Metal‐to‐metal charge transfer (MMCT) describes electron transfer between metal ions, to generate valence isomers with markedly different electronic configurations. In particular, MMCT changes the ...spin states of single‐metal sites and the coupling interactions between them, while also changing the symmetry in charge distribution. The result is a drastic change in both magnetic and electric properties of the affected material. Moreover, MMCT causes significant variation in bond length and absorption spectra, and induces unusual thermal expansion and photochromic behavior. Thus, materials demonstrating MMCT in response to external stimuli are excellent candidates for switchable multifunctional devices with synergistic responses. In this Minireview, recent progress in utilizing MMCT units as actuators to tune magnetic, electric, thermal expansion, and photochromic properties in cyanide‐bridged systems is highlighted, and emphasis is given to the remaining challenges and future perspectives in the field.
Switched on: Metal‐to‐metal charge transfer (MMCT) is widely studied in valence tautomerism compounds and can be used to construct switchable functional materials. Recent progress in the development of MMCT actuators is summarized; including, modulation of molecular nanomagnets, electric and thermal expansion, and photochromic properties.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Magnetic bistable materials that feature magnetic hysteresis are comparable to elementary binary units and promising for application in switches and memory devices. In this work, we report a material ...that consists of parallel cyanide-bridged Fe
-W
coordination chains linked together through rigid bis(imidazolyl)-benzene ligands and displays multiple magnetic states. The paramagnetic high-spin and diamagnetic low-spin states of the spin-crossover Fe
ions can be interconverted by reversible light-induced excited spin state trapping (LIESST) by alternating between light irradiation of 808 and 473 nm. At 1.8 K, under 808-nm-light irradiation, magnetic interactions between the photogenerated paramagnetic high-spin Fe
centres and the W
centres lead to long fragments that exhibit single-chain magnet behaviour, with a wide magnetic hysteresis and a large coercive field of 19 kOe; under a 473 nm light, isolated Fe
-W
fragments behave as single-molecule magnets instead. At 3.3 K, the high-spin form still displays magnetic hysteresis, albeit narrower, whereas the low-spin one does not.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
It is very challenging to synthesize stable trivalent rare‐earth complexes in which the coordination number is lower than 3 for the high oxidation state, there is a large ion radius and nearly ...non‐bonding character of trivalent lanthanide ions. The bulky phenol ligand ArOH (Ar=2,6‐Dipp2C6H3, Dipp=2,6‐diisopropylphenyl) was utilized to construct low‐coordinate lanthanide compound (ArO)Ln(OAr′) (Ar′=6‐Dipp‐2‐(2′‐iPr‐6′‐CHMe(CH2−)C6H3)C6H3O−; Ln=Tb, Dy, Ho, Er, Tm). These complexes and the free ligand ArOH were isostructural. Magnetic measurements and theoretical studies demonstrated that both the oblate‐type dysprosium and prolate‐type erbium analogues exhibited single‐ion magnet (SIM) behavior. The bulky phenol ligands provided strong uniaxial ligand field, making the dysprosium SIM possessing blocking barrier up to 961 K.
SIM city: Low‐coordinate single‐ion magnets were achieved by intercalation of dysprosium and erbium into a bulky phenol matrix. Both the oblate‐type dysprosium and prolate‐type erbium analogues exhibited single‐ion magnet (SIM) behavior. Furthermore, the dysprosium SIM exhibited blocking barrier up to 961 K.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Mesenchymal stem cells (MSCs) protect the endothelial barrier complex and survival, implicated in the pathogenesis of acute lung injury (ALI) via paracrine hepatocyte growth factor (HGF). However, ...the mechanism of HGF in endothelial regulation remains unclear. Here, we introduced a coculture protocol of pulmonary microvascular endothelial cells (PMVECs) and overexpression of the HGF gene of MSCs (MSC‐HGF). Immunofluorescence and endothelial permeability analysis revealed that MSC‐HGF protected endothelial tight junction protein occludin expression and attenuated cellular permeability as well as endothelial apoptosis. To investigate the novel mechanism mammalian TOR (mTOR)/ signal transducer and activator of transcription 3 (STAT‐3) signaling in HGF protective effects against endothelial barrier and apoptosis, we used recombinant mouse HGF in endothelial cells. In addition, we used mTOR inhibitor rapamycin to inhibit the mTOR pathway. Our study demonstrated that rapamycin decreased the protective effects of HGF on the endothelium by decreasing tight junction protein occludin expression and cell proliferation, and raising lipopolysaccharide (LPS)‐induced endothelial permeability, endothelial cell injury factors ET‐1 and vWF. Similarly, the protective effects of HGF on reducing endothelial barrier and apoptosis were weakened when PMVECs were treated with the STAT‐3 inhibitor S3I‐201. Moreover, mTOR/STAT‐3 were activated by HGF demonstrated as raising mTOR (Ser2448) and STAT3 (Ser727) phosphorylation proteins, leading to endothelial barrier improvement and survival. Reversely, rapamycin or S3I‐201 inhibited mTOR/STAT‐3 activation. Taken together, our findings highlight that the activation of the mTOR/STAT‐3 pathway provides novel mechanistic insights into MSC‐secreted HGF protection against LPS‐induced vascular endothelial permeability dysfunction and apoptosis, which contributes to decreasing microvascular loss and lung injury.
Our findings highlight that activating mammalian TOR (mTOR)/ signal transducer and transcription 3 (STAT‐3) pathway provides novel mechanistic insights into mesenchymal stem cell (MSC)‐secreted hepatocyte growth factor (HGF) protective against lipopolysaccharide (LPS)‐induced vascular endothelial permeability dysfunction and apoptosis, which contributes to decreasing microvascular loss and lung injury.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Structure-based stabilization of protein–protein interactions (PPIs) is a promising strategy for drug discovery. However, this approach has mainly focused on the stabilization of native PPIs, and ...non-native PPIs have received little consideration. Here, we identified a non-native interaction interface on the three-dimensional dimeric structure of the N-terminal domain of the MERS-CoV nucleocapsid protein (MERS-CoV N-NTD). The interface formed a conserved hydrophobic cavity suitable for targeted drug screening. By considering the hydrophobic complementarity during the virtual screening step, we identified 5-benzyloxygramine as a new N protein PPI orthosteric stabilizer that exhibits both antiviral and N-NTD protein-stabilizing activities. X-ray crystallography and small-angle X-ray scattering showed that 5-benzyloxygramine stabilizes the N-NTD dimers through simultaneous hydrophobic interactions with both partners, resulting in abnormal N protein oligomerization that was further confirmed in the cell. This unique approach based on the identification and stabilization of non-native PPIs of N protein could be applied toward drug discovery against CoV diseases.
Evidence on preventing Alzheimer's disease (AD) is challenging to interpret due to varying study designs with heterogeneous endpoints and credibility. We completed a systematic review and ...meta-analysis of current evidence with prospective designs to propose evidence-based suggestions on AD prevention.
Electronic databases and relevant websites were searched from inception to 1 March 2019. Both observational prospective studies (OPSs) and randomised controlled trials (RCTs) were included. The multivariable-adjusted effect estimates were pooled by random-effects models, with credibility assessment according to its risk of bias, inconsistency and imprecision. Levels of evidence and classes of suggestions were summarised.
A total of 44 676 reports were identified, and 243 OPSs and 153 RCTs were eligible for analysis after exclusion based on pre-decided criteria, from which 104 modifiable factors and 11 interventions were included in the meta-analyses. Twenty-one suggestions are proposed based on the consolidated evidence, with Class I suggestions targeting 19 factors: 10 with Level A strong evidence (education, cognitive activity, high body mass index in latelife, hyperhomocysteinaemia, depression, stress, diabetes, head trauma, hypertension in midlife and orthostatic hypotension) and 9 with Level B weaker evidence (obesity in midlife, weight loss in late life, physical exercise, smoking, sleep, cerebrovascular disease, frailty, atrial fibrillation and vitamin C). In contrast, two interventions are not recommended: oestrogen replacement therapy (Level A2) and acetylcholinesterase inhibitors (Level B).
Evidence-based suggestions are proposed, offering clinicians and stakeholders current guidance for the prevention of AD.
Photo-switched spin-crossover (SCO) complexes, especially iron(
ii
)-based ones, have been widely studied in the past few decades owing to their promising applications in high density information ...storage, optical memory materials, magneto-optical devices and light-responsive switches. In particular, photo-induced spin-crossover involves not only the changing of the spin state and magnetic anisotropy of metal centers, but also the magnetic coupling interactions between neighbouring metal centers, which is also of vital importance to the overall magnetic properties. The exchange interactions can be reversibly switched on and off
via
light-induced excited spin-state trapping (LIESST) and reverse processes, leading to an abrupt changing of the magnetization value, spontaneous magnetization, and even molecular nanomagnet properties, depending on their dimensionalities and topologies. In this feature article, we will discuss the recent progress on the photoswitchable magnetic coupling in spin-crossover complexes reported by both our group and other groups and highlight the role of magnetic coupling in determining their magnetic properties. The design strategy of magnetically coupled photo-switched SCO complexes will be discussed. Finally, a perspective with respect to the remaining challenges and growing trends in this field will be given.
This feature article summarizes the recent progress in the magnetically coupled spin-crossover (SCO) complexes. The photo-switched molecular nanomagnet property, long range magnetic ordering, and the perspectives of SCO complexes are also presented.
The aetiology of Alzheimer's disease (AD) is believed to involve environmental exposure and genetic susceptibility. The aim of our present systematic review and meta-analysis was to roundly evaluate ...the association between AD and its modifiable risk factors.
We systematically searched PubMed and the Cochrane Database of Systematic Reviews from inception to July 2014, and the references of retrieved relevant articles. We included prospective cohort studies and retrospective case-control studies.
16,906 articles were identified of which 323 with 93 factors met the inclusion criteria for meta-analysis. Among factors with relatively strong evidence (pooled population >5000) in our meta-analysis, we found grade I evidence for 4 medical exposures (oestrogen, statin, antihypertensive medications and non-steroidal anti-inflammatory drugs therapy) as well as 4 dietary exposures (folate, vitamin E/C and coffee) as protective factors of AD. We found grade I evidence showing that one biochemical exposure (hyperhomocysteine) and one psychological condition (depression) significantly increase risk of developing AD. We also found grade I evidence indicative of complex roles of pre-existing disease (frailty, carotid atherosclerosis, hypertension, low diastolic blood pressure, type 2 diabetes mellitus (Asian population) increasing risk whereas history of arthritis, heart disease, metabolic syndrome and cancer decreasing risk) and lifestyle (low education, high body mass index (BMI) in mid-life and low BMI increasing the risk whereas cognitive activity, current smoking (Western population), light-to-moderate drinking, stress, high BMI in late-life decreasing the risk) in influencing AD risk. We identified no evidence suggestive of significant association with occupational exposures.
Effective interventions in diet, medications, biochemical exposures, psychological condition, pre-existing disease and lifestyle may decrease new incidence of AD.
Abstract Background Neuropsychiatric symptoms (NPS) are being increasingly recognized as common serious problems in Alzheimer’s disease (AD). However, published data on the prevalence of NPS in ...persons with AD are conflicting. This meta-analysis aimed to estimate the prevalence of NPS in persons with AD. Methods Studies published from 1964 to September 30, 2014, were identified from PubMed and Embase database, reference lists and conference abstracts. We calculated prevalence rates and conducted meta-regression analysis with random-effects model, according to study characteristics, population demographics or condition information. Results We identified 48 eligible articles, which provided data for 12 NPS reported in Neuropsychiatric Inventory (NPI). The most frequent NPS was apathy, with an overall prevalence of 49% (95% CI 41–57%), followed by depression, aggression, anxiety and sleep disorder, the pooled prevalence estimates of which were 42% (95% CI 37–46%), 40% (95% CI 33–46%), 39% (95% CI 32–46%) and 39% (95% CI 30–47%), respectively. The less prevalent NPS were irritability (36%, 31–41%), appetite disorder (34%, 27–41%), aberrant motor behavior (32%, 25–38%), delusion (31%, 27–35%), disinhibition (17%, 12–21%) and hallucination (16%, 13–18%). Least common was euphoria, with an overall prevalence of 7% (95% CI 5–9%). Limitations Several aspects, such as the quality of included studies were not always optimal and there was significant heterogeneity of prevalence estimate across studies. Conclusions NPS were observed to be highly prevalent in AD patients. Disease duration, age, education level, population origin and the severity of cognitive impairment had influence on the prevalence of some NPS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We sought to identify the risk factors for predicting the progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD).
We searched 6 electronic databases for cohort studies published ...from January 1966 to March 2015. Eligible studies were required to be relevant to the subject and provide sufficient data for our needs.
60 cohort studies with 14,821 participants from 16 countries were included in the meta-analysis. The strongest positive associations between risk factors and the progression from MCI to AD were found for abnormal cerebrospinal fluid (CSF), phosphorylated τ (p-τ) (relative risk (RR)=2.43, 95% CI=1.70 to 3.48), abnormal CSF τ/Aβ1-42 (RR=3.77, 95% CI=2.34 to 6.09), hippocampal atrophy (RR=2.59, 95% CI=1.95 to 3.44), medial temporal lobe atrophy (RR=2.11, 95% CI=1.70 to 2.63) and entorhinal atrophy (RR=2.03, 95% CI=1.57 to 2.62). Further positive associations were found for the presence of apolipoprotein E (APOE)ε4ε4 and at least 1 APOEε4 allele, CSF total-τ (t-τ), white matter hyperintensity volume, depression, diabetes, hypertension, older age, female gender, lower mini-mental state examination (MMSE) score and higher AD assessment scale cognitive subscale (ADAS-cog) score. Negative associations were found for high body mass index (RR=0.85, 95% CI=0.76 to 0.96) and higher auditory verbal learning test delay score (RR=0.86, 95% CI=0.77 to 0.96).
Patients with MCI with APOEε4, abnormal CSF τ level, hippocampal and medial temporal lobe atrophy, entorhinal atrophy, depression, diabetes, hypertension, older age, female gender, lower MMSE score and higher ADAS-cog score, had a high risk for the progression to AD.
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