Reported herein is a novel visible‐light photoredox system with Pd(PPh3)4 as the sole catalyst for the realization of the first direct cross‐coupling of C(sp3)−H bonds in N‐aryl ...tetrahydroisoquinolines with unactivated alkyl bromides. Moreover, intra‐ and intermolecular alkylations of heteroarenes were also developed under mild reaction conditions. A variety of tertiary, secondary, and primary alkyl bromides undergo reaction to generate C(sp3)−C(sp3) and C(sp2)−C(sp3) bonds in moderate to excellent yields. These redox‐neutral reactions feature broad substrate scope (>60 examples), good functional‐group tolerance, and facile generation of quaternary centers. Mechanistic studies indicate that the simple palladium complex acts as the visible‐light photocatalyst and radicals are involved in the process.
Pd, just do it! A novel visible‐light photoredox system with Pd(PPh3)4 as the sole catalyst leads to the direct alkylation of C−H bonds with unactivated alkyl bromides under mild reaction conditions. These redox‐neutral reactions feature high yields, broad substrate scope (>60 examples), facile generation of quaternary centers, and good functional‐group tolerance.
Toxocariasis is a neglected parasitic zoonosis that afflicts millions of the pediatric and adolescent populations worldwide, especially in impoverished communities. This disease is caused by ...infection with the larvae of Toxocara canis and T. cati, the most ubiquitous intestinal nematode parasite in dogs and cats, respectively. In this article, recent advances in the epidemiology, clinical presentation, diagnosis and pharmacotherapies that have been used in the treatment of toxocariasis are reviewed.
Over the past two decades, we have come far in our understanding of the biology and epidemiology of toxocariasis. However, lack of laboratory infrastructure in some countries, lack of uniform case definitions and limited surveillance infrastructure are some of the challenges that hindered the estimation of global disease burden. Toxocariasis encompasses four clinical forms: visceral, ocular, covert and neural. Incorrect or misdiagnosis of any of these disabling conditions can result in severe health consequences and considerable medical care spending. Fortunately, multiple diagnostic modalities are available, which if effectively used together with the administration of appropriate pharmacologic therapies, can minimize any unnecessary patient morbidity.
Although progress has been made in the management of toxocariasis patients, there remains much work to be done. Implementation of new technologies and better understanding of the pathogenesis of toxocariasis can identify new diagnostic biomarkers, which may help in increasing diagnostic accuracy. Also, further clinical research breakthroughs are needed to develop better ways to effectively control and prevent this serious disease.
A novel car-following model was proposed to describe the motion of the vehicles on a single lane gyroidal road. We explore the related effects of gyroidal road upon uniform traffic flow analytically ...and numerically. The analytical result shows that the related factors of gyroidal road including the friction coefficient, radius of curvature and slope have great influences on the stability of the uniform flow respectively. The modified KdV (Korteweg–de Vries) equation is derived in the unstable area and the kink solution is obtained near the critical point. A series of simulations are conducted to verify the effects upon uniform traffic flow under different road conditions. It is shown that the amplitudes of the headway oscillation wave were affected by the friction coefficient, radius of curvature and slope respectively. The numerical results are in good agreement with the analytical results.
•We proposed a new traffic flow model considering triple factors on a gyroidal road.•Stability analysis was conducted with three factors.•Nonlinear analysis was taken to derive the mKdV equation and to solve the kink solution.
Due to the development of the modern scientific technology, autonomous vehicles may realize to connect with each other and share the information collected from each vehicle. An improved forward ...considering car-following model was proposed with mean expected velocity field to describe the autonomous vehicles flow behavior. The new model has three key parameters: adjustable sensitivity, strength factor and mean expected velocity field size. Two lemmas and one theorem were proven as criteria for judging the stability of homogeneousautonomous vehicles flow. Theoretical results show that the greater parameters means larger stability regions. A series of numerical simulations were carried out to check the stability and fundamental diagram of autonomous flow. From the numerical simulation results, the profiles, hysteresis loop and density waves of the autonomous vehicles flow were exhibited. The results show that with increased sensitivity, strength factor or field size the traffic jam was suppressed effectively which are well in accordance with the theoretical results. Moreover, the fundamental diagrams corresponding to three parameters respectively were obtained. It demonstrates that these parameters play almost the same role on traffic flux: i.e. before the critical density the bigger parameter is, the greater flux is and after the critical density, the opposite tendency is. In general, the three parameters have a great influence on the stability and jam state of the autonomous vehicles flow.
•A new car-following model was proposed with mean expected velocity field.•Two lemmas and one theorem were proven as criteria for judging stability.•Stability and fundamental diagram were examined with different parameters.
In recent years, due to excessive emission of industrial waste, wastewater irrigation, and unreasonable utilization of fertilizers, pesticides and plastic sheeting, heavy metal pollution is ...increasing rapidly, resulting in many environmental problems. Silicon （Si）, as the second most abundant element in the soil, can not only stimulate plant growth, but alleviate various biotic and abiotic stresses, including heavy metal stress. Here, we reviewed recent advances in the mechanisms for Si-mediated heavy metal tolerance in plants. These mechanisms included reducing active heavy metal ions in growth media, reducing heavy metal transport to the shoot, stimulating enzymatic and non-enzymatic antioxidants, chelation, compartmentation, regulation of the expression of metal transport genes, and structural changes in plants. Further research orientation is also discussed.
A state feedback control strategy of modern control theory is proposed to analyze the classical car-following system. From the point of view of control theory, the influence of changing two important ...states velocity and headway on the stability of the car-following system is analyzed. The stability conditions of the control parameters are obtained by the conditions for roots of characteristic polynomials and the small gain theorem in the control theory. A dynamical car-following model is derived by the state feedback control method. Simulation experiments are conducted to verify the state feedback control strategy on traffic flow stability by the new model under the conditions of open boundary and periodic boundary respectively. The simulation results show that with the increase of the influence coefficient, the stability of the traffic flow system is enhanced, and the simulation results are consistent with the theoretical analysis results.
•A state feedback control strategy was presented to analyze the car-following system.•The stability of car-following system with state feedback control strategy was analyzed.•The control parameters’ effects was verified with the numerical simulation.
A speed feedback control mechanism was introduced into the system to improve the dynamical performance of the traffic flow. The modern control theory was used to analyze the stability of the system. ...It is found that the stability region varies with the feedback coefficient proportionally. In addition, the unit step responses in time domain and phase–frequency curves in frequency domain were given with different feedback coefficients in step response diagram and Bode diagram respectively. The overshoot and phase margins are inversely proportional to the speed feedback coefficients in an underdamped condition. The simulations were conducted to verify the validity of the improvement. The conclusion can be drawn that the analytical result and the simulation result are in good agreement with each other.
•A speed feedback control mechanism was introduced into car-following system.•The stability of traffic flow system under different feedback coefficients was discussed.•The unit step response and phase margins were analyzed based on control theory.
The tropical liver fluke, Fasciola gigantica causes fasciolosis, an important disease of humans and livestock. We characterized dynamic transcriptional changes associated with the development of the ...parasite in its two hosts, the snail intermediate host and the mammalian definitive host.
Differential gene transcription analysis revealed 7445 unigenes transcribed by all F. gigantica lifecycle stages, while the majority (n = 50,977) exhibited stage-specific expression. Miracidia that hatch from eggs are highly transcriptionally active, expressing a myriad of genes involved in pheromone activity and metallopeptidase activity, consistent with snail host finding and invasion. Clonal expansion of rediae within the snail correlates with increased expression of genes associated with transcription, translation and repair. All intra-snail stages (miracidia, rediae and cercariae) require abundant cathepsin L peptidases for migration and feeding and, as indicated by their annotation, express genes putatively involved in the manipulation of snail innate immune responses. Cercariae emerge from the snail, settle on vegetation and become encysted metacercariae that are infectious to mammals; these remain metabolically active, transcribing genes involved in regulation of metabolism, synthesis of nucleotides, pH and endopeptidase activity to assure their longevity and survival on pasture. Dramatic growth and development following infection of the mammalian host are associated with high gene transcription of cell motility pathways, and transport and catabolism pathways. The intra-mammalian stages temporally regulate key families of genes including the cathepsin L and B proteases and their trans-activating peptidases, the legumains, during intense feeding and migration through the intestine, liver and bile ducts. While 70% of the F. gigantica transcripts share homology with genes expressed by the temperate liver fluke Fasciola hepatica, gene expression profiles of the most abundantly expressed transcripts within the comparable lifecycle stages implies significant species-specific gene regulation.
Transcriptional profiling of the F. gigantica lifecycle identified key metabolic, growth and developmental processes the parasite undergoes as it encounters vastly different environments within two very different hosts. Comparative analysis with F. hepatica provides insight into the similarities and differences of these parasites that diverged > 20 million years ago, crucial for the future development of novel control strategies against both species.
Acephalic spermatozoa syndrome is a rare type of teratozoospermia that severely impairs the reproductive ability of male patients, and genetic defects have been recognized as the main cause of ...acephalic spermatozoa syndrome. Spermatogenesis and centriole-associated 1 like (SPATC1L) is indispensable for maintaining the integrity of sperm head-to-tail connections in mice, but its roles in human sperm and early embryonic development remain largely unknown. Herein, we conducted whole-exome sequencing (WES) of 22 infertile men with acephalic spermatozoa syndrome. An in silico analysis of the candidate variants was conducted, and WES data analysis was performed using another cohort consisting of 34 patients with acephalic spermatozoa syndrome and 25 control subjects with proven fertility. We identified biallelic mutations in SPATC1L (c.910C>T:p.Arg304Cys and c.994G>T:p.Glu332X) from a patient whose sperm displayed complete acephalia. Both SPATC1L variants are rare and deleterious. SPATC1L is mainly expressed at the head-tail junction of elongating spermatids. Plasmids containing pathogenic variants decreased the level of SPATC1L in vitro. Moreover, none of the patient's four attempts at intracytoplasmic sperm injection (ICSI) resulted in a transplantable embryo, which suggests that SPATC1L defects might affect early embryonic development. In conclusion, this study provides the first identification of SPATC1L as a novel gene for human acephalic spermatozoa syndrome. Furthermore, WES might be applied for patients with acephalic spermatozoa syndrome who exhibit reiterative ICSI failures.
To evaluate the possible predictive value and clinicopathological characteristics of Delphian lymph node metastasis in papillary thyroid carcinoma.
A retrospective analysis of papillary thyroid ...carcinoma patients with Delphian lymph node metastasis in a single institution and meta-analysis of literature reports were performed.
In own series, Delphian lymph node metastasis was detected in 19 (9.9%) of 192 papillary thyroid carcinoma patients and was significantly associated with tumor size≥1 cm (P = 0.003), multifocality (P = 0.006) and extrathyroid extension (P < 0.001) in the multivariate analysis. Female was a protective factor for Delphian lymph node metastasis (P = 0.001). Delphian lymph node metastasis was highly predictive of further central lymph node metastasis (positive predictive value = 89.5%, negative predictive value = 67.6%) and moderately predictive of lateral lymph node metastasis (positive predictive value = 26.3%, negative predictive value = 95.4%). In this meta-analysis, there was a strong correlation between Delphian lymph node metastasis and aggressive clinicopathologic characteristics with regards to multifocality (P = 0.0008), bilaterality (P = 0.04), extrathyroid extension (P < 0.00001), lymphovascular invasion (P < 0.00001), further central lymph node metastasis (P < 0.00001) and lateral lymph node metastasis (P < 0.00001).
This single-institution observational study and meta-analysis identified that Delphian lymph node metastasis was significantly associated with unfavorable clinicopathological characteristics and had a strong predictive power for further disease in the central compartment.
The clinical study was retrospectively registered to UMIN clinical trials registry (the registry number: UMIN000033835 ).
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