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إدارة الأزمات في زمن الأوبئة : مقالات لـ 56 عالما في الإدارة
يضم هذا الكتاب خلاصة تجارب وعصارة أفكار 56 عالما، هم من أبرز علماء الإدارة في الصين، وقد حملوا على عاتقهم مسؤولية قيادة المؤسسات الصينية لسنوات عديدة، وهو كتاب مرجعي لكل المؤسسات على المستوى العالمي والتي إن حدث لها ضرر في فترات الأزمات أو الأوبئة، فلن يتوقف هذا الضرر عند ملاكها أو المنتفعين منها، بل سيمتد أثره إلى قطاعات عريضة من العمالة، وسيضرب القوة الإنتاجية ولا سيما الصادرات والواردات وغيرها من الموارد. ومن ثم فهم محاربون على الخطوط الأولى، مثلهم مثل الأطباء في أزمة انتشار فيروس كورونا المستجد، وإن كان مجال تخصص كل مختلفا منهم عن الآخر، ففريق منهم ينقذ حياة الناس، بينما الفريق الآخر ينقذ أقواتهم. ولغة الكتاب لغة سهلة وبسيطة، تنطلق أفكاره من مواقف عامة وليست من مواقف خاصة محددة، ومن هنا تعد أفكاره صالحة للتطبيق على المؤسسات الصغيرة والمتوسطة في كل مكان، والتي أصبح لزاما عليها أن تلجأ للابتكار والإبداع إن أرادت الاستمرار على قيد الحياة، وبات عليها أن تبحث وسط ركام الأزمة عن الإيجابيات التي يمكن أن تهب لها حياة جديدة وسبلا مبتكرة للخلاص.
Book
Observation of dynamic non-Hermitian skin effects
Non-Hermitian physics has emerged as a new paradigm that profoundly changes our understanding of non-equilibrium systems, introducing novel concepts such as exceptional points, spectral topology, and non-Hermitian skin effects (NHSEs). Most existing studies focus on non-Hermitian eigenstates, whereas dynamic properties have been discussed only recently, and the dynamic NHSEs are not yet confirmed in experiments. Here, we report the experimental observation of non-Hermitian skin dynamics using tunable one-dimensional nonreciprocal double-chain mechanical systems with glide-time symmetry. Remarkably, dynamic NHSEs are observed with various behaviors in different dynamic phases, which can be understood via the generalized Brillouin zone and the related concepts. Moreover, the observed dynamic NHSEs, amplifications, bulk unidirectional wave propagation, and boundary wave trapping provide promising ways to manipulate waves in a controllable and robust way. Our findings open a new pathway toward non-Hermitian dynamics, which will fertilize the study of non-equilibrium phases of matter.
Characterizing and classifying dynamic non-Hermitian skin effect is a key challenge in nonHermitian physics. Here, authors illustrated rich non-Hermitian skin dynamics and dynamic phases in one-dimensional systems with glide-time reversal symmetry.
Journal Article
Structural mechanism for NEK7-licensed activation of NLRP3 inflammasome
The NLRP3 inflammasome can be activated by stimuli that include nigericin, uric acid crystals, amyloid-β fibrils and extracellular ATP. The mitotic kinase NEK7 licenses the assembly and activation of the NLRP3 inflammasome in interphase. Here we report a cryo-electron microscopy structure of inactive human NLRP3 in complex with NEK7, at a resolution of
3
.8 Å. The earring-shaped NLRP3 consists of curved leucine-rich-repeat and globular NACHT domains, and the C-terminal lobe of NEK7 nestles against both NLRP3 domains. Structural recognition between NLRP3 and NEK7 is confirmed by mutagenesis both in vitro and in cells. Modelling of an active NLRP3–NEK7 conformation based on the NLRC4 inflammasome predicts an additional contact between an NLRP3-bound NEK7 and a neighbouring NLRP3. Mutations to this interface abolish the ability of NEK7 or NLRP3 to rescue NLRP3 activation in NEK7-knockout or NLRP3-knockout cells. These data suggest that NEK7 bridges adjacent NLRP3 subunits with bipartite interactions to mediate the activation of the NLRP3 inflammasome.
A cryo-electron microscopy structure of human NLRP3 in complex with the mitotic kinase NEK7 provides insights into the interactions that mediate the activation of the NLRP3 inflammasome.
Journal Article
Casting inorganic structures with DNA molds
Controlling the size and shape of nanoparticles synthesized in solution can be challenging, especially if the goal is to create less symmetric shapes for use in electronic and plasmonic applications. Sun et al. show that DNA “origami”—nanostructures in which the contacts between DNA strands are designed to assemble a particular shape—are sufficiently stiff to act as a mold for the growth of gold and silver nanostructures. The authors created shapes, including a gold particle with a rectangular cross section and a silver triangle with designed plasmonic properties. Science , this issue 10.1126/science.1258361 Shape-tunable metal nanoparticles form by replicating the hollow space inside designed DNA nanostructures. We report a general strategy for designing and synthesizing inorganic nanostructures with arbitrarily prescribed three-dimensional shapes. Computationally designed DNA strands self-assemble into a stiff “nanomold” that contains a user-specified three-dimensional cavity and encloses a nucleating gold “seed.” Under mild conditions, this seed grows into a larger cast structure that fills and thus replicates the cavity. We synthesized a variety of nanoparticles with 3-nanometer resolution: three distinct silver cuboids with three independently tunable dimensions, silver and gold nanoparticles with diverse cross sections, and composite structures with homo- and heterogeneous components. The designer equilateral silver triangular and spherical nanoparticles exhibited plasmonic properties consistent with electromagnetism-based simulations. Our framework is generalizable to more complex geometries and diverse inorganic materials, offering a range of applications in biosensing, photonics, and nanoelectronics.
Journal Article
Cryo-EM structures and dynamics of substrate-engaged human 26S proteasome
The proteasome is an ATP-dependent, 2.5-megadalton molecular machine that is responsible for selective protein degradation in eukaryotic cells. Here we present cryo-electron microscopy structures of the substrate-engaged human proteasome in seven conformational states at 2.8–3.6 Å resolution, captured during breakdown of a polyubiquitylated protein. These structures illuminate a spatiotemporal continuum of dynamic substrate–proteasome interactions from ubiquitin recognition to substrate translocation, during which ATP hydrolysis sequentially navigates through all six ATPases. There are three principal modes of coordinated hydrolysis, featuring hydrolytic events in two oppositely positioned ATPases, in two adjacent ATPases and in one ATPase at a time. These hydrolytic modes regulate deubiquitylation, initiation of translocation and processive unfolding of substrates, respectively. Hydrolysis of ATP powers a hinge-like motion in each ATPase that regulates its substrate interaction. Synchronization of ATP binding, ADP release and ATP hydrolysis in three adjacent ATPases drives rigid-body rotations of substrate-bound ATPases that are propagated unidirectionally in the ATPase ring and unfold the substrate.
Cryo-electron microscopy structures and dynamics of a substrate-engaged human 26S proteasome reveal in atomic detail three principal modes of coordinated ATP hydrolysis that regulate different steps in the degradation of a ubiquitylated protein.
Journal Article
Insight on multiple morphological abnormalities of sperm flagella in male infertility: what is new?
The syndrome of multiple morphological abnormalities of the sperm flagella (MMAF) is a specific kind of asthenoteratozoospermia with a mosaic of flagellar morphological abnormalities (absent, short, bent, coiled, and irregular flagella). MMAF was proposed in 2014 and has attracted increasing attention; however, it has not been clearly understood. In this review, we elucidate the definition of MMAF from a systematical view, the difference between MMAF and other conditions with asthenoteratozoospermia or asthenozoospermia (such as primary mitochondrial sheath defects and primary ciliary dyskinesia), the knowledge regarding its etiological mechanism and related genetic findings, and the clinical significance of MMAF for intracytoplasmic sperm injection and genetic counseling. This review provides the basic knowledge for MMAF and puts forward some suggestions for further investigations.
Journal Article
Measuring entanglement entropy and its topological signature for phononic systems
Entanglement entropy is a fundamental concept with rising importance in various fields ranging from quantum information science, black holes to materials science. In complex materials and systems, entanglement entropy provides insight into the collective degrees of freedom that underlie the systems’ complex behaviours. As well-known predictions, the entanglement entropy exhibits area laws for systems with gapped excitations, whereas it follows the Gioev-Klich-Widom scaling law in gapless fermion systems. However, many of these fundamental predictions have not yet been confirmed in experiments due to the difficulties in measuring entanglement entropy in physical systems. Here, we report the experimental verification of the above predictions by probing the nonlocal correlations in phononic systems. We obtain the entanglement entropy and entanglement spectrum for phononic systems with the fermion filling analog. With these measurements, we verify the Gioev-Klich-Widom scaling law. We further observe the salient signatures of topological phases in entanglement entropy and entanglement spectrum.
Entanglement entropy exhibits rich phenomenology connected to different kinds of phases in condensed matter. Here, the authors confirm some of these predictions by experimentally probing nonlocal correlations in 1D and 2D phononic crystal based on interconnected resonating acoustic cavities.
Journal Article
Loss of Setd2 promotes Kras-induced acinar-to-ductal metaplasia and epithelia–mesenchymal transition during pancreatic carcinogenesis
ObjectiveSETD2, the sole histone H3K36 trimethyltransferase, is frequently mutated or deleted in human cancer, including pancreatic ductal adenocarcinoma (PDAC). However, whether SETD2/H3K36me3 alteration results in PDAC remains largely unknown.DesignTCGA(PAAD) public database and PDAC tissue array with SETD2/H3K36me3 staining were used to investigate the clinical relevance of SETD2 in PDAC. Furthermore, to define the role of SETD2 in the carcinogenesis of PDAC, we crossed conditional Setd2 knockout mice (Pdx cre Setd2 flox/flox) together with Kras G12D mice. Moreover, to examine the role of SETD2 after ductal metaplasia, Crisp/cas9 was used to deplete Setd2 in PDAC cells. RNA-seq and H3K36me3 ChIP-seq were performed to uncover the mechanism.ResultsSETD2 mutant/low expression was correlated with poor prognosis in patients with PDAC. Next, we found that Setd2 acted as a putative tumour suppressor in Kras-driven pancreatic carcinogenesis. Mechanistically, Setd2 loss in acinar cells facilitated Kras-induced acinar-to-ductal reprogramming, mainly through epigenetic dysregulation of Fbxw7. Moreover, Setd2 ablation in pancreatic cancer cells enhanced epithelia–mesenchymal transition (EMT) through impaired epigenetic regulation of Ctnna1. In addition, Setd2 deficiency led to sustained Akt activation via inherent extracellular matrix (ECM) production, which would favour their metastasis.ConclusionTogether, our findings highlight the function of SETD2 during pancreatic carcinogenesis, which would advance our understanding of epigenetic dysregulation in PDAC. Moreover, it may also pave the way for development of targeted, patients-tailored therapies for PDAC patients with SETD2 deficiency.
Journal Article
The effect of yoga on sleep quality and insomnia in women with sleep problems: a systematic review and meta-analysis
Background
To examine the effectiveness and safety of yoga of women with sleep problems by performing a systematic review and meta-analysis.
Methods
Medline/PubMed, ClinicalKey, ScienceDirect, Embase, PsycINFO, and the Cochrane Library were searched throughout the month of June, 2019. Randomized controlled trials comparing yoga groups with control groups in women with sleep problems were included. Two reviewers independently evaluated risk of bias by using the risk of bias tool suggested by the Cochrane Collaboration for programming and conducting systematic reviews and meta-analyses. The main outcome measure was sleep quality or the severity of insomnia, which was measured using subjective instruments, such as the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), or objective instruments such as polysomnography, actigraphy, and safety of the intervention. For each outcome, a standardized mean difference (SMD) and confidence intervals (CIs) of 95% were determined.
Results
Nineteen studies in this systematic review included 1832 participants. The meta-analysis of the combined data conducted according to Comprehensive Meta-Analysis showed a significant improvement in sleep (SMD = − 0.327, 95% CI = − 0.506 to − 0.148,
P
< 0.001). Meta-analyses revealed positive effects of yoga using PSQI scores in 16 randomized control trials (RCTs), compared with the control group in improving sleep quality among women using PSQI (SMD = − 0.54; 95% CI = − 0.89 to − 0.19;
P
= 0.003). However, three RCTs revealed no effects of yoga compared to the control group in reducing insomnia among women using ISI (SMD = − 0.13; 95% CI = − 0.74 to 0.48;
P
= 0.69). Seven RCTs revealed no evidence for effects of yoga compared with the control group in improving sleep quality for women with breast cancer using PSQI (SMD = − 0.15; 95% CI = − 0.31 to 0.01;
P
= 0.5). Four RCTs revealed no evidence for the effects of yoga compared with the control group in improving the sleep quality for peri/postmenopausal women using PSQI (SMD = − 0.31; 95% CI = − 0.95 to 0.33;
P
= 0.34). Yoga was not associated with any serious adverse events.
Discussion
This systematic review and meta-analysis demonstrated that yoga intervention in women can be beneficial when compared to non-active control conditions in term of managing sleep problems. The moderator analyses suggest that participants in the non-breast cancer subgroup and participants in the non-peri/postmenopausal subgroup were associated with greater benefits, with a direct correlation of total class time with quality of sleep among other related benefits.
Journal Article