Denoised single-pixel imaging in a Fourier acquisition mode.

The degradation of imaging quality caused by environmental noise during Fourier single pixel imaging (FSPI) is a big problem. In this paper, we propose simple and efficient denoised single-pixel imaging schemes by using linear filters to reduce the impact. Two filters, such as an average filter and Gaussian filter, are employed, and their corresponding schemes are named SCH-A and SCH-G, respectively. The experimental and simulation results show that both schemes can effectively reduce the impact of environmental noise and have greater robustness in comparison with those using the deringing SPI and conventional SPI. Compared with SCH-A, the reconstructed image by SCH-G keeps more details and edges. With the increase of template size, SCH-A and SCH-G have better filtering effects with the same variance. Meanwhile, the larger the template size is, the better filtering effect SCH-A has. This conclusion is also applicable to SCH-G under the same variance.

Encrypting orbital angular momentum holography with ghost imaging.

In this paper, we propose a multiple images simultaneous encryption scheme by encrypting the orbital angular momentum (OAM) holography with ghost imaging. By controlling the topological charge of the incident OAM light beam on the OAM-multiplexing hologram, different images can be selectively obtained for ghost imaging (GI). Followed by the random speckles illumination, the bucket detector values in GI are obtained and then considered as the ciphertext transmitted to the receiver. The authorized user can distill the correct relationship between the bucket detections and the illuminating speckle patterns with the key and the additional topological charges, so that each holographic image can be successfully recovered, while the eavesdropper can not obtain any information about the holographic image without the key. The eavesdropper even can not get clear holographic image when all the key is eavesdropped but without topological charges. The experimental results show that the proposed encryption scheme has a higher capacity for multiple images because there is no theoretical topological charge limit for the selectivity of OAM holography, and the results also show that the proposed encryption scheme is more secure and has a stronger robustness. Our method may provide a promising avenue for multi-image encryption and has the potential for more applications.

Diffractive deep neural network based adaptive optics scheme for vortex beam in oceanic turbulence.

Vortex beam carrying orbital angular momentum (OAM) is disturbed by oceanic turbulence (OT) when propagating in underwater wireless optical communication (UWOC) system. Adaptive optics (AO) is a powerful technique used to compensate for distortion and improve the performance of the UWOC system. In this work, we propose a diffractive deep neural network (DDNN) based AO scheme to compensate for the distortion caused by OT, where the DDNN is trained to obtain the mapping between the distortion intensity distribution of the vortex beam and its corresponding phase screen representing OT. In the experiment, the distorted vortex beam is input into the DDNN model where the diffractive layers are solidified and fabricated, and the intensity distribution of the modulated light field of the vortex beam can be recorded. The experiment results show that the proposed scheme can extract quickly the characteristics of the intensity pattern of the distorted vortex beam, and the predicted compensation phase screen can correct the distortion caused by OT in time. The mode purity of the compensated vortex beam is significantly improved, even with a strong OT. Our scheme may provide a new avenue for AO techniques, and is expected to promote the communication quality of UWOC system immediately.

Secret sharing scheme based on spread spectrum ghost imaging.

(n,n) secret sharing is a procedure for splitting the key into several pieces so that no subset is sufficient to read the encrypted message except the entire one. In this paper, we propose a novel, to the best of our knowledge, secret sharing scheme based on spread spectrum ghost imaging (SSGI). In the scheme, a dealer divides a secret key, which is obtained by a modulo 2 addition over n sequences from a Hadamard matrix, into n pieces to n participants, and then the dealer uses the secret key as a direct sequence code to encrypt an image using the SSGI method. The resultant bucket signal, as the ciphertext, is then shared with n participants, and the modulated speckle patterns in SSGI are also transmitted to nparticipants by private channels for preventing eavesdropping. An independent signal is used as a protective signal to prevent the information leakage in SSGI. In the decryption process, only if all participants are honest and cooperative, the secret key can be obtained; thus, the ciphertext can be decrypted to the correct image using the second-order correlation algorithm. Otherwise, the image information cannot be extracted. The theoretical analysis shows that the probability of finding out others' pieces for successfully reconstructing the image for one dishonest participant is (1/2N)n-1, where N is the length of the secret key, and n is the number of participants. The simulation and experimental results demonstrate that the proposed scheme has a stronger data security capacity in optical information encryption.

Sending-or-Not-Sending Twin-Field Quantum Key Distribution with a Passive Decoy-State Method.

Twin-field quantum key distribution (TF-QKD) has attracted considerable attention because it can exceed the basic rate-distance limit without quantum repeaters. Its variant protocol, sending or not-sending quantum key distribution (SNS-QKD), not only fixes the security vulnerability of TF-QKD, but also can tolerate large misalignment errors. However, the current SNS-QKD protocol is based on the active decoy-state method, which may lead to side channel information leakage when multiple light intensities are modulated in practice. In this work, we propose a passive decoy-state SNS-QKD protocol to further enhance the security of SNS-QKD. Numerical simulation results show that the protocol not only improves the security in source, but also retains the advantages of tolerating large misalignment errors. Therefore, it may provide further guidance for the practical application of SNS-QKD.

Prefixed-Threshold Real-Time Selection for Free-Space Sending-or-Not Twin-Field Quantum Key Distribution.

As a variant of the twin-field quantum key distribution (TF-QKD), the sending-or-not twin-field quantum key distribution (SNS TF-QKD) is famous for its higher tolerance of misalignment error, in addition to the capacity of surpassing the rate-distance limit. Importantly, the free-space SNS TF-QKD will guarantee the security of the communications between mobile parties. In the paper, we first discuss the influence of atmospheric turbulence (AT) on the channel transmittance characterized by the probability distribution of the transmission coefficient (PDTC). Then, we present a method called prefixed-threshold real-time selection (P-RTS) to mitigate the interference of AT on the free-space SNS TF-QKD. The simulations of the free-space SNS TF-QKD with and without P-RTS are both given for comparison. The results showed that it is possible to share the secure key by using the free-space SNS TF-QKD. Simultaneously, the P-RTS method can make the free-space SNS TF-QKD achieve better and more stable performance at a short distance.

Full color single pixel imaging by using multiple input single output technology.

In this paper, we propose a novel full color single pixel imaging by using multiple input single output (MISO) technology. In the scheme, the MISO technology, which is widely used in the wireless communications, is used to simultaneously produce three (red, green and blue) detection signal components corresponding to the red, green and blue components of the object with only one single pixel bucket detector respectively. Then, a full color image of object can be produced by synthesizing the reconstructed red, green and blue component images of object, where the red (green or blue) component image can be recovered by utilizing the speckle patterns and corresponding detection signal components. The experimental results demonstrate that our scheme can be robust against the interference of the intensity fluctuations of ambient light and improve the imaging quality. Moreover, our scheme requires only one single pixel bucket detector, which reduces the numbers of bucket detectors that need to be used. Our scheme provides a promising avenue to realize the full color single pixel imaging with MISO technology and has the potential to be extended to high quality multispectral single pixel imaging by using only one single pixel detector.

Isotropic and anisotropic edge enhancement with a superposed-spiral phase filter.

In this paper, we present edge detection schemes with specially designed superposed spiral phase plate (SSPP) filters in the Fourier domain both for intensity or phase objects. A special SSPP whose function is equivalent to Sobel operator in space domain is firstly designed by weighting different topological charge spiral phase plate (SPP) filters. Later, a SSPP with controllable direction parameters is then discussed to enhance the anisotropic edges by controlling the direction parameter. Numerical simulation and experimental results show that either isotropic or anisotropic edge information can be enhanced by using our proposed schemes. The signal-to-noise ratio and the root-mean-square-error performance are improved in comparison with those using traditional SPP filter. Importantly, it is the first time to present the special ways of superposing and the SSPP can be designed before the experiment so that a clear edge can be achieved at real time without the convolutional operation.

Decoy-state phase-matching quantum key distribution with source errors.

The phase-matching quantum key distribution (PM-QKD), one of the variants of Twin-Field (TF) QKD protocol, was recently proposed to overcome the rate-distance limits of point to point protocol without quantum repeaters. In this paper, we propose a more practical PM-QKD protocol version with four-intensity decoy states and source errors, since neither the infinite decoy states nor the precise control of the light source is available in practice. We present the formulation of the secure key rate of the proposed protocol and analyze the performances of the protocol with and without source errors by numerical simulations.

Multi-Gaussian correlated Hankel-Bessel beam properties in anisotropic oceanic turbulence.

We introduce the model of a multi-Gaussian correlated Hankel-Bessel (MGCHB) beam generated by a multi-Gaussian Shell-model source and investigate the properties of the beam in anisotropic oceanic turbulence. Under Rytov approximation, the detection probability of the MGCHB beam and the channel capacity with MGCHB beams are derived; both the influence of oceanic turbulence and initial beam parameters on them are discussed by numerical simulations. The results show that the increase of the dissipation rate of kinetic energy per unit mass of fluid, the anisotropic coefficient, and the inner scale factor, as well as the decrease of the dissipation rate of mean-squared temperature and the temperature-salinity contribution ratio, can significantly improve the detection probability and the channel capacity. The results also indicate that the MGCHB beam is a better candidate than an Airy vortex beam for mitigating the influence of oceanic turbulence. Furthermore, smaller topological charge and larger orbital angular momentum modes number are beneficial to improve the detection probability and channel capacity, respectively. Moreover, the performance of the MGCHB beam with longer wavelength, smaller beam index, and larger transverse coherence width is conducive to enhancing the transmission quality through oceanic turbulence.

Role of platelet infiltration as independent prognostic marker for gastric adenocarcinomas.

BACKGROUND: In recent years, the relationship between malignant tumors and platelets has been paid more attention. The increase of platelets is an independent risk factor for the poor prognosis of some malignant tumors. METHODS: This study retrospectively analyzed the clinical and pathological data of 114 patients with initial gastric cancer from August 2005 to August 2018 in Shandong Provincial Hospital. Single-factor and multifactor survival analysis were used to evaluate the effect of platelet elevation on postoperative survival. The gastric cancer tissues of the Jinan Central Hospital and its matched paracancerous tissues were collected. The expression of platelets in tissues was detected by immunofluorescence technique. Different numbers of platelets were co-cultured with MKN-45 cells, CCK-8 assay and transwell assay were performed, and the expression of epithelial-mesenchymal transition-related proteins was detected. RESULTS: Platelet count was independent factors affecting prognosis. The stratified analysis showed that there was a statistically significant difference in the 5-year survival rate between the platelet-increase group and the normal platelet group in the TNM stages I-II. The expression of platelets in gastric cancer tissues was higher than that in adjacent tissues. The results of CCK-8 and transwell showed that platelets significantly enhanced the proliferation and metastasis capability of MKN-45 cells in a concentration-dependent manner. After co-culture, the expression level of E-cadherin protein in MKN-45 cells decreased, and the protein expression levels of N-cadherin, vimentin, and VEGFA increased. CONCLUSION: Platelet elevation is closely related to the occurrence, development, and metastasis of gastric cancer, and platelet count can be used as a prognostic indicator for malignant tumors.

Analytical comparison between two hematological analyzer systems: Mindray BC-5180 vs Sysmex XN-1000.

BACKGROUND: To compare the Mindray BC-5180 and Sysmex XN-1000 instruments by analyzing the results of complete blood count in the external quality assessment in Shandong Province in 2018. METHODS: In the external quality assessment, 10 batches of quality control materials were issued throughout the year. The test items were WBC, RBC, Hb, PLT, and HCT. The laboratories using Mindray BC-5180 and Sysmex XN-1000 were screened, and the results were analyzed by t test, Passing-Bablok regression analysis, and Bland-Altman analysis. RESULTS: Thirty-six laboratories using Mindray BC-5180 instruments and thirty-six laboratories using Sysmex XN-1000 instruments were screened, and the average difference between the two instruments results is not significant (P > 0.05, t test). Passing-Bablok regression analysis showed that the 95% confidence interval of the regression equation interception of each test item included 0, and the 95% confidence interval of the slope contained 1, r > 0.98, which showed that the correlation is good. The Bland-Altman analysis showed that both instruments had more than 95% of the points within the 95% consistency limit (WBC97.2%, RBC95.6%, PLT97.2%, Hb96.7%, HCT97.5%). Within the consistency limit, the absolute value of the difference between the Mindray BC-5180 instrument and the Sysmex XN-1000 instrument is WBC 0.14%, RBC 0.26%, PLT 2.7%, and Hb 1.9%. HCT is 0.69%, and the difference is clinically acceptable. CONCLUSION: It can be considered that the two instruments have good correlation and consistency, and the two instruments can replace each other.

Manipulating orbital angular momentum entanglement by using the Heisenberg uncertainty principle.

Orbital angular momentum entanglement (OAM) is one of the very intriguing topics in quantum physics. In addition to discovering and exploring its underlying mechanics, recent studies have also demonstrated a progress towards expanding degree of its entanglement. In this paper, we explore OAM entanglement by applying the Heisenberg uncertainty principle to the quantum position correlation within the azimuthal region. In particular, we decompose the pump light into a set of pump cone states characterized by their radii. The OAM entanglement can then be manipulated by controlling the radius of the pump cone state, the length of the nonlinear crystal and also the OAM carried by the pump field. That is followed by a detailed discussion and analysis. Such an exploration not only bring us a deeper understanding of OAM entanglement, but also help us to implement the high-dimensional quantum information tasks based on OAM entanglement.

Edge detection based on single-pixel imaging.

In the paper, we propose a new edge detection schemes, based on a single-pixel imaging in the frequency domain. In SCHEME-I, special sinusoidal patterns for the x-direction edge and also y-direction edge of the unknown object are first designed. The frequency spectrum for the edge is then obtained using the a four-step phase-shifting technique with the designed sinusoidal patterns in a single-pixel imaging system. In SCHEME-II, the frequency spectrum of the unknown object is first obtained, then the frequency spectrum for the edge is obtained by calculations. The resulting edges are finally obtained by the inverse Fourier transform on their frequency spectrum. We have also verified the proposed schemes by experiments and numerical simulations. The results show that the proposed schemes can produce higher quality edges of character and also image objects. Comparing with SCHEME-II, the application of SCHEME-I to high frequency components has greatly improved signal-to-noise ratio of the received data in the bucket detector, resulting in better experimental results. Comparing with the edge detection scheme by speckle-shifting in ghost imaging systems, the proposed SCHEME-I shows an improvement in the signal-to-noise ratio. Since a single-pixel imaging system is used, the proposed schemes are capable of reconstructing edges from indirect measurements. The number of measurements required can be effectively reduced due to the sparsity of natural images in the Fourier domain and the conjugate symmetry of real-valued signals' Fourier spectrum.

Colistin Resistance Mechanisms and Molecular Epidemiology of Enterobacter cloacae Complex Isolated from a Tertiary Hospital in Shandong, China.

Background: Enterobacter cloacae complex (ECC), which includes major nosocomial pathogens, causes urinary, respiratory, and bloodstream infections in humans, for which colistin is one of the last-line drugs. Objective: This study aimed to analyse the epidemiology and resistance mechanisms of colistin-resistant Enterobacter cloacae complex (ECC) strains isolated from Shandong, China. Methods: Two hundred non-repetitive ECC strains were collected from a tertiary hospital in Shandong Province, China, from June 2020 to June 2022. Whole-genome sequencing and bioinformatics analyses were performed to understand the molecular epidemiology of the colistin-resistant ECC strains. The nucleotide sequences of heat shock protein (hsp60) were analyzed by using BLAST search to classify ECC. The gene expression levels of ramA, soxS, acrA, acrB, phoP, and phoQ were assessed using RT-qPCR. MALDI-TOF MS was used to analyse the modification of lipid A. Results: Twenty-three colistin-resistant strains were detected among the 200 ECC clinical strains (11.5%). The hsp60 cluster analysis revealed that 20 of the 23 ECC strains belonged to heterogeneous resistance clusters. Variants of mgrB, phoPQ, and pmrAB, particularly phoQ and pmrB, were detected in the 23 ECC strains. The soxS and acrA genes were significantly overexpressed in all 23 colistin-resistant ECC strains (P < 0.05). Additionally, all 23 ECC strains contained modified lipid A related to colistin resistance, which showed five ion peaks at m/z 1876, 1920, 1955, 2114, and 2158. Among the 23 ECC strains, 6 strains possessed a phosphoethanolamine (pETN) moiety, 16 strains possessed a 4-amino-4-deoxy-L-arabinose (-L-Ara4N) moiety, and one strain had both pETN and -L-Ara4N moieties. Conclusion: This study suggests that diverse colistin resistance existed in ECC, including unknown resistance mechanisms, exist in ECC. Mechanistic investigations of colistin resistance are warranted to optimise colistin use in clinical settings and minimise the emergence of resistance.

B-Type Fumonisins in Post-Fermented Tea: Occurrence and Consumer Dietary Exposure in Guangxi, China.

Post-fermented tea (PFT), a commonly consumed beverage worldwide, is characterized by the rapid growth of its microbial groups and the substantial changes they undergo. Consequently, PFT may contain mycotoxins such as B-type fumonisins (FBs). This study aimed to assess the intake of FBs through the consumption of PFT among consumers in Guangxi, China. A novel quantitative method using high-performance liquid chromatography-mass spectrometry was used to determine the FB concentration in PFT products. Additionally, a PFT consumption survey was conducted using a face-to-face questionnaire, recording their body weight and PFT consumption patterns based on a three-day dietary recall method. Finally, hazard index was calculated to estimate the health risk of FBs from the consumption of PFT products in Guangxi. The results revealed that the occurrence of FBs in PFT was 20% (24/120), with a concentration ranging from 2.14 to 18.28 µg/kg. The results of the survey showed that the average daily consumption of PFT by consumers was 9.19 ± 11.14 g. The deterministic risk assessment revealed that only 0.026% of the provisional maximum tolerable daily intake of FBs was consumed through PFT, indicating that FB contamination in PFT is not a public health risk.

Metatranscriptomic analysis revealed Prevotella as a potential biomarker of oropharyngeal microbiomes in SARS-CoV-2 infection.

Background and objectives: Disease severity and prognosis of coronavirus disease 2019 (COVID-19) disease with other viral infections can be affected by the oropharyngeal microbiome. However, limited research had been carried out to uncover how these diseases are differentially affected by the oropharyngeal microbiome of the patient. Here, we aimed to explore the characteristics of the oropharyngeal microbiota of COVID-19 patients and compare them with those of patients with similar symptoms. Methods: COVID-19 was diagnosed in patients through the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Characterization of the oropharyngeal microbiome was performed by metatranscriptomic sequencing analyses of oropharyngeal swab specimens from 144 COVID-19 patients, 100 patients infected with other viruses, and 40 healthy volunteers. Results: The oropharyngeal microbiome diversity in patients with SARS-CoV-2 infection was different from that of patients with other infections. Prevotella and Aspergillus could play a role in the differentiation between patients with SARS-CoV-2 infection and patients with other infections. Prevotella could also influence the prognosis of COVID-19 through a mechanism that potentially involved the sphingolipid metabolism regulation pathway. Conclusion: The oropharyngeal microbiome characterization was different between SARS-CoV-2 infection and infections caused by other viruses. Prevotella could act as a biomarker for COVID-19 diagnosis and of host immune response evaluation in SARS-CoV-2 infection. In addition, the cross-talk among Prevotella, SARS-CoV-2, and sphingolipid metabolism pathways could provide a basis for the precise diagnosis, prevention, control, and treatment of COVID-19.

[A preliminary study on the relationship between HLA-Cw polymorphism and susceptibility to pulmonary tuberculosis].

OBJECTIVE: To analyze the relationship between HLA-Cw polymorphism and susceptibility to pulmonary tuberculosis (PTB), and therefore to explore the susceptible or resistant genes of PTB. METHODS: A hundred and twelve patients who were confirmed to have secondary PTB in Shandong Chest Hospital from May 2010 to May 2011 were selected as the PTB group, including 62 males and 50 females aged 19 - 69 years (mean 41.7). According to the acid-fast staining results, PTB patients were divided into a smear-negative group (SN group, 77 cases) and a smear-positive group (SP group, 35 cases). A hundred and ten subjects who underwent physical examination in Shandong Chest Hospital at the same period were selected as the control group, including 59 males and 51 females aged 21 - 67 years (mean 38.3). After genomic DNA was extracted, genotyping of HLA-Cw was conducted by sequence specific primer polymerase chain reaction (PCR-SSP) method. Then Hardy-Weinberg (H-W) equilibrium was tested, and gene frequencies(%) were estimated = 1-(1-phenotype frequencies)(1/2). Gene frequencies were compared between the PTB group and the control group, and between the SN group and SP group by χ(2) test. According to Bonferroni's principle, α was divided by the number of alleles (n = 8), and P < 0.006 25 was regarded as statistically significant. RESULTS: The frequency of HLA-Cw08 was significantly higher in PTB patients (43.6%, 75/112) compared with the controls (27.4%, 52/110), χ(2) = 8.790, P < 0.006 25. Among PTB patients, HLA-Cw04 had a significantly higher frequency in the SP group (20.7%, 13/35) than in the SN group (4.7%, 7/77), while HLA-Cw08 had a significantly lower frequency in the SP group (22.5%, 14/35) than in the SN group (54.4%, 61/77), χ(2) = 12.909, 16.732, both P < 0.006 25. CONCLUSIONS: HLA-Cw polymorphism is related to susceptibility to PTB. HLA-Cw08 may be one of the susceptible genes for PTB, and HLA-Cw04 and 08 may be related to MTB infectious status and clinical outcomes.

Ghost edge detection based on HED network.

In this paper, we present an edge detection scheme based on ghost imaging (GI) with a holistically-nested neural network. The so-called holistically-nested edge detection (HED) network is adopted to combine the fully convolutional neural network (CNN) with deep supervision to learn image edges effectively. Simulated data are used to train the HED network, and the unknown object's edge information is reconstructed from the experimental data. The experiment results show that, when the compression ratio (CR) is 12.5%, this scheme can obtain a high-quality edge information with a sub-Nyquist sampling ratio and has a better performance than those using speckle-shifting GI (SSGI), compressed ghost edge imaging (CGEI) and subpixel-shifted GI (SPSGI). Indeed, the proposed scheme can have a good signal-to-noise ratio performance even if the sub-Nyquist sampling ratio is greater than 5.45%. Since the HED network is trained by numerical simulations before the experiment, this proposed method provides a promising way for achieving edge detection with small measurement times and low time cost.

Dynamic expression of Qa-2 during acute graft rejection.

Human leukocyte antigen (HLA)-G exhibits immunotolerogenicity and is related to allograft acceptance. Qa-2 is the murine homolog of HLA-G; it has structure and functions similar to those of HLA-G. We investigated the dynamic expression of Qa-2 in skin allografts by immunohistochemistry and on peripheral blood lymphocyte subsets by flow cytometry during the entire process of acute graft rejection (AGR) with a murine skin transplantation model to determine its relationship with the pathological changes of allografts and the influence of immunosuppressive therapy. In grafts without immunosuppressive treatment, Qa-2 did not exhibit obvious changes in syngeneic and allogeneic recipients. In contrast, with immunosuppressant-treated grafts, positive expression of Qa-2 was observed. It remained at high levels in the immunosuppressant-treated syngeneic group; however, it became weakly positive and even negative in infiltrating inflammatory cells as AGR advanced, but it remained strongly positive in other skin tissues throughout the AGR process. Qa-2 expression on CD4(+) and CD8(+) peripheral blood lymphocyte subsets remained stable at a normal level in the non-immunosuppressant-treated syngeneic group. Immunosuppressive treatment can also significantly upregulate Qa-2. In the allogeneic groups, decreased expression was observed when AGR was at histological grades 1 to 2 (well before gross rejection was observed). Qa-2 was upregulated again after the graft was rejected completely. The results suggest that the increase in Qa-2 may be attributed to the use of immunosuppressive treatments. Moreover, Qa-2 expression decreased significantly with AGR progression, suggesting that it may be a potential marker for predicting AGR, especially in the presence of immunosuppressive agents.