Visible-light promoted atom transfer radical addition-elimination (ATRE) reaction for the synthesis of fluoroalkylated alkenes using DMA as electron-donor

Here, we describe a mild, catalyst-free and operationally-simple strategy for the direct fluoroalkylation of olefins driven by the photochemical activity of an electron donor-acceptor (EDA) complex between DMA and fluoroalkyl iodides. The significant advantages of this photochemical transformation are high efficiency, excellent functional group tolerance, and synthetic simplicity, thus providing a facile route for further application in pharmaceuticals and life sciences

Effect of sidewall on the flame extension characteristics beneath a ceiling induced by carriage fire in a channel

Laboratory tests were firstly conducted in a reduced scale channel to investigate the conditions for flame ejections when the carriage was at the centre of the channel. The ejected flames were recorded by two cameras and the temperature inside the enclosure and on the ceiling were measured. The lower critical heat release rate (HRR) which would result in intermittent flame ejection and upper critical HRR which would lead to continuous external flame were analysed with regards to their variations with the ventilation factor. Correlations for the longitudinal and transverse flame extension lengths and flame extension area beneath the ceiling were proposed. Subsequently further experimental investigations were conducted to study the effect of sidewall constraint on flame extension by changing the position of the carriage along the transverse direction to vary the distance between the sidewall and the carriage opening, which was also systematically varied. With the decrease of the sidewall-to-opening distance, the longitudinal flame extension length was found to increase whereas the transverse flame extension length decreased. The changes are most significant when sidewall-to-opening distance was relatively small. These trends are different from those observed in previous wall-attached fires or corner fires in channels, where the flame extension length beneath the ceiling firstly increased with the decrease of sidewall-source distance, and then decreased slightly when the fire source was attached to the wall. New correlations were proposed to account for the effect of sidewall-to-opening distance for longitudinal and transverse flame extension lengths under the ceiling. They captured well the measurements for all the present cases and some published cases not used in their derivation, demonstrating the potential for fire safety engineering applications

Chromosomal instability in Streptomyces avermitilis: major deletion in the central region and stable circularized chromosome

<p>Abstract</p> <p>Background</p> <p>The chromosome of <it>Streptomyces </it>has been shown to be unstable, frequently undergoing gross chromosomal rearrangements. However, the mechanisms underlying this phenomenon remain unclear, with previous studies focused on two chromosomal ends as targets for rearrangements. Here we investigated chromosomal instability of <it>Streptomyces avermitilis</it>, an important producer of avermectins, and characterized four gross chromosomal rearrangement events, including a major deletion in the central region. The present findings provide a valuable contribution to the mechanistic study of genetic instability in <it>Streptomyces</it>.</p> <p>Results</p> <p>Thirty randomly-selected "bald" mutants derived from the wild-type strain all contained gross chromosomal rearrangements of various types. One of the bald mutants, SA1-8, had the same linear chromosomal structure as the high avermectin-producing mutant 76-9. Chromosomes of both strains displayed at least three independent chromosomal rearrangements, including chromosomal arm replacement to form new 88-kb terminal inverted repeats (TIRs), and two major deletions. One of the deletions eliminated the 36-kb central region of the chromosome, but surprisingly did not affect viability of the cells. The other deletion (74-kb) was internal to the right chromosomal arm. The chromosome of another bald mutant, SA1-6, was circularized with deletions at both ends. No obvious homology was found in all fusion sequences. Generational stability analysis showed that the chromosomal structure of SA1-8 and SA1-6 was stable.</p> <p>Conclusions</p> <p>Various chromosomal rearrangements, including chromosomal arm replacement, interstitial deletions and chromosomal circularization, occurred in <it>S. avermitilis </it>by non-homologous recombination. The finding of an inner deletion involving in the central region of <it>S. avermitilis </it>chromosome suggests that the entire <it>Streptomyces </it>chromosome may be the target for rearrangements, which are not limited, as previously reported, to the two chromosomal ends.</p

Experimental study on the radiant heat flux of wall-attached fire plume generated by rectangular sources

Radiant heat flux of fire plume is an essential parameter indicating the hazards of a fire. In this work, fire experiments of a wall-attached fire with different aspect ratios were conducted. In addition, the effect of the sidewall on mean flame height and radiant heat flux of the rectangular fire was investigated. The sidewall causes a decrease in air entrainment; therefore, the mean flame height is observed to increase. The radiant heat flux increased owing to the increase in flame height and thermal radiation from the heated sidewall. Experimental results of the mean flame height are consistent with those predicted by an existing model. This validated the reliability of the experimental setup for a rectangular wall-attached fire. Furthermore, a model based on the increase in flame height and thermal radiation from the heated sidewall was developed to estimate the radiant heat flux from a rectangular wall-attached fire. The error in prediction was less than 15% for this model

Botulinum toxin injection combined with traditional swallowing rehabilitation improved cricopharyngeal dysfunction in neuromyelitis optica spectrum disorder: A case report

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune diseases of the central nervous system, and often influence optic nerve and medulla oblongata. Previous studies found out that brain abnormalities were not rare in these patients. Medulla oblongata (MO) was commonly involved and usually located at dorsal part. Patients who diagnosed NMOSD with MO lesions were more likely to have dysphagia. Previous reports indicated that the symptoms and signs of NMOSD patients could be controlled after immunosuppressive therapy. This patient was a 49-year-old Asian woman presented with recurrent vomiting and diagnosed NMOSD with MO involvement. However, after immunotherapy in other hospital, she still suffered from dysphagia. She then came to our department and completed videofluoroscopic swallowing study (VFSS) and high-resolution pharyngeal manometry (HRPM). Her UES was not opening with aspiration and the UES residue pressure was higher than normal range, we figured that she had cricopharyngeal (CP) dysfunction. Then the SLP gave her traditional treatment, including catheter balloon dilation. But she failed improvement after treatment for 2 weeks. Then the clinicians decided to inject botulinum toxin (BTX) into her CP muscles, which needed specific location and appropriate dosage. Her UES residue pressure decreased after three times BTX injection. During this time, her SLP adjusted the treatment strategies based on her VFSS and HRM results. Combined BTX injection with traditional treatment, she can now eat food orally without restrictions. This case report we presented can provide treatment strategies for similar patients with dysphagia

Electroacupuncture Inhibits Inflammation Reaction by Upregulating Vasoactive Intestinal Peptide in Rats with Adjuvant-Induced Arthritis

Acupuncture is emerging as an alternative therapy for rheumatoid arthritis (RA). However, the molecular mechanism underlying this beneficial effect of acupuncture has not been fully understood. Here, we demonstrated that electroacupuncture at acupoints Zusanli (ST36), Xuanzhong (GB39); and Shenshu (BL23) markedly decreased the paw swelling and the histologic scores of inflammation in the synovial tissue, and reduced the body weight loss in an adjuvant-induced arthritis rat model. However, the electrical stimulation at nonacupoint did not produce any beneficial effects against the experimental arthritis. Most interestingly, the electroacupuncture treatment resulted in an enhanced immunostaining for vasoactive intestinal peptide (VIP), a potent anti-inflammatory neuropeptide, in the synovial tissue. Moreover, the VIP-immunostaining intensity was significantly negatively correlated with the scores of inflammation in the synovial tissue (r = −0.483, P = .0026). In conclusion, these findings suggest that electroacupuncture may offer therapeutic benefits for the treatment of RA, at least partially through the induction of VIP expression