backward bifurcation phenomenon, which is caused by the presence of exogenous re-infection. However, further investigation reveals that the absence of incomplete treatment has the potential to reduce the backward bifurcation range significantly. The global dynamics of the TB model without exogenous re-infection is completely determined by the basic reproduction number under certain modifications on parameters. Furthermore, the model is extended to include three time-dependent control functions, such as public awareness campaign, treatment effort, and preventive control against incomplete treatment. The existence of the optimal control for the nonautonomous model is proven and the three controls are characterized using Pontryagin's maximum principle. Numerical simulations are performed to show the significance of singular implementation of each of the controls and combination of the three controls in minimizing the TB burden in the population.     

高血压患者用药问题探讨

随着人们生活水平的提高,高血压患者的人数在逐年增加,但有些人常常忽视了高血压的危害,长期高血压可影响重要脏器心、脑、肾的功能;甚至导致脏器功能衰竭造成病残或死亡;同时也给患者造成很大负担。为提高患者对治病的顺应性、延缓高血压对重要脏器的损害,高血压患者的用药问题必须极高的关注。     

Automatic sorting of toxicological information into the IUCLID (International Uniform Chemical Information Database) endpoint-categories making use of the semantic search engine Go3R

The knowledge-based search engine Go3R, www.Go3R.org, has been developed to assist scientists from industry and regulatory authorities in collecting comprehensive toxicological information with a special focus on identifying available alternatives to animal testing. The semantic search paradigm of Go3R makes use of expert knowledge on 3Rs methods and regulatory toxicology, laid down in the ontology, a network of concepts, terms, and synonyms, to recognize the contents of documents. Search results are automatically sorted into a dynamic table of contents presented alongside the list of documents retrieved. This table of contents allows the user to quickly filter the set of documents by topics of interest. Documents containing hazard information are automatically assigned to a user interface following the endpoint-specific IUCLID5 categorization scheme required, e.g. for REACH registration dossiers. For this purpose, complex endpoint-specific search queries were compiled and integrated into the search engine (based upon a gold standard of 310 references that had been assigned manually to the different endpoint categories). Go3R sorts 87% of the references concordantly into the respective IUCLID5 categories. Currently, Go3R searches in the 22 million documents available in the PubMed and TOXNET databases. However, it can be customized to search in other databases including in-house databanks.     

Biomechanical characteristics of the human esophagus

Biochemechanical wall properties of the human esophagus were studied. A probe, with a balloon designed for simultaneous measurement of cross-sectional area and intraluminal pressure, was placed in the esophagus 30 cm from the incisors. Tone was not detected before inflation of the balloon. When the balloon was inflated stepwise with pressures up to 40 cm H₂O (30.7 mm Hg), measurement of cross-sectional area allowed calculation of distensibility and circumferential wall tension. Balloon cross-sectional area increased linearly with increased balloon pressure. Balloon distension induced contractions, both proximal to the balloon and at the site of distension, at a balloon pressure of about 15 cm H₂O (11.5 mm Hg). The cross-sectional area for the threshold for distension induced contractions was 153±12 mm² (diameter 14 mm). At the onset of these contractions, the contraction force was 15–20 cm H₂O (11.5–15.3 mm Hg) and it increased to 47–58 cm H₂O (36.1–44 mm Hg) at a balloon pressure of 20–40 cm H₂O (15.3–30.7 mm Hg). Circumferential wall tension increased with increasing intraluminal pressure in an almost exponential manner. The pressure elastic modulus increased steeply at lower balloon pressures (10–20 cm H₂O) (7.7–11.5 mm Hg), but at higher balloon pressures (20–40 cm H₂O) (15.3–30.7 mm Hg) this increase was less. The circumferential wall tension and wall stiffness of the human esophagus increased with increasing balloon pressure and cross-sectional area. When a threshold is reached, distension induced contractions both proximal and distal to the balloon and at the distension site.This work was supported by a National Institutes of Health grant DK 11242.