Chemical characterisation of a new estuarine pollutant (2,4-Dichloro-6-Nitrophenol) and assessment of the acute toxicity of its quinoid form for Artemia salina

It is known that the compound 2,4-dichloro-6-nitrophenol (2,4DC6NP) is formed upon nitration of 2,4-dichlorophenol, which in turn is a transformation intermediate of the herbicide dichlorprop. However, the chemical and spectroscopic characteristics of 2,4DC6NP, as well as its toxicity, are poorly known. This work shows that 2,4DC6NP behaves as a diprotic acid in aqueous solutions, with pK_a values of 3.0?±?0.9 and 4.9?±?0.5. At pH?<?3, 2,4DC6NP would undergo protonation. The absorption spectra suggest that anionic 2,4DC6NP, which prevails at pH?>?5 would have an ortho-quinoid structure that is responsible for the absorption peak centred at 428?nm. Considering that 2,4DC6NP has been detected in the brackish lagoons of the Rhône delta (southern France), where its levels are comparable to those of the parent herbicide, it is necessary to examine the possible effects of 2,4DC6NP on the species living in that environment. For this reason, the acute toxicity of the anionic form of 2,4DC6NP was assessed for the brine shrimp Artemia salina, a zooplankton species that lives both in brackish and in saline aquatic environments. The toxicity test yielded a LC₂₀ value of 8?±?2?mg?L^?1 and a LC₅₀ value of 18.7?±?0.8?mg?L^?1. Such values are safely higher than the maximum detected concentration of 2,4DC6NP in the Rhône delta lagoons. Further studies should be concentrated on the long-term effects of 2,4DC6NP, and in particular on its potential genotoxicity.     

Effects of Physical Agents on Muscle Healing with a Focus on Animal Model Research

Skeletal muscle injury is caused by a variety of events, such as muscle laceration, contusions, or strain. Muscle fibers respond to minor damage with immediate repair mechanisms that reseal the cell membrane. On the other hand, repair of irreversibly damaged fibers is achieved by activation of muscle precursor cells. Muscle repair is not always perfect, especially after severe damage, and can lead to excessive fibroblast proliferation that results in the formation of scar tissue within muscle fibers. Remaining scar tissue can impair joint movement, reduce muscular strength, and inhibit exercise ability; therefore, to restore muscle function, minimizing the extent of injury and promoting muscle regeneration are necessary. Various physical agents, such as cold, thermal, electrical stimulation, and low-intensity pulsed ultrasound therapy, have been reported as treatments for muscle healing. Although approaches based on the muscle regeneration process have been under development, the most efficacious physiological treatment for muscle injury remains unclear. In this review, the influence of these physical agents on muscle injury is described with a focus on research using animal models.     

High-field magnetic resonance imaging using solenoid radiofrequency coils

High-resolution magnetic resonance imaging using dedicated high-field radiofrequency micro-coils at 16.4 T (700 MHz) was investigated. Specific solenoid coils primarily using silver and copper as conductors with enamel and polyurethane coatings were built to establish which coil configuration produces the best image. Image quality was quantified using signal-to-noise ratio and signal variation over regions of interest. Benchmarking was conducted using 5-mm diameter coils, as this size is comparable to an established coil of the same size. Our 1.4-mm-diameter coils were compared directly to each other, from which we deduce performance as a function of conductor material and coating. A variety of materials and conductor coatings allowed us to choose an optimal design, which we used to image a kidney section at 10-micron resolution. We applied zero-fill extrapolation to achieve 5-micron resolution.     

ELECTROPHYSIOLOGICAL EVIDENCE FOR HYPERALGESIA IN THE PERIPHERAL NEUROPATHY

A peripheral neuropathy was produced in adult rats by placing loosely constrained ligature around the common sciatic nerve. At the ligature region of the nerve, demyelination developed. The postoperative behavior of these rats indicated that hyperalgesia and allodynia were produced. The electrical activity pattern of the damaged fibers was remarkably different from those of normal nerves: there were some abnormal spontaneous afferent firings from the injured fibers; multi-impulse responses of C-fiber to single shock was recorded; a lasting firing was elicited after the injured region was gently pressed or by oil drops at 40℃; an antidromic electric stimulus to the injured region, stimulations of L, sympathetic ganglion or systemic administration of noradrenalin, all caused an increase in on-goingspontaneous discharges of the injured fibers or brought the silent fibers into firing. Stimulation of the dorsal roots of the sciatic nerve produced no effect on their activities or caused a pause of the on-goi     

Enhanced renal image contrast by ethanol fixation in phase‐contrast X‐ray computed tomography

Phase‐contrast X‐ray imaging using a crystal X‐ray interferometer can depict the fine structures of biological objects without the use of a contrast agent. To obtain higher image contrast, fixation techniques have been examined with 100% ethanol and the commonly used 10% formalin, since ethanol causes increased density differences against background due to its physical properties and greater dehydration of soft tissue. Histological comparison was also performed. A phase‐contrast X‐ray system was used, fitted with a two‐crystal X‐ray interferometer at 35 keV X‐ray energy. Fine structures, including cortex, tubules in the medulla, and the vessels of ethanol‐fixed kidney could be visualized more clearly than that of formalin‐fixed tissues. In the optical microscopic images, shrinkage of soft tissue and decreased luminal space were observed in ethanol‐fixed kidney; and this change was significantly shown in the cortex and outer stripe of the outer medulla. The ethanol fixation technique enhances image contrast by approximately 2.7–3.2 times in the cortex and the outer stripe of the outer medulla; the effect of shrinkage and the physical effect of ethanol cause an increment of approximately 78% and 22%, respectively. Thus, the ethanol‐fixation technique enables the image contrast to be enhanced in phase‐contrast X‐ray imaging.     

Some theorems in the X-M-PN space

ＬｅｔＲｂｅｔｈｅｓｅｔｄｅｎｏｔｉｎｇａｌｌｒｅａｌｎｕｍｂｅｒｓ,Ｒ ｂｅｔｈｅｓｅｔｄｅｎｏｔｉｎｇａｌｌｎｏｎｎｅｇａｔｉｖｅｒｅａｌｎｕｍｂｅｒｓ.ＡｍａｐｐｉｎｇＦ:Ｒ→Ｒ ｉｓｃａｌｌｅｄａｄｉｓｔｒｉｂｕｔｉｏｎｆｕｎｃｔｉｏｎ,ｉｆｉｔｉｓａｎｏｎｄｅｃｒｅａｓｉｎｇｆｕｎｃｔｉｏｎａｎｄｌｅｆｔｃｏｎｔｉｎｕａｔｉｏｎｓａｔｉｓｆｙｉｎｇｔｈｅｆｏｌｌｏｗｉｎｇｃｏｎｄｉｔｉｏｎｓ:ｉｎｆｔ∈ＲＦ(ｔ)=0,ｓｕｐｔ∈ＲＦ(ｔ)=1,Ｄ ｔｈｅｓｅｔｏｆａｌｌｄｉｓｔｒｉｂｕｔｉｏｎｆｕｎｃｔ…     

Ultrasound-assisted preparation of ‘Ready-to-use’ extracts from Radix Paeoniae Rubra with natural deep eutectic solvents and neuroprotectivity evaluation of the extracts against cerebral ischemic/ reperfusion injury

Natural deep eutectic solvent (NaDES) is widely applied in the extraction of nutrients from natural resources as a greener alternative for fossil solvent. In the present work, 27 different NaDESs were screened for the extraction of paeoniflorin (PF) and galloyl paeoniflorin (GPF) from Radix Paeoniae Rubra (RPR). After screening and extraction parameter optimization, the extraction yields of PF and GPF reached up to 182.8 mg/g and 77.4 mg/g with the selected NaDES, ChCl-Sor. Furthermore, the antioxidant activity in vitro and neuroprotectivity in vivo of the ‘ready-to-use’ extracts were evaluated comprehensively. Especially in vivo, the cerebral ischemic/ reperfusion injury model was established in rats and the protective effects of the RPR extracts were determined. The results not only proved that NaDES is a valuable green extraction media, but also indicated the safety and potential pharmaceutical application of NaDES based ‘ready-to-use’ extracts from medical plants.     

Prediction of vascular injury by cavitation microbubbles in a focused ultrasound field

Many studies have shown that microbubble cavitation is one mechanism for vascular injury under ultrasonic excitation. Previous work has attributed vascular damage to vessel expansions and invaginations due to the expansion and contraction of microbubbles. However, the mechanisms of vascular damage are not fully understood. In this paper, we investigate, theoretically and experimentally, the vessel injury due to stress induced by ultrasound-induced cavitation (UIC). A bubble-fluid-vessel coupling model is constructed to investigate the interactions of the coupling system. The dynamics process of vessel damage due to UIC is theoretically simulated with a finite element method, and a focused ultrasound (FU) setup is carried out and used to assess the vessel damage. The results show that shear stress contributes to vessel injury by cell detachment while normal stress mainly causes distention injury. Similar changes in cell detachment in a vessel over time can be observed with the experimental setup. The severity of vascular injury is correlated to acoustic parameters, bubble-wall distance, and microbubble sizes, and the duration of insonation..     

支气管哮喘发作期血清部分微量元素的研究

对60例支气管哮喘发作患者血清中部分微量元素进行了观察,并同正常人群进行了对照。发现与正常人群有一定的差别。讨论了其原因。     

补肾调肝法治疗对精液异常患者精液微量元素改变的观察

研究了２６例精液异常患者使用补肾调肝法治疗后其精液锌、铜、铅等元素的改变。２６例患者在治疗后精液质量有明显改善,其中精液中锌含量与治疗前相比有明显提高,治疗前后分别为（２．０６＋１．０９）ｍｍｏｌ．Ｌ和（２．４８±１．０５）ｍｍｏｌ·Ｌ（Ｐ＜０.０１）,差异具有显著性意义。精液中的铜含量也有所提高。铅含量比治疗前减少,但并不具显著性。