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Background/Purpose: The global coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulted in significant mortality, social disorder and economic hardships. We set out to understand why certain individuals could resolve the disease successfully without serious complications by immune profiling of PBMCs from convalescent COVID-19 patients (n = 14) with mild disease trajectory. Methods: We designed 7 peptides targeting the receptor binding region (RBD) of the spike protein of SARS-CoV-2, that encompass broad HLA class I / II alleles, with the aid of the Immune Epitope Database and Analysis Resource (IEDB) website. The RBD site was chosen as it was shown to be protective when neutralising antibodies against this region could negate binding of viral spike protein to host cell ACE-2 receptor. Convalescent COVID-19 patients enrolled in this study were screened and selected for positive antibody titre against the RBD region. PBMCs from convalescent COVID-19 patients were stimulated with/without the peptides for 72hrs and immune profiled (n = 70 markers across two panels) with the high dimensional single cell mass cytometry platform (CyToF). Results: Convalescent COVID-19 patients elicited a robust recall memory T follicular helper response (CD3 + CD4 + CD45RO + CXCR5 + Tigit + ;∗∗∗∗ p < 0.0001) demonstrating peptide efficacy. Unsupervised clustering (FlowSOM) of the CD4 T cell immune landscape reaffirmed increase in memory T follicular subsets and additionally CD4 + CD45RO + CXCR5 -subsets. Further gating of antigen specific memory cells (CD45RO + CD69 + ) revealed an increase in Tbet + CXCR3 + T effectors in both CD4 and CD8 compartments. Strikingly we detected a parallel increase in CD4 + Treg (CD25 + FoxP3 + ) CXCR3 + Tbet + CD45RO + CD152 + Tigit + expression. Conclusions: COVID-19 patients that successfully resolve the viral infection not only mount a robust T effector and follicular response but also in tandem a similar T regulatory profile.

In this paper, we demonstrate fabrication and characterization of Ge-doped flat fibres. The Ge-doped flat fibre was fabricated from a 6 mol% Ge-doped preform. The flat fibre was successfully fabric...

Sensor-to-actuator delay is inevitable in any complex control system, be it one for a free-flying insect or a mimicking insectlike robotic flyer. In this work, we analyze the effects of control delay (latency) on the hovering performance of a model insect flyer, as exemplified by the hummingbird hawkmoth $\mathrm{Re}\ensuremath{\sim}3000$, and determine how control coefficients or gains may be modified to ameliorate the adverse effects of latency. The analyses are based on a simplified or reduced dynamic model of the hovering flyer. The longitudinal dynamics of the hovering flyer comprises the coupled forward (backward) and vertical translations and pitch rotation of the flyer, with kinematical wing actions being governed by proportional-differential (PD) closed-loop control. Keeping to the same PD control coefficients as a stable reference zero-delay case, the flight system becomes overly responsive at a small control delay, eventually diverging when delay approaches around one wing cycle. Stable hovering may be regained for control delay of up to several wingbeats by suitably reducing or softening the PD control coefficients. The results of the analyses are validated by a series of time-based simulations using the simplified dynamic model and a high-fidelity three-dimensional computational fluid dynamics with fluid structure--body interaction model of the hovering flyer. The simulations also show that noncyclic asymptotic oscillations about the mean equilibrium hovering state are enhanced with larger control delay. The analyses and simulations have helped us to gain a better understanding of the effects of control latency in insect free flight, which may be relevant for the design of mimetic insect flyers.

In this paper we discuss the design of an indoor positioning system (IPS) using Bluetooth Low Energy (BLE) scanners and beacons. We deployed the prototype system in a laboratory where its dimension is measured at 990⨯770cm2, Range test has been carried out to study the relationship between distance and Received Signal Strength (RSSI) of the BLE devices. Using the highest RSSI values received from 3 of the scanners, we use K-Nearest Neighbour algorithm to predict the region where the beacon is possibly located. We further demonstate that our system is able to estimate the location region of the target beacon with good accuracy.

An approach to obtain single-mode operation on a semirectangular large core area Flat Fiber (FF) slab waveguide is proposed. A new design of FF with two defect eye holes is presented, and its single-mode guiding is analyzed by simulation. To validate the simulation results, a proof of concept FF with a core area $ > 1200{\rm{\ \mu }}{{\rm{m}}^2}$ was fabricated, and its modal behavior was examined. It was found that higher order propagation modes could be discriminated from the large core area by introducing a high-refractive index region in the FF eye holes. Experimental results confirmed a single Gaussian mode profile (mode field diameter of $ \approx745{\rm{\ \mu m}})$ output of this large core FF, thus validating the simulation results.

The properties of the singly resonant and double-pass pump fiber optical parametric oscillators (FOPO) are experimentally investigated. An idler removal filter is utilized to eliminate the idler component in a Fabry-Pérot cavity to minimize the effect of modulation instability. For singly resonant FOPO, the pump is also filtered out and leaves the signal to oscillate in the cavity. For double-pass pump FOPO, the idler removal filter is designed to allow propagation of signal and pump in the cavity. The results show that double-pass pump FOPO brings several important enhancements over the conventional singly resonant FOPO. Among them are the low threshold of 0.247 W with improvement by 51% at 0.45 W pump power. It is also found that the conversion efficiency of the two configurations has no significant difference.

Under repeated deformation, the mechanical properties of polydimethylsiloxane (PDMS) elastomer evolve. This paper aims to investigate the effect of curing agent concentration on the mechanical response of PDMS elastomer under cyclic compressive loading. PDMS elastomer samples containing various curing agent concentrations were prepared following ASTM D575 standard. Three different curing agent concentrations were investigated: 6.25, 9.09 and 16.67 wt%. Monotonic compressive test up to failure and 100 cycles of cyclic compressive test were performed using Instron 3369 50 kN dual column testing machine at a constant crosshead displacement rate of 12 mm/min. It was found that the compressive modulus increases with the curing agent concentration. The effects of cyclic compression on strain hardening, compressive modulus, and creep were also investigated. Results showed that cyclic compression contributes to the stabilization of the materials. Moreover, the number of cycles required to reach strain hardening stabilization decreases as the curing agent concentration increases. Keywords: Mechanical properties, PDMS, Cyclic compression, Strain hardening, Viscoelasticity, Sylgard 184

A microwave photonic filter based on multiwavelength Brillouin-erbium fiber laser (BEFL) is proposed and experimentally demonstrated. By precisely controlling the output channels of the BEFL, the 3-dB bandwidth of the filter spectrum can be adjusted at a resolution of $\sim 24$ MHz. The free spectral range of the filter can be tuned by changing the Brillouin gain fiber of the BEFL in addition to changing the length of the dispersion fiber, which adds flexibility to the filter system.

The generation of multiwavelength Brillouin fiber laser assisted by four wave mixing has been demonstrated. A maximum of 18 channels of laser Stokes lines are generated at a Brillouin Pump (BP) of 190 mW (∼22.5 dBm). The multiple peaks have a wavelength spacing of 0.176 nm (∼20 GHz). A tunable optical bandpass filter is incorporated to the design to suppress up to 6 dB of the noise floor hump exhibited at the multiwavelength laser spectrum while limiting the laser peaks attenuation thereby providing a much cleaner and better OSNR.

The fabrication process of photonic crystal fibers based on a stack-and-draw method is presented in full detail in this article. In addition, improved techniques of photonic crystal fiber preform preparation and fabrication are highlighted. A new method of connecting a handle to a preform using only a fiber drawing tower is demonstrated, which eliminates the need for a high-temperature glass working lathe. Also, a new technique of modifying the photonic crystal fiber structural pattern by sealing air holes of the photonic crystal fiber cane is presented. Using the proposed methods, several types of photonic crystal fibers are fabricated, which suggests potential for rapid photonic crystal fibers fabrication in laboratories equipped with and limited to only a fiber drawing tower.

This paper demonstrates a method to remove the gain ripple profile specifically for a two-segment fiber optical parametric amplifier arising from the dispersion differences between the fiber gain medium and the standard single mode fiber attached to the optical components. This is achieved by using a simple design that incorporates a gain smoothening filter at the mid-stage of the amplifier. This simple yet practical method is useful when isolators are adopted for stimulated Brillouin scattering suppression but it comes with the expense of parametric gain.

We demonstrate a continuous wave tunable fiber optical parametric oscillator in a Fabry–Perot cavity consisting of a 500-m highly nonlinear fiber. In this work, the pump propagates in both directions together with the signal, thus making full use of its parametric gain. The resultant laser peak power is uneven across the wavelength range of interest due to wavelength-dependent phase modulation by the single-mode fiber sections in the cavity. This can be solved by filtering the idler spectral component from the oscillating cavity.

An all-optical widely tunable Raman fiber laser has been realized by incorporating a highly nonlinear fiber in a ring cavity. By feedback a portion of Raman Stokes wave back into the highly nonlinear gain medium, a Raman fiber laser is generated. We found that the lasing wavelength of Raman fiber laser can be tuned from 1537 to 1568 nm with peak power fluctuation within 1 dB, giving a total wavelength tunability of 31 nm. The optical signal-to-noise ratio is found to be wavelength dependent, and the highest optical signal-to-noise ratio of about 59 dB is recorded. The lasing threshold of the Raman fiber laser with this configuration is found to be as low as 300 mW.

Rphq2 , a minor gene for partial resistance to Puccinia hordei , was physically mapped in a 188 kbp introgression with suppressed recombination between haplotypes of rphq2 and Rphq2 barley cultivars. Partial and non-host resistances to rust fungi in barley (Hordeum vulgare) may be based on pathogen-associated molecular pattern (PAMP)-triggered immunity. Understanding partial resistance may help to understand non-host resistance, and vice versa. We constructed two non-gridded BAC libraries from cultivar Vada and line SusPtrit. Vada is immune to non-adapted Puccinia rust fungi, and partially resistant to P. hordei. SusPtrit is susceptible to several non-adapted rust fungi, and has been used for mapping QTLs for non-host and partial resistance. The BAC libraries help to identify genes determining the natural variation for partial and non-host resistances of barley to rust fungi. A major-effect QTL, Rphq2, for partial resistance to P. hordei was mapped in a complete Vada and an incomplete SusPtrit contig. The physical distance between the markers flanking Rphq2 was 195 Kbp in Vada and at least 226 Kbp in SusPtrit. This marker interval was predicted to contain 12 genes in either accession, of which only five genes were in common. The haplotypes represented by Vada and SusPtrit were found in 57 and 43 %, respectively, of a 194 barley accessions panel. The lack of homology between the two haplotypes probably explains the suppression of recombination in the Rphq2 area and limit further genetic resolution in fine mapping. The possible candidate genes for Rphq2 encode peroxidases, kinases and a member of seven-in-absentia protein family. This result suggests that Rphq2 does not belong to the NB-LRR gene family and does not resemble any of the partial resistance genes cloned previously.

A microwave photonic filter based on double-Brillouin-frequency spaced multiwavelength Brillouin-erbium fiber laser (BEFL) is experimentally demonstrated. The filter selectivity can be easily adjusted by tuning and apodizing the optical taps generated from the multiwavelength BEFL. Reconfiguration of different frequency responses are demonstrated.

Sunny PCF is proposed and numerically investigated. By adding the sunny structure to a normal PCF (air-filling ratio of 0.8), the sensitivity at 1500nm is boosted up from 12.35% to 16.85% without significant confinement loss.

250-m long 125-µm×315-µm size semi-trench-assisted multicore flat fiber is fabricated using undoped-secondary-cladding as the trench. Crosstalk at 630 nm is fully suppressed in the fiber with 4.2-µm and 27.5-µm core and pitch size, respectively.

In the present paper, natural convective heat transfer in horizontal eccentric annulus is numerically studied by applying the differential quadrature (DQ) method to solve the vorticity–stream function formulation. An explicit formulation for computing the stream function value on the inner cylinder wall is derived from the pressure single-value condition. It is demonstrated in this paper that the DQ method is an efficient approach in computing the weak global circulation in the domain. The present method was validated by comparing its numerical results with available experimental data. Very good agreement has been achieved. Then, a systematic study is conducted for the effect of eccentricity and angular position on the flow and thermal fields.

We demonstrate a linear cavity fiber optical parametric oscillator with extended pump-signal separation of 14.3 THz (116 nm). The signal laser is provided by a pair of 1675nm fiber Bragg gratings and a tunable idler from 1456.12 nm to 1462.48 nm is generated by detuning the pump wavelength in the anomalous dispersion regime of a highly nonlinear fiber. At such large pump-signal separation, we are still able to record a parametric conversion efficiency of more than −35 dB and idler optical signal-to-noise-ratio of 50 dB on average. The stability of the lasing signal and idler is examined and result shows both signal and idler peak power fluctuation is less than 1 dB over a period of 30 minutes.

The rural communities in Sarawak which consist of approximately 22% of the state's population are still relying on expensive and noisy diesel generator sets for a couple of hours every night simply because they are located in remote areas where people have limited access to electrical grid. If electricity is generated by means of potential Renewable Energy (RE) resources which are incorporated with smart microgrid for rural Sarawakians, there are many advantages that could be insightful for the society and the environment. In this paper, the availability of RE resources in Sarawak and their potentials to supply power to rural areas in Sarawak is first discussed. A smart microgrid concept for rural electrification in the state is also discussed to provide an overview on its characteristics and challenges.

In this paper, exact solutions to the stagnation flow over a compliant surface and the flow about a rotating disk coated by a compliant layer are discussed. The compliant layer is modelled by the Mooney rubberlike material. In the stagnation flow, the deformation of the rubber layer depends on two dimensionless groups: one is the ratio of pressure to the shear modulus of the material, and the other is the ratio of the boundary layer thickness to the thickness of the layer. It is shown that this deformation has a limit point at a critical value of the pressure force, beyond which the solution does not exist. In the rotating-disk flow, the deformation of the rubber layer depends on two dimensionless groups, one is a material parameter, and the other is a flow loading parameter, the ratio of the flow-induced viscous stress to the shear modulus multiplied by the ratio of the thickness of the layer to the boundary layer thickness. At large value of a material parameter, it is found that this deformation has a limit point at a critical value of the flow loading parameter.

International audience; Key message We developed 'Golden SusPtrit', i.e., a barley line combining SusPtrit's high susceptibility to non-adapted rust fungi with the high amenability of Golden Promise for transformation. Nonhost and partial resistance to Puccinia rust fungi in barley are polygenically inherited. These types of resistance are principally prehaustorial, show high diversity between accessions of the plant species and are genetically associated. To study nonhost and partial resistance, as well as their association, candidate gene(s) for resistance must be cloned and tested in susceptible material where SusPtrit would be the line of choice. Unfortunately, SusPtrit is not amenable to Agrobacterium-mediated transformation. Therefore, a doubled haploid (DH) mapping population (n = 122) was created by crossing SusPtrit with Golden Promise to develop a 'Golden SusPtrit', i.e., a barley line combining SusPtrit's high susceptibility to non-adapted rust fungi with the high amenability of Golden Promise for transformation. We identified nine genomic regions occupied by resistance quantitative trait loci (QTLs) against four non-adapted rust fungi and P. hordei isolate 1.2.1 (Ph.1.2.1). Four DHs were selected for an Agrobacterium-mediated transformation efficiency test. They were among the 12 DH lines most susceptible to the tested non-adapted rust fungi. The most efficiently transformed DH line was SG062N (11-17 transformants per 100 immature embryos). The level of non-adapted rust infection on SG062N is either similar to or higher than the level of infection on SusPtrit. Against Ph.1.2.1, the latency period conferred by SG062N is as short as that conferred by SusPtrit. SG062N, designated 'Golden SusPtrit', will be a valuable experimental line that could replace SusPtrit in nonhost and partial resistance studies, especially for stable transformation using candidate genes that may be involved in rust-resistance mechanisms.

Prefabricated vertical drains (PVDs) normally consist of a core and a filter (sleeve) made with polymeric materials. Modern installation rigs are capable of installing them at considerable speed in soft soil deposits. This note reports the tension developed in a PVD filter sleeve during the installation process, which was monitored with strain gauges. A tension of about 1,000 N was measured near the shoe shortly after the commencement of mandrel withdrawal. The need to watch the stresses in PVD in relation to the material properties of the components is highlighted.

In this paper we calculate the dispersion values of our home-made solid core photonic crystal fiber (PCF) based on step index fiber model. Material dispersion and waveguide dispersion is taken into account while carrying out the calculation. The dispersion values predicted by this model agree well with that obtained by a commercial finite element method (FEM) solver.

We demonstrate an L-band fiber laser based on nonlinear four-wave mixing effect. The laser produced can be tuned across 1565 nm to 1610 nm, which is the entire wavelength range of the tunable bandpass filter used in the setup. The laser produced has no significant power decay at the upper wavelength limit of the tunable bandpass filter. This means the laser wavelength tuning range is only limited by the component used in the setup and it can be potentially tuned further e.g. into U-band region.

This paper examines the linear stability of the Blasius boundary layer over compliant walls to three-dimensional (oblique) disturbance wave modes. The formulation of the eigenvalue problem is applicable to compliant walls possessing general material anisotropy. Isotropic-material walls and selected classes of anisotropic-material walls are studied. When the properties of the wall are identical with respect to all oblique wave directions, the stability eigenvalue problem for unstable three-dimensional wave modes may be reduced to an equivalent problem for two-dimensional modes. The results for isotropic-material walls show that three-dimensional Tollmien–Schlichting instability modes are more dominant than their two-dimensional counterparts when the walls are sufficiently compliant. The critical Reynolds number for Tollmien-Schlichting instability may be given by three-dimensional modes. Furthermore, for highly compliant walls, calculations based solely on two-dimensional modes are likely to underestimate the maximum disturbance growth factor needed for transition prediction and correlation. However, because the disturbance growth rates on highly compliant walls are much lower than those on a rigid wall, significant delay of transition may still be possible provided compliance-induced instabilities are properly suppressed. Walls featuring material anisotropy which have reduced stiffness to shear deformation in the transverse and oblique planes are also investigated. Such anisotropy is found to be effective in reducing the growth rates of the three-dimensional modes relative to those of the two-dimensional modes.

In this paper, the projection/level set method is used to simulate the liquid film flow down on an inclined plate for both Newtonian and non-Newtonian fluids. Special numerical treatments are designed to cope with the viscous terms. The simulation is carried out for different inclined plate angles ranging from 20 � to 90 � . The effects of the inclined angle, surface tension, and shear thinning on the flow are discussed. It is found that surface tension reduces the contact angle, increases the film thickness, and promotes a fuller flow front. The effect of shear thinning is to increase the velocity near the wall, make the contact angle larger, and reduce the film thickness. It is also found that the variation of rheological properties and surface tension may produce a complex flow behaviour due to the swollen flow front.

In this paper, we are concerned with waves that form on a compliant surface when it is subjected to a turbulent flow. Two types of waves have been observed so far in the experiments: a fast travelling wave on nearly elastic surfaces, and a nearly stationary or slowly moving wave on surfaces with significant damping. In their incipient state, the fast waves have small amplitude and propagate at speeds ranging from 0.3–0.5 times the freestream speed U∞, whereas the slow waves (also termed static divergence waves) have large amplitude and move forward at speeds of less than 0.05U∞ . Details of these waves were recorded in experimental studies by Gad-el-Hak et al. (1984), Gad-el-Hak (1986) and Hansen et al. (1980). This paper discusses the progress that has been made in the theoretical modelling of these waves. Emphasis is given to the recent works and the new insight that they offer about unstable interaction between turbulent flow and compliant surface. Quasipotential flow approximations have been fairly successful in predicting some of the qualitative and quantitative aspects of the observed waves. However, the quasipotential models are reliant on the availability of accurate parameter inputs from other experiments or additional modelling for them to work well. In this regard, they are not self-sufficient for general application. The effects of viscosity and turbulence are needed to produce a complete and self-consistent model for the accurate prediction of onset wave conditions. While linear stability models are generally adequate for predicting onset flow velocities for the waves, nonlinear wave effects are necessary to explain the detailed features of the observed waves.

We experimentally demonstrate optical delay in the second-order Brillouin gain spectrum by incorporating a double Brillouin-frequency shifter into the system. By coinciding the seed signal with the second-order Brillouin gain spectrum, it was found that the seed signal experienced significantly larger delay as compared to the Brillouin slow light generated from the first-order Brillouin spectrum. At a Brillouin gain of 17 dB, the delay was found to be at maximum of 60 ns. This widens the window of promising opportunities into the deployment of all optical tunable delay into the existing optical signal processing.

In this article, we describe the characteristics of 12 human colorectal-carcinoma cell lines established from 6 primary tumors and 6 metastatic sites of 11 Korean colorectal-carcinoma patients, including the morphology in vivo and in vitro and mutations of K-ras2, p15, p16, p53, APC, beta-catenin, hMLH1 and hMSH2 genes in vitro. No lines were contaminated with Mycoplasma or bacteria. All lines were proven to be unique by DNA-fingerprinting analysis. All lines expressed the surface carcino-embryonic antigen and secreted it into the supernatant fluid. The morphological correlation between the original tumors and cultured cells suggested that the original tumors showing mucinous adenocarcinoma correlated with floating aggregates in culture, and degree of desmoplasia in the original tumor correlated with attached growth in culture. Five of the cell lines showed mutations in the K-ras2 gene, and 6 of the cell lines showed mutations in the p53 gene. The p15 gene was deleted in 2 cell lines, and the p16 gene was hypermethylated in 3 cell lines. The mutation of mismatch-repair genes (hMLH1 and hMSH2) was found in 4 lines, the APC gene and beta-catenin gene were mutated in 9 and 2 lines respectively. These well-characterized colorectal-cancer cell lines should serve as useful tools for investigating the biological characteristics of colorectal cancer.

We report 8 newly established gastric-carcinoma cell lines (SNU-216, 484, 520, 601, 620, 638, 668, 719) from Korean patients. Morphologic study was carried out using light and electron microscopes. CEA, alpha FP, and CA 19-9 and TPA in supernatant and in cell lysate were measured by radioimmunoassay. p53 and c-Ki-ras gene mutations were screened and confirmed by sequencing. The cell lines, derived from tumors with moderate differentiation, grew as a diffuse monolayer, and those from tumors with poor differentiation and minimal desmoplasia grew exclusively as non-adherent. Out of the 8 gastric-cancer cell lines, 5 had detectable levels of CEA both in supernatant and in cell lysate; there was no expression or secretion of alpha FP in these cells; 4 cell lines showed high levels of CA 19-9 in cell pellets. All cell lines except SNU-484 had high concentrations of TPA both in cell lysate and in supernatants. p53 mutation was found in 6 cell lines (75%): 2 (SNU-216 and SNU-668) had mutations in exon 6, and other 3 in exon 8. The c-Ki-ras mutation was found in 2 cell lines (25%), SNU-601 and SNU-668. The former showed GGT-to-GAT transition mutation at codon 12, while the latter showed CAA-to-AAA transversion mutation at codon 61. DNA profiles using restriction endonuclease HinfI and polymorphic DNA probes ChdTC-15 and ChdTC-114 showed different unique patterns; which suggests that these cell lines are unique and not cross-contaminated. We believe that the newly characterized gastric-cancer cell lines presented in this paper will provide a useful in vitro model for studies related to human gastric cancer.

Characteristics of fiber optical parametric amplifier (FOPA) with double-pass pump configuration are experimentally investigated. The double-pass pump FOPA exhibits more than two-fold steeper gain slope in comparison to the conventional FOPA due to elongation of effective fiber length. In the L-band amplification band, a secondary idler is generated and used as the transmission signal in lieu of the original L-band signal. Gain measurement and bit error rate experiments are performed on the secondary idler and the results prove the usability of secondary idler, which is potentially useful for distribution networks.

A novel 1-V full-swing BiCMOS logic circuit, using a positive feedback base-boost technique for high-speed applications, is described. Simulation results show that the circuit outperforms the best existing non-complementary BiCMOS circuits in terms of speed, power consumption and chip area. Based on 0.35 /spl mu/m BiCMOS technology, the proposed circuit offers 49% delay reduction with negligible increase in power dissipation over the CMOS circuit at a supply voltage of 1 V and a load capacitance of 1pF. The crossover capacitance of the proposed circuit is as low as 0.1 pF, and experimental results confirm its circuit operation.