Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
56,606
result(s) for
"Li, B."
Sort by:
Understanding colossal barocaloric effects in plastic crystals
Plastic crystal neopentylglycol (NPG) exhibits colossal barocaloric effects (BCEs) with record-high entropy changes, offering exciting prospects for the field of solid-state cooling through the application of moderate pressures. Here, we show that the intermolecular hydrogen bond plays a key role in the orientational order of NPG molecules, while its broken due to thermal perturbation prominently weakens the activation barrier of orientational disorder. The analysis of hydrogen bond strength, rotational entropy free energy and entropy changes provides insightful understanding of BCEs in order-disorder transition. External pressure reduce the hydsrogen bond length and enhance the activation barrier of orientational disorder, which serves as a route of varying intermolecular interaction to tune the order-disorder transition. Our work provides atomic-scale insights on the orientational order-disorder transition of NPG as the prototypical plastic crystal with BCEs, which is helpful to achieve superior caloric materials by molecular designing in the near future.
Colossal barocaloric effects with high entropy changes is reported in plastic crystal neopentylglycol, while microscopic mechanism needs to be further explored. Here, the authors show hydrogen bond related reorientational dynamics of neopentylglycol and provide insights in order-disorder transition.
Journal Article
Managing cyclic vomiting syndrome in children: beyond the guidelines
Cyclic vomiting syndrome (CVS) in children is characterized by frequent hospitalizations, multiple comorbidities, and poor quality of life. In the absence of robust data, the treatment of CVS remains largely empiric starting with the 2008 NASPGHAN Consensus Statement recommendations of cyproheptadine for children < 5 years of age and amitriptyline for those ≥ 5 years with propranolol serving as the second-line agent. Comprehensive management begins with lifestyle alterations, and extends to medications, supplements, and stress reduction therapies. Standard drug therapy is organized by the four phases of the illness: (1) interictal (preventative medications and mitochondrial supplements), (2) prodromal (abortive agents), (3) vomiting (fluids/energy substrates, antiemetics, analgesics, and sedatives) and (4) recovery (supportive care and nutrition). Because the response to treatment is heterogeneous, clinicians often trial several different preventative strategies including NK1 antagonists, cautious titration of amitriptyline to higher doses, anticonvulsants, Ca2+-channel blockers, and other TCA antidepressants. When the child remains refractory to treatment, reconsideration of possible missed diagnoses and further mono- or combination therapy and psychotherapy can be guided by accompanying comorbidities (especially anxiety), specific subphenotype, and when available, genotype. For hospital intervention, IV fluids with 10% dextrose, antiemetics, and analgesics can lessen symptoms while effective sedation in some instances can truncate severe episodes.Conclusion: Although management of CVS remains challenging to the clinician, approaches based upon recent literature and accumulated experience with subgroups of patients has led to improved treatment of the refractory and hospitalized patient.What is Known:•Cyclic vomiting syndrome is a complex disorder that remains challenging to manage.•Previous therapy has been guided by the NASPGHAN Consensus Statement of 2008.What is New:•New prophylactic approaches include NK1 antagonists and higher dosages of amitriptyline.•Strategies based upon comorbidities and subphenotype are helpful in refractory patients.
Journal Article
50 years of ASEAN and Singapore
\"On the 8th of August 2017, ASEAN will celebrate the 50th anniversary of its founding. ASEAN is of great importance to Singapore, the region and the world. In 1967, the Association of Southeast Asian Nations, or ASEAN in short, was founded by five countries in Southeast Asia which had just gained independence from their former colonial masters, united by a determination for the region to live in peace and stability. Singapore was one of the five founding members of ASEAN, together with Indonesia, Malaysia, Philippines and Thailand. The grouping was joined later by Brunei (1984), Vietnam (1995), Laos and Myanmar (1997), and finally, Cambodia (1999). ASEAN is today a very successful inter-governmental organization which promotes peace, stability, economic development and regional integration. This volume brings together 50 essays written by Singaporeans who have played a part in the partnership between ASEAN and Singapore. The reader will be able to glean an insight into the workings of ASEAN and Singapore's contributions to ASEAN through the lens of diplomats, academics, civil society leaders and officials\"--Provided by publisher.
Book
LncRNA HULC triggers autophagy via stabilizing Sirt1 and attenuates the chemosensitivity of HCC cells
Considerable evidences have shown that autophagy has an important role in tumor chemoresistance. However, it is still unknown whether the lncRNA HULC (highly upregulated in liver cancer) is involved in autophagy and chemoresistance of hepatocellular carcinoma (HCC). In this study, we for the first time demonstrated that treatment with antitumor reagents such as oxaliplatin, 5-fluorouracil and pirarubicin (THP) dramatically induced HULC expression and protective autophagy. Silencing of HULC sensitized HCC cells to the three antitumor reagents via inhibiting protective autophagy. Ectopic expression of HULC elicited the autophagy of HCC cells through stabilizing silent information regulator 1 (Sirt1) protein. The investigation for the corresponding mechanism by which HULC stabilized Sirt1 revealed that HULC upregulated ubiquitin-specific peptidase 22 (USP22), leading to the decrease of ubiquitin-mediated degradation of Sirt1 protein by removing the conjugated polyubiquitin chains from Sirt1. Moreover, we found that miR-6825-5p, miR-6845-5p and miR-6886-3p could decrease the level of USP22 protein by binding to the 3′-untranlated region of USP22 mRNA. All the three microRNAs (miRNAs) were downregulated by HULC, which resulted in the elevation of USP22. In addition, we showed that the level of HULC was positively correlated with that of Sirt1 protein in human HCC tissues. Collectively, our data reveals that the pathway ‘HULC/USP22/Sirt1/ protective autophagy’ attenuates the sensitivity of HCC cells to chemotherapeutic agents, suggesting that this pathway may be a novel target for developing sensitizing strategy to HCC chemotherapy.
Journal Article
اتجاهات السياسة الأمريكية في عهد الرئيس جو بايدن : تفكيك وتحليل الأيام المئة الأولى من حكم الرئيس
إن تقييم الأيام المئة الأولى من إدارة الرئيس الأمريكي جو بايدن ليس حكما نهائيا على طريقة حكمه بأي حال من الأحوال، بل يلقي بعض الضوء على الوجهة التي تسير نحوها إدارته. وكثيرا ما يشار إلى الأيام المئة الأولى باسم \"فترة شهر العسل\"، وقد انتهت الآن، وتعهد بايدن بإعادة مكتب الرئاسة إلى المكانة التي كان يتمتع بها قبل تولي سلفه دونالد ترامب المنصب. ركزت العديد من قرارات بايدن التنفيذية على مكافحة فيروس كورونا المستجد \"كوفيد-19\"، ولكن معظم خطة عمله أو أجندته الخاصة بالسياستين الداخلية والخارجية تختلف أسلوبا وجوهرا عن خطة الرئيس السابق دونالد ترامب. سوف تدرس هذه المجموعة من الدراسات، التي كتبها خبراء دوليون معروفون، التحديات التي تواجه الرئيس بايدن وتقدم توقعات بشأن أربع مجالات سياساتية رئيسية، هي : طبيعة التغيرات التي شهدتها أو يتوقع أن تشهدها السياسة الداخلية الأمريكية، وعلاقات واشنطن مع كل من روسيا، والصين، والشرق الأوسط. ويناقش المؤلفون توجهات السياستين الداخلية والخارجية للرئيس بايدن ويقدمون بعض التوقعات حول التداعيات المحتملة التي ربما تأتي من هذه السياسات أو تنشأ عنها.
BOOK
HXMT identification of a non-thermal X-ray burst from SGR J1935+2154 and with FRB 200428
Fast radio bursts (FRBs) are short pulses observed in the radio band from cosmological distances1. One class of models invokes soft gamma-ray repeaters (SGRs), or magnetars, as the sources of FRBs2. Some radio pulses have been observed from some magnetars3, but no FRB-like events have been detected in association with any magnetar burst, including one giant flare4. Recently, a pair of FRB-like bursts (termed FRB 200428) separated by 29 milliseconds were detected from the general direction of the Galactic magnetar SGR J1935+2154 (refs. 5,6). Here, we report the detection of a non-thermal X-ray burst in the 1–250 keV energy band with the Insight-HXMT satellite7, which we identify as having been emitted from SGR J1935+2154. The burst showed two hard peaks with a separation of 34 milliseconds, broadly consistent with that of the two bursts in FRB 200428. The delay time between the double radio peak and the X-ray peaks is about 8.62 s, fully consistent with the dispersion delay of FRB 200428. We thus identify the non-thermal X-ray burst to be associated with FRB 200428, whose high-energy counterpart is the two hard X-ray peaks. Our results suggest that the non-thermal X-ray burst and FRB 200428 share the same physical origin in an explosive event from SGR J1935+2154.Insight-HXMT detected a double-peaked X-ray burst from Galactic magnetar SGR J1935+2154, consistent with two fast radio bursts (FRBs) observed from the same object within seconds. This coincidence suggests a common physical origin, and gives insight into the mechanism behind the origin of FRBs.
Journal Article
The First GECAM Observation Results on Terrestrial Gamma‐Ray Flashes and Terrestrial Electron Beams
Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) is a space‐borne instrument dedicated to monitoring high‐energy transients, including Terrestrial Gamma‐ray Flashes (TGFs) and Terrestrial Electron Beams (TEBs). We implemented a TGF/TEB search algorithm for GECAM, with which 147 bright TGFs, 2 typical TEBs and 2 special TEB‐like events are identified during an effective observation time of ∼9 months. We show that, with gamma‐ray and charged particle detectors, GECAM can effectively identify and distinguish TGFs and TEBs, and measure their temporal and spectral properties in detail. A very high TGF‐lightning association rate of ∼80% is obtained between GECAM and GLD360 in east Asia region.
Plain Language Summary
Terrestrial gamma‐ray flashes (TGFs) and Terrestrial Electron Beams (TEBs) represent the most energetic radioactive phenomena in the atmosphere of the Earth. They reflect a natural particle accelerator that can boost electrons up to at least several tens of mega electron volts and produce gamma‐ray radiation. With novel detection technologies, Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) is a new powerful instrument to observe TGFs and TEBs, as well as study their properties. For example, it is difficult for most space‐borne high‐energy instruments to distinguish between TGFs and TEBs. However, we show here that, with the joint observation of gamma‐ray and charged particle detectors, GECAM can effectively identify TGFs and TEBs. GECAM can also reveal their fine features in the light curves and spectra.
Key Points
During 9‐month observation, Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) has detected 147 bright Terrestrial Gamma‐ray Flashes (TGFs), 2 typical Terrestrial Electron Beams (TEBs), and 2 special TEB‐like events
With novel detector design, GECAM can effectively classify TGFs and TEBs, and reveal their fine temporal features
We obtained a very high TGF‐lightning association rate (∼80%) between GECAM and GLD360 in east Asia region
Journal Article