Search Results (5)

Skin aging is a multifactorial process driven by both intrinsic mechanisms—such as telomere shortening, oxidative stress, hormonal decline, and impaired autophagy—and extrinsic influences including ultraviolet radiation, pollution, smoking, and diet. Together, these factors lead to the structural and functional deterioration of the skin, manifesting as wrinkles, pigmentation disorders, thinning, and reduced elasticity. This review provides an integrative overview of the biological, molecular, and clinical dimensions of skin aging, emphasizing the interplay between inflammation, extracellular matrix degradation, and senescence-associated signaling pathways. We examine histopathological hallmarks and molecular markers and discuss the influence of genetic and ethnic variations on aging phenotypes. Current therapeutic strategies are explored, ranging from topical agents (e.g., retinoids, antioxidants, niacinamide) to procedural interventions such as lasers, intense pulsed light, photodynamic therapy, microneedling, and injectable biostimulators. Special attention is given to emerging approaches such as microneedle delivery systems, with mention of exosome-based therapies. The review underscores the importance of personalized anti-aging regimens based on biological age, phototype, and lifestyle factors. As the field advances, integrating mechanistic insights with individualized treatment selection will be key to optimizing skin rejuvenation and preserving long-term dermal health. Full article

Laser plasma acceleration has made remarkable progress in the last few decades, but it also faces many challenges. Although the high gradient is a great potential advantage, the beam quality of the laser accelerator has a certain gap, or it is different from that of traditional accelerators. Therefore, it is important to explore and utilize its own features. In this article, some recent research progress on laser proton acceleration and its irradiation application, which was carried out on the compact laser plasma accelerator (CLAPA) platform at Peking University, have been introduced. By combining a TW laser accelerator and a monoenergetic beamline, proton beams with energies of less than 10 MeV, an energy spread of less than 1%, and with several to tens of pC charge, have been stably produced and transported in CLAPA. The beamline is an object–image point analyzing system, which ensures the transmission efficiency and the energy selection accuracy for proton beams with large initial divergence angle and energy spread. A spread-out Bragg peak (SOBP) is produced with high precision beam control, which preliminarily proved the feasibility of the laser accelerator for radiotherapy. Some application experiments based on laser-accelerated proton beams have also been carried out, such as proton radiograph, preparation of graphene on SiC, ultra-high dose FLASH radiation of cancer cells, and ion-beam trace probes for plasma diagnosis. The above applications take advantage of the unique characteristics of laser-driven protons, such as a micron scale point source, an ultra-short pulse duration, a wide energy spectrum, etc. A new laser-driven proton therapy facility (CLAPA II) is being designed and is under construction at Peking University. The 100 MeV proton beams will be produced via laser–plasma interaction by using a 2-PW laser, which may promote the real-world applications of laser accelerators in malignant tumor treatment soon. Full article

Enhanced proton acceleration to high energy by relatively modest ultrashort laser pulses and structured dynamic plasma snow targets was demonstrated experimentally. High proton yield emitted to narrow solid angle with energies of up 25 MeV were detected from interaction of a 5 TW laser with snow targets. The high yield was attributed to a carefully planned prepulse and microstructured snow targets. We studied experimentally the minimal energy requirements for the adequate prepulse and we are using PIC simulations to study the dynamics of acceleration process. Based on our simulations, we predict that using the proposed scheme protons can be accelerated to energies above 150 MeV by 100 TW laser systems. Full article

We present a new external-beam radiation therapy system using very-high-energy (VHE) electron/photon beams generated by a centimeter-scale laser plasma accelerator built in a robotic system. Most types of external-beam radiation therapy are delivered using a machine called a medical linear accelerator driven by radio frequency (RF) power amplifiers, producing electron beams with an energy range of 6–20 MeV, in conjunction with modern radiation therapy technologies for effective shaping of three-dimensional dose distributions and spatially accurate dose delivery with imaging verification. However, the limited penetration depth and low quality of the transverse penumbra at such electron beams delivered from the present RF linear accelerators prevent the implementation of advanced modalities in current cancer treatments. These drawbacks can be overcome if the electron energy is increased to above 50 MeV. To overcome the disadvantages of the present RF-based medical accelerators, harnessing recent advancement of laser-driven plasma accelerators capable of producing 1-GeV electron beams in a 1-cm gas cell, we propose a new embodiment of the external-beam radiation therapy robotic system delivering very high-energy electron/photon beams with an energy of 50–250 MeV; it is more compact, less expensive, and has a simpler operation and higher performance in comparison with the current radiation therapy system. Full article

It has been known for about sixty years that proton and heavy ion therapy is a very powerful radiation procedure for treating tumors. It has an innate ability to irradiate tumors with greater doses and spatial selectivity compared with electron and photon therapy and, hence, is a tissue sparing procedure. For more than twenty years, powerful lasers have generated high energy beams of protons and heavy ions and it has, therefore, frequently been speculated that lasers could be used as an alternative to radiofrequency (RF) accelerators to produce the particle beams necessary for cancer therapy. The present paper reviews the progress made towards laser driven hadron cancer therapy and what has still to be accomplished to realize its inherent enormous potential. Full article