Abstract
Rare earth (RE
3+
)-doped phosphors generally suffer from thermal quenching, in which their photoluminescence (PL) intensities decrease at high temperatures. Herein, we report a class of ...unique two-dimensional negative-thermal-expansion phosphor of Sc
2
(MoO
4
)
3
:Yb/Er. By virtue of the reduced distances between sensitizers and emitters as well as confined energy migration with increasing the temperature, a 45-fold enhancement of green upconversion (UC) luminescence and a 450-fold enhancement of near-infrared downshifting (DS) luminescence of Er
3+
are achieved upon raising the temperature from 298 to 773 K. The thermally boosted UC and DS luminescence mechanism is systematically investigated through in situ temperature-dependent Raman spectroscopy, synchrotron X-ray diffraction and PL dynamics. Moreover, the luminescence lifetime of
4
I
13/2
of Er
3+
in Sc
2
(MoO
4
)
3
:Yb/Er displays a strong temperature dependence, enabling luminescence thermometry with the highest relative sensitivity of 12.3%/K at 298 K and low temperature uncertainty of 0.11 K at 623 K. These findings may gain a vital insight into the design of negative-thermal-expansion RE
3+
-doped phosphors for versatile applications.
In addition to coding proteins, RNA molecules, especially long noncoding RNAs (lncRNAs), have well‐established functions in regulating gene expression. The number of studies focused on the roles ...played by different types of lncRNAs in a variety of plant biological processes has markedly increased. These lncRNA roles involve plant vegetative and reproductive growth and responses to biotic and abiotic stresses. In this review, we examine the classification, mechanisms, and functions of lncRNAs and then emphasize the roles played by these lncRNAs in the communication between plants and the environment mainly with respect to the following environmental factors: temperature, light, water, salt stress, and nutrient deficiencies. We also discuss the consensus among researchers and the remaining challenges and underscore the exciting ways lncRNAs may affect the biology of plants.
Core Ideas
We summarize the classification, mechanisms, and functions of lncRNAs in plants.
We emphasize the roles of lncRNAs in the communication between plants and the environment.
We focus on the environmental factors including temperature, light, water, salt stress, and nutrient deficiencies.
AbstractObjectiveTo examine the protective effects of appropriate personal protective equipment for frontline healthcare professionals who provided care for patients with coronavirus disease 2019 ...(covid-19).DesignCross sectional study.SettingFour hospitals in Wuhan, China.Participants420 healthcare professionals (116 doctors and 304 nurses) who were deployed to Wuhan by two affiliated hospitals of Sun Yat-sen University and Nanfang Hospital of Southern Medical University for 6-8 weeks from 24 January to 7 April 2020. These study participants were provided with appropriate personal protective equipment to deliver healthcare to patients admitted to hospital with covid-19 and were involved in aerosol generating procedures. 77 healthcare professionals with no exposure history to covid-19 and 80 patients who had recovered from covid-19 were recruited to verify the accuracy of antibody testing.Main outcome measuresCovid-19 related symptoms (fever, cough, and dyspnoea) and evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, defined as a positive test for virus specific nucleic acids in nasopharyngeal swabs, or a positive test for IgM or IgG antibodies in the serum samples.ResultsThe average age of study participants was 35.8 years and 68.1% (286/420) were women. These study participants worked 4-6 hour shifts for an average of 5.4 days a week; they worked an average of 16.2 hours each week in intensive care units. All 420 study participants had direct contact with patients with covid-19 and performed at least one aerosol generating procedure. During the deployment period in Wuhan, none of the study participants reported covid-19 related symptoms. When the participants returned home, they all tested negative for SARS-CoV-2 specific nucleic acids and IgM or IgG antibodies (95% confidence interval 0.0 to 0.7%).ConclusionBefore a safe and effective vaccine becomes available, healthcare professionals remain susceptible to covid-19. Despite being at high risk of exposure, study participants were appropriately protected and did not contract infection or develop protective immunity against SARS-CoV-2. Healthcare systems must give priority to the procurement and distribution of personal protective equipment, and provide adequate training to healthcare professionals in its use.
Molecular ferroelectrics with high-temperature reversible phase-transition behaviors are very rare and have currently become one of the hotspots in the field of ferroelectric materials. Herein we ...display two new crown ether clathrates possessing unusual high-temperature ferroelectric phase-transition behaviors, cyclohexyl ammonium 18-crown-6 tetrafluoroborate (or perchlorate), Hcha-(18-crown-6)+ BF4− (1) and Hcha-(18-crown-6)+ClO4− (2) (Hcha = protonated cyclohexyl ammonium). We have proven their reversible structural phase transitions by variable-temperature PXRD measurements and temperature evolutions of Raman bands. Both clathrates exhibit clear ferroelectric phase transitions at about 397 and 390 K, respectively, revealed by the thermal anomalies of differential scanning calorimetry (DSC) measurements, together with abrupt dielectric anomalies in the heating and cooling processes. The measurements on ferroelectric properties using the single crystals showed optimized spontaneous polarization (P s) of ca. 3.27 μC cm–2 for 1 and 3.78 μC cm–2 for 2.
Molecular magnetorefrigerant materials for low-temperature magnetic refrigeration and single-molecule magnets for high-density information storage and quantum computing have received extensive ...attention from chemists and magnetic experts. Lanthanide ions with unique magnetic properties have always been considered as ideal candidates for the construction of such materials. This frontier article focuses on Gd
III
-based molecular magnetorefrigerants and lanthanide-based single-molecule magnets and highlights the most significant advances.
The progress of lanthanide molecular magnetic materials from Gd
III
-based molecular magnetorefrigerants to lanthanide-based single-molecule magnets has been reviewed, and the most important advances in this field have also been highlighted.
A nanocomposite is described that consists of TmPO
and graphene oxide (GO) and is used to modify a glassy carbon electrode (GCE) to obtain a sensor for simultaneous determination of ascorbic acid ...(AA), dopamine (DA) and uric acid (UA). GO and TmPO
were synthesized via the Hummers method and by a hydrothermal method, respectively. The nanocomposite was characterized by transmission electron microscopy, energy dispersive X-ray spectroscopy, powder X-ray diffraction and Fourier transform infrared spectroscopy. The electrochemical properties of the modified GCE were studied by electrochemical impedance spectroscopy and cyclic voltammetry. The good performance of the modified GCE results from the synergistic effects between GO with its good electrical conductivity and of TmPO
as the electron mediator that accelerates the electron transfer rate. Compared to a bare GCE, a GO/GCE and a TmPO
/GCE, the GO/TmPO
/GCE exhibits three well-defined and separated oxidation peaks (at -0.05, +0.13 and + 0.26 V vs. SCE). Responses to AA, DA and UA are linear in the 0.1-1.0 mM, 2-20 μM and 10-100 μM concentration ranges, respectively. Graphical abstract Schematic presentation of a nanocomposite that consists TmPO
and graphene oxide (GO) and is used to modify a glassy carbon electrode (GCE) to obtain a sensor for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA).
Metal-organic frameworks (MOFs) are a novel class of hybrid porous multi-functional materials consisting of metal ions/clusters and organic ligands. MOFs have exclusive benefits due to their tunable ...structure and diverse properties. Luminescent MOFs (LMOFs) exhibit both porosity and light emission. They display abundant host and guest responses, making them conducive to sensing. Currently, LMOF sensing research is gaining more depth, with attention given to their device and practical applications. This work reviews recent advancements and device applications of LMOFs as chemical sensors toward ions, volatile organic compounds, biomolecules, and environmental toxins. Furthermore, the detection mechanism and the correlation between material properties and structure are elaborated. This analysis serves as a valuable reference for the preparation and efficient application of targeted LMOFs.
Recent progress in luminescent metal-organic frameworks for detecting ions, volatile organic compounds, biomolecules and environmental toxins and device fabrication has been reviewed.
As alternatives to the expensive and increasing shortage of
3
He for ultralow-temperature refrigeration, molecule-based magnetorefrigerant materials have attracted much attention in past decades. ...Among these, Gd(
iii
)-based inorganic polymers, metal-organic frameworks, and coordination polymers with large magnetic densities and weak magnetic interactions have become a research focus. In this review, the synthesis, structures, and magnetism of Gd(
iii
)-based inorganic polymers, metal-organic frameworks, and coordination polymers based on various inorganic and organic ligands are summarized and discussed, with an emphasis on the synthetic strategy towards molecular magnetorefrigerants with good stability and a large magnetocaloric effect. In addition, the conclusions and perspectives for Gd(
iii
)-based magnetorefrigerants are presented and new insights for the further development of this promising area. Therefore, this review should serve as a tutorial for newcomers as well as a summary of the research progress in the field of magnetic refrigeration.
Gd(
iii
)-based molecular magnetorefrigerants are reviewed and discussed in detail, with an emphasis on the synthetic strategy towards good stability and large magnetocaloric effect.
A series of four conjugated porous polymer CPPs (
CPs1-4
) with various geometries have all been readily synthesized
via
direct C-H arylation between bithiophene (BT) and 1,3,6,8-tetrabromopyrene ...(TBPy), 2,2′,7,7′-tetrabromo-9,9′-spirofluorene (TBSF), 1,3,5-tribromobenzene (TBB) and 1,4-dibromobenzene (DB) respectively. The photocatalytic hydrogen evolution from water splitting by these CPPs under visible light irradiation is studied in detail. An amazing hydrogen evolution rate (HER) of 95.85 μmol h
−1
was successfully achieved by the four-directional Py-BT-based CPP (
CP1
, 6 mg), using ascorbic acid (AA) and
N
,
N
-dimethylformamide (DMF)/water as a sacrificial agent and co-solvents respectively. Such a HER value is 8-fold higher than that of applying commonly used MeOH/water as a co-solvent in the same photocatalytic system. Significantly, when a 0.5 wt% platinum (Pt) co-catalyst was added into the above photocatalytic system, an unprecedented HER of 184.86 μmol h
−1
(6 mg) was further realized. The combination of atom-economically synthesized CPPs and accelerating the HER by means of simply tuning the composition of co-solvents provided herein represents a promising step toward accessing green energy by green chemistry.
An atom-economic synthetic method is developed to access CPP materials used for photocatalytic H
2
production from H
2
O, and the PHP reaction can be greatly accelerated by DMF cosolvent, leading to an HER of 15 975 μmol g
−1
h
−1
without the aid of Pt.
Plants have the remarkable ability to generate callus, a pluripotent cell mass that acquires competence for subsequent tissue regeneration. Global chromatin remodeling is required for this cell fate ...transition, but how the process is regulated is not fully understood. Chromatin-enriched noncoding RNAs (cheRNAs) are thought to play important roles in maintaining chromatin state. However, whether cheRNAs participate in somatic cell regeneration in plants has not yet been clarified.
To uncover the characteristics and functions of cheRNAs during somatic cell reprogramming in plants, we systematically investigate cheRNAs during callus induction, proliferation and regeneration in rice. We identify 2284 cheRNAs, most of which are novel long non-coding RNAs or small nucleolar RNAs. These cheRNAs, which are highly conserved across plant species, shuttle between chromatin and the nucleoplasm during somatic cell regeneration. They positively regulate the expression of neighboring genes via specific RNA motifs, which may interact with DNA motifs around cheRNA loci. Large-scale mutant analysis shows that cheRNAs are associated with plant size and seed morphology. Further detailed functional investigation of two che-lncRNAs demonstrates that their loss of function impairs cell dedifferentiation and plant regeneration, highlighting the functions of cheRNAs in regulating the expression of neighboring genes via specific motifs. These findings support cis- regulatory roles of cheRNAs in influencing a variety of rice traits.
cheRNAs are a distinct subclass of regulatory non-coding RNAs that are required for somatic cell regeneration and regulate rice traits. Targeting cheRNAs has great potential for crop trait improvement and breeding in future.
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