Search

Concerns regarding publicly traded companies' R&D investment have long existed among academics domestically and overseas. Scholars have conducted much research on the R&D investment of enterprises from different angles. This study starts from the perspective of market expectation and loss aversion, taking the data of Chinese quoted companies from 2011 to 2020 as a sample and using the empirical analysis method to research the impact of changes in market value on quoted companies' innovation decisions. Robustness tests effectively corroborate the findings of the study, which found a substantial positive association between changes in the market value of listed businesses and the degree of innovation investment. Additionally, this study conducts a group regression test on the R&D investment growth rate (RDI) of state-owned companies (SOEs) and non-state-owned firms using the two explanatory variables of total market value growth rate (RDI) and Tobin's Q value (Tobin's Q) (NSOEs). It is discovered that NSOEs are more vulnerable to market capitalization change than SOEs are, and the listed businesses' intentions to innovate are influenced by changes in market capitalization through the loss aversion mechanism.

The rapid promotion of single-cell omics in various fields has begun to help solve many problems encountered in research, including precision medicine, prenatal diagnosis, and embryo development. Meanwhile, single-cell techniques are also constantly updated with increasing demand. For some specific target cells, the workflow from droplet screening to single-cell sequencing is a preferred option and should reduce the impact of operation steps, such as demulsification and cell recovery. We developed an all-in-droplet method integrating cell encapsulation, target sorting, droplet picoinjection, and single-cell transcriptome profiling on chips to achieve labor-saving monitoring of TCR-T cells. As a proof of concept, in this research, TCR-T cells were encapsulated, sorted, and performed single-cell transcriptome sequencing (scRNA-seq) by injecting reagents into droplets. It avoided the tedious operation of droplet breakage and re-encapsulation between droplet sorting and scRNA-seq. Moreover, convenient device operation will accelerate the progress of chip marketization. The strategy achieved an excellent recovery performance of single-cell transcriptome with a median gene number over 4000 and a cross-contamination rate of 8.2 ± 2%. Furthermore, this strategy allows us to develop a device with high integrability to monitor infused TCR-T cells, which will promote the development of adoptive T cell immunotherapy and their clinical application.

The rapid promotion of single-cell omics in various fields has begun to help solve many problems encountered in research including precision medicine, prenatal diagnosis, and embryo development. Meanwhile, single-cell techniques are also constantly updated with increasing demand. For some specific target cells, the workflow from droplet screening to single-cell sequencing is a preferred option, which also should reduce the impact of operation steps such as demulsification and cell recovery. We developed an all-in-droplet method integrating cell encapsulation, target sorting, droplet picoinjection, and single-cell transcriptome profiling on chips to achieve a labor-saving monitor of TCR-T cells. As a proof of concept, in this research, TCR-T cells were encapsulated, sorted, and performed single-cell transcriptome sequencing (scRNA-seq) by injecting reagents into droplet. It avoided the tedious operation of droplet breakage and re-encapsulation between droplet sorting and scRNA-seq. Moreover, convenient device operation will accelerate the progress of chip marketization. The strategy achieved an excellent recovery performance of single cell transcriptome with a median gene number over 4000 and a cross-contamination rate of 8.2 ± 2%. Furthermore, this strategy allows us to develop a device with high integrability to monitor infused TCR-T cells, which will promote the development of adoptive T cell immunotherapy and their clinical application.

Combinatorial drug therapy reduces drug resistance and disease relapse, but informed drug combinations are lacking due to the high scale of possible combinations and the relatively simple phenotyping strategies. Here we report combinatorial perturbation sequencing (CP-seq) on single cells using microwell-base droplet random pairing. CP-seq uses oligonucleotides to barcode drugs, encapsulates drugs and cells in separate droplets, and pairs cell droplets with two drug droplets randomly on a microwell array chip to complete combinatorial drug treatment and barcode-tagging on cells. The subsequent single-cell RNA sequencing simultaneously detects the single-cell transcriptomes and drug barcodes to demultiplex the corresponding drug treatment. The microfluidic droplet operations had robust performance, with overall success rate among the microwells being up to 83%. We then progressively validated the CP-seq by performing single drug treatment and then combinatorial drug treatment. Leveraging the advantage of droplet microfluidics in massive multiplexing, the CP-seq can test thousands of drug combinations in a single experiment and represents a great technology for combinatorial perturbation screening with high throughput and comprehensive profiling.

Meningiomas are the most common benign intracranial tumors and frequently present with a gradual onset of neurological deficits; conversely, their acute presentation with hemorrhagic onset appears to be a rare event. Nonetheless, as early surgical evacuation is the foundation of treatment, a timely diagnosis of this rare type of intracranial hemorrhage is necessary. The purpose of the present single-center study was to investigate the radiological characteristics and propose a new bleeding classification for guiding the diagnosis and treatment. A total of 19 patients consecutively diagnosed with hemorrhagic meningioma were enrolled in this retrospective study. Intracranial extra-axial mass, tumor-associated hemorrhage and peritumoral brain edema were the three main radiological features of the hemorrhagic meningiomas. The site of tumor-associated hemorrhage included the peritumoral space, subarachnoid space, subdural space, brain parenchyma and/or intratumor region. Based on the anatomical relationship between meningioma and hematoma, the spontaneous hemorrhage stemming from meningiomas was further summarized into three bleeding patterns involving purely intratumoral hemorrhage (type I), purely extratumoral hemorrhage (type II) and combined intra/extratumoral hemorrhage (type III); furthermore, the type III hemorrhage usually came from type I bleeding that extended into the surrounding regions. The symptoms in type I patients were generally mild and early surgery was performed following adequate preoperative evaluations. The symptoms in type II patients were mild in certain cases and moderate to severe in others, so early or emergency surgery was chosen according to the clinical status of the patient. Almost all type III patients had moderate to severe symptoms and these patients usually required emergency surgery. In addition, patients with different bleeding types may have different pathological mechanisms underlying the tumor bleeding. Apart from being convenient for diagnosis, this concise and practical bleeding classification may aid in the selection of the treatment strategy and facilitate the understanding of the associated mechanisms.

The reaction of chlorine atom Cl(2P) (Cl(2P3/2) and Cl∗(2P1/2)) with D2 was investigated at collision energy from 4.5 kcal/mol to 6.5 kcal/mol with a high-resolution crossed molecular beam apparatus using the technique of D-atom Rydberg tagging detection. The contribution from the spin-orbit excited reaction Cl∗(2P1/2)+D2, which is prohibited by Born-Oppenheimer (BO) approximation, was observed. Collision-energy dependence of differential cross sections (DCSs) near the backward scattering direction was measured. The BO-forbidden reaction Cl∗+D2 was found to be dominant at lower collision energy. As collision energy increases, reactivity of BO-allowed reaction Cl+D2 increases much faster than that of BO-forbidden reaction and becomes dominant at higher collision energy. Our experiment indicates that the additional energy of spin-orbit excitation in Cl∗ facilitates BO-forbidden reaction to pass through the barrier at lower collision energy, while BO approximation is still valid at collision energy near and above the reaction barrier. This tendency of reactivity of Cl/Cl∗+D2 is similar to the isotopic reaction of Cl/Cl∗+H2.

Vibrationally excited reaction of Cl + D2 (v = 1, j = 0) → DCl + D was investigated by a high-resolution crossed beam experiment, with D2 molecules in the vibrationally excited state prepared by th...

Avian influenza A virus H5N1 is a highly pathogenic and persistently a major threat to global health. Vaccines and antibodies targeting hemagglutinin (HA) protein are the primary management strategies for the epidemic virus. Although camelids possess unique immunological features, the immune response induced by specific antigens has not yet been thoroughly investigated. Herein, we immunized an alpaca with the HA antigen of the H5N1 virus and performed single-cell transcriptome profiling for analysis of longitudinal peripheral blood mononuclear cell (PBMCs) behavior using single-cell sequencing technology (scRNA-seq). We revealed multiple cellular immunities during the immunization. The monocytes continued to expand after immunization, while the plasma cells reached their peak three days after the second antigen stimulation. Both monocytes and B cells were stimulated by the HA antigen and produced cell-type-specific cytokines to participated in the immune response. To our knowledge, this is the first study to examine the HA-specific immunological dynamics of alpaca PBMCs at the single-cell level, which is beneficial for understanding the anti-viral immune system and facilitating the development of more potent vaccines and antibodies in camelid animals.

The reaction dynamics of the fluorine atom with vibrationally excited D2(v=1, j=0) was investigated using the crossed beam method. The scheme of stimulated Raman pumping was employed for preparation of vibrationally excited D2 molecules. Contribution from the reaction of spin-orbit excited F*(2P1/2) with vibrationally excited D2 was not found. Reaction of spin-orbit ground F(2P3/2) with vibrationally excited D2 was measured and DF products populated in v′=2, 3, 4, 5 were observed. Compared with the vibrationally ground reaction, DF products from the vibrationally excited reaction of F(2P3/2)+D2(v=1, j=0) are rotationally “hotter”. Differential cross sections at four collision energies, ranging from 0.32 kcal/mol to 2.62 kcal/mol, were obtained. Backward scattering dominates for DF products in all vibrational levels at the lowest collision energy of 0.32 kcal/mol. As the collision energy increases, angular distribution of DF products gradually shifts from backward to sideway. The collision-energy dependence of differential cross section of DF(v′=5) at forward direction was also measured. Forward-scattered signal of DF(v′=5) appears at the collision energy of 1.0 kcal/mol, and becomes dominated at 2.62 kcal/mol.

With the advent of cloud computing, data privacy has become one of critical security issues and attracted much attention as more and more mobile devices are relying on the services in cloud. To protect data privacy, users usually encrypt their sensitive data before uploading to cloud servers, which renders the data utilization to be difficult. The ciphertext retrieval is able to realize utilization over encrypted data and searchable public key encryption is an effective way in the construction of encrypted data retrieval. However, the previous related works have not paid much attention to the design of ciphertext retrieval schemes that are secure against inside keyword-guessing attacks (KGAs). In this paper, we first construct a new architecture to resist inside KGAs. Moreover we present an efficient ciphertext retrieval instance with a designated tester (dCRKS) based on the architecture. This instance is secure under the inside KGAs. Finally, security analysis and efficiency comparison show that the proposal is effective for the retrieval of encrypted data in cloud computing.

Recently, how to retrieve the encrypted data efficiently from a cloud storage system becomes a hot topic. Public key encryption with keyword search (PEKS) can allow one to search the encrypted data with a keyword efficiently. Due to the booming of post-quantum cryptography, we propose public key encryption with keyword search from lattice assumption, which can resist quantum computer attacks. We delegate a particular cloud server to search the results, thus only the designated cloud server can finish the test process. Our scheme has been proved ciphertext indistinguishability in the standard model, which can reflect its security in the real world. To the best of our knowledge, our scheme is the first construction based on lattice in the standard model, which is a step stone in the post-quantum cryptographic communication.

Salicylic acid (SA), 2-hydroxy benzoic acid, is a small phenolic compound with multifunction that is involved in plant growth, development, and the acquisition of stress tolerance. In recent years, hydrogen sulfide (H2S) has been found to have similar functions, but cross talk between SA and H2S in the acquisition of heat tolerance is not clear. In this study, pretreatment of maize seedlings with SA improved the survival percentage of seedlings under heat stress, indicating that SA pretreatment could improve the heat tolerance of maize seedlings. In addition, treatment with SA enhanced the activity of L-cysteine desulfhydrase (L-DES), a key enzyme in H2S biosynthesis, which in turn induced accumulation of endogenous H2S. Interestingly, SA-induced heat tolerance was enhanced by addition of NaHS, a H2S donor, but weakened by specific inhibitors of H2S biosynthesis DL-propargylglycine (PAG) and its scavenger hydroxylamine (HT). Furthermore, pretreatment with paclobutrazol (PAC) and 2-aminoindan-2-phosphonic acid (AIP), inhibitors of SA biosynthesis, had no significant effect on NaHS-induced heat tolerance of maize seedlings. Similarly, significant change in the activities of phenylalanine ammonia lyase (PAL) and benzoic-acid-2-hydroxylase (BA2H), the key enzymes in SA biosynthesis, and the content of endogenous SA, was not observed in maize seedlings by NaHS treatment. All of the above-mentioned results suggest that SA pretreatment could improve the heat tolerance of maize seedlings, and H2S might be a novel downstream signal molecule in SA-induced heat tolerance.

The evolution of microstructure and grain boundaries were investigated in coarse-grained Ni–48Al intermetallics during plastic deformation at 1075 °C with the initial strain rate of 1.5 × 10 −3 s −1 using electron backscatter diffraction (EBSD) technique. Before deformation, most grain boundaries were high-angled (HAGBs), with several particular angles being predominant. During initial deformation, low-angle grain boundaries (LAGBs) with misorientation less than 5° began to evolve. The misorientation of the newly-formed LAGBs increased with the increase of deformation, meanwhile, grain boundaries with misorientations between 6 and 15° were gradually observed, and finally transformed into HAGBs (misorientation angle > 15°). There appeared a steady state transition from the formation of new LAGBs to the transformation into high-angle grain boundaries. As a result, the grain size was refined continuously with the deformation strain.

With networking became prevalent, the amount of data to be stored and managed on networked servers rapidly increases. Meanwhile, with the improvement of awareness of data privacy, the user’s sensitive data is usually encrypted before uploading them to the cloud server. The searchable public-key encryption provides an efficient mechanism to achieve data retrieval in encrypted storage. Therefore, it is a critical technique on promoting secure and efficient cloud storage. Unfortunately, only few the existing schemes are secure to resist outside keyword guessing attacks. In this paper, we propose two efficient searchable public-key encryption schemes with a designated tester (dPEKS). One is a basic dPEKS, where the dPEKS ciphertext indistinguishability is proved without the random oracle. Meanwhile, the basic scheme is secure to resist the outside KGA since it satisfies the property of trapdoor indistinguishability. Comparing with the existing dPEKS schemes which use expensive pairing computation, our scheme is more efficient since we only need multi-exponentiation. Another is an enhanced dPEKS scheme. With the sender’s identity is kept secret from server, this scheme can provide stronger security.

In this paper, we present an effective fully homomorphic encryption (FHE) from ring learning with errors (RLWE) assumption without using Gentry’s standard squashing and bootstrapping techniques. Our FHE scheme is to modify the recent FHE scheme of Brakerski. We use the re-linearization technique to reduce the length of ciphertext considerably, and use the modulus reduction technique to manage the noise level and decrease the decryption complexity without introducing additional assumptions. Furthermore, with the key-homomorphic property, we extend our FHE scheme to a threshold fully homomorphic encryption (TFHE), which allows parties to cooperatively decrypt a ciphertext without learning anything but the plaintext. The TFHE scheme can be protected from related-key attacks, as long as we add extra smudging noise during sensitive operations.

In order to enhance the cleaning speed, reduce the cleaning cost and solve other problems of the existing cleaning equipment for blanket cylinder, we put forward a new-type unpowered cleaning equipment for blanket cylinder after a comparative analysis between powered spurt brush type cleaning equipment and unpowered cleaning cloth type cleaning equipment with respect to their structures and characteristics. Furthermore, after we study the cylinder structure of printing press and the cleaning effect of the existing cleaning equipments, a spurt brush type is proposed. We obtain the optimal pressure of this cleaning equipment through repeated experimental analyses on the pressure exerted by brush roller on blanket cylinder. The velocity parameter is determined by analyzing the cleaning principle of brush roller.

For paper forward unit of the current forward type flute laminating machine, the contact surface of the paper forward unit may damage paper during high speed paper forwarding. In view of this phenomenon, a solution is proposed through the study on the feeding unit of the flute laminating machine. In this paper, the corresponding sprocket driveshaft is controlled by a servo motor to slowly forward paper at the beginning and accelerate its forwarding speed gradually, until the entire feeding process is completed. In this way, the problem of paper pile-up and damages during the paper forwarding process can be solved, while matching backing paper feeding, so as to improve the feeding accuracy of the full-automatic flute laminating machine and hence its laminating accuracy.

Variable head sizes of paper roll will influence the stability of paper feeding device and hence the printing quality. Therefore, it is necessary to improve the printing quality by improving the stability of paper feeding device based on dynamic analysis on the phenomenon of variable head sizes of paper roll. It is found through dynamic analysis that the effect of variable head sizes on the support force of bearings is nearly five times that of the case when such effect does not exist. Vibration performance analysis of paper feeding device using finite element analysis obtains the natural frequencies of the first 6 orders for paper carriage and their dominant vibrational modes. This provides theoretical basis for the improvement of paper feeding device.

With the improvement of awareness of data privacy, the user's sensitive data is usually encrypted before uploading them to the cloud. The searchable public-key encryption with keyword search provides an efficient mechanism to achieve the encrypted data retrieval without the complicated key management of symmetric encryption. Therefore, it is a critical technique on promoting secure and efficient cloud storage. Unfortunately, only one existing construction of ciphertext retrieval scheme is secure against inside keyword guessing attacks (KGA). In this paper, we build a framework to resist insider attacks. Additionally, we propose an efficient ciphertext retrieval with keyword search scheme with a designated tester (dCRKS), which is secure against inside keyword guessing attacks (KGA). Our security proof and performance analysis demonstrate that our scheme is practical for retrieval data stored in the cloud server.

With the improvement of awareness of data privacy, the user's sensitive data are usually encrypted before uploading them to cloud. Searchable encryption is a critical technique on promoting secure and efficient cloud storage. In particular, publickey encryption with keyword search (PEKS) provides an elegant approach to achieve data retrieval in encrypted storage. All existing searchable publickey encryption schemes only provide the security based on classical cryptography hardness assumption. With the development of quantum computers, these schemes will be insecure. Based on the lattice hardness assumptions, we propose a new searchable publickey encryption scheme with a designated tester (dPEKS). Our scheme has advantages: First, our scheme is the first searchable publickey encryption scheme that is considered to be secure even if quantum computers are ever developed. Second, our scheme achieves the trapdoor indistinguishability. The trapdoor indistinguishability implies the security against outside offline keyword guessing attacks (KGAs). Last, our scheme can achieve the trapdoor anonymity for server.

The reaction of fluorine atom with vibrationally excited H2 at v = 1 has been studied using a high resolution crossed molecular beam apparatus at collision energies of 0.52 and 0.90 kcal/mol. Product HF rotational state-resolved differential cross sections (DCSs) were measured at v' = 2, 3, 4 levels. The product angular distributions are predominantly backward scattered except for a small forward signal of HF(v' = 4) at 0.90 kcal/mol. At the collision energy of 0.52 kcal/mol, the forward scattering peak of the HF(v' = 2) product, which arises in F + H2(v = 0) reaction from the Feshbach resonances, disappears in F + H2(v = 1) reaction. Oscillatory structures do not appear in the backward direction of the scattering as the collision energy increases from 0.4 to 2.0 kcal/mol, indicating there are no explicit reaction resonances in the F + H2(v = 1, j = 0) → HF + H reaction in the studied energy range. Quantum dynamics calculations on a highly accurate potential energy surface are in good agreement with the experimental results and reveal that the reaction occurs via likely a direct abstraction mechanism, not via long-lived reactive resonances.

Group signatures allow a group member to sign messages anonymously on behalf of the group. Generally, group signatures have anonymity, traceability and authentication. It has been well applied in practical distributed security communication environments. However, very few schemes can achieve the non-frameability and support dynamic membership management. In this paper, we propose a new group signature scheme. Our scheme achieves the non-frameability without the trusted issuer. Meanwhile, this scheme can support dynamic members join and revocation without incurring other secure threats. Furthermore, in our scheme, the size of group member's private key and the size of group public key are shorter than other schemes while the costs to be kept constant for signing and verifying. In particular, we prove that our scheme achieves anonymity, traceability and non-frameability under the random oracle model.