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Hybrid cavities composed of a Fabry-Perot (FP) cavity and awhispering-gallery mode (WGM) microcavity have been proposed anddemonstrated for modulating mode $Q$ factor to realize singlemode and optical bistable lasers. In this article, we report hybrid cavity lasers witha pentagon microcavity and a square microcavity, respectively. Thereflectivity spectra of different microcavities are simulated to selectmicrocavities for hybrid cavities. Mode coupling with mode $Q$ factor enhancement is investigated numerically and experimentally.Stable single mode operations with a high coupling efficiency to a singlemode fiber are realized for a hybrid cavity laser with a square microcavity.Furthermore, optical bistability hybrid lasers are investigated as themicrocavity is unbiased, due to saturable absorption in the microcavity andmode competition, respectively. All-optical flip-flop is demonstrated usingtrigger optical pulses with a width of 100 ps for mode competitionbistability. The stable single mode operation and optical bistability ofhybrid cavity lasers may shed light on the applications for photonicintegrated circuits and optical signal processing.

If the blocks of a GDD $${(X, \mathcal{G}, \mathcal{A})}$$ with block size 4, index 3 and type g u can be arranged into a (gu)/4 × (gu) array, such that: (1) the main diagonal consists of u empty subarrays of size g/4 × g; (2) the blocks in each column form a partition of X\G for some $${G \in \mathcal{G}}$$ , while the blocks in each row contains every element of X\G 3 times and no element of G for some $${G \in \mathcal {G}}$$ , then the design is called a frame generalized balanced tournament design and denoted by FrGBT D(4, g u ). The necessary conditions for the existence of such a design are $${u \geq 6}$$ and $${g \equiv 0}$$ (mod 4). In this paper, the sufficiency of these conditions is proved with some possible exceptions.

In this letter, by using Whiteman's generalized cyclotomy of order 2 over ℤ pq , where p,q are twin primes, we construct new perfect Gaussian integer sequences of period pq.

Influenza vaccines are the primary intervention to prevent the substantial health burden of seasonal and pandemic influenza. Subunit and split influenza vaccines are formulated, released for clinical use, and tested for stability based on their content of immunologically active (capable of eliciting functional antibodies) hemagglutinin (HA). Single-radial immunodiffusion (SRID), the standard in vitro potency assay in the field, is believed to specifically detect immunologically active HA. We confirmed that, with conformationally homogeneous HA preparations, SRID specifically detected native, pre-fusion HA, which elicited influenza neutralizing and hemagglutination inhibiting (HI) antibodies in mice, and it did not detect low-pH stressed, post-fusion HA, which was selectively removed from the SRID gel during a blotting step and was significantly less immunologically active. This selective detection was due to the SRID format, not a conformational specificity of the sheep antiserum used in the SRID, as the same antiserum detected non-stressed and low-pH stressed HA similarly when used in an ELISA format. However, when low-pH stressed HA was mixed with non-stressed HA, SRID detected both forms in mixed immunoprecipitin rings, leading to over-quantification of pre-fusion HA. We previously reported that trypsin digestion of antigen samples selectively degrade stressed HA, so that an otherwise conformationally insensitive biophysical quantification technique, reversed-phase high pressure liquid chromatography (RP-HPLC), can specifically quantify trypsin-resistant, immunologically active, pre-fusion HA. Here, we report that trypsin digestion can also improve the specificity of SRID so that it can quantify immunologically active, pre-fusion HA when it is mixed with less immunologically active, post-fusion HA.

In this paper, we propose new constructions of binary sequences based on an interleaving technique. In our constructions, we make use of any binary sequences with ideal 2-level autocorrelation, a special shift sequence as well as the perfect binary sequence or sequence (0,1,1) in the interleaved structure to get the new sequences. Except for the most autocorrelation values of our new sequences, we find that the unexpected autocorrelation values only occur four or two times in each period no matter how long the period is. We state that the sequences have a good autocorrelation in this case. In particular, the autocorrelation distribution of our sequences is determined.

Recently, Yu, Gong and Tang found new constructions of binary sequences of period 4N with optimal autocorrelation magnitude by different interleaved structure of sequences and sequences which had special correlation property, respectively. In this paper, we derive more results on binary sequences of period 4N which also have optimal autocorrelation.

N36(L6)C34 is a recombinant protein that forms a six-helix bundle with high thermal stability. It consists of the N-terminal heptad-repeat region (N36 peptide) and the C-terminal heptad-repeat region (C34) of HIV-1 gp41, connected by six polar amino acids. The protein inhibits HIV-1 envelope-induced membrane fusion. Whether inhibition occurs while N36(L6)C34 is in its six-helix bundle configuration was investigated. Mutating a critical residue within the N36 region to promote dissociation of C34 from the grooves of the N36 coiled coil reduced bundle stability and increased the inhibition of fusion. In contrast, mutating a key residue within the C34 region to reduce bundle stability decreased inhibitory potency. The data provide strong evidence that the proteins inhibit fusion while they expose their C34 segments, rather than as six-helix bundles. Thus, despite high thermal stability of the bundle, the recombinants' less folded structures are present in sufficient concentration to inhibit fusion at physiological temperatures.

Gene-based hepatitis B virus (HBV) vaccines have been proposed as a novel approach to improve the immunogenicity toward non-responders and to allow for protection against potential viral escape mutants. Furthermore, there is significant interest in using DNA or viral vector vaccines to serve as therapeutic agents to treat chronic HBV infections that are resistant to existing drug therapies. However, the key protective antigen of HBV, the surface protein (HBsAg), can be expressed in three different sizes due to its multiple translational initiation sites: small, middle, and large forms of HBsAg. It is not clear whether the immunogenicity of these HBsAg is same, especially their ability to elicit HBsAg-specific B cell and T cell immune responses in addition to the traditional serum HBsAg-specific antibody responses. In the current study, the immunogenicity of three forms of HBsAg DNA vaccines was analyzed individually in a mouse model. Our results indicated that different forms of the HBsAg have unique immunogenicity profiles and this information is useful for the selection of optimal gene-based HBV vaccines for further improved prophylactic and therapeutic applications.