用于浅层肿瘤重离子治疗的终端束流诊断控制系统

 设计了中国科学院近代物理研究所利用兰州重离子研究装置（HIRFL）进行浅层肿瘤临床治疗试验研究中所使用的束流诊断安全控制系统。该系统包括束流强度监测及保护、剂量测量、扫描波形监测及保护3个部分。系统基于PXI系统及LabVIEW软件,给出了该系统的各部分结构。从系统建立时的多次测试结果以及实际临床治疗试验研究时的长期运行结果来看,该束流诊断控制系统在控制辐照剂量以及安全保护方面能够满足当前重离子加速器浅层肿瘤临床治疗试验的基本要求,为试验研究的顺利进行提供了可靠的保证。     

慢病毒载体研究进展

慢病毒作为一种特殊的逆转录病毒,与通常使用的逆转录病毒载体和腺病毒载体比较,具有可感染分裂细胞及非分裂细胞、转移基因片段容量较大、目的基因表达时间长、不易诱发宿主免疫反应等优点,已成为当前基因治疗和转基因动物中载体研究的热点。近年来对其基础生物学特性、载体改造及其应用等研究均取得了较大进展。本文就慢病毒载体及应用方面的研究进展作一综述。     

南亚热带山地常绿阔叶林林隙及其自然干扰特征研究

【目的】通过对大明山南亚热带山地常绿阔叶林85个林隙的调查,了解南亚热带山地常绿阔叶林林隙的基本特征和自然干扰规律。【方法】在大明山3.2hm^2永久样地内仔细寻找每一个林隙,记录林隙形成木的种类,测量其胸径和高度,判断林隙形成木和林隙的年龄,绘制树冠投影图。【结果】扩展林隙（EG）和冠空隙（CG）在南亚热带山地常绿阔叶林中的面积比例分别为71.70%和52.90%,干扰频率分别为1.793%·a^-1和1.323%·a^-1,林隙干扰的返回间隔期约为76a。南亚热带山地常绿阔叶林中,由树木翻蔸形成的林隙最为普遍,占51.88%,其次是干中折断而形成的,占37.88%。林隙大多由0~1株树木形成,平均每个林隙拥有形成木3.45株。EG的大小多在200~600m^2,其中以200~300m^2者所占的面积比例最大（占56.47%）;CG的大小多在200m^2以下,以100~200m^2者所占的面积比例最大（占37.65%）。大部分林隙是在2年前形成的,占68.40%。林隙形成木种类超过42种,主要是云贵山茉莉（Huodendron biaristatum）、罗浮槭（Acer fabri）、栓皮木姜子（Litsea suberosa）、百色猴欢喜（Sloanea chingiana）、刨花润楠（Machilus pauhoi）、天目紫茎（Stewartia gemmata）、糙皮桦（Betula utilis）和罗浮柿（Diospyros morrisiana）,占形成木个体数的68.51%。林隙形成木分布最多的径级在15~20cm。【结论】南亚热带山地常绿阔叶林林隙特征不同于热带山地雨林,也与南亚热带低地的常绿阔叶林存在显著区别。2008年特大冰冻干扰是造成大明山山地常绿阔叶林林隙分异的主要因素。     

Logging damage and injured tree mortality in tropical forest management

Using insights from the forest ecology literature, we analyze the effect of injured trees on stand composition and carbon stored in above‐ground biomass and the implications for forest management decisions. Results from a Faustmann model with data for a tropical forest on Kalimantan show that up to 50% of the basal area of the stand before harvest can consist of injured trees. Considering injured trees leads to an increase in the amount of carbon in above‐ground biomass of up to 165%. These effects are larger under reduced impact logging than under conventional logging. The effects on land expectation value and cutting cycle are relatively small. The results suggest that considering injured trees in models for tropical forest management is important for the correct assessment of the potential of financial programs to store carbon and conserve forest ecosystem services in managed tropical forests, such as reducing emissions from deforestation and forest degradation and payment for ecosystem services. Recommendations for Resource Managers

• Considering the role of injured trees is important for managing tropical forests
• These trees can cover up to 50% of basal area and contain more than 50% of the carbon stored in above‐ground biomass
• Reduced impact logging leads to a larger basal area of injured trees and more carbon stored in injured trees than conventional logging
• Injured trees play an important role when assessing the potential for carbon storage in the context of payment for forest ecosystem services.

     

Low Band Gap Donor‐Acceptor Conjugated Polymer Nanoparticles and their NIR‐mediated Thermal Ablation of Cancer Cells

Low band gap D‐A conjugated PNs consisting of 2‐ethylhexyl cyclopentadithiophene co‐polymerized with 2,1,3‐benzothiadiazole (for nano‐PCPDTBT) or 2,1,3‐benzoselenadiazole (for nano‐PCPDTBSe) have been developed. The PNs are stable in aqueous media and showed no significant toxicity up to 1 mg · mL^?1. Upon exposure to 808 nm light, the PNs generated temperatures above 50 °C. Photothermal ablation studies of the PNs with RKO and HCT116 colorectal cancer cells were performed. At concentrations above 100 µg · mL^?1 for nano‐PCPDTBSe, cell viability was less than 20%, while at concentrations above 62 µg · mL^?1 for nano‐PCPDTBT, cell viability was less than 10%. The results of this work demonstrate that low band gap D‐A conjugated polymers 1) can be formed into nanoparticles that are stable in aqueous media; 2) are non‐toxic until stimulated by IR light and 3) have a high photothermal efficiency.

     

Alginate‐Based Microcapsules with a Molecule Recognition Linker and Photosensitizer for the Combined Cancer Treatment

A reactive template method was used to fabricate alginate‐based hydrogel microcapsules. The uniform and well‐dispersed hydrogel capsules have a high drug loading capacity. After they are coated by a folate‐linked lipid mixture on the surface, the capsules possess higher cell uptake efficiency by the molecule recognition between folate and the folate‐receptor overexpressed by the cancer cells. Moreover, in this bioconjugate, the lipid could remarkably reduce the release rate of hydrophilic doxorubicin from the hydrogel microcapsules and encapsulate the hydrophobic photosensitizer hypocrellin B. The biointerfaced capsules could be used as drug carriers for combined treatment against cancer cell proliferation in vitro; this was much more effective than chemotherapy or photodynamic therapy alone.     

Surfactant-mediated wetting and spreading: Recent advances and applications

Surfactant-mediated wetting and spreading are ubiquitous. Understanding of these phenomena in-depth allows precise tailoring of wetting performance which can contribute to global challenges in the food supply chain, healthcare, ecology and industrial processes. The first part of this review shows how surfactants can be used to improve the efficacy of fertilisers and pesticides in agriculture, enhanced oil recovery, treatment of lung diseases and extinguishing fires involving flammable liquids. The second part provides analysis of recent studies on wetting and spreading over solid substrates. It includes discussion on the effect of surfactants on the outcome of the impact of liquid drops, the wetting state after impact, autophobic effect and spreading kinetics for both partial and complete wetting, including superspreading. Perspectives of future development in the area of surfactant-assisted wetting and spreading on solid substrates are outlined.     

Combined nanosuspensions from two natural active ingredients for cancer therapy with reduced side effects

Tumor drug resistance and systemic side effects of chemotherapeutic drugs are the main reasons for the failure of cancer treatment. In recent years, it was found that some natural active ingredients can reverse MDR and regulate body immunity to enhance the efficacy and reduce toxicity of chemotherapeutic drugs. In this paper, a new nanosuspensions, HCPT and QUR hybrid nanosuspensions (HQ-NPs), was prepared by the microprecipitation-high pressure homogenization method to reverse tumor drug resistance, reduce toxicity, and increase therapeutic efficacy. The in vitro investigation results showed that HQ-NPs had a unique shape (particle size was about 216.3 ± 5.9 nm), changed crystalline, and different dissolution rates compared with HCPT-NPs and QUR-NPs, which is attributed to the strong intermolecular forces between HCPT and QUR as indicated by the results of the molecule dock. It was verified that the HQ-NPs could double the retention of HCPT in cells and enhance the cytotoxicity to A549/PTX cells in vitro tests compared with HCPT-NPs. We also found that HQ-NPs can significantly enhance the accumulation of HCPT in tumor sites, improve the antitumor activity of HCPT, and protect the immune organs and other normal tissues (P < 0.01), compared with HCPT-NPs. Therefore, hybrid nanosuspensions can offer promising potential as the drug delivery system for HCPT and QUR to increase the therapeutic efficacy and reduce the toxicity of HCPT.     

Bioorthogonal Turn-On BODIPY-Peptide Photosensitizers for Tailored Photodynamic Therapy

Photodynamic therapy (PDT) leads to cancer remission via the production of cytotoxic species under photosensitizer (PS) irradiation. However, concomitant damage and dark toxicity can both hinder its use. With this in mind, we have implemented a versatile peptide-based platform of bioorthogonally activatable BODIPY-tetrazine PSs. Confocal microscopy and phototoxicity studies demonstrated that the incorporation of the PS, as a bifunctional module, into a peptide enabled spatial and conditional control of singlet oxygen (¹O₂) generation. Comparing subcellular distribution, PS confined in the cytoplasmic membrane achieved the highest toxicities (IC₅₀=0.096±0.003 μm ) after activation and without apparent dark toxicity. Our tunable approach will inspire novel probes towards smart PDT.     

Two‐Dimensional Nanomaterials for Photothermal Therapy

Two‐dimensional (2D) nanomaterials are currently explored as novel photothermal agents because of their ultrathin structure, high specific surface area, and unique optoelectronic properties. In addition to single photothermal therapy (PTT), 2D nanomaterials have demonstrated significant potential in PTT‐based synergistic therapies. In this Minireview, we summarize the recent progress in 2D nanomaterials for enhanced photothermal cancer therapy over the last five years. Their unique optical properties, typical synthesis methods, and surface modification are also covered. Emphasis is placed on their PTT and PTT‐synergized chemotherapy, photodynamic therapy, and immunotherapy. The major challenges of 2D photothermal agents are addressed and the promising prospects are also presented.