Two atmospheric circulation systems, the mid-latitude Westerlies and the Asian summer monsoon (ASM), play key roles in northern-hemisphere climatic changes. However, the variability of the Westerlies in Asia and their relationship to the ASM remain unclear. Here, we present the longest and highest-resolution drill core from Lake Qinghai on the northeastern Tibetan Plateau (TP), which uniquely records the variability of both the Westerlies and the ASM since 32 ka, reflecting the interplay of these two systems. These records document the anti-phase relationship of the Westerlies and the ASM for both glacial-interglacial and glacial millennial timescales. During the last glaciation, the influence of the Westerlies dominated; prominent dust-rich intervals, correlated with Heinrich events, reflect intensified Westerlies linked to northern high-latitude climate. During the Holocene, the dominant ASM circulation, punctuated by weak events, indicates linkages of the ASM to orbital forcing, North Atlantic abrupt events, and perhaps solar activity changes.
Ti-based alloys are finding ever-increasing applications in biomaterials due to their excellent mechanical, physical and biological performance. Nowdays, low modulus β-type Ti-based alloys are still being developed. Meanwhile, porous Ti-based alloys are being developed as an alternative orthopedic implant material, as they can provide good biological fixation through bone tissue ingrowth into the porous network. This paper focuses on recent developments of biomedical Ti-based alloys. It can be divided into four main sections. The first section focuses on the fundamental requirements titanium biomaterial should fulfill and its market and application prospects. This section is followed by discussing basic phases, alloying elements and mechanical properties of low modulus β-type Ti-based alloys. Thermal treatment, grain size, texture and properties in Ti-based alloys and their limitations are dicussed in the third section. Finally, the fourth section reviews the influence of microstructural configurations on mechanical properties of porous Ti-based alloys and all known methods for fabricating porous Ti-based alloys. This section also reviews prospects and challenges of porous Ti-based alloys, emphasizing their current status, future opportunities and obstacles for expanded applications. Overall, efforts have been made to reveal the latest scenario of bulk and porous Ti-based materials for biomedical applications.
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AbstractPurpose-To compare dose-volume histograms (DVHs) for intensity-modulated proton therapy (IMPT) with intensity-modulated radiation therapy (IMRT) and passive scattering proton therapy (PSPT) for stage IIIB non-small cell lung cancer (NSCLC) and explore the possibility of individualized radical radiotherapy.Methods and Materials-DVHs for IMPT, PSPT, and IMRT designed to deliver IMRT at 60 to 63 Gy, PSPT at 74 Gy, and IMPT at the same doses and individualized radical radiotherapy in patients with extensive stage IIIB NSCLC (N = 10 for each approach) were compared. These patients were selected based on their extensive disease and considered to have no or borderline tolerance of IMRT at 60 to 63 Gy based on normal tissue dose-volume constraints (lung V20<35%, total mean lung dose <20 Gy; spinal cord dose, <45 Gy). The possibility of increasing the total tumor dose with IMPT for each patient without exceeding the dose-volume constraints (maximum tolerant dose, MTD) was also investigated.Results-Compared with IMRT, IMPT spared more lung, heart, spinal cord, and esophagus even with dose escalation from 63 Gy to 83.5 Gy, with a mean MTD of 74 Gy. Compared with PSPT, IMPT allowed further dose escalation from 74 Gy to mean MTD of while keeping all parameters of normal tissue sparing lower or similar. In addition, IMPT prevented lower target coverage in patients with complicated tumor anatomies. Conclusions: IMPT reduces the normal tissue dose and allows individualized radical radiotherapy for extensive stage IIIB NSCLC.
Stabilizing high-efficiency perovskite solar cells (PSCs) at operating conditions remains an unresolved issue hampering its large-scale commercial deployment. Here, we report a star-shaped polymer to improve charge transport and inhibit ion migration at the perovskite interface. The incorporation of multiple chemical anchor sites in the star-shaped polymer branches strongly controls the crystallization of perovskite film with lower trap density and higher carrier mobility and thus inhibits the nonradiative recombination and reduces the charge-transport loss. Consequently, the modified inverted PSCs show an optimal power conversion efficiency of 22.1% and a very high fill factor (FF) of 0.862, corresponding to 95.4% of the Shockley-Queisser limited FF (0.904) of PSCs with a 1.59-eV bandgap. The modified devices exhibit excellent long-term operational and thermal stability at the maximum power point for 1000 hours at 45°C under continuous one-sun illumination without any significant loss of efficiency.
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