High-dimensional single photon based quantum secure direct communication using time and phase mode degrees.

Quantum secure direct communication (QSDC) can guarantee security using the characteristics of quantum mechanics even when a message is directly transmitted through a quantum channel without using a secret key. However, the transmission rate of the QSDC is limited by the dead time of a single photon detector (SPD) as well as channel loss over the distance. To overcome this limited transmission rate, we propose a high-dimensional single photon-based QSDC protocol that applies two optical degrees of freedom: time and phase state. First, an N-dimensional time and phase state generation method that considers the dead time is proposed to minimize the measurement loss of a transmitted message. Second, among the two types of quantum states, the phase state with relatively low measurement efficiency is used only for eavesdropping detection, and the time state is used for sending messages with differential delay time bin-based encoding techniques. Lastly, we propose an efficient method for measuring N-dimensional time and phase-based quantum states and recovering classical bit information. This study performs security analysis against various attacks, and verifies the transmission rate improvement effect through simulation. The result indicates that our proposal can guarantee higher security and transmission rates compared to the conventional DL04 QSDC.

Effect of Treated Time of Hydrothermal Etching Process on Oxide Layer Formation and Its Antibacterial Properties.

Inspired by natural materials, we developed an antibacterial surface on titanium (Ti) using hydrothermal etching techniques and examined the effect of treated time on oxide layer formation, its antibacterial properties, and surface defects. Hydrothermal etching was conducted on Grade 2 commercially pure Ti immersed in 5M NaOH at 250 °C during a range of time of 0-12 h. Nanopillars generated on the surface had ~100 nm thickness, which resulted in decreased attachment and rupturing of the attached bacteria. The results also showed that 6 h and 8 h of etching time provided a desirable uniform nanopillar structure with the most effective prevention of bacterial adherence on the surface. Multiscale SEM observations revealed that the longer the etching was conducted, the more cracks propagated, which led to an increase in dissociated fragments of the oxide layer. In the 12 h of etching, a higher density of bacterial adherence was observed than that of the untreated and the shorter time treated samples, indicating that etching took longer than 10 h worsened the antibacterial properties of the nano-patterned surface of Ti. This study demonstrated that the optimal time duration is 6-8 h for the oxide layer formation to maximize antibacterial activity and minimize cracking formation on the surface. For future studies, we suggest exploring many possible conditions to generate a more uniform nanopattern without structural defects to secure the integration between a newly deposited oxide layer and the substrate.

CRISPR-Cas9 modified bacteriophage for treatment of Staphylococcus aureus induced osteomyelitis and soft tissue infection.

Osteomyelitis, or bone infection, is often induced by antibiotic resistant Staphylococcus aureus strains of bacteria. Although debridement and long-term administration of antibiotics are the gold standard for osteomyelitis treatment, the increase in prevalence of antibiotic resistant bacterial strains limits the ability of clinicians to effectively treat infection. Bacteriophages (phages), viruses that in a lytic state can effectively kill bacteria, have gained recent attention for their high specificity, abundance in nature, and minimal risk of host toxicity. Previously, we have shown that CRISPR-Cas9 genomic editing techniques could be utilized to expand temperate bacteriophage host range and enhance bactericidal activity through modification of the tail fiber protein. In a dermal infection study, these CRISPR-Cas9 phages reduced bacterial load relative to unmodified phage. Thus we hypothesized this temperate bacteriophage, equipped with the CRISPR-Cas9 bactericidal machinery, would be effective at mitigating infection from a biofilm forming S. aureus strain in vitro and in vivo. In vitro, qualitative fluorescent imaging demonstrated superiority of phage to conventional vancomycin and fosfomycin antibiotics against S. aureus biofilm. Quantitative antibiofilm effects increased over time, at least partially, for all fosfomycin, phage, and fosfomycin-phage (dual) therapeutics delivered via alginate hydrogel. We developed an in vivo rat model of osteomyelitis and soft tissue infection that was reproducible and challenging and enabled longitudinal monitoring of infection progression. Using this model, phage (with and without fosfomycin) delivered via alginate hydrogel were successful in reducing soft tissue infection but not bone infection, based on bacteriological, histological, and scanning electron microscopy analyses. Notably, the efficacy of phage at mitigating soft tissue infection was equal to that of high dose fosfomycin. Future research may utilize this model as a platform for evaluation of therapeutic type and dose, and alternate delivery vehicles for osteomyelitis mitigation.

Effect of a DNA-based immunostimulant on growth, performance, and expression of inflammatory and immune mediators in beef calves abruptly weaned and introduced to a complete ration.

The effect of a DNA immunostimulant on inflammatory and immune responses, performance, and health in calves following abrupt weaning and introduction to a concentrate diet was tested. Sixty-four single source Angus crossbred steers were weaned on day 1 and assigned to receive a DNA immunostimulant (TRT) or saline (CON) on days 0, 2, 4, and 6. On day 0, steers received clostridial and respiratory vaccines and anthelmintic; they were then transported 2 h, allocated to pens (n = 8 per pen), and introduced to total mixed ration. Daily intake, ADG, and feed efficiency were measured. Serum haptoglobin, tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1ß) were assayed by ELISA or AlphaLISA on days 0, 2, 4, 6, 14, and 28; serum-neutralizing antibodies (SNA) to bovine herpesvirus-1 and bovine viral diarrhea virus-1 (BVDV-1) were quantified on days 0, 28, 68, and 135. In a subset of cattle (n = 6 to 8 per treatment group), the percent macrophages and activated gamma delta (γδ) T cells in blood was determined by flow cytometry on days 2 and 6, and expression of mRNA for TNF-α, interferon-gamma (IFN-γ), IL-4, and IL-10 by stimulated blood mononuclear cells was assessed by real-time reverse transcriptase PCR on day 6. After 70 d, cattle were shipped 1,205 km to a feedlot and performance and health were followed. There was a significant effect of time on serum TNF-α, IL-1ß, haptoglobin, and SNA (P < 0.001); the range in concentration among cattle on each day was large. The ratio of IFN-γ to IL-4 expression was significantly higher (P = 0.03) for TRT cattle, suggesting that treatment activated T-helper type 1 cells. There was a trend toward an improved feed conversion (P = 0.10) for TRT steers over the 70-d backgrounding period. There was no effect of treatment on feedlot performance or carcass merit (P > 0.10). During backgrounding, 1 TRT steer died of enterocolitis. In spite of backgrounding, cattle experienced an outbreak of bovine respiratory disease (BRD) in the feedlot and 1 of 31 TRT cattle and 5 of 32 CON cattle died of BRD. The immunostimulant modified some immune responses during backgrounding. Large variability in inflammatory responses during backgrounding indicated that events around weaning induce systemic inflammation that varies substantially among cattle.