Control of the signaling role of PtdIns(4)P at the plasma membrane through H2O2-dependent inactivation of synaptojanin 2 during endocytosis

Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] is implicated in various processes, including hormone-induced signal transduction, endocytosis, and exocytosis in the plasma membrane. However, how H2O2 accumulation regulates the levels of PtdIns(4,5)P2 in the plasma membrane in cells stimulated with epidermal growth factors (EGFs) is not known. We show that a plasma membrane PtdIns(4,5)P2-degrading enzyme, synaptojanin (Synj) phosphatase, is inactivated through oxidation by H2O2. Intriguingly, H2O2 inhibits the 4-phosphatase activity of Synj but not the 5-phosphatase activity. In EGF-activated cells, the oxidation of Synj dual phosphatase is required for the transient increase in the plasma membrane levels of phosphatidylinositol 4-phosphate [PtdIns(4)P], which can control EGF receptor-mediated endocytosis. These results indicate that intracellular H2O2 molecules act as signaling mediators to fine-tune endocytosis by controlling the stability of plasma membrane PtdIns(4)P, an intermediate product of Synj phosphoinositide dual phosphatase.

Precise and selective macroscopic assembly of a dual lock-and-key structured hydrogel

Macroscopic assembly offers immense potential for constructing complex systems due to the high design flexibility of the building blocks. In such assembly systems, hydrogels are promising candidates for building blocks due to their versatile chemical compositions and ease of property tuning. However, two major challenges must be addressed to facilitate application in a broader context: the precision of assembly and the quantity of orthogonally matching pairs must both be increased. Although previous studies have attempted to address these challenges, none have successfully dealt with both simultaneously. Here, we propose topology-based design criteria for the selective assembly of hydrogel building blocks. By introducing the dual lock-and-key structures, we demonstrate highly precise assembly exclusively between the matching pairs. We establish principles for selecting multiple orthogonally matching pairs and achieve selective assembly involving simple one-to-one matching and complex assemblies with multiple orthogonal matching points. Moreover, by harnessing hydrogel tunability and the abundance of matching pairs, we synthesize complementary single-stranded structures for programmable assembly and successfully assemble them in the correct order. Finally, we demonstrate a hydrogel-based self-assembled logic gate system, including a YES gate, an OR gate, and an AND gate. The output is generated only when the corresponding inputs are provided according to each logic.

Statistically unbiased prediction enables accurate denoising of voltage imaging data

Here we report SUPPORT (statistically unbiased prediction utilizing spatiotemporal information in imaging data), a self-supervised learning method for removing Poisson-Gaussian noise in voltage imaging data. SUPPORT is based on the insight that a pixel value in voltage imaging data is highly dependent on its spatiotemporal neighboring pixels, even when its temporally adjacent frames alone do not provide useful information for statistical prediction. Such dependency is captured and used by a convolutional neural network with a spatiotemporal blind spot to accurately denoise voltage imaging data in which the existence of the action potential in a time frame cannot be inferred by the information in other frames. Through simulations and experiments, we show that SUPPORT enables precise denoising of voltage imaging data and other types of microscopy image while preserving the underlying dynamics within the scene.

Expandable ELAST for super-resolution imaging of thick tissue slices using a hydrogel containing charged monomers

Hydrogels have been utilized extensively as a material for retaining position information in tissue imaging procedures, such as tissue clearing and super-resolution imaging. Immunostaining thick biological tissues, however, poses a bottleneck that restricts sample size. The recently developed technique known as entangled link-augmented stretchable tissue-hydrogel (ELAST) accelerates the immunostaining process by embedding specimens in long-chain polymers and stretching them. A more advanced version of ELAST, magnifiable entangled link-augmented stretchable tissue-hydrogel (mELAST), achieves rapid immunostaining and tissue expansion by embedding specimens in long-chain neutral polymers and subsequently hydrolyzing them. Building on these techniques, we introduce a variant of mELAST called ExELAST. This approach uses charged monomers to stretch and expand tissue slices. Using ExELAST, we first tested two hydrogel compositions that could permit uniform expansion of biological specimens. Then, we apply the tailored hydrogel to the 500-μm-thick mouse brain slices and demonstrated that they can be stained within two days and imaged with a resolution below the diffraction limit of light.

[Efficacy and outcomes of shunt surgery for secondary hydrocephalus]

Records of secondary hydrocephalus patients undergoing shunt surgery in the Department of Neurosurgery of Peking Union Medical College Hospital from September 2012 to April 2022 and their clinical characteristics and outcomes were retrospectively reviewed and analyzed. Among 121 patients who received first time shunt placement, the most common causes of secondary hydrocephalus were brain hemorrhage (55, 45.5%) and trauma (35, 28.9%). Cognition decline (106, 87.6%), abnormal gait (50, 41.3%) and incontinence (40, 33.1%) were the most prevalent manifestations. Postoperative central nervous system infection (4, 3.3%), shunt obstruction (3, 2.5%) and subdural hematoma/effusion (4, 3.3%) were the most frequent neurological complications. Overall incidence of postoperative complications was 9% (11 cases) in the current cohort. And 50.5% (54/107) of the patients receiving shunting achieved a Glasgow outcome scale (GOS) score of at least 4. Shunt surgery is preferred for secondary hydrocephalus, especially for secondary normal pressure hydrocephalus. Moreover, it is recommended to complete cranioplasty in staged operation or one-stage operation for the patients with decompressive craniectomy.

Human hand-inspired all-hydrogel gripper with a high load capacity formed by the split-brushing adhesion of diverse hydrogels

Human hands are highly versatile. Even though they are primarily made of materials with high water content, they exhibit a high load capacity. However, existing hydrogel grippers do not possess a high load capacity due to their innate softness and mechanical strength. This work demonstrates a human hand-inspired all-hydrogel gripper that can bear more than 47.6 times its own weight. This gripper is made of two hydrogels: poly(methacrylamide-co-methacrylic acid) (P(MAAm-co-MAAc)) and poly(N-isopropylacrylamide) (PNIPAM). P(MAAm-co-MAAc) is extremely stiff but becomes soft above its transition temperature. By taking advantage of the difference in the kinetics of the stiff-soft transition of P(MAAm-co-MAAc) hydrogels and the swelling-shrinking transition of PNIPAM hydrogels, this gripper can be switched between its stiff-bent and stiff-stretched states by simply changing the temperature. The assembly of these two hydrogels into a gripper necessitated the development of a new hydrogel adhesion method, as existing topological adhesion methods are not applicable to such stiff hydrogels. A new hydrogel adhesion method, termed split-brushing adhesion, has been demonstrated to satisfy this need. When applied to P(MAAm-co-MAAc) hydrogels, this method achieves an adhesion energy of 1221.6 J m^-2, which is 67.5 times higher than that achieved with other topological adhesion methods.

In situ silver nanoparticle development for molecular-specific biological imaging via highly accessible microscopies

In biological studies and diagnoses, brightfield (BF), fluorescence, and electron microscopy (EM) are used to image biomolecules inside cells. When compared, their relative advantages and disadvantages are obvious. BF microscopy is the most accessible of the three, but its resolution is limited to a few microns. EM provides a nanoscale resolution, but sample preparation is time-consuming. In this study, we present a new imaging technique, which we termed decoration microscopy (DecoM), and quantitative investigations to address the aforementioned issues in EM and BF microscopy. For molecular-specific EM imaging, DecoM labels proteins inside cells using antibodies bearing 1.4 nm gold nanoparticles (AuNPs) and grows silver layers on the AuNPs' surfaces. The cells are then dried without buffer exchange and imaged using scanning electron microscopy (SEM). Structures labeled with silver-grown AuNPs are clearly visible on SEM, even they are covered with lipid membranes. Using stochastic optical reconstruction microscopy, we show that the drying process causes negligible distortion of structures and that less structural deformation could be achieved through simple buffer exchange to hexamethyldisilazane. Using DecoM, we visualize the nanoscale alterations in microtubules by microtubule-severing proteins that cannot be observed with diffraction-limited fluorescence microscopy. We then combine DecoM with expansion microscopy to enable sub-micron resolution BF microscopy imaging. We first show that silver-grown AuNPs strongly absorb white light, and the structures labeled with them are clearly visible on BF microscopy. We then show that the application of AuNPs and silver development must follow expansion to visualize the labeled proteins clearly with sub-micron resolution.

Glycation-mediated tissue-level remodeling of brain meningeal membrane by aging

Collagen is a prominent target of nonenzymatic glycation, which is a hallmark of aging and causes functional alteration of the matrix. Here, we uncover glycation-mediated structural and functional changes in the collagen-enriched meningeal membrane of the human and mouse brain. Using an in vitro culture platform mimicking the meningeal membrane composed of fibrillar collagen, we showed that the accumulation of advanced glycation end products (AGEs) in the collagen membrane is responsible for glycation-mediated matrix remodeling. These changes influence fibroblast-matrix interactions, inducing cell-mediated ECM remodeling. The adherence of meningeal fibroblasts to the glycated collagen membrane was mediated by the discoidin domain-containing receptor 2 (DDR2), whereas integrin-mediated adhesion was inhibited. A-kinase anchoring protein 12 (AKAP12)-positive meningeal fibroblasts in the meningeal membrane of aged mice exhibited substantially increased expression of DDR2 and depletion of integrin beta-1 (ITGB1). In the glycated collagen membrane, meningeal fibroblasts increased the expression of matrix metalloproteinase 14 (MMP14) and less tissue inhibitor of metalloproteinase-1 (TIMP1). In contrast, the cells exhibited decreased expression of type I collagen (COL1A1). These results suggest that glycation modification by meningeal fibroblasts is intimately linked to aging-related structural and functional alterations in the meningeal membrane.

Strong, Chemically Stable, and Enzymatically On-Demand Detachable Hydrogel Adhesion Using Protein Crosslink

Achieving strong adhesion between hydrogels and diverse materials is greatly significant for emerging technologies yet remains challenging. Existing methods using non-covalent bonds have limited pH and ion stability, while those using covalent bonds typically lack on-demand detachment capability, limiting their applications. In this study, a general strategy of covalent bond-based and detachable adhesion by incorporating amine-rich proteins in various hydrogels and inducing the interfacial crosslinking of the hydrogels using a protein-crosslinking agent is demonstrated. The protein crosslink offers topological adhesion and can reach a strong adhesion energy of ≈750 J m^-2 . The chemistry of the adhesion is characterized and that the inclusion of proteins inside the hydrogels does not alter the hydrogels' properties is shown. The adhesion remains intact after treating the adhered hydrogels with various pH solutions and ions, even at an elevated temperature. The detachment is triggered by treating proteinase solution at the bonding front, causing the digestion of proteins, thus breaking up the interfacial crosslink network. In addition, that this approach can be used to adhere hydrogels to diverse dry surfaces, including glass, elastomers and plastics, is shown. The stable chemistry of protein crosslinks opens the door for various applications in a wide range of chemical environments.

Bi-directional crosstalk between cells and extracellular matrix leads to network morphogenesis in multi-layered tissues

Cell-generated mechanical forces drive many cellular and tissue-level movements and rearrangements required for the tissue or organ to develop its shape1, 2, 3, 4, 5. The prevalent view of tissue morphogenesis relies on epithelial folding resulting in compressed epithelial monolayers, overlooking the involvement of stroma in morphogenesis1, 4, 6, 7. Here, we report a giant web-like network formation of stromal cells in the epithelium-stroma interface, resulting from a multi-scale mechano-reciprocity between migrating cells and their extracellular environment. In multi-layered tissues, surface wrinkles form by a stromal cell-mediated tensional force exerted at the basement membrane. The topographical cue is transmitted to the stromal cell, directing its protrusion and migration along the wrinkles. This inductive movement of the cells conveys traction forces to its surrounding extracellular matrix, remodeling the local architectures of the stroma. In this manner, stromal cells and wrinkles communicate recursively to generate the cellular network. Our observation provides a rational mechanism for network formation in living tissues and a new understanding of the role of cellular-level tensional force in morphogenesis.

Chitosan-coated mesoporous silica particles as a plastic-free platform for photochemical suppression and stabilization of organic ultraviolet filters

Photochemical instability and reactivity of organic ultraviolet (UV) filters not only degrade the performance of sunscreen formulations but also generate toxic photodegradation products and reactive oxygen species (ROS). Although the encapsulation of organic UV filters into synthetic polymer particles has been widely investigated, synthetic plastics were recently banned for personal care and cosmetic products due to marine and coastal pollution issues. Here we present a plastic-free, photochemically stable and inactive UV filter platform based on chitosan-coated mesoporous silica microparticles, denoted 'mSOCPs', incorporating octyl methoxycinnamate (OMC) as a sunscreen agent. Sunlight induced the degradation of ∼80% free OMC in artificial sweat in 1 h at room temperature, while only 20% of OMC degraded for 3 h when encapsulated within mSOCPs. Moreover, mSOCPs efficiently suppressed the photochemical generation of ROS by about 99% through the combined effects of the mesoporous silica structure and chitosan coating. Accordingly, mSOCPs substantially increased the cell viability of fibroblasts exposed to UV irradiation. This work demonstrates that the biopolymer coatings of mesoporous inorganic particles can be a promising approach to the plastic-free encapsulation of organic UV filters for suppressing their photochemical reactivity and degradation.

Multiscale Functional Metal Architectures by Antibody-Guided Metallization of Specific Protein Assemblies in Ex Vivo Multicellular Organisms

Biological systems consist of hierarchical protein structures, each of which has unique 3D geometries optimized for specific functions. In the past decades, the growth of inorganic materials on specific proteins has attracted considerable attention. However, the use of specific proteins as templates has only been demonstrated in relatively simple organisms, such as viruses, limiting the range of structures that can be used as scaffolds. This study proposes a method for synthesizing metallic structures that resemble the 3D assemblies of specific proteins in mammalian cells and animal tissues. Using 1.4 nm nanogold-conjugated antibodies, specific proteins within cells and ex vivo tissues are labeled, and then the nanogold acts as nucleation sites for growth of metal particles. As proof of concept, various metal particles are grown using microtubules in cells as templates. The metal-containing cells are applied as catalysts and show catalytic stability in liquid-phase reactions due to the rigid support provided by the microtubules. Finally, this method is used to produce metal structures that replicate the specific protein assemblies of neurons in the mouse brain or the extracellular matrices in the mouse kidney and heart. This new biotemplating approach can facilitate the conversion of specific protein structures into metallic forms in ex vivo multicellular organisms.

Abstract 2457: PICASSO: Ultra-multiplexed imaging technique for spatial protein analysis of tumor microenvironments

In recent cancer research in medicine, various combinatorial biomarkers are simultaneously visualized to study molecular heterogeneity of the tumor microenvironment in detail. These kinds of study aim to provide enhanced precise diagnostic system, optimal treatment decision, and more accurate prediction of survival or recurrence rates for each independent patient case. Conventional immunofluorescence-based approach, however, has been faced an intrinsic limitation in terms of spectral overlap among fluorophores, which allows only 3-4 fluorescent channels per single imaging cycle. Various alternatives, including mass cytometry or linear unmixing, have been proposed to overcome and enhance the multiplexing capability, while they could not totally replace the conventional immunofluorescence technique due to its requirement of specialized equipment and high barrier to entry. Here we report a state-of-the-art multiplexed imaging technique, termed PICASSO, which can perform an unprecedented high multiplexing capability even with a conventional microscopy platform. PICASSO is mainly composed of three parts; 1. antibody complex preformation technique for multiple target staining without host issue, 2. acquiring spectrally mixed images at different spectral ranges, in which each channel included one of those fluorophores’ emission peaks, indicating the number of image acquisitions equal to the number of fluorophores, and 3. fluorescent signals unmixing via mutual information (MI) minimization algorithm. Fifteen-color multiplexed imaging has been experimentally demonstrated within a single staining and imaging cycle via PICASSO. As a cyclic staining method, we demonstrated that PICASSO enables more than 40-color imaging within 3 staining and imaging rounds. Moreover, we demonstrated multiplexed imaging of mouse brains using commercialized bandpass filter-based microscopy. Other than mouse brain samples, various formalin-fixed paraffin-embedded (FFPE) specimens (e.g., breast, kidney, bladder, colon, prostate, thymus, etc.) could be utilized for PICASSO unmixing demonstration, which infers the feasibility of PICASSO technique in various pathological studies in medicine. In addition, PICASSO can be applied to 3D multiplexed imaging, mRNA multiplexed imaging, and large-area multiplexed imaging. We anticipate that PICASSO will provide a new perspective in multiplexed imaging field with high accessibility in cancer research and promote how we see and understand the molecular profiles of tumors and their microenvironments. Acknowledgments: This work was supported by Samsung Research Funding & Incubation Center for Future Technology (SRFC-IT1702-09).

Citation Format: Junyoung Seo, Yeonbo Sim, Jeewon Kim, Hyunwoo Kim, In Cho, Hoyeon Nam, Young-Gyu Yoon, Jae-Byum Chang. PICASSO: Ultra-multiplexed imaging technique for spatial protein analysis of tumor microenvironments [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2457.

Fabrication of heterogeneous chemical patterns on stretchable hydrogels using single-photon lithography

Curved hydrogel surfaces bearing chemical patterns are highly desirable in various applications, including artificial blood vessels, wearable electronics, and soft robotics. However, previous studies on the fabrication of chemical patterns on hydrogels employed two-photon lithography, which is still not widely accessible to most laboratories. This work demonstrates a new patterning technique for fabricating curved hydrogels with chemical patterns on their surfaces without two-photon microscopy. In this work, we show that exposing hydrogels in fluorophore solutions to single photons via confocal microscopy enables the patterning of fluorophores on hydrogels. By applying this technique to highly stretchable hydrogels, we demonstrate three applications: (1) improving pattern resolution by fabricating patterns on stretched hydrogels and then returning the hydrogels to their initial, unstretched length; (2) modifying the local stretchability of hydrogels at a microscale resolution; and (3) fabricating perfusable microchannels with chemical patterns by winding chemically patterned hydrogels around a template, embedding the hydrogels in a second hydrogel, and then removing the template. The patterning method demonstrated in this work may facilitate a better mimicking of the physicochemical properties of organs in tissue engineering and may be used to make hydrogel robots with specific chemical functionalities.

FRACTAL: Signal amplification of immunofluorescence via cyclic staining of target molecules

In this article, we demonstrate fluorescent signal amplification via cyclic staining of target molecules (FRACTAL), a technique that can amplify the signal intensity of immunofluorescence staining more than nine-fold via simple cyclic staining of secondary antibodies. We also show that FRACTAL is compatible with four-color imaging and expansion microscopy imaging.

Super-Resolution Three-Dimensional Imaging of Actin Filaments in Cultured Cells and the Brain via Expansion Microscopy

Actin is an essential protein in almost all life forms. It mediates diverse biological functions, ranging from controlling the shape of cells and cell movements to cargo transport and the formation of synaptic connections. Multiple diseases are closely related to the dysfunction of actin or actin-related proteins. Despite the biological importance of actin, super-resolution imaging of it in tissue is still challenging, as it forms very dense networks in almost all cells inside the tissue. In this work, we demonstrate multiplexed super-resolution volumetric imaging of actin in both cultured cells and mouse brain slices via expansion microscopy (ExM). By introducing a simple labeling process, which enables the anchoring of an actin probe, phalloidin, to a swellable hydrogel, the multiplexed ExM imaging of actin filaments was achieved. We first showed that this technique could visualize the nanoscale details of actin filament organizations in cultured cells. Then, we applied this technique to mouse brain slices and visualized diverse actin organizations, such as the parallel actin filaments along the long axis of dendrites and dense actin structures in postsynaptic spines. We examined the postsynaptic spines in the mouse brain and showed that the organizations of actin filaments are highly diverse. This technique, which enables the high-throughput 60 nm resolution imaging of actin filaments and other proteins in cultured cells and thick tissue slices, would be a useful tool to study the organization of actin filaments in diverse biological circumstances and how they change under pathological conditions.

Expansion microscopy imaging of various neuronal structures

Visualization of the spatial distribution of biomolecules with nanoscale precision is essential to understanding the molecular mechanisms of biological phenomena and diseases. Among several state-of-the-art visualization techniques, expansion microscopy (ExM) is an attractive tool, as it can achieve sub-20-nm resolution imaging of biological specimens, even with conventional diffraction-limited microscopy. This chapter first introduces the concept of ExM and its variants and then provides practical guidelines for implementing expansion microscopy and related techniques.

Directed self-assembly of a two-state block copolymer system

In this work, ladder-shaped block copolymer structures consisting of parallel bars, bends, and T-junctions are formed inside square confinement. We define binary states by the two degenerate alignment orientations, and study properties of the two-state system. We control the binary states by creating openings around the confinement, changing the confinement geometry, or placing lithographic guiding patterns inside the confinement. Self-consistent field theory simulations show templating effect from the wall openings and reproduce the experimental results. We demonstrate scaling of a single binary state into a larger binary state array with individual binary state control.

[The surgical treatment in adults with idiopathic normal pressure hydrocephalus]

Objective: To investigate the effect of Ventriculoperitoneal shunt (VPS)in adult patients with idiopathic normal pressure hydrocephalus (iNPH). Methods: The patients with idiopathic normal pressure hydrocephalus were reviewed, who were admitted into the Peking union medical college hospital from October 2010 to October 2016.The patients treated via VPS were retrospectively analyzed by collecting the data including clinic features, iNPH score and imaging data. Results: 33 patients were included in the group.3 months after operation, the iNPH scores were significantly decreased (3.0±1.0 vs 6.0±2.5, P<0.01), and there were no difference among 3 month, 6 month and 12 month post operation.The Evans index and the width of the three ventricles were also significantly decreased.1 patient suffered from subdural hematoma and no other complications such as infection, obstruction or death occurred. Conclusions: VPS is an effective treatment approach of iNPH and multidisciplinary team is the key in diagnosis.

Feasibility of 3D Reconstruction of Neural Morphology Using Expansion Microscopy and Barcode-Guided Agglomeration

We here introduce and study the properties, via computer simulation, of a candidate automated approach to algorithmic reconstruction of dense neural morphology, based on simulated data of the kind that would be obtained via two emerging molecular technologies-expansion microscopy (ExM) and in-situ molecular barcoding. We utilize a convolutional neural network to detect neuronal boundaries from protein-tagged plasma membrane images obtained via ExM, as well as a subsequent supervoxel-merging pipeline guided by optical readout of information-rich, cell-specific nucleic acid barcodes. We attempt to use conservative imaging and labeling parameters, with the goal of establishing a baseline case that points to the potential feasibility of optical circuit reconstruction, leaving open the possibility of higher-performance labeling technologies and algorithms. We find that, even with these conservative assumptions, an all-optical approach to dense neural morphology reconstruction may be possible via the proposed algorithmic framework. Future work should explore both the design-space of chemical labels and barcodes, as well as algorithms, to ultimately enable routine, high-performance optical circuit reconstruction.

[The diagnosis and treatment of systemic lupus erythematosus complicated with hydrocephalus]

Objective: To investigate the pathogenesis and management of the hydrocephalus in patients with systemic lupus erythematosus (SLE). Methods: Eight cases of hospitalized lupus patients with hydrocephalus in Peking Union Medical College Hospital from Jan 1990 to Mar 2017 were analyzed retrospectively.We collected the patients' medical records including medical history, CT and/or MRI images and analysis of cerebrospinal fluid via lumbar puncture in order to investigate the pathogenesis of the hydrocephalus in patients with SLE and summarize treatment experience. Results: All the 8 patients with SLE complicated with hydrocephalus were treated with steroids or immunosuppressive agents, and 5 cases were diagnosed with the central nervous system infection. Three cases received ventriculoperitoneal shunt, 5 cases received treatment of medicine.They all were followed up for 2-12 months, of which 3 cases were markedly effective, 1 case effective and 4 cases dead. Conclusion: The pathogenesis of lupus combined with hydrocephalus may have a certain relationship with the central infection, should take effective anti-infection treatment.We recommend cerebrospinal fluid shunt surgery intervention.

Nanoscale imaging of RNA with expansion microscopy

The ability to image RNA identity and location with nanoscale precision in intact tissues is of great interest for defining cell types and states in normal and pathological biological settings. Here, we present a strategy for expansion microscopy of RNA. We developed a small-molecule linker that enables RNA to be covalently attached to a swellable polyelectrolyte gel synthesized throughout a biological specimen. Then, postexpansion, fluorescent in situ hybridization (FISH) imaging of RNA can be performed with high yield and specificity as well as single-molecule precision in both cultured cells and intact brain tissue. Expansion FISH (ExFISH) separates RNAs and supports amplification of single-molecule signals (i.e., via hybridization chain reaction) as well as multiplexed RNA FISH readout. ExFISH thus enables super-resolution imaging of RNA structure and location with diffraction-limited microscopes in thick specimens, such as intact brain tissue and other tissues of importance to biology and medicine.

Hybrid Microscopy: Enabling Inexpensive High-Performance Imaging through Combined Physical and Optical Magnifications

To date, much effort has been expended on making high-performance microscopes through better instrumentation. Recently, it was discovered that physical magnification of specimens was possible, through a technique called expansion microscopy (ExM), raising the question of whether physical magnification, coupled to inexpensive optics, could together match the performance of high-end optical equipment, at a tiny fraction of the price. Here we show that such "hybrid microscopy" methods--combining physical and optical magnifications--can indeed achieve high performance at low cost. By physically magnifying objects, then imaging them on cheap miniature fluorescence microscopes ("mini-microscopes"), it is possible to image at a resolution comparable to that previously attainable only with benchtop microscopes that present costs orders of magnitude higher. We believe that this unprecedented hybrid technology that combines expansion microscopy, based on physical magnification, and mini-microscopy, relying on conventional optics--a process we refer to as Expansion Mini-Microscopy (ExMM)--is a highly promising alternative method for performing cost-effective, high-resolution imaging of biological samples. With further advancement of the technology, we believe that ExMM will find widespread applications for high-resolution imaging particularly in research and healthcare scenarios in undeveloped countries or remote places.

The Orientations of Large Aspect-Ratio Coiled-Coil Proteins Attached to Gold Nanostructures

Methods for patterning biomolecules on a substrate at the single molecule level have been studied as a route to sensors with single-molecular sensitivity or as a way to probe biological phenomena at the single-molecule level. However, the arrangement and orientation of single biomolecules on substrates has been less investigated. Here, the arrangement and orientation of two rod-like coiled-coil proteins, cortexillin and tropomyosin, around patterned gold nanostructures is examined. The high aspect ratio of the coiled coils makes it possible to study their orientations and to pursue a strategy of protein orientation via two-point attachment. The proteins are anchored to the surfaces using thiol groups, and the number of cysteine residues in tropomyosin is varied to test how this variation affects the structure and arrangement of the surface-attached proteins. Molecular dynamics studies are used to interpret the observed positional distributions. Based on initial studies of protein attachment to gold post structures, two 31-nm-long tropomyosin molecules are aligned between the two sidewalls of a trench with a width of 68 nm. Because the approach presented in this study uses one of twenty natural amino acids, this method provides a convenient way to pattern biomolecules on substrates using standard chemistry.

Two-Dimensional Nanoparticle Supracrystals: A Model System for Two-Dimensional Melting

In a Langmuir trough, successive compression cycles can drive a two-dimensional (2D) nanoparticle supracrystal (NPSC) closer to its equilibrium structure. Here, we show a series of equilibrated 2D NPSCs consisting of gold NPs of uniform size, varying solely in the length of their alkanethiol ligands. The ordering of the NPSC is governed by the ligand length, thus providing a model system to investigate the nature of 2D melting in a system of NPs. As the ligand length increases the supracrystal transitions from a crystalline to a liquid-like phase with evidence of a hexatic phase at an intermediate ligand length. The phase change is interpreted as an entropy-driven phenomenon associated with steric constraints between ligand shells. The density of topological defects scales with ligand length, suggesting an equivalence between ligand length and temperature in terms of melting behavior. On the basis of this equivalence, the experimental evidence indicates a two-stage 2D melting of NPSCs.

Three-dimensional nanofabrication by block copolymer self-assembly

Thin films of block copolymers are widely seen as enablers for nanoscale fabrication of semiconductor devices, membranes, and other structures, taking advantage of microphase separation to produce well-organized nanostructures with periods of a few nm and above. However, the inherently three-dimensional structure of block copolymer microdomains could enable them to make 3D devices and structures directly, which could lead to efficient fabrication of complex heterogeneous structures. This article reviews recent progress in developing 3D nanofabrication processes based on block copolymers.

Aligned sub-10-nm block copolymer patterns templated by post arrays

Self-assembly of block copolymer films can generate useful periodic nanopatterns, but the self-assembly needs to be templated to impose long-range order and to control pattern registration with other substrate features. We demonstrate here the fabrication of aligned sub-10-nm line width patterns with a controlled orientation by using lithographically formed post arrays as templates for a 16 kg/mol poly(styrene-block-dimethylsiloxane) (PS-b-PDMS) diblock copolymer. The in-plane orientation of the block copolymer cylinders was controlled by varying the spacing and geometry of the posts, and the results were modeled using 3D self-consistent field theory. This work illustrates how arrays of narrow lines with specific in-plane orientation can be produced, and how the post height and diameter affect the self-assembly.

Assembly of sub-10-nm block copolymer patterns with mixed morphology and period using electron irradiation and solvent annealing

Block copolymer self-assembly generates patterns with periodicity in the ∼10-100 nm range and is increasingly recognized as a route to lithographic patterning beyond the resolution of photolithography. Block copolymers naturally produce periodic patterns with a morphology and length-scale determined by the molecular architecture, and considerable research has been carried out to extend the range of patterns that can be produced from a given block copolymer, but the ability to control the period of the pattern over a wide range and to achieve complex structures with mixed morphologies from a given block copolymer is limited. Here we show how patterns consisting of coexisting sub-10-nm spheres and cylinders and sphere patterns with a range of periods can be created using a combination of serial solvent anneal processes and electron-beam irradiation of selected areas of a film of poly(styrene-block-dimethylsiloxane). These techniques extend the capabilities of block copolymer lithography, enabling complex aperiodic nanoscale patterns to be formed from a single block copolymer thin film.

Highly ordered square arrays from a templated ABC triblock terpolymer

Square-symmetry patterns are of interest in nanolithography but are not easily obtained from self-assembly of a diblock copolymer. Instead, we demonstrate highly ordered 44 nm period square patterns formed in a thin film of polyisoprene-block-polystyrene-block-polyferrocenylsilane (PI-b-PS-b-PFS) triblock terpolymer blended with 15% PS homopolymer by controlling the film thickness, solvent anneal conditions, the surface chemistry and topography of the substrates. The square patterns consist of PFS pillars that remained after removal of the PI and PS with an oxygen plasma. On an unpatterned smooth substrate, the average grain size of the square pattern was increased dramatically to several micrometers by the use of brush layers and specific solvent anneal conditions. Templated self-assembly of well-ordered square patterns was demonstrated on substrates containing nanoscale topographical sidewalls and posts, written by electron beam lithography, in which the sidewalls and base of the substrate were independently chemically functionalized.

Sub-10 nm structures on silicon by thermal dewetting of platinum

A study of the dewetting behavior of platinum-thin-films on silicon was carried out to determine how variation of dewetting parameters affects the evolution of film morphology and to pinpoint which parameters yielded the smallest, most circular features. Platinum film thickness as well as dewetting time and temperature were varied and the film morphology characterized by means of scanning electron microscopy (SEM) analysis. Two different pathways of dewetting predicted in the literature (Vrij 1966 Discuss. Faraday Soc. 42 23, Becker et al 2003 Nat. Mater. 2 59-63) were observed. Depending on the initial criteria, restructuring of the film occurred via hole or droplet formation. With increased annealing time, a transition from an intermediate network structure to separated islands occurred. In addition, the formation of multilayered films, silicide crystals and nanowires occurred for certain parameters. Nevertheless, the dewetting behavior witnessed could be related to physical processes. Droplets with a mean diameter of 9 nm were formed by using a 1.5 nm thick platinum film annealed at 800 °C for 30 s. To demonstrate the suitability of the annealed films for further processing, we then used the dewetted films as masks for reactive ion etching to transfer the pattern into the silicon substrate, forming tapered nanopillars.

Complex self-assembled patterns using sparse commensurate templates with locally varying motifs

Templated self-assembly of block copolymer thin films can generate periodic arrays of microdomains within a sparse template, or complex patterns using 1:1 templates. However, arbitrary pattern generation directed by sparse templates remains elusive. Here, we show that an array of carefully spaced and shaped posts, prepared by electron-beam patterning of an inorganic resist, can be used to template complex patterns in a cylindrical-morphology block copolymer. We use two distinct methods: making the post spacing commensurate with the equilibrium periodicity of the polymer, which controls the orientation of the linear features, and making local changes to the shape or distribution of the posts, which direct the formation of bends, junctions and other aperiodic features in specific locations. The first of these methods permits linear patterns to be directed by a sparse template that occupies only a few percent of the area of the final self-assembled pattern, while the second method can be used to selectively and locally template complex linear patterns.

A path to ultranarrow patterns using self-assembled lithography

The templated self-assembly of block copolymer (BCP) thin films can generate regular arrays of 10-50 nm scale features with good positional and orientational accuracy, but the ordering, registration and pattern transfer of sub-10-nm feature sizes is not well established. Here, we report solvent-annealing and templating methods that enable the formation of highly ordered grating patterns with a line width of 8 nm and period 17 nm from a self-assembled poly(styrene-b-dimethylsiloxane) (PS-PDMS) diblock copolymer. The BCP patterns can be registered hierarchically on a larger-period BCP pattern, which can potentially diversify the available pattern geometries and enables precise pattern registration at small feature sizes. Sub-10-nm-wide tungsten nanowires with excellent order and uniformity were fabricated from the self-assembled patterns using a reactive ion etching process.

ApoEε4 allele is associated with incidental hallucinations and delusions in patients with AD

Of 135 patients with Alzheimer disease (AD), 56 without psychiatric symptoms at the first visit were followed for a mean period of 51.9 +/- 10.3 months to identify incident psychiatric symptoms. The hazard ratios of ApoE epsilon4 allele in developing psychiatric symptoms were calculated by Cox regression hazard analyses. The presence of the ApoE epsilon4 allele carried a 19.0-fold risk for developing hallucinations and a 3.4-fold risk for delusions.

Determinants and distributions of plasma total homocysteine concentrations among school children in Taiwan

BACKGROUND

Plasma total homocysteine (tHcy) level is an independent risk factor for cardiovascular disease (CVD) even among children. The purpose of this study is to evaluate the determinants and distributions of plasma tHcy levels and the relationship between plasma tHcy, folate and vitamin B12 levels among school children in Taipei.

METHODS

After multi-stage sampling, we randomly selected 1234 school children (609 boys and 625 girls) with the mean age of 13 years (from 12 to 15 years) in this study. Fasting plasma tHcy levels were measured using an ABBOTT IMx analyzer (Axis Biochemicals ASA, Oslo, Norway). Plasma folate and vitamin B12 levels were measured by ACS:180 automated chemiluminescence analyzer (Bayer, Tarrytown, NY, USA).

RESULTS

The distribution of plasma tHcy levels were skewed to the right with the mean values of 10.50 and 8.95 micromol/l and medians of 9.67 and 8.474 micromol/l for boys and girls, respectively. Plasma tHcy concentrations were lower in younger children and progressively increased with increasing age. Boys had significantly higher plasma tHcy levels than girls (10.50 +/- 4.134 vs. 8.95 +/- 2.61 micromol/l, p < 0.01) and lower plasma folate levels (6.05 +/- 2.85 vs. 6.39 +/- 2.58 nmol/l, p < 0.01), and vitamin B12 levels (444.8 +/- 158.4 vs. 495.0 +/- 181.5 pmol/l, p < 0.001). Plasma tHcy levels were significantly positively associated with anthropometric measures in boys; but these characteristics attenuated and became insignificant after adjusting for other potential confounders in girls. Plasma tHcy levels were negatively associated with plasma folate and vitamin B12 levels even after adjusting for BMI and other potential confounders in both genders.

CONCLUSIONS

From this study, the distributions of tHcy levels were skewed to the right and the boys had higher plasma tHcy levels than girls. Plasma tHcy levels were significantly positively associated with BMI among boys. Further studies are needed to evaluate the relationship between tHcy and CVD risk factors among children for the better prevention of heart disease in early life.

The effect of surgical stress on insulin sensitivity, glucose effectiveness and acute insulin response to glucose load

Hyperglycemia after stress is a very common clinical phenomenon. It is generally hypothesized that the underlying cause is a neuroendocrine-mediated deterioration in glucose metabolism. However, the detailed roles of insulin sensitivity, glucose effectiveness and acute insulin response to glucose load in response to stress have not been well established. Hernioplasty was used as a minor stress model for studying stress-induced hyperglycemia. Eleven healthy young men were enrolled voluntarily in this study. Their mean age was 22.0 +/- 0.9 yr and BMI 23.3 +/- 0.6 kg/m2. Frequently sampled i.v. glucose tolerance tests were performed one day before and one day after the surgery. Insulin sensitivity (SI), glucose effectiveness (EG) and area under acute insulin response (AIR) were calculated from "minimal model" algorithms. We also measured fasting concentrations of human GH, ACTH and F on the days of the test. Compared to the pre-operation data, levels of ACTH and F did not change significantly after the surgery. Only GH levels were marginally significant. On the other hand, the SI (0.75 +/- 0.1, 0.52 +/- 0.9 x 10(-5) min(-1)/pmol, p = 0.04), EG (0.023 +/- 0.03, 0.016 +/- 0.003 min(-1), p = 0.01) and AIR (6738.5 +/- 1111.6, 5130.0 +/- 1047.2 pmol, p = 0.005) were all significantly decreased after surgery. The percentages of decrease were 16.3 +/- 15.5, 32.1 +/- 10.3 and 17.8 +/- 10.3%, respectively. Finally, only the changes of EG positively correlate with the changes of ACTH before and after surgery. No significant changes were noted among other stress hormones and the changes of SI, EG and AIR. In conclusion, hernioplasty results in reduced SI, EG and AIR. Among them, although not statistically significant, the EG showed the most distinct decrease after the surgery, which has not been found in previous literature.

Spread of 60Co contaminated steel and its legal consequences in Taiwan

Since 1992, over 200 civilian residential and school buildings in Taiwan have been identified to have contained 60Co contaminated steel rebar emitting excessive gamma-radioactivity in living environments. These buildings were mostly constructed in early 1983 and 1984 by employing steels from one steel mill, which had recycled unknown 60Co orphan sources in northern Taiwan. In 1994, a group of residents who once stayed for a protracted period up to 10 y in the contaminated Ming-Sheng Villa filed a civil action against Taiwan's nuclear regulatory office, the Atomic Energy Council, for state tort compensation of 3.4 M U.S. dollars in equivalent. After three years of court processes, the Taipei District Court handed down a decision in partial favor of the exposed residents. Both parties soon appealed against this judgment to the Taiwan Appellate Court. This article analyzes the main legal issues involved, including government's obligations to prevent and eliminate contamination, to take preventive measures, and to take necessary remedial measures; and plaintiffs' assertion on any legal right against governmental offices. Moreover, discussion issues contain the scope of damage and compensation, causation analysis, absence of effective and efficient regulation over radioactive contamination, limit of tort compensation law and compensation amount, weight of medical evidence as well as role of expert witnesses, and related comparative legal studies.

Infrainguinal revascularizations in octogenarians and septuagenarians

OBJECTIVE

Severe atherosclerosis is a major contributor for death in octogenarians and a cause of multiple vascular-related ailments, including claudication and limb loss. Advanced age and health may limit the success of limb-salvaging procedures. Mortality, morbidity, and outcome of infrainguinal grafts have been examined in octogenarians and septuagenarians.

METHODS

After 128 femoropopliteal and 99 femorotibial bypass grafts in 209 octogenarians and 242 femoropopliteal and 166 femorotibial bypass grafts in 383 septuagenarians, survival, primary patency, limb salvage, myocardial infarction and stroke rates were determined. The survival, myocardial infarction, and stroke rates of controls, 1514 octogenarians and 2011 septuagenarians, were compared.

RESULTS

After a bypass graft, 5-year survival of octogenarians (54%) and septuagenarians (64%) was similar (P >.2) and was 89% and 89% for controls. The 5-year primary patency rates were 74% for octogenarians and 68% for septuagenarians (P >.2). Five-year limb salvage rates were 86% for octogenarians and 86% for septuagenarians. After a bypass graft, the respective rates of myocardial infarction were 4.1% and 3.9% per year and of a stroke 3.2% and 3.2% per year for octogenarians and septuagenarians, which occurred more frequently (P <.05) than in controls.

CONCLUSIONS

Death and cardiovascular events are higher after revascularization in octogenarians and septuagenarians, compared with controls, and are related to the severity of atherosclerosis and not age. Patency rates are excellent and similar. Limb salvage procedures should be considered for most octogenarians.

Relationship between single voided urine protein/creatinine ratio and 24-hour urine protein excretion rate among children and adolescents in Taiwan

BACKGROUND

As there have been few studies conducted on children or adolescents, the purpose of this study was evaluate the relationship between single voided urine protein/creatinine (Up/Ucr) ratio and 24-hour urine protein excretion rate (PER), especially among children and adolescents in Taiwan.

METHODS

After multistage random sampling, we collected 1,072 fasting single voided urine samples and 125 24-hour urine samples from seven- to 18-year-old students in Taiwan. We calculated the Up/Ucr of single voided urine samples and the 24-hour PER in urine.

RESULTS

The mean value and the 95th percentile of the fasting single voided urine Up/Ucr ratio were 0.118 and 0.235, respectively. The mean value and the 95th percentile of the 24-hour PER were 3.61 and 5.66 mg/h/m2, respectively. There was no significant difference in Up/Ucr ratio between boys and girls. Up/Ucr ratio decreased significantly as age increased. The fasting single voided Up/Ucr ratio was highly correlated with 24-hour PER, with r2 = 0.95 (p < 0.001).

CONCLUSIONS

Fasting single voided Up/Ucr ratio is a good marker of 24-hour PER. It is also a simple, easy, convenient and speedy method to measure Up excretion. The single voided Up/Ucr ratio may also serve as a reference for the clinical diagnosis of Up excretion among normal subjects.

[Direct optical resolution of acidic biphenyl drugs by high performance liquid chromatography on tris(3,5-dimethylphenylcarbamate) of cellulose]

A chiral stationary phase was prepared by coating cellulose-tris(3, 5-dimethylphenylcarbamate) onto aminopropylated silica gel. A series of enantiomeric acidic biphenyl drugs were directly resolved on the chiral stationary phase (CSP) by normal-phase high performance liquid chromatography (HPLC). A hexane-2-propanol eluting system containing 1% of trifluoroacetic acid was used as mobile phase. Efficient optical resolution of the acidic biphenyl drugs has been attained. The factors that influence chiral discrimination such as structural characeristic of the samples and mobile phase were investigated. An interaction model between the stationary phase and the samples was discussed. The results showed that efficient optical resolution of racemic carboxylic acids could be attained by normal-phase HPLC on CSP using a hexane-2-propanol eluting system containing 1% of trifluoroacetic acid.

[Analysis of imidacloprid and damanlin by high performance liquid chromatography]

A new method for determination of imidacloprid and damanlin by using HPLC was established. It was carried out on a mu Bondapak C18 column (3.9 mm i.d. x 300 mm) with ACN-MeOH-H2O (60:10:30, V/V) as eluent and detected at 240 nm using photodiode array detector. The results of imidacloprid and damanlin were 3.71% and 15.65% respectively. The standard deviations for imidacloprid and damanlin were 0.88% and 0.76% respectively.

Lipoprotein profiles, not anthropometric measures, correlate with serum lipoprotein(a) values in children: the Taipei children heart study

OBJECTIVE

Plasma lipoprotein(a) [Lp(a)] is a risk factor for cardiovascular disease. The purpose of this study is to evaluate the correlation of anthropometric measures, lipids and lipoprotein profiles and serum Lp(a) values among children in Taiwan. We will attempt to find parameters that will be able to predict Lp(a) levels in children.

DESIGN AND METHODS

After a probability-proportional-to size, multi-stages sampling procedure, we randomly sampled 1500 schoolchildren from 10 schools in Taipei city. Anthropometric measures including body weight, body height, waist and hip circumference and skinfolds were measured. We used standard methods to measure serum total cholesterol (CHOL), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), apolipoprotein A1 and B (ApoA1 and ApoB) and Lp(a) levels. We also calculated low density lipoprotein-cholesterol (LDL-C) and CHOL HDL-C ratio (TCHR) by formula.

RESULTS

We sampled 1283 children (635 boys and 648 girls) with a mean age of 13.3 years (from 12 to 16 years) in this study. The mean and medium serum Lp(a) levels were 16.8 and 8.8 mg/dl among boys and 20.8 and 11.9 mg/dl among girls. Children in the highest quintile of Lp(a) (mean = 49.6 and 58.6 mg/dl for boys and girls, respectively) had higher CHOL, LDL-C, ApoB levels and TCHR than children in the lowest quintile (mean = 3.1 and 3.7 mg/dl for boys and girls, respectively). Lipids and lipoprotein profiles, such as CHOL, LDL-C, Apo-B and TCHR were positively correlated with Lp(a) levels in both genders. Furthermore, the children with Lp(a) levels greater than or equal to 30 mg/dl had higher CHOL, LDL-C and Apo-B levels when compared to children with Lp(a) levels less than 30 mg/dl. After adjusting for age, cigarette smoking, alcohol drinking, puberty development and heart rates, LDL-C and ApoB levels were significantly positively associated with Lp(a) levels while ApoA1 was negatively associated among boys. Among girls, only Apo-B was significantly positively associated with Lp(a) and TG was negatively associated with Lp(a) levels. Most importantly, none of the anthropometric measures were significantly correlated with Lp(a) levels.

CONCLUSIONS

From this study, we found that lipids and lipoproteins profiles, rather than degree of adiposity as reflected by anthropometric measures, are significantly associated with serum Lp(a) levels among school children.

Management of Carotid Artery Stenosis: A Review

Carotid endarterectomy clearly benefits high stroke-risk patients, but its value for asymptomatic patients is still being debated. If a high exposure is necessary for redo procedures or distal aneurysms, mandibular subluxation and styloidectomy may be required. Perioperative mortality and morbidity are acceptably low. Restenosis occurs in few patients.http://link.springer-ny.com/link/service/journals/00547/bibs/8n3p139.html