谈医学逻辑学

一、医学逻辑学的形成和发展随着医学科学的日益发展,产生了许多医学分支学科和边缘科学。医学逻辑学的出现,经历了一个漫长的发展过程。由于社会发展的客观需要,医学逻辑应运而生。在它的发展进程中,也表现为一个由初级到高级的发展趋向。朴素的医学逻辑,首先出现在我国。两千多年前,古代医典《黄帝内经》就有运用逻辑进行诊断的记载。例如《素问》中说:“知内者按而纪之,知外者终而始之……‘此乃’持脉之大法”。译成白话文就是:“要知道在内五脏的虚实,可按其与时相应的部位来得出它的纲领,要知道在外阴阳的变化,可根据四时的次序来推断其经络的演变……这是诊脉必须掌握的重要方法”。

High-Speed,Robust CMOS Dynamic Circuit Design

A novel circuit with a narrow pulse driving structure is proposed for enhancing the noise immunity and improving the performance of wide fan-in dynamic circuits. Also,an analytical mode that agrees well with simulations is presented for transistor sizing. Simulation results show that an improvement of up to 12% over the conventional technique at 1GHz is obtained with this circuit,which can run 1.6 times faster than the existing technique with the same noise immunity.

Intravenous administration of glutathione protects parenchymal and non-parenchymal liver cells against reperfusion injury following rat liver transplantation

AIM:To investigate the effects of intravenous administration of the antioxidant glutathione (GSH) on reperfusion injury following liver transplantation. METHODS:Livers of male Lewis rats were transplanted after 24 h of hypothermic preservation in University of Wisconsin solution in a syngeneic setting.During a 2-h reperfusion period either saline (controls,n=8) or GSH (50 or 100 μmol/(h·kg),n=5 each) was continuously administered via the jugular vein. RESULTS:Two hours after starting reperfusion plasma ALT increased to 1 457±281 U/L (mean±SE) in controls but to only 908±187 U/L (P<0.05) in animals treated with 100 μmol GSH/(h·kg).No protection was conveyed by 50μmol GSH/(h·kg).Cytoprotection was confirmed by morphological findings on electron microscopy:GSH treatment prevented detachment of sinusoidal endothelial cells (SECs) as well as loss of microvilli and mitochondrial swelling of hepatocytes.Accordingly,postischemic bile flow increased 2-fold.Intravital fluorescence microscopy revealed a nearly complete restoration of sinusoidal blood flow and a significant reduction of leukocyte adherence to sinusoids and postsinusoidal venules.Following infusion of 50μmol and 100 μmol GSH/(h·kg),plasma GSH increased to 65±7 mol/L and 97±18 mol/L,but to only 20±3 mol/L in untreated recipients. Furthermore,plasma glutathione disulfide (GSSG) increased to 7.5±1.0 mol/L in animals treated with 100μmol/(h·kg) GSH but infusion of 50μmol GSH/(h·kg) did not raise levels of untreated controls (1.8±0.5 mol/L vs 2.2±0.2 mol/L). CONCLUSION:Plasma GSH levels above a critical level may act as a “sink” for ROS produced in the hepatic vasculature during reperfusion of liver grafts.Therefore,GSH can be considered a candidate antioxidant for the Drevention of reperfusion injury after liver transplantation,in particular since it has a low toxicity in humans.

Changes in Agricultural Biodiversity: Implications for Sustainable Livelihood in the Himalaya

Himalayan mountain system is distinguished globally for a rich biodiversity and for its role in regulating the climate of the South Asia. Traditional crop-livestock mixed farming in the Himalaya is highly dependent on forests for fodder and manure prepared from forest leaf litter and livestock excreta. Apart from sustaining farm production, forests provide a variety of other tangible and intangible benefits, which are critical for sustainable livelihood of not only 115 million mountain people, but also many more people living in the adjoining plains. Extension of agricultural land- use coupled with replacement of traditional staple food crops by cash crops and of multipurpose agroforestry trees by fruit trees are widespread changes. Cultivation of Fagopyrum esculentum, Fagopyrum tataricum, Panicum miliaceum, Setaria italica and Pisum arvense has been almost abandoned. Increasing stress on cash crops is driven by a socio-cultural change from subsistence to market economy facilitated by improvement in accessibility andsupplyofstaplefoodgrainsatsubsidizedpriceby the government. Farmers have gained substantial economic benefits from cash crops. However, loss of agrobiodiversity implies more risks to local livelihood in the events of downfall in market price/demand of cashcrops,terminationofsupplyofstaplefoodgrains at subsidized price, pest outbreaks in a cash crop dominated homogeneous landscape and abnormal climate years. Indigenous innovations enabling improvement in farm economy by conserving and/enhancing agrobiodiversity do exist, but are highly localized. The changes in agrobiodiversity are such that soil loss and run-off from the croplands have dramatically increased together with increase in local pressure on forests. As farm productivity is maintained with forest-based inputs, continued depletion of forest resources will result in poor economic returns from agriculture to local people, apart from loss of global benefits from Himalayan forests. Interventions including improvement in traditionalmanureandmanagementofon-farm trees, participatorydevelopmentofagroforestryindegraded forestlandsandpoliciesfavoringeconomicbenefitsto local people from non-timber forest products could reduce the risks of decline in agricultural biodiversity and associated threats to livelihoods and Himalayan ecosystems.

Improvement of chromium biosorption through protoplast electrofusion between Candida tropicalis and Candida lipolytica

Protoplasts from Candida tropicalis and Candida lipolytica were fused under an optimized electrofusion （electrical pulse strength 6 kV/cm, pulse duration time 40μs and pulse times 5） and then regenerated on YEPD media for achieving new genotypes with higher chromium loading capacity. A target fusant RHJ-004 was screened out by its chromium resistance and chromium-sorbing capacity tests for further research. The comparative study of applicability shows that the fusant has better performance than its parent strains in respect of solution pH, biomass concentration and chromium loading capacity. Especially for treating low concentration Cr（VI） （〈20 mg/L）, above 80% chromium is sequestered from the aqueous phase at pH 1-9. Atomic force microscopy （AFM） visualizes the distribution of chromium on the binding sites of the cells, suggesting that the altered surface structure and intracellular constitutes of the fusant associate with its increased biosorption capacity. The rapid biosorption processes of chromium foUow the Langmuir model well.

A clinical study on continuous transarterial infusion chemotherapy and systemic venous chemotherapy with gemcitabine and 5-fluorouracil in treating patients with advanced pancreatic carcinoma

Objective: To compare the curative effectiveness of continuous transarterial infusion chemotherapy and systemic venous chemotherapy in treating patients with advanced pancreatic cancer, and to evaluate the value of selective continu-ous transarterial infusion chemotherapy in treating advanced pancreatic cancer. Methods: Of the 51 patients with advanced pancreatic cancer receiving chemotherapy with gemcitabine and 5-fluorouracil, 25 patients were treated with selective con-tinuous transarterial infusion chemotherapy, 26 were treated with systemic venous chemotherapy, and curative effective-ness was analyzed retrospectively. Curative effectiveness included tumor volume, clinical benefit response (CBR), acute and subacute toxic reactions of antitumor drugs, survival rate and median survival time. Results: The objective effective rate in transarterial group was 32.0% versus 23.1% in systemic group without any significant difference (P = 0.475). Clinical benefit rates in transarterial group and systemic group were 80.0% and 50.0% respectively (P = 0.025). The 6-, 9-and 12-month accumulated survival rates and median survival time in transarterial group were higher than those of the systemic group (P = 0.002), the differences were statistically significant. However, the adverse reactions between the two groups were not statistically significant. Conclusion: Compared with systemic chemotherapy, continuous transarterial infusion chemotherapy with gemcitabine and 5-fluorouracil could improve clinical benefit rate and survival time of patients with advanced pancreatic cancer, it is safe and reliable, and the adverse reactions is less.

Effect of transcatheter aortic valve replacement on P-wave duration, P-wave dispersion and left atrial size

Background P-wave dispersion （PWD）, a measure of heterogeneity of atrial refractoriness, is defined as the difference between the maximum and minimum P-wave duration. In patients with severe aortic stenosis （AS）, P-wave duration and PWD were shown to be increased, indicating atrial electrical remodeling. However, the effect of transcatheter aortic valve replacement （TAVR） on P-wave morphology has not been established yet. The aim of this study is to assess the short and long-term effects of TAVR with two types of bioprosthetic valves on P-wave duration and PWD in association with left atrial （LA） size. Methods Fifty-two （36 female） eligible patients in sinus rhythm who underwent transfemoral TAVR between June 01, 2012 and July 31, 2014 with either a Medtronic CoreValve （MCV） （n = 32） or an Edwards SAPIEN XT Valve （n = 20） were enrolled. Standard 12-lead electrocardiogram and echocardiographic evaluations were per- formed pre-procedurally, post-TAVR day one and 6 months post-TAVR. P-wave duration and PWD were measured and correlation analyses with echocardiographic variables were performed. Results P-wave duration and PWD were significantly decreased on post-TAVR day one （P 〈 0.05）. They continued to decrease during the six month follow-up period, but were not significantly different from short-term values （P 〉 0.05）. The decrease of LA diameter was found significant at the sixth-months of follow-up （P 〈 0.05）. These changes were independent from the types of bioprosthetic valves implanted （P 〉 0.05）. A positive correlation was detected between minimum P-wave duration and maximum aortic valve gradients at post-TAVR day one （r = 0.297, P = 0.032）. Conclusions P-wave duration and PWD were significantly reduced early after TAVR indicating early reverse atrial electrical remodeling. Moreover, structural reverse remodeling of atrium was detected at the 6-months of follow-up. The effects of two types of bioprosthetic valves on atrial remodeling were similar.

Synthesis and spark plasma sintering of Al-Mg-Zr alloys

Although casting is commonly used to process aluminum alloys, powder metallurgy remains a promising technique to develop aluminum based materials for structural and functional applications. The possibility to synthesize Al-Mg-Zr alloys through mechanical alloying and spark plasma sintering techniques was explored. Al-10Mg-5Zr and Al-5Mg-1Zr alloyed powders were synthesized through wet ball milling the appropriate amount of elemental powders. The dried milled powders were spark plasma sintered through passing constant pulsed electric current with fixed pulse duration at a pressure of 35 MPa. The samples were vacuum sintered at 450, 500, 550, 600 and 620 ℃ for 10, 15 and 20 min. The Al-10Mg-5Zr alloy displays poor densification at lower sintering temperatures of 450, 500, 550 and 600 ℃. Its sinterability is improved at a temperature of 620 ℃ whereas sintering temperatures higher than 620 ℃ leads to partial melting of the alloy. It is possible to sinter the Al-5Mg-1Zr alloy at 450, 500 and 550 ℃. The increase of sintering temperature improves its densification and increases its hardness. The Al-5Mg-IZr alloy displays better densification and hardness compared to Al-10Mg-5Zr alloys.

Continuous-infusion 5-Fluorouracil versus Xeloda for gastrointestinal cancer: A safety and efficacy observation

Objective： We assessed the safety and efficacy of two regimens for patients with gastrointestinal cancers： continuous-infusion （CI） schedules of 5-Fluorouracil （5-Fu） plus a platinum （cisplatin or oxaliplatin） with/or without paclitaxel （regimen A） versus Xeloda plus a platinum （cisplatin or oxaliplatin） with/or without paclitaxel for oral use （regimen B） in patients with gastrointestinal cancers. Methods： Between May 2003 and May 2005, 84 patients diagnosed in Jiangsu Cancer Hospital ＆ Research Institute with locally advanced esophageal, gastnc or colorectal cancer were registered. Regimen A and B consisted of either 5-Fu 0.375 CI days 1-14, every 28 days （n = 44）, or Xeloda 1000 mg twice daily, days 1-14, every 28 days （n = 40）. For both regimen A and B, IV cisplatin 25 mg/m^2 was administered on day 1, 2 and 3 （or Oxaliplatin 75mg/m^2 on day 1, 8 and 15） with or without paclitaxel 60-75 mg/m^2 on day1, 8 and 15. Results： Patients receiving regimen B experienced significantly less stomatitis （P 〈 0.05） and diarrhea （P 〈 0.05）, than those receiving regimen A. Prevalence of nausea/vomiting, alopecia, neutropenia, and hand-foot syndrome without significant difference between two regimens. No treatment related death occurred during study period. Regimen B demonstrates a similar, favorable safety profile in this study. Response rates and rates of clinical benefit for regimen A and B were 40.9%, 40.0% and 43.2%, 65.0% respectively. Conclusion： Based on its improved safety profile and improved rate of clinical benefit, Xeloda has the potential to replace CI 5-FU as an alternative treatment for patients with gastrointestinal cancers.

Update on pharmacological treatment of acute coronary syndrome without persistent ST segment elevation myocardial infarction in the elderly

The increase in cardiovascular disease prevalence with ageing has been attributed to several age-related changes such as changes in the vascular wall elasticity, the coagulation and haernostatic system and endothelial dysfunction, among other causes. There is a 50% increased mortality risk per 10-year increase in age starting at 65 years old. Here, we aimed to discuss pharmacological treatment in acute coronary syndrome （ACS） without persistent ST segment elevation myocardial infarction in the elderly. The main aim of ACS treatment in elderly people is at preventing ischemia, myocardial damage and complications. A meta-analysis suggests that invasive revascularization therapy is probably most useful in older patients. Dual antiplatelet therapy is currently the standard of care post-ACS. Platelet P2Y12 inhibitors are among the most commonly used medications worldwide, due to their established benefits in the treatment and prevention of arterial throm- bosis. The main recommendation is to tailor antithrombotic treatment, considering body weight, renal function （Class I, level C） and careful evaluation of life expectancy, comorbidities, risk/benefit profile, quality of life and fxailty when invasive strategies are considered （Class IIa, level A） on top of the different recommendations given for a general non ST elevation ACS population. It is obvious that potent P2Y12 in- hibitors will continue to play an important role in pharmacological treatment for elderly ACS patients in the future.

On High Brightness Temperature of Pulsar Giant Pulses

A wide range of events observed at the giant pulses （high energy density, observed localization of giant pulses GPs relative to the average pulse, fine structure of GPs with duration up to some nanoseconds, observed circular polarization of GPs, correlation between the GP phase and the phase of the hard pulsar emission X-ray and gamma） can be explained from the viewpoint that the internal polar gap is a cavity-resonator stimulated by discharges and radiating through the breaks in the magnetosphere. The new results in this field [the electromagnetic （era） waves generation in the gap in the process of longitudinal acceleration in the electric field vanishing on the star surface, high frequency break in the spectrum as a result of switching off this generation, formation in this process a power-low spectrum with a high frequency （hf） break, the possibility determination of pulsar magnetic field by the hf break position, the difference between main pulse and inter pulse mechanism generation, quantization of em tornado rotation in the gap and appearance of the bands in the inter pulse spectrum, influence the high energy density in the gap on pair generation and position of the dead line in pulsars] are added in the intermediate epilogue.

Effects of Parameters in Femtosecond Laser Micromachining on Ablation of Silicon

A series of ablation experiments on silicon surface by femtosecond laser system of 775 nm and 150 fs duration pulses were carried out.The morphological characteristics and the associated effect in the ablation were tested by atomic force microscope(AFM),scanning electron microscope(SEM),focused ion beam(FIB),and the optic microscope.The single pulse threshold can be obtained directly.For the multiple pulses,the ablation threshold varies with the number of pulses applied to the surface due to the incubation effect.By analyzing the experimental data,the thresholds of laser fluences under various laser pulse numbers were obtained,and the relationships between ablation area and laser energy and laser pulse number were concluded.Meanwhile,the periodic ripple structure on silicon surface was found.Under the condition of certain laser power,the number of laser pulse can influence the formation of ripples.

Features of Excitation of a Two-Level System by Short Nonresonance Laser Pulses

This paper is devoted to theoretical investigation of characteristic features arising during excitation by short nonresonance laser pulses. The treatment is made within the applicability of perturbation is given to the dependence of total excitation probability from eigenfrequency of TLS. Various laser pulse shapes of TLS on the pulse duration for different detuning are considered. two-level system （TLS） approach. Main attention of carrier laser frequency

Optical-field-induced memory effect of nematic liquid crystal doped with zinc porphyrin dimers

In this paper, the optical-field-induced reorientation ofnematic liquid crystal （5CB） doped with a volume fraction of 1.0% of zinc porphyrin dimers ο, ο-C2-（L-Thr）-C2-（TPP）2Zn（II）2 has been studied. Excited by 1.06 lain, YAG laser pulse with 10 ns pulse duration and 100 mJ pulse energy, both of the doped 5CB and pure 5CB perform the reorientation. When the exciting laser pulse withdraws, the doped 5CB retains the reorientation and without back to the initial orientation, and the memory effect is formed accordingly, whereas the pure 5CB relax to the initial orientation. A model considering the intermolecular coupling change between the dopant and host 5CB, and together with the aligning surface adsorption process of deformed dopant are present to explain this memory effect. In order to prove this mechanism, 5CB doped with another dopant （zinc porphyrin, ZnTPP） was used for contrast, which induces no such memory effect. This phenomenon is very useful to study the optical data storage and memory display.

Theoretical Analysis on Optical Limiting Properties of Newly Synthesized Graphene Oxide-Porphyrin Composites

Optical limiting （OL） properties and two-photon absorption （TPA） of a series of covalently linked graphene oxide-porphyrin composite materials have been investigated by numerically solving the rate equations and field intensity equation with an iterative predictor-corrector finite-difference time-domain technique in nanosecond time domain. Our results show that graphene oxide-porphyrin composites exhibit enhanced OL behavior and possess larger TPA cross section compared with individual porphyrins. Interestingly~ unlike the previous result that porphyrin with heavier central metal shows better nonlinear abilities than that with- out metal substitute, graphene oxide-metal free porphyrin composite has stronger nonlinear absorption properties compared with graphene oxide-metal porphyrin composite. The com- putational results are in reasonable agreement with the experimental ones. Special attention has been paid to the influence of thickness of the medium and pulse width on TPA cross sections, which presents that larger TPA cross sections are obtained as the medium is thicker or the pulse duration is wider.

Ion Acceleration in Laser-Plasma Interaction: Shock, Sheath, and Scaling

Some notes and comments on ion acceleration in laser-plasma interaction is given, in particular for the implication of shock, sheath and sealing. A simple model is proposed for ion acceleration by the combination of shock and sheath. The obtained scaling relations between the maximum ion energy and laser parameters （power, pulse duration） as well plasma parameter （plasma density）for example α PL 7/12 Eion,max α TL1/3 and Eion,max α ne2/3,are compared to the previous works. Some deficiencies and implications of model and results are discussed.

Short-Wave Emission and Microdischarges during Self-Propagating High-Temperature Synthesis

Emission in the X-ray and ultraviolet （200-300 nanometers） region of spectrum is found out during combustion of heterogeneous systems with the formation of condensed products, and pulses from microwave emission with short duration are recorded as well. Combustion of a Ti-B powder system showed that self-propagating high-temperature synthesis （SHS） is accompanied by two types of X-ray radiation. Radiation of the first type has the maximum quantum energy - 5 keV. It is supposed that this type is caused by micro-breakdowns due to the charge separation in combustion products. Runaway electrons and soft X-ray radiation are generated due to the concentration of electric field on microparticles during breakdown. Radiation of the second type has the quantum energy up to - 15 keV. It is supposed that it is caused by exoemission of photons. UV radiation in the region of 200-300 nm is recorded during SHS in different gases （He, Ar, N2）. This radiation is shown to have the highest intensity in helium at the pressure - 25 x 103 Pa.

Sensitivity of Some Biological Objects to Repetitive Submicrosecond Microwave Pulses

The effect of repetitive pulsed microwaves （10 GHz, pulse duration of 100-300 ns, pulse repetition rate of 4-25 pulse per second, peak power density of 0.04-3.5 kW/cm^2） on mastocytoma P815, Ehrlich carcinoma, normal spleen cells and wound healing was investigated. It was found that short-time irradiation with an intensity of 0.9-1.5 kW/cm^2 inhibited proliferation of tumor cells in vitro, whereas at same time it contributes to proliferation of normal spleen cells in vitro. The repetitive pulsed microwaves with an intensity of 0.04-1.5 kW/cm^2 stimulated healing of skin wounds and ulcerations in mice. The effects showed a dependence on the pulse repetition rate and irradiation intensity.

Formation of RF Plasma Transport Channel in External B-Field

The paper describes experiments on formation of a plasma channel with imbedded B-field for transporting high power ion beam. The plasma was generated with a 5-turn loop inductive antenna driven by an H-bridge type RF generator. The azimuthal B-field in the channel of 0.5-1.5 kG was formed by a pulsed current from external capacitor bank. Control of the hydrogen gas pressure was provided by an electromagnetic puffvalve. The paper describes experimental devices and results on the generated plasma parameters as function of RF frequency, antenna voltage, pulse duration and puffgas pressure. When operating at-1 kG B-field, ambient gas pressure in the range of few -10 mTorr, and 5 kV antenna voltage at resonant frequency of 150 kHz, the plasma density range was （3-7）×10^12 cm3 with a temperature of a few eV.