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In view of recent advancements in HIV prevention and care for men who have sex with men (MSM) during the COVID-19 outbreak, the study conducted a literature review to comprehend how restriction-related interventions to minimize Coronavirus illness effect sexual behavior change among MSM, access to HIV services, and mental health and clinical health outcomes among MSM. The findings indicate that MSM populations altered their sexual behavior throughout the pandemic, including a drop in the number of sexual partners and sexual activities, but an unmet requirement for condom use. HIV services were impacted during COVID-19, in addition to behavioral and structural interventions. Overburdened public health systems are forcing resources to be diverted to pandemic treatment, with plans to suspend related HIV services to reduce population infections. Additionally, the MSM's need for self-protection and obstacles to engaging in sexual relations are considerations. Poor psychological and clinical outcomes among MSM, particularly those with HIV, are dramatically worsened. The results also imply that telemedicine interventions should be implemented for MSM populations during this disease to address the burden of the services for HIV and continuity of care. Further investigation is needed to determine how sexual behavior, HIV treatment, and service interruptions affect MSM's psychological and physical health.

DNA computing has gained considerable attention due to the characteristics of high-density information storage and high parallel computing for solving computational problems. Building addressable logic gates with biomolecules is the basis for establishing biological computers. In the current calculation model, the multiinput AND operation often needs to be realized through a multilevel cascade between logic gates. Through experiments, it was found that the multilevel cascade causes signal leakage and affects the stability of the system. Using DNA strand displacement technology, we constructed a domino-like multiinput AND gate computing system instead of a cascade of operations, realizing multiinput AND computing on one logic gate and abandoning the traditional multilevel cascade of operations. Fluorescence experiments demonstrated that our methods significantly reduce system construction costs and improve the stability and robustness of the system. Finally, we proved stability and robustness of the domino AND gate by simulating the tic-tac-toe process with a massively parallel computing strategy.

DNA molecules have been used as novel computing tools, by which Synthetic DNA was designed to execute computing processes with a programmable sequence. Here, we proposed a parallel computing method using DNA origamis as agents to solve the three-color problem, an example of the graph problem. Each agent was fabricated with a DNA origami of ∼50 nm diameter and contained DNA probes with programmable sticky ends that execute preset computing processes. With the interaction of different nanoagents, DNA molecules self-assemble into spatial nanostructures, which embody the computation results of the three-color problem with polynomial numbers of computing nanoagents in a one-pot annealing step. The computing results were confirmed by atomic force microscopy. Our method is completely different from existing DNA computing methods in its computing algorithm, and it has an advantage in terms of computational complexity and results detection for solving graph problems.

DNA origami can be applied as a "ruler" for nanoscale calibration or super-resolution fluorescence microscopy with an ideal structure for defining fluorophore arrangement, allowing the distance between fluorophores to be precisely controlled at the nanometer scale. DNA origami can also be used as a nanotag with arbitrary programmable shapes for topological identification. In this study, we formed a hexagonal origami structure embedded with three different fluorescent dyes on the surface. The distance between each fluorescent block was ~120 nm, which is below the diffraction limit of light, allowing for its application as a nano-ruler for super-resolution fluorescence microscopy. The outside edge of the hexagonal structure was redesigned to form three different substructures as topological labels. Atomic and scanning force microscopy demonstrated the consistent nanoscale distance between morphological and fluorescent labels. Therefore, this fluorophore-embedded hexagonal origami platform can be used as a dual nanoruler for optical and topological calibration.

Interactive news recommendation has been launched and attracted much attention recently. In this scenario, user's behavior evolves from single click behavior to multiple behaviors including like, comment, share etc. However, most of the existing methods still use single click behavior as the unique criterion of judging user's preferences. Further, although heterogeneous graphs have been applied in different areas, a proper way to construct a heterogeneous graph for interactive news data with an appropriate learning mechanism on it is still desired. To address the above concerns, we propose a graph-based behavior-aware network, which simultaneously considers six different types of behaviors as well as user's demand on the news diversity. We have three main steps. First, we build an interaction behavior graph for multi-level and multi-category data. Second, we apply DeepWalk on the behavior graph to obtain entity semantics, then build a graph-based convolutional neural network called G-CNN to learn news representations, and an attention-based LSTM to learn behavior sequence representations. Third, we introduce core and coritivity features for the behavior graph, which measure the concentration degree of user's interests. These features affect the trade-off between accuracy and diversity of our personalized recommendation system. Taking these features into account, our system finally achieves recommending news to different users at their different levels of concentration degrees., 18 pages

Conflicting findings have been reported concerning the survival of patients treated with limb salvage and amputation for osteosarcoma. This study aimed to identify predictors associated with surgery types and survival difference. Patients with osteosarcoma were selected from the Surveillance Epidemiology and End Results database (1975–2016). Multivariable logistic regression analysis was conducted, and a nomogram was further established. Propensity score matching (PSM)-adjusted Kaplan–Meier curves, log-rank tests, Cox proportional hazards regression analysis were performed to compare overall survival (OS) and cancer-specific survival (CSS). Among 3363 patients with osteosarcoma, 2447 and 916 underwent limb salvage and amputation. Predictors associated with amputation in the nomogram included age, gender, primary tumor site, tumor grade, tumor stage, tumor size and radiotherapy. Totally 900 pairs of patients treated with limb salvage and amputation were matched after PSM. Limb salvage was significantly associated with improved OS (HR, 0.773; 95% CI, 0.670–0.892; p

A new method, namely DNA strand displacement (DSD), has recently emerged in the field of biocomputing. DSD uses the toehold domain as a starting point to cover the strand in the migration domain. In this study, a molecular full adder composed of a molecular basic logic gate, including AND and XOR logic gates, is constructed based on strand displacement and Visual DSD. We used Visual DSD to simulate the molecular full adder. The experimental results show that the molecular full adder can be used for addition logic calculation. In addition, it can realize multi-bit addition logic calculation through a multi-stage cascade reaction. The simulation results verified the efficiency and reliability of our multi-bit molecular full adder, and our method can be used to design complex DNA integrated circuits. This research will lay the foundation for the formation of more complex molecular logic circuit structures and functions, as well as provide new coding ideas for various biocomputing related fields.

Since the discovery of the DNA Strand Displacement mechanism, researchers have implemented a lot of applications, such as DNA computing, DNA Circuits, Logic gates, and Chemical Reaction network. To achieve those functions, a well-designed system is essential, among which the toehold domains and migration domains play a vital role. In this paper, we designed three basic logic gates based on the toehold mediates DNA strand displacement mechanism, and utilized them to struct a three-layer multiplexer DNA logic circuit. However, the traditional INHIBIT gate annihilated all the inputs strands which obscure the multiplexer in further applications. Therefore, we improved the INHIBIT gate, so the desired input strand can be selected, and the corresponding output strand can be identified. Lastly, we adjusted the multiplexer and realized a cyclic DNA circuit. The simulation results verified the efficiency and reliability of our multiplexer DNA logic circuits. Our method has the ability in architecting complex DNA integrated circuits.

DNA, as an excellent nano-engineering material, contributes to a new computing model, namely, DNA computing. This model is a type of biological computing, which takes advantage of the high density and high parallelism of molecules. One of the current methods of implementing DNA computing is to construct DNA circuits, among which the toehold-mediated DNA strand displacement technique is an important method. The hybridization of toehold domains provides the start position and accelerates the branch migration process. Toehold-based DNA combinatorial displacement is a practical method for designing and implementing DNA circuits. In this paper, we designed and simulated a multiplexer using the DNA combinatorial displacement mechanism to verify its practicability. Additionally, we improved and optimized the existing logic INHIBIT gate by leveraging the DNA combinatorial displacement mechanism so that the DNA strands in the entire chemical reaction network (CRN) system are capable of coexisting in large quantities. Moreover, we applied this improvement to the demultiplexer. Our method provides more capabilities to larger and more complicated DNA integrated circuits.

DNA molecular as the material for logical computing and information storage has been widely applied. An important mechanism for DNA logical computing is the toehold-mediated DNA Strand Displacement (DSD). Researchers have used the DSD mechanism and designed various DNA circuits to perform logical computing processes. However, the logy reaction speed in some logic gates limited the speed of response, the output response is not sensitive enough. Therefore, no output response is often misjudged to logic “0”, high output response is not accurate to logic “1”. In this paper, we proposed a highly creditable step function gate, which consists of a step function module and a threshold module. The output signal in this proposed gate is highly sensitive and accurate to logic “0” & “1”. The proposed gate can recognize the difference between “no input” and “low input”. Besides, we built the OR, AND, NOT, XOR circuits by the proposed step function gate, and the simulation results are highly supported.

We combined two types of DNA SSTs with DNA origami to develop a different approach to assemble a filled nanostructure with predesigned shapes. SSTs will assemble to a desired rigid shape after they fill within a thin border.

Nanoscale structures demonstrate considerable potential utility in the construction of nanorobots, nanomachines, and many other devices. In this study, a hexagonal DNA origami ring was assembled and visualized via atomic force microscopy. The DNA origami shape could be programmed into either a hexagonal or linear shape with an open or folded pattern. The flexible origami was robust and switchable for dynamic pattern recognition. Its edges were folded by six bundles of DNA helices, which could be opened or folded in a honeycomb shape. Additionally, the edges were programmed into a concave-convex pattern, which enabled linkage between the origami and dipolymers. Furthermore, biotin-streptavidin labels were embedded at each edge for nanoscale calibration. The atomic force microscopy results demonstrated the stability and high-yield of the flexible DNA origami ring. The polymorphous nanostructure is useful for dynamic nano-construction and calibration of structural probes or sensors.

Background: DNA origami can be applied as a “ruler” for nanoscale calibration or super-resolution fluorescence microscopy with an ideal structure for defining fluorophore arrangement, allowing the distance between fluorophores to be precisely controlled at the nanometer scale. DNA origami can also be used as a nanotag with arbitrary programmable shapes. Result: We formed a hexagonal origami structure embedded with three different fluorescent dyes on the surface. The distance between each fluorescent block was ~120 nm, which is below the diffraction limit of light, allowing for its application as a nano-ruler for super-resolution fluorescence microscopy. The outside edge of the hexagonal structure was redesigned to form three different substructures as topological labels. Atomic and scanning force microscopy demonstrated consistency of the nanoscale distance between morphological and fluorescent labels. Conclusion: We assembled the hexagonal origami platform and confirmed the fluorescent and topological lables, this fluorophore-embedded hexagonal origami platform can be used as a dual nano-ruler for both optical and topological calibration.

Self-assembled DNA nanostructures significantly contribute to DNA nanotechnology. Algorithmic guiding of the assembly of DNA arrays remains a challenge in nanoarchitecture. Usually, the more sophisticated a DNA nanoarchitecture, the more DNA connections with specific sequences are required. This study aimed to investigate the feasibility of using the minimum pairs of DNA connection strands to implement algorithm-based self-assembly with finite DNA origamis. We found that the DNA origami linking complexity was markedly reduced. By rotating and turning the origami tile in different linking directions, we obtained 2 × 2 arrays of DNA origamis using a pair of DNA connections, 2 × 4 arrays using two pairs of DNA connections, and 4 × 4 arrays using three pairs of connection strands. We further analysed the effects of distortion on array formation. Overall, this study presents a hierarchical assembly strategy with minimal connections to generate multi-scale DNA arrays.

DNA origami is a powerful tool in nanotechnology that can be used to construct arbitrary structures for several nanoengineering applications. Generally, the more complex and sophisticated the construction, the greater is the number of origamis and connection strands that will be needed. Therefore, developing an effective and low-cost method for multiform DNA architecture is important in nanoengineering. Here, we adopted an oblique linking strategy to connect cross-shaped DNA origami with a controlled curing angle. The size of the DNA rings ranged from four blocks of approximately 200 nm to eleven blocks of c.a. 600 nm. We observed that the minimum size of the DNA ring structure was limited by the width of a single block. The largest rings were negatively affected by thermodynamic randomness, and thus, DNA rings consisting of more than eleven blocks were not observed. This strategy facilitates the generation of various DNA origami rings, whose size can be controlled by adjusting the length of the connection strands.

The aim of this study was to explore how to modulate the expression of estrogen receptors (ER) alpha and beta and to verify the role of ERalpha and beta in relationship to estrogen and tamoxifen (TAM). A series of oligodeoxyribonucleotides (ODN) corresponding to regions of the ERalpha or beta was tested in human endometrial cancer cell lines (HEC-1B). The change in HEC-1B proliferation in response to 17beta-estradiol (E(2)) and TAM under the impact of antisense ODN was studied. The results of the study are as follows: 1) transfection with antisense ODN significantly inhibited ERalpha and ERbeta protein production, 2) the cells lost the ability to proliferate in response to E(2) after transfection with ERalpha antisense ODN especially at 24, 48, and 72 h. There was no obvious change in response to E(2) in HEC-1B cell lines that were transfected with ERbeta antisense ODN, and 3) after transfection with ERalpha antisense ODN, HEC-1B cells lost the ability to proliferate in response to TAM at 48 h. This inhibition was also observed after transfection with ERbeta antisense ODN at 24 h. ERalpha may be the primary receptor in the proliferation of HEC-1B cells in response to E(2). Both ERalpha and ERbeta are involved in the agonist impact of TAM on endometrial cancer cells.