Epitaxial Growth of Germanium on Silicon for Light Emitters

National Basic Research Program of China [2007CB613404, 2012CB933503]; National Natural Science Foundation of China [61036003, 60837001, 61176092]; Fundamental Research Funds for the Central Universities [2010121056]This paper describes the role of Ge as an enabler for light emitters on a Si platform. In spite of the large lattice mismatch of similar to 4.2% between Ge and Si, high-quality Ge layers can be epitaxially grown on Si by ultrahigh-vacuum chemical vapor deposition. Applications of the Ge layers to near-infrared light emitters with various structures are reviewed, including the tensile-strained Ge epilayer, the Ge epilayer with a delta-doping SiGe layer, and the Ge/SiGe multiple quantum wells on Si. The fundamentals of photoluminescence physics in the different Ge structures are discussed briefly

Association of clinical outcomes and the predictive value of T lymphocyte subsets within colorectal cancer patients

IntroductionTumor immunity is a hot topic in tumor research today, and human immunity is closely related to tumor progression. T lymphocyte is an important component of human immune system, and the changes in their subsets may influence the progression of colorectal cancer (CRC) to some extent. This clinical study systematically describes and analyzes the association of CD4+ and CD8+ T-lymphocyte content and CD4+/CD8+ T-lymphocyte ratio with CRC differentiation, clinical pathological stage, Ki67 expression, T-stage, N-stage, carcinoembryonic antigen (CEA) content, nerve and vascular infiltration, and other clinical features, as well as preoperative and postoperative trends. Furthermore, a predictive model is constructed to evaluate the predictive value of T-lymphocyte subsets for CRC clinical features.MethodsStrict inclusion and exclusion criterion were formulated to screen patients, preoperative and postoperative flow cytometry and postoperative pathology reports from standard laparoscopic surgery were assessed. PASS and SPSS software, R packages were invoked to calculate and analyze.ResultsWe found that a high CD4+ T-lymphocyte content in peripheral blood and a high CD4+/CD8+ ratio were associated with better tumor differentiation, an earlier clinical pathological stage, lower Ki67 expression, shallower tumor infiltration, a smaller number of lymph node metastases, a lower CEA content, and a lower likelihood of nerve or vascular infiltration (P < 0.05). However, a high CD8+ T-lymphocyte content indicated an unpromising clinical profile. After effective surgical treatment, the CD4+ T-lymphocyte content and CD4+/CD8+ ratio increased significantly (P < 0.05), while the CD8+ T-lymphocyte content decreased significantly (P < 0.05). Further, we comprehensively compared the merits of CD4+ T-lymphocyte content, CD8+ T-lymphocyte content, and CD4+/CD8+ ratio in predicting the clinical features of CRC. We then combined the CD4+ and CD8+ T-lymphocyte content to build models and predict major clinical characteristics. We compared these models with the CD4+/CD8+ ratio to explore their advantages and disadvantages in predicting the clinical features of CRC.DiscussionOur results provide a theoretical basis for the future screening of effective markers in reflecting and predicting the progression of CRC. Changes in T lymphocyte subsets affect the progression of CRC to a certain extent, while their changes also reflect variations in the human immune system

Self-assembling supramolecular dendrimer nanosystem for PET imaging of tumors

Bioimaging plays an important role in cancer diagnosis and treatment. However, imaging sensitivity and specificity still constitute key challenges. Nanotechnology-based imaging is particularly promising for overcoming these limitations because nanosized imaging agents can specifically home in on tumors via the "enhanced permeation and retention" (EPR) effect, thus resulting in enhanced imaging sensitivity and specificity. Here, we report an original nanosystem for positron emission tomography (PET) imaging based on an amphiphilic dendrimer, which bears multiple PET reporting units at the terminals. This dendrimer is able to self-assemble into small and uniform nanomicelles, which accumulate in tumors for effective PET imaging. Benefiting from the combined dendrimeric multivalence and EPR-mediated passive tumor targeting, this nanosystem demonstrates superior imaging sensitivity and specificity, with up to 14-fold increased PET signal ratios compared with the clinical gold reference 2-fluorodeoxyglucose ([18F]FDG). Most importantly, this dendrimer system can detect imaging-refractory low-glucose-uptake tumors that are otherwise undetectable using [18F]FDG. In addition, it is endowed with an excellent safety profile and favorable pharmacokinetics for PET imaging. Consequently, this dendrimer nanosystem constitutes an effective and promising approach for cancer imaging. Our study also demonstrates that nanotechnology based on self-assembling dendrimers provides a fresh perspective for biomedical imaging and cancer diagnosis

Preclinical and Clinical Advances of GalNAc-Decorated Nucleic Acid Therapeutics

A main challenge in realizing the full potential of nucleic acid therapeutics is efficient delivery of them into targeted tissues and cells. N-acetylgalactosamine (GalNAc) is a well-defined liver-targeted moiety benefiting from its high affinity with asialoglycoprotein receptor (ASGPR). By conjugating it directly to the oligonucleotides or decorating it to a certain delivery system as a targeting moiety, GalNAc has achieved compelling successes in the development of nucleic acid therapeutics in recent years. Several oligonucleotide modalities are undergoing pivotal clinical studies, followed by a blooming pipeline in the preclinical stage. This review covers the progress of GalNAc-decorated oligonucleotide drugs, including siRNAs, anti-miRs, and ASOs, which provides a panorama for this field. Keywords: GalNAc, siRNA, anti-miR, ASO, liver-targeted delivery, ASGPR, oligonucleotide, RNA

LMP estimation considering the uncertainty of wind power

One of the impediments to large-scale use of wind generation within power system is its variable and uncertain real-time availability. Due to the low marginal cost of wind power, its output will change the merit order of power markets and influence the Locational Marginal Price (LMP). For the large scale of wind power, LMP calculation can't ignore the essential variable and uncertain nature of wind power. This paper proposes an algorithm to estimate LMP. The estimation result of conventional Monte Carlo simulation is taken as benchmark to examine accuracy. Case study is conducted on a simplified SE Australian power system, and the simulation results show the feasibility of proposed method

Extracellular vesicle‐based nucleic acid delivery

Abstract Extracellular vesicles (EVs) are a heterogeneous class of natural vesicles that facilitate intercellular communication by functional transfer of lipids and biomolecular cargoes, such as miRNAs, mRNAs and proteins. As a naturally occurring delivery vehicle for nucleic acids, EVs are characterized by multiple advantageous characteristics, such as unique size and structure, excellent biocompatibility, immunologically inert, increased stability in circulation, intrinsic targeting capacity and the capability of membrane fusion and crossing biological barriers. Of note, the delivery properties of EVs can be further improved by genetic engineering of donor cells or direct modification of EVs. Over the last decade, EVs have sparkled intensive interest for delivery of small RNAs, including small interfering RNAs (siRNAs) and microRNAs (miRNAs). In recent years, increasing attention has been focused on exploring a variety of strategies to harness EVs for delivery of more nucleic acid types. In the present perspective, we provide a capsule overview of the latest accomplishments and trends in the field of EV‐based delivery systems for siRNAs, miRNAs, messenger RNAs (mRNAs), clustered regularly interspaced short palindromic repeats‐associated endonuclease (CRISPR/Cas) systems, antisense oligonucleotides (ASOs), circular RNA (circRNAs), long noncoding RNAs (lncRNAs) and DNAs. This perspective may offer insights into the rational design of more cutting‐edge extracellular vesicle‐based nucleic acid delivery nanoplatforms

Constructing Pd/ferroelectric Bi4Ti(3)O(12) nanoflake interfaces for O-2 activation and boosting NO photo-oxidation

Photo-oxidative NOx removal often encountered with sluggish charge carrier separation kinetics and poor selectivity. Herein, Pd/ferroelectric Bi4Ti3O12 nanoflakes (Pd/BTO NF) were constructed to investigate the photo-excited charge separation, O2 activation and the generated reactive oxygen species (ROS) in dictating NO removal. Results showed that the depolarization field of ferroelectric BTO NF significantly promoted bulk charge separation, leading to boosted NO removal reaction kinetics (10 times higher) for Pd/BTO NF comparing with Pd/TiO2. Revealed by electronic paramagnetic resonance and radical scavenging tests, it is observed that the primary O2 activation species differed among Pd, Ag and Pt supported BTO NF photocatalysts, which resulted in different selectivity. The underlying mechanism of NO photo-oxidative conversion pathway was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy. This work illustrate that metal/ferroelectric interfaces can be tuned to obtain differing O2 activation species, and notable selectivity changes in photocatalysis mediated environmental remediation reactions

Selection and Identification of an ssDNA Aptamer for Fibroblast Activation Protein

As a type II transmembrane serine protease, fibroblast activation protein (FAP) is specifically expressed on the surface of fibroblasts associated with a variety of epithelial-derived malignancies such as pancreatic cancer, breast cancer, and colon cancer. It participates in the processes of tumorigenesis, progression, and immunosuppression. FAP constitutes an important target for tumor treatment; however, the current studies on FAP are mainly related to structural characteristics, enzymatic properties, and biological functions, and aptamers of FAP have not been investigated. In this work, by using recombinant human FAP as the target, five candidate aptamers, which are AptFAP-A1, AptFAP-A2, AptFAP-A3, AptFAP-A4, and AptFAP-A5, were selected by capillary electrophoresis–systematic evolution of ligands by exponential enrichment (CE-SELEX), and their secondary structures were predicted to be mainly stem-loop. Moreover, the CE-laser-induced fluorescence (LIF) method was used to determine the equilibrium dissociation constant KD values between the FAP protein and candidate aptamers, and the KD value was in the low molar range. Finally, Cy5-labeled aptamers were co-incubated with human pancreatic cancer-associated fibroblasts highly expressing FAP protein, and confocal microscopy imaging showed that aptamer AptFAP-A4 had the highest affinities with the cells. The FAP aptamers screened in this study provide a promising direction for the development of rapid tumor diagnosis and targeted therapy

Physical and electrical properties of thermally oxidized dielectrics on Si-capped Ge-on-Si substrate

National Basic Research Program of China [2012CB933503]; National Natural Science Foundation of China [61036003, 61176092]; Fundamental Research Funds for the Central Universities [2010121056]Thermal oxidation of silicon (Si)-capped germanium (Ge) epilayer on Si substrate is performed to study the effect of the physical interface on the electrical properties of Ge metaloxide-semiconductor capacitors. During the growth and oxidation of the Si cap layer, Ge atoms diffuse through the Si cap layer, and they are oxidized to GeO2. Once the Si cap layer is consumed, more Ge suboxides are generated, resulting in the serious degradation of the capacitance-voltage characteristics. Both the positive fixed charges generated by the evaporation of GeO and the negative fixed charges induced by the formation of Si-O-dangling bonds are proposed to affect the flat-band voltage shifts. These results suggest that the deposition of a thin Si cap layer on Ge is effective in suppressing the generation of Ge sub-oxides during thermal oxidation, thereby improving the performance of Ge capacitors. (C) 2012 American Vacuum Society. [DOI: 10.1116/1.3668115