(3+1)-dimensional Pearcey-Gaussian wave packet with arbitrary velocity driven by flying focus.

The group velocity (GV) modulation of space-time wave packets (STWPs) along the transverse and longitudinal directions in free space is constrained by various factors. To surmount this limitation, a technique called "flying focus" has been developed, which enables the generation of laser pulses with dynamic focal points that can propagate at arbitrary velocities independent of GV. In this Letter, we propose a (3+1)-dimensional Pearcey-Gauss wave packet based on the "flying focus" technique, which exhibits superluminal propagation, transverse focus oscillation, and longitudinal periodic autofocusing. By selecting appropriate parameters, we can flexibly manipulate the position, the size, and the number of focal points- or make the wave packet follow a desired trajectory. This work may pave the way for the advancement of space-time structured light fields.

Transient second-degree type 2 atrioventricular block after infliximab infusion in a patient with Crohn's disease and heterozygous familial hypercholesterolemia.

Current treatments for patients in the active phase of Crohn's disease (CD) include conventional treatments and biological treatments. Infliximab (IFX), a TNF-α antagonist, is recommended to induce remission in patients with moderate-to-severe CD who have not responded to conventional therapy. IFX terminates the inflammatory cascade by inhibiting the nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and caspase signaling pathways and increases the apoptosis of activated T cells in inflamed tissues.

Transient second-degree type 2 atrioventricular block after infliximab infusion in a patient with Crohn’s disease and heterozygous familial hypercholesterolemia

Current treatments for patients in the active phase of Crohn's disease (CD) include conventional treatments and biological treatments. Infliximab (IFX), a TNF-α antagonist, is recommended to induce remission in patients with moderate-to-severe CD who have not responded to conventional therapy. IFX terminates the inflammatory cascade by inhibiting the nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and caspase signaling pathways and increases the apoptosis of activated T cells in inflamed tissues. (AU)

Virtual sources for structured partially coherent light fields.

A virtual source (VS) is a hypothetical source instead of an actual physical entity, but provides a distinctive perspective to understand physical fields in a source-free area. In this work, we generalize the VS theory to structured partially coherent light fields (PCLFs) by establishing the partially coherent inhomogeneous Helmholtz equation, then demonstrate that PCLFs can be generated from the incoherent extended VS in imaginary space. Especially, we put forward an understanding of the Gaussian Schell-model beam, which consists of a group of partially coherent paraxial complex rays. The mutual coherence between these rays depends on the included angle between them. In previous studies, the analytical solution of the partially coherent Airy beam was obtained with difficulty by the Huygens-Fresnel integral; however, by applying the VS, we put forward, to our knowledge, an unprecedented analytical solution for a partially coherent Airy beam. We believe this example will qualify the VS as an important perspective to understand structured PCLFs.

Space-time wave packets with both arbitrary transverse and longitudinal accelerations.

The group velocity in the free space of space-time wave packets (STWPs) and light bullets can be flexibly regulated by many advanced strategies; however, these regulations are restricted to only the longitudinal group velocity. In this work, a computational model based on catastrophe theory is proposed, to devise STWPs with both arbitrary transverse and longitudinal accelerations. In particular, we investigate the attenuation-free Pearcey-Gauss STWP, which enriches the family of non-diffracting STWPs. This work may advance the development of space-time structured light fields.

Generation and control of the circle Olver beams: erratum.

We have found an error in our work reported in [Opt. Express31(4), 6241 (2023)10.1364/OE.483433], which we correct in this erratum. The authors apologize for this error and emphasize that none of the results are affected by this error.

Generation and control of the circle Olver beams.

The circle Olver beams (COBs) generated by modulation on the basis of a new type of Olver beam are presented numerically and experimentally. The zeroth order COB is the circle Airy beam. We demonstrate auto-focusing of the COBs with both inward and outward accelerations, where the odd order COBs display auto-defocusing while the even order COBs (ECOBs) tend to focus more abruptly. We also explore the effect of the decay factor and the scaling factor on the beams' focusing properties, such as the initial energy distribution, the focusing position, the focusing intensity and the focusing depth, by using the parity mode. In addition, we verify the self-healing property of the COBs. Finally, we set up an experimental platform to implement particle capture and manipulation with the ECOBs. Our results offer practical applications for particle manipulation, laser processing, etc.

Asymmetrical inseparable coherent structures.

A novel, to the best of our knowledge, class of coherent structures of inseparability, incorporating phases asymmetrically cross-coupled by two position vectors, is introduced in theory and experiment. These phases disappear in the environment of complete coherence, but the vanishment is avoidable in the coexistent state of extreme incoherence and full coherence. The radiated beams intrinsically possess a controllable rotation but undergo an intermediate process quite different from the twisted Gaussian Schell-model beams. Analysis shows a novel association between the magnitude and the phase of the coherent structure which displays both synergy and opposition. Our work further reveals the inner mechanism of the inseparable coherent structures and extends a new horizon for the optical twist.

Shaping autofocusing Airy beams through the modification of Fourier spectrum.

A new type of Airy beam arisen from the modification of Fourier spectrum is introduced numerically and experimentally. The autofocusing Airy beam (AAB) exhibits the features of off-axis autofocusing and transverse self-accelerating, producing a needle-like focus in the longitudinal direction and a tiny focal spot at the focusing plane. Furthermore, the focusing properties such as focusing position, focal spot size, focusing intensity and depth of focus can be adjusted by modulating parameters of the AAB. Experimental demonstrations of particle trapping and manipulation with the AAB are also presented. The number of trapped particles can be controlled by changing the focal spot size at the autofocusing plane. Our results offer practical applications in particle manipulation, fluorescent imaging technology, laser spectroscopy and so on.

Tuning the stability of alkoxyisopropyl protection groups.

Five different 2-alkoxypropan-2-yl groups are introduced as acid-labile protecting groups for the 5'- and 3'-hydroxy groups of a 2'-deoxynucleoside. All studied protecting groups were readily introduced with good to excellent yields using the appropriate enol ether as a reagent and 0.5 to 1 mol % p-toluenesulfonic acid as a catalyst. The protected compounds could be purified by silica gel column chromatography without degradation. The compatibility of these protecting groups in parallel use with benzoyl and silyl groups was verified. The stabilities of the different alkoxy acetal protecting groups were compared by following the kinetics of their hydrolysis at 25.0 °C in buffered solutions through an HPLC method. In the pH range 4.94 to 6.82 the hydrolysis reactions are of first order in the hydronium ion. The rate of hydrolysis correlates with the electron-donating or electron-withdrawing ability of the corresponding alkoxy group. The studied 2-alkoxypropan-2-yl groups and the relative rate constants for their cleavage from the 5'-hydroxy group of 2'-deoxythymidine were: cyclohexyloxy (k rel = 7.7), isopropoxy (7.4), methoxy (1), benzyloxy (0.6) and 2,2,2-trifluoroethyloxy (0.04). The attachment of the same groups to the 3'-hydroxy group are from 1.3 to 1.9-fold more stable. The most reactive of these acetone-based acetal groups are faster removed than a dimethoxytrityl group, and they are easier to cleave completely in solution. The structural variation allows steering of the stability and lipophilicity of the compounds in some range.