三种阔叶树瘤材的酸碱性质对UF胶固化时间的影响

为了给瘤材的定向培育和合理加工利用提供科学依据,以自然生长的、带有树瘤的毛白杨、旱柳、洋槐为试验材料,对各树种的正常材和瘤材的pH值、酸碱缓冲容量、与脲醛树脂胶固化时间等指标,进行对比研究。结果表明:3种树种的正常材和瘤材均呈弱酸性,毛白杨和旱柳瘤材的pH值、酸缓冲容量、与UF胶固化时间,均比正常材小,而洋槐正相反。瘤材与正常材各指标的差异显著性,根据各树种的不同而有所不同。

旱柳瘤材解剖特征及物理性质的研究

以自然生长的带有树瘤的旱柳为研究对象,对瘤材和正常材的解剖特征和物理性质进行对比研究。结果表明:瘤材的纤维宽度、纤维壁厚、纤维的壁腔比等指标均有增加,纤维的长度、纤维长宽比、导管长度、导管宽度、导管长宽比等有所减小;密度、顺纹干缩率增加,径向干缩率和弦向干缩率减小;差异干缩量减小,接近于1;水容量也有所降低。

三种阔叶树树瘤化学成分的研究

利用自然生长的、带有树瘤的毛白杨、旱柳、洋槐为研究材料,对各树种的正常材、瘤材的化学成分进行对比研究。结果表明:瘤材中的水抽提物含量、1%氢氧化钠抽提物含量、苯醇抽提物含量、木素、聚戊糖的含量有所增加,但纤维素含量却有所减少。

Free perforation of the small intestine in collagenous sprue

A 67-year-old man with celiac disease developed recurrent diarrhea,profound weakness and weight loss, with evidence of marked protein depletion.His clinical course was refractory to a strict gluten-free diet and steroid therapy.Postmortem studies led to definition of unrecognized collagenous sprue that caused ulceration and small intestinal perforation.Although PCR showed identical monoclonal T-cell populations in antemortem duodenal biopsies and postmortem jejunum,careful pathological evaluation demonstrated no frank lymphoma.Rarely,overt or even cryptic T-cell lymphoma may complicate collagenous sprue,however, small intestinal ulcers and perforation may also develop independently.The dramatic findings here may reflect an underlying or early molecular event in the eventual clinical appearance of overt T-cell lymphoma.

Recent advance in near-infrared/ultrasound-sensitive 2D-nanomaterials for cancer therapeutics

In recent years,the emerging two-dimensional(2 D)nanomaterials have shown great potential for a variety of applications such as electronics,catalysis,supercapacitors,and energy materials.In the biomedical arena,these nanomaterials,especially 2 D-ultrathin nanomaterials,have also been regarded as promising nano-carriers and/or diagnostic agents for cancer diagnosis and treatment,owing to their remarkable mechanical,photothermal,and optical properties.In this review,we provide the recent development of the nanoplatforms based on near-infrared/ultrasound-sensitive 2 D-materials,representatively such as graphdiyne(GDY),black phosphorus,transition metal dichalcogenides(TMDs),and antimonene,for non-invasive cancer therapeutics including photothermal,photodynamic and sonodynamic approaches.The general properties of these 2 D nanomaterials linking to biomedical interests are first introduced,followed by the fabrication processes of diverse nano-platforms and related outcomes of cancer diagnosis and treatments.We also outline the current challenges and prospects of the 2 D materials for non-invasive approaches to cancer treatments in the future.

Toxicity of graphene oxide and multi-walled carbon nanotubes against human cells and zebrafish

Graphene possesses unique physical and chemical properties, which have inspired a wide range of potential biomedical applications. However, little is known about the adverse effects of graphene on the human body and ecological environment. The purpose of our work is to make assessment on the toxicity of graphene oxide (GO) against human cell line (human bone marrow neuroblastoma cell line and human epithelial carcinoma cell line) and zebrafish (Danio rerio) by comparing the toxic effects of GO with its sister, multi-walled carbon nanotubes (MWNTs). The results show that GO has a moderate toxicity to organisms since it can induce minor (about 20%) cell growth inhibition and slight hatching delay of zebrafish embryos at a dosage of 50 mg/L, but did not result in significant increase of apoptosis in embryo, while MWNTs exhibit acute toxicity leading to a strong inhibition of cell proliferation and serious morphological defects in developing embryos even at relatively low concentration of 25 mg/L. The distinctive toxicity of GO and MWNTs should be ascribed to the different models of interaction between nanomaterials and organisms, which arises from the different geometric structures of nanomaterials. Collectively, our work suggests that GO does actual toxicity to organisms posing potential environmental risks and the result is also shedding light on the geometrical structure-dependent toxicity of graphitic nanomaterials.

Biodegradable magnesium implants:a potential scaffold for bone tumor patients

Relapse and metastasis of tumor may occur for osteosarcoma(OS)patients after clinical resection.Conventional metallic scaffolds provide sufficient mechanical support to the defected bone but fail to eradicate recurring tumors.Here we report that biodegradable magnesium(Mg)wirebased implant can inhibit OS growth.In brief,the Mg wires release Mg ions to activate the transport of zinc finger protein Snail1 from cytoplasm to cell nucleus,which induces apoptosis and inhibits proliferation of OS cells through a parallel antitumor signaling pathway of miRNA-181d-5p/TIMP3 and miRNA-181c-5p/NLK downstream.Simultaneously,the hydrogen gas evolution from Mg wires eliminates intracellular excessive reactive oxygen species,by which the growth of bone tumor cells is suppressed.The subcutaneous tumor-bearing experiment of OS cells in nude mice further confirms that Mg wires can effectively inhibit the growth of tumors and prolong the survival of tumor-bearing mice.In addition,Mg wires have no toxicity to normal cells and tissues.These results suggest that Mg implant is a potential anti-tumor scaffold for OS patients.

Transfection of 3′,3′′-bis-peptide-siRNA conjugate by cationic lipoplexes mixed with a neutral cytosin-1-yl-lipid

Cationic lipids have been applied to siRNA delivery for tumor therapeutics. However, the excess positive charges of these nanoplexes may lead to high cytotoxicity and nonnegligible immunogenicity both in vitro and in vivo, which limited the applications of gene drugs. We constructed multi-component lipoplex to delivery 3＇,3＂-bis-peptide-siRNA conjugate （pp-siRNA） by the treatment of melanoma. Based on the previous studies that the gemini lipid （CLD） encapsulated pp-siRNA, a novel neutral cytosin-l-yl- lipid （DNCA） was considered to replace a certain ration of CLD by hydrogen bonds and ~t-n stacking for reducing the cytotoxicity. It similarly retained in both the loading efficiency and targeted mRNA inhibition when DNCA was accounted for 40% in the lipoplex, with lower toxicity. Moreover, CLD/DNCA/pp-siRNA nanoplex could be uptake in A375 cells and internalized mainly by macropinocytosis and caveolin-mediated endocytosis. Besides, 90% CLD/DNCA/pp-siRNA nanoplexes presented the highest efficient knockdown for the mutant B-RAF mRNA （-80%）. All the results demonstrated that the mixed cationic and neutral lipids could efficiently realize the delivery of pp-siRNA and had potential application for cancer therapy.

Multifunctional FeCo-Graphitic Carbon Nanocrystals for Combined Imaging, Drug Delivery and Tumor-Specific Photothermal Therapy in Mice

Ultrasmall FeCo-graphitic carbon shell nanocrystals （FeCo/GC） are promising multifunctional materials capable of highly efficient drug delivery in vitro and magnetic resonance imaging in vivo. In this work, we demonstrate the use of FeCo/GC for highly effective cancer therapy through combined drug delivery, tumor-selective near-infrared photothermal therapy, and cancer imaging of a 4T1 syngeneic breast cancer model. The graphitic carbon shell of the ~4 nm FeCo/GC readily loads doxorubicin （DOX） via π-π stacking and absorbs near-infrared light giving photothermal heating. When used for cancer treatment, intravenously administrated FeCo/GC-DOX led to complete tumor regression in 45% of mice when combined with 20 min of near-infrared laser irradiation selectively heating the tumor to 43-45 ℃. In addition, the use of FeCo/GC-DOX results in reduced systemic toxicity compared with free DOX and appears to be safe in mice monitored for over 1 yr. FeCo/GC-DOX is shown to be a highly integrated nanoparticle system for synergistic cancer therapy leading to tumor regression of a highly aggressive tumor model.

Functional tumor imaging based on inorganic nanomaterials

Inorganic nanomaterials have attracted substantial research interest due to their unique intrinsic physicochemical properties. We highlighted recent advances in the applications of inorganic nanoparticles regarding their imaging efficacy, focusing on tumor-imaging nanomaterials such as metal-based and carbon-based nanomaterials and quantum dots. Inorganic nanoparticles gain excellent in vivo tumor-imaging functions based on their specific characteristics of strong near-infrared optical absorption and/or X-ray attenuation capability. The specific response signals from these novel nanornaterials can be captured using a series of imaging techniques, i.e., optical coherence tomography （OCT）, X-ray computed tomography （CT） imaging, two-photon luminescence （TPL）, photoacoustic tomography （PAT）, magnetic resonance imaging （MRI）, surface-enhanced Raman scattering （SERS） and positron emission tomography （PET）. In this review, we summarized the rapid development of inorganic nanomaterial applications using these analysis techniques and discussed the related safety issues of these materials.