Fluorescence Enhancement of a Metal-Organic Framework for Ultra-Efficient Detection of Trace Benzene Vapor

Indoor detection of volatile organic compounds (VOCs) concentration is necessary due to the serious toxicity hazards even at trace level. However, physisorbents usually exhibit weak interactions especially in the presence of trace concentrations of VOCs, thus exhibiting poor responsive signal. Herein, we report a new flexible metal-organic framework (MOF) that exhibits interesting pore-opening behavior after immersing in H2O. The pore-opening phase shows significant (~116 folds) and extremely fast (< 1 minute) fluorescence enhancement after being exposed to saturated benzene vapor. The limit of detection concentration for benzene vapor can be calculated as 0.133 mg L-1. Thus this material represents the first MOF to achieve visual detection of trace benzene vapor by the naked eyes. Theoretical calculations and single-crystal structure reveal that the special "bilateral π-π stacking" interactions between the host and guest, which facilitate electron transfer and greatly enhance the intensity of fluorescence.

A series of naphthalenediimide-based metal-organic frameworks: synthesis, photochromism and inkless and erasable printing

Three new three-dimensional metal-organic frameworks were synthesized based on a naphthalenediimide derivative ligand, all of which exhibit photochromic behaviour due to the presence of the naphthalenediimide core. Interestingly, two of them possess significant colour changes under light, excellent stability, and appropriate photochromic lifetimes, thus showing potential for application in inkless and erasable printing media.

[Desquamative interstitial pneumonia: report of one case and review of literature]

Objective: To analyze the clinical features, diagnosis, and treatment of desquamative interstitial pneumonia(DIP). Methods: The clinical manifestation, radiology, and pathology were analyzed in one patient with DIP in Beijing Hospital following review of the literatures. Results: The patient was a 55-year-old male presented with cough, shortness of breath and hypoxemia.Previous history of smoking and exposure to a variety of metals. A CT scan of the chest revealed diffuse ground-glass densities. A diagnosis of desquamative interstitial pneumonia (DIP) was confirmed by a thoracoscopic open lung biopsy. After treatment with hormone, the condition improved.A total of 66 cases were included in this study, the smoking groupof 20 cases, non-smokers of 46 cases.The smoking group was older than the non-smoking group [(47.5±12.1)years vs (26.1±22.5) years]; the present of chest pain, shortness of breath(4/20 vs 0/46; 8/20 vs 3/46) was higher in smoking group than in non-smoking group, and ground glass opacity in the chest image(15/20 vs 20/46) was also higher in smoking group than in non-smoking group.Pulmonary function showed more diffuse dysfunction(12/14 vs 6/13) in smoking group than in non-smoking group. Conclusions: As a rare disorder, DIP is associated with current or former cigarette smoking and many other risk factors. The clinical presents of non-smoker is atypical.DIP is curable to glucocorticoid and has a good prognosis.There is a possible of recurrence.

Genetic diversity of rhg1 and Rhg4 loci in wild soybeans resistant to soybean cyst nematode race 3

Over-utilization of germplasms that are resistant to the soybean cyst nematode (SCN) in soybean breeding programs can lead to genetic vulnerability in resistant cultivars. Resistant wild soybean (Glycine soja) is considered an invaluable gene source for increasing the genetic diversity of SCN resistance. In this study, we genotyped 23 G. soja accessions that are resistant to SCN race 3 for polymorphisms in the resistance genes, rhg1, Rhg4, and SHMT, and investigated their genetic relationship with eight Glycine max resistant cultivars. We identified 89 single nucleotide polymorphisms (SNPs) and 11 DNA insertion-deletions (InDels), of which 70 SNPs and 8 InDels were found in rhg1, 9 SNPs were found in Rhg4, and 10 SNPs and 3 InDels were found in SHMT. Nucleotide diversity was π = 0.00238 and θ = 0.00235, and haplotype diversity was 1.000. A phylogenetic tree comprising four clusters was constructed using sequence variations of the 23 G. soja and 8 G. max resistant accessions. Five G. soja accessions in subcluster A2, and four G. soja accessions in cluster B were genetically distant from G. max genotypes. Eight resistance-associated SNPs in the three resistance genes formed nine haplotypes in total. G. soja resistant accessions had different haplotypes (H2, H4, H5, H6, H7, and H8) compared with those of G. max (H1, H3, and H9). These results provide vital information on the use of wild soybeans for broadening the genetic base of SCN resistance.

Double spectral theorem and two type magnitude-squared coherence functions

Studying frequency domain representation for the coherence between two signals is an important basic theoretical problem in the fundamental theories of signal processing. However, the old magnitude-squared coherence function (OMSCF) has been proved identical to 1, so that to cannot be used to extract any coherence information. Here, we will prove a core theorem in frequency domain coherence theories in signal processing, called as the double spectral theorem (DST). Based on the theorem, we presented the two types of new magnitude-squared coherence functions (MSCFs), called as the same type magnitude-squared coherence function (SMSCF) and the difference magnitude-squared coherence function (DMSCF) respectively, which were mathematically derived from DST and the conditions that they are equal to 1 or 0 can be theoretically derived from DST. Here, we further demonstrated that SMSCF and DMSCF could be used to exactly extract the coherence between two signals by each component.