高中化学实验运用多媒体教学技术浅析

随着网络的普及,高中化学学科引入多媒体教学技术非常必要。它可以打破学生的时间和空间的限制,对有关问题进行深入地推理探讨,也可以重点观察每一个实验细节,还可以培养学生的提取信息、归纳和整理信息的能力。它以其时效性、可观性、安全性博得了广大师生的喜爱,强有力地促进了本学科的发展。本文就多媒体技术在高中化学实验中的应用详析、高中化学实验教学要把投影技术运用到课堂中和在高中化学实验教学中渗入摄像和放像技术等三大问题进行了详细阐述。

Endoscopic ultrasound and magnetic resonance imaging for re-staging rectal cancer after radiotherapy

AIM： To compare the sensitivity and specificity of two imaging techniques, endoscopic ultrasound （EUS） and magnetic resonance imaging （MRI）, in patients with rectal cancer after neoadjuvant chemoradiation therapy. And we compared EUS and MRI data with histological findings from surgical specimens. METHODS： Thirty-nine consecutive patients （51.3% Male; mean age： 68.2 ＋ 8.9 years） with histologically confirmed distal rectal cancer were examined for staging. All patients underwent EUS and MRI imaging before and after neoadjuvant chemoradiation therapy. RESULTS： After neoadjuvant chemoradiation, EUS and MRI correctly classified 46% （18/39） and 44% （17/39） of patients, respectively, in line with their histological T stage （P 〉 0.05）. These proportions were higher for both techniques when nodal involvement was considered： 69% （27/39） and 62% （24/39）. When patients were sorted into T and N subgroups, the diagnostic accuracy of EUS was better than MRI for patients with T0-T2 （44% vs 33%, P 〉 0.05） and NO disease （87% vs 52%, P = 0.013）. However, MRI was more accurate than EUS in T and N staging for patients with more advanced disease after radiotherapy, though these differences did not reach statistical significance. CONCLUSION： EUS and MRI are accurate imaging techniques for staging rectal cancer, However, after neoadjuvant RT-CT, the role of both methods in the assessment of residual rectal tumors remains uncertain.

Autofluorescence imaging and magnification endoscopy

It is well known that angiogenesis is critical in the transition from premalignant to malignant lesions.Consequently,early detection and diagnosis based on morphological changes to the microvessels are crucial.In the last few years,new imaging techniques which utilize the properties of light-tissue interaction have been developed to increase early diagnosis of gastrointestinal(GI) tract neoplasia.We analyzed several "red-flag" endoscopic techniques used to enhance visualization of the vascular pattern of preneoplastic and neoplastic lesions(e.g.trimodal imaging including autofluorescence imaging,magnifying endoscopy and narrow band imaging).These new endoscopic techniques provide better visualization of mucosal microsurface structure and microvascular architecture and may enhance the diagnosis and characterization of mucosal lesions in the GI tract.In the near future,it is expected that trimodal imaging endoscopy will be practiced as a standard endoscopy technique as it is quick,safe and accurate for making a precise diagnosis of gastrointestinal pathology,with an emphasis on the diagnosis of early GI tract cancers.Further large-scale randomized controlled trials comparing these modalities in different patient subpopulations are warranted before their endorsement in the routine practice of GI endoscopy.

Can post-mortem computed tomography be considered an alternative for autopsy in deaths due to hemopericardium？

Hemopericardium is a common finding at autopsy, but it may represent a challenge for the forensic pathologist when the etiopathologi-cal relationship in causing death is requested. Hemopericardium and cardiac tamponade can be evaluated in living people using radiological techniques, in particular computer tomography （CT）. Only a few studies are reported in literature involving post-mortem （PM） cases, where PMCT imaging has been used in order to investigate acute hemopericardium, and they have shown a good accuracy of this technique. Here we report a case involving a 70-year-old white male found dead on the beach, with a medical history of hepatitis C and chronic hypertension with a poor pharmacological response. A PMCT was performed about 3 h after the discovery of the body. The PMCT examination showed an intrapericardial aortic dissection associated to a periaortic hematoma, a sickle-shaped intramural hematoma, a false lumen, and a hemop-ericardium consisting in fluid and clotted blood. In this case, the PMCT was able to identify the cause of death, even though a traditional autopsy was required to confirm the radiological findings. PMCT is a reliable technique, which in chosen cases, can be performed without the need for a traditional autopsy to be carried out.

Tumor Molecular Imaging with Nanoparticles

Molecular imaging(MI)can provide not only structural images using traditional imaging techniques but also functional and molecular information using many newly emerging imaging techniques.Over the past decade,the utilization of nanotechnology in MI has exhibited many significant advantages and provided new opportunities for the imaging of living subjects.It is expected that multimodality nanoparticles(NPs)can lead to precise assessment of tumor biology and the tumor microenvironment.This review addresses topics related to engineered NPs and summarizes the recent applications of these nanoconstructs in cancer optical imaging,ultrasound,photoacoustic imaging,magnetic resonance imaging(MRI),and radionuclide imaging.Key challenges involved in the translation of NPs to the clinic are discussed.

Image-guided radiation therapy: basic concepts and clinical potentials

The adaptation and integration of imaging into the process of cancer detection, diagnosis, and intervention is an area of medicine that is undergoing extremely rapid development. Radiation therapy is a prime example of this change. While the objectives of these developments are clear, they raise numerous issues regarding the skills and resources that assure these technologies are appropriately integrated and applied. We will explore the basic concepts related to image guidance in various radiotherapy-related procedures with special emphasis on the clinical potentials of this impressive technology.

Labeling and experimental studies of infection imaging agent ^(99m)Tc-CPF

Objective： To discuss the biodistribution of ^99mTc-Ciprofloxacin （^99mTc-CPF） and its effectiveness of imaging in infection disease in mice. Methods： CPF was labeled with ^99mTc and its radiochemical purity and labeling rate were measured. Mice model of infection was established and the biodistribution of ^99m Tc-CPF in the model and whole-body scintigraphy were achieved. Results： ^99mTc-Ciprotech was stable within 6 hours at room temperature. The labeling rate of ^99mTc-CPF was over 90%. Most of radioactivity was cleared in liver and kidney, and the clearance from blood was rapid. Both biodistribution and imaging results showed a high uptake of ^99mTc-CPF in infection site. The infection tissue/normal tissue reached a peak as 4.30 at 4 h after injection. Condusion： ^99mTc-CPF is a sensitive radiopharmaceutical agent for scintigraphy of infection lesions, and it is easy to prepare.

Reynolds number dependence of flow past a shallow open cavity

Measurements were carried out in a shallow open cavity with particle image velocimetry technique.The cavity has a lengthto-depth ratio of 4:1,and the upstream inflow conditions include laminar,transient,and turbulent regimes at seven different Reynolds numbers.The measured instantaneous velocities were analyzed through ensemble average,vortex extraction,and proper orthogonal decomposition(POD)to investigate overall flow circulations,Reynolds stress distribution,spanwise vortex population,and the characteristics of the POD modes.The results reveal distinctive Reynolds number dependence of the cavity flow,e.g.an increase in Reynolds number results in constant migration of the overall circulation,enhancement of Reynolds stress,reduction of correlation between vortex and Reynolds stress,and decrease of fractional energy of the characteristic POD modes.Finally,a phenomenological model was proposed to describe various features of cavity flow.