Lou Yimin

Bio: Lou Yimin is an academic researcher from Zhejiang Sci-Tech University. The author has contributed to research in topic(s): Depth of field & Display device. The author has an hindex of 4, co-authored 15 publication(s) receiving 47 citation(s).

Improved Intracellular Delivery of Polyarginine Peptides with Cargoes.

Abstract: Complementary to endocytosis, cell-penetrating peptides (CPPs) at high concentrations can penetrate the cell membrane in a direct way, which further makes CPPs popular candidates for delivering therapeutic or diagnostic agents. Although featured as rapid uptake, the translocation efficiency and potential toxicity of the direct penetration are usually affected by cargoes, which is still unclear. Here, using coarse-grained molecular dynamics simulations, we show that the polyarginine (R8) peptides penetrate the membrane through a water pore in the membrane, and the transmembrane efficiency is improved by conjugating to small nanoparticles (NPs) with proper linkers. It can be attributed to both the extension of the lifetime of the water pore by the NPs and outward diffusion of negative lipids in the asymmetry membrane, which induces the surrounding R8-NP conjugates to the water pore before it is closed. The translocation efficiency is closely related to the length of the linkers, and it gets the maximum value when the length of the linkers is around half of the membrane thickness. Overlong linkers not only decrease the transmembrane efficiency because of the blockage of NPs in the water pore but may also cause cytotoxicity because of the unclosed water pore. The results provide insights into the internalization of CPPs and facilitate the design of CPP and drug conjugates with high efficiency and low toxicity.

Bandwidth-enhanced depth priority integral imaging using a band-limited diffusing illumination technique.

Abstract: The display bandwidth and display mechanism determine the performance of the three-dimensional (3D) display system. In this paper, a bandwidth-enhanced depth priority integral imaging (DPII) technique is proposed. Information transmission efficiency (ITE) defined as the output display bandwidth divided by the input display bandwidth is used to assess the II system. By analyzing the ITE, we find that only a part of the input display bandwidth is used efficiently to present the 3D image in the traditional DPII system. The DPII system sacrifices the ITE for depth enhancement. The low ITE that fundamentally limits the 3D performance of the DPII system is ascribed to the diffusing illumination mechanism of the display system. To enhance the 3D performance, a collimated illumination DPII system as a special case of band-limited diffusing illumination technique has been proposed and demonstrated first. The bandwidth and ITE of such a DPII system are increased. The depth of field (DOF) of the system is doubled. The resolution of the 3D image is increased to the level of the resolution priority II system without sacrificing the viewing angle. A more general case, band-limited illumination DPII system is also demonstrated. By modulating the divergence angle of the illumination system, the 3D image’s resolution and DOF can be controlled. The bandwidth and ITE of the DPII system using band-limited illumination are also higher than that of the traditional DPII system. Experiments are presented to prove the bandwidth-enhanced mechanism of the DPII system.

Design and fabrication of ultrathin lighting responsive security device based on moiré imaging phenomenon

Abstract: Security authentication of high- and low-value products is a pressing issue. Security technologies should be upgraded before they are counterfeited. In this study, an ultrathin lighting responsive moire imaging device, which is different from traditional security device is developed for security authentication. Some interesting lighting responsive moire imaging phenomena including light-activated three-dimensional floating imaging and light-controlled image transformation have been developed as covert security features for advanced authentication. These security features can be verified instantly using a point light source such as a white light-emitting diode configured in a smart phone. A compact defocus optical structure consisting of a micro lens-mirror array (MLMA) and a micro-pattern array is designed to fabricate the lighting responsive moire imaging device. The structure makes the device ultrathin, which enables the easy integration of the device. The MLMA also overcame the difficulty in the fabrication of high numerical aperture micro-lens array required in traditional moire imaging system. Flexible devices with 78- μ m thickness were fabricated by photolithography, imprinting, and gravure-like techniques. Such thin device allows its potential integration with banknotes, currency, or other valuable documents/products.

Twin imaging phenomenon of integral imaging

Abstract: The imaging principles and phenomena of integral imaging technique have been studied in detail using geometrical optics, wave optics, or light filed theory. However, most of the conclusions are only suit for the integral imaging systems using diffused illumination. In this work, a kind of twin imaging phenomenon and mechanism has been observed in a non-diffused illumination reflective integral imaging system. Interactive twin images including a real and a virtual 3D image of one object can be activated in the system. The imaging phenomenon is similar to the conjugate imaging effect of hologram, but it base on the refraction and reflection instead of diffraction. The imaging characteristics and mechanisms different from traditional integral imaging are deduced analytically. Thin film integral imaging systems with 80μm thickness have also been made to verify the imaging phenomenon. Vivid lighting interactive twin 3D images have been realized using a light-emitting diode (LED) light source. When the LED is moving, the twin 3D images are moving synchronously. This interesting phenomenon shows a good application prospect in interactive 3D display, argument reality, and security authentication.

Large-depth-of-field true-three-dimensional augmented reality display method and system

Abstract: The invention discloses a large-depth-of-field true three-dimensional augmented reality display method and system. An information display module group formed by a micro display device and a lens arrayis irradiated by a plurality of point light sources and a virtual true three-dimensional image is obtained in three-dimensional space; and information of the virtual true three-dimensional image is superposed to a realistic objective environment by the information display module group to realize true three-dimensional augmented reality displaying. The micro display device is not arranged at a doubled focal length of the lens array and the superposition depths of the virtual true three-dimensional image are different under point light source irradiation at different positions. Therefore, problems that the depth of field of the image is limited in the current augmented reality display system, a conflict between the focusing of an observer and a convergence competition exists in the currentaugmented reality display system and the depth-of-field control mechanism is complicated and the response speed is low of the current augmented reality display system can be solved; and thus real-time-response 3D image augmented reality displaying of the large-depth-of-field true three-dimensional image is realized.

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Novel peptide linkers for highly potent antibody-auristatin conjugates

Abstract: 4907 A great deal of interest has surrounded the use of monoclonal antibodies (mAbs) for the selective delivery of cytotoxic agents to tumor cells. We have previously demonstrated that mAb-auristatin conjugates are highly active, leading to cures and regressions of established tumors in nude mice. These antibody-drug conjugates (ADCs) contain a dipeptide valine-citrulline-p-aminobenzylcarbamate (vc-PABC) linker used to join the antimitotic drugs monomethylauristatin E or F (MMAE, MMAF) to a series of antitumor mAbs. This linker was selected for plasma stability and cleavage by lysosomal enzymes such as cathepsin B. Here, we describe several other dipeptide sequences, many of which are not cathepsin B substrates, for the attachment of auristatins to mAb carriers. More than 20 mAb-dipeptide-PABC-MMAF ADCs were prepared, all of which were active in vitro and in vivo independent of peptide sequence. There was no apparent improvement over the vc-PABC linker, since the PABC group facilitated lysosomal drug release. In contrast, a new series of mAb-MMAF conjugates was prepared in which the dipeptide linkers were directly attached to the C-terminal phenylalanine on the drug without using an intervening PABC spacer. Many of the dipeptide sequences contained unnatural amino acids in order to increase the stringency of drug release. Peptide sequences were identified within the new conjugates that led to both greater tolerability and higher potency compared to corresponding vc-PABC ADCs. The new linkers play an important role in ADC activity and tolerability, and mAb-auristatin conjugates derived from them are candidates for future development.

Cell-penetrating peptide: a means of breaking through the physiological barriers of different tissues and organs

Abstract: The selective infiltration of cell membranes and tissue barriers often blocks the entry of most active molecules. This natural defense mechanism prevents the invasion of exogenous substances and limits the therapeutic value of most available molecules. Therefore, it is particularly important to find appropriate ways of membrane translocation and therapeutic agent delivery to its target site. Cell penetrating peptides (CPPs) are a group of short peptides harnessed in this condition, possessing a significant capacity for membrane transduction and could be exploited to transfer various biologically active cargoes into the cells. Since their discovery, CPPs have been employed for delivery of a wide variety of therapeutic molecules to treat various disorders including cranial nerve involvement, ocular inflammation, myocardial ischemia, dermatosis and cancer. The promising results of CPPs-derived therapeutics in various tumor models demonstrated a potential and worthwhile scope of CPPs in chemotherapy. This review describes the detailed description of CPPs and CPPs-assisted molecular delivery against various tissues and organs disorders. An emphasis is focused on summarizing the novel insights and achievements of CPPs in surmounting the natural membrane barriers during the last 5 years.

Light field head-mounted display with correct focus cue using micro structure array

Abstract: A new type of light field display is proposed using a head-mounted display(HMD)and a micro structure array(MSA,lens array or pinhole array).Each rendering point emits abundant rays from different directions into the viewer’s pupil,and at one time the dense light field is generated inside the exit pupil of the HMD through the eyepiece.Therefore,the proposed method not only solves the problem of accommodation and convergence conflict in a traditional HMD,but also drastically reduces the huge data in real three-dimensional(3D)display.To demonstrate the proposed method,a prototype is developed,which is capable of giving the observer a real perception of depth.

Rotation-Selective Moiré Magnification of Structural Color Pattern Arrays.

Abstract: When a microlens array is aligned and overlaid on an array of patterns with similar periodicity, a highly magnified image of the patterns is observed. This effect, known as moire magnification, is ...