Search

Mycobacterium tuberculosisis the causative agent of tuberculosis (TB), which is still the leading cause of mortality from a single infectious disease worldwide. The development of novel anti-TB drugs and vaccines is severely hampered by the complicated and time-consuming genetic manipulation techniques for M. tuberculosis.Here, we harnessed an endogenous type III-A CRISPR/Cas10 system of M. tuberculosisfor efficient gene editingand RNA interference (RNAi). This simple and easy method only needs to transform a single mini-CRISPR array plasmid, thus avoiding the introduction of exogenous protein and minimizing proteotoxicity. We demonstrated that M. tuberculosisgenes can be efficiently and specifically knocked in/out by this system as confirmed by DNA high-throughput sequencing. This system was further applied to single- and multiple-gene RNAi. Moreover, we successfully performed genome-wide RNAi screeningto identify M. tuberculosisgenes regulating in vitroand intracellular growth. This system can be extensively used for exploring the functional genomics of M. tuberculosisand facilitate the development of novel anti-TB drugs and vaccines.

Excessive residual stress of the girth weld in pipes will directly damage the pipe strength during its operation. Accurate measurement and effective reduction of the residual stress can ensure the safety of natural gas pipes during their service. In this paper, an X80-type large-diameter natural gas pipe section with girth welds is taken as the research object. The coercive force method is used to characterize the residual stress of the girth weld and its surroundings, and then the distribution law of the residual stress of the girth weld and its surroundings is obtained based on the measurement results of the Blind-hole method; the ultrasonic impact method was used to reduce the girth weld residual stress, and the effect of the ultrasonic impact method on the residual stress reduction was studied by comparing changes of the distribution characteristics of the coercive force in the girth weld and its surroundings before and after the residual stress reduction in the natural gas pipes. Lastly, the in-situtest specimen is made to carry out the uniaxial tensile test so as to study the effect of the ultrasonic impact method on the tensile mechanical properties of pipe welds. This study clarifies the influence law of the ultrasonic impact on the mechanical properties of weld toe materials, and provided technical theoretical guidance for the reduction of field residual stress in natural gas pipes.

Mycobacterium tuberculosisis the causative agent of tuberculosis (TB), which is still the leading cause of mortality from a single infectious disease worldwide. The development of novel anti-TB drugs and vaccines is severely hampered by the complicated and time-consuming genetic manipulation techniques for M. tuberculosis.Here, we harnessed an endogenous type III-A CRISPR/Cas10 system of M. tuberculosisfor efficient gene editingand RNA interference (RNAi). This simple and easy method only needs to transform a single mini-CRISPR array plasmid, thus avoiding the introduction of exogenous protein and minimizing proteotoxicity. We demonstrated that M. tuberculosisgenes can be efficiently and specifically knocked in/out by this system as confirmed by DNA high-throughput sequencing. This system was further applied to single- and multiple-gene RNAi. Moreover, we successfully performed genome-wide RNAi screeningto identify M. tuberculosisgenes regulating in vitroand intracellular growth. This system can be extensively used for exploring the functional genomics of M. tuberculosisand facilitate the development of novel anti-TB drugs and vaccines.

Objective: Intradural nerve anastomosis for bladder innervation has been demonstrated to be useful. However, its clinical application remains limited because of the complex surgery, its complications and extensive bony destruction. The purpose of the current study was to demonstrate the feasibility of extradural spinal root anastomosis for bladder innervation in canines.Methods: Ten beagle dogs were used. The length of the extradural segment of the nerve root, upper nerve root outlet (the point at which it emerges from the spinal dura mater) to S2 (dS2), the S3 (dS3) nerve root outlet distance, and the diameters of the extradural spinal roots were measured. The numbers of nerve fibers from L6 to S3 ventral roots were calculated using immunohistochemical staining.Results: The extradural spinal roots could be divided into a ventral root (VR) and a dorsal root (DR) before the ganglionic enlargement of the dorsal root, and the extradural motor nerve roots situate ventrally to their corresponding sensory nerve roots. The extradural nerve root lengths of S1 and parts of L7 were longer than the corresponding dS2. The numbers of nerve and motor nerve fibers, and the diameters of extradural nerve roots, were gradually descending from L6 to S3.Conclusion: The S1 VRs and parts of the L7 VRs can be extradurally anastomosed to the S2 nerves without tension. A nerve graft was needed for extradural anastomosis of L6 VRs and parts of L7 VRs to S2 VRs. This study demonstrated the feasibility of extradural spinal nerve anastomosis for treating neurogenic bladder in canines.

This paper presents a theoretical and numerical study of angle steel joints for conductors in transmission tower structures in the medium and heavy icing area. The results show that the deformation of the angle steel joint in suspension towers is controlled by the vertical load, and the deformation of the angle steel joint in strain towers is controlled by the tension load. The bolt of the angle steel joint for conductors is tension-controlled. A theoretical method considering the bending stiffness ratio of the angle steel plate and the bolt is derived. The proposed theoretical method quantifies the bending stiffness difference in the angle steel plate and bolt group, and the effects of bolt layout and load cases are considered. The numerical results are in good agreement with theoretical results by validating the internal forces and neutral axis depth. The accuracy of the proposed theoretical method is higher than that of theoretical methods based on steel structure principles. The proposed theoretical method is of great significance to the development of transmission tower structure design.

ObjectiveTo investigate the anatomical and histological features of spinal nerve roots and provide base data for neuroanastomosis therapy for paraplegia.MethodsSpinal nerve roots from C1 to S5 were exposed on six adult cadavers. The diameter and the number of nerve fibers of each nerve root were measured, respectively, with a caliper and image analysis software.ResultsAs for ventral roots, the diameter of C5 (2.50 ± 0.55 mm) was the largest in cervical segments. In thoracic and lumbosacral segments, the diameter gradually increased from T11 to S1 and then decreased from S1 to S5 except L3. S1 (1.43 ± 0.16 mm) was the thickest root and S5 (0.14 ± 0.02 mm) was the thinnest one. As for dorsal roots, the diameter of C7 (4.61 ± 0.87 mm) was the largest in cervical segments. From T11 to S1, the diameter increased and then decreased gradually from S1 to S5. The diameter of dorsal roots from T1 to S5 was largest at S1 (2.95 ± 0.57 mm) and smallest at S5 (0.27 ± 0.13 mm), respectively. C7 (8467 ± 1019), T12 (6538 ± 892), L3 (9169 ± 1160), and S1 (8253 ± 1419) ventral roots contained the most nerve fibers in cervical, thoracic, lumbar, and sacral segments, respectively. Similarly, C7 (39 653 ± 8458), T1 (26 507 ± 7617), L5 (34 455 ± 2740), and S1 (41 543 ± 3036) dorsal roots, respectively, contained the most nerve fibers in their corresponding segments.ConclusionThe findings in the current study provided the imperative data and may be valuable for spinal nerve root microanastomosis surgery in the paraplegic patients.

In this protocol we describe a method to obtain telomere length parameters using Southern blots of terminal restriction fragments (TRFs). We use this approach primarily for epidemiological studies that examine leukocyte telomere length. However, the method can be adapted for telomere length measurements in other cells whose telomere lengths are within its detection boundaries. After extraction, DNA is inspected for integrity, digested, resolved by gel electrophoresis, transferred to a membrane, hybridized with labeled probes and exposed to X-ray film using chemiluminescence. Although precise and highly accurate, the method requires a considerable amount of DNA (3 μg per sample) and it measures both the canonical and noncanonical components of telomeres. The method also provides parameters of telomere length distribution in each DNA sample, which are useful in answering questions beyond those focusing on the mean length of telomeres in a given sample. A skilled technician can measure TRF length in ∼130 samples per week.

The aim of this study was to determine the feasibility of using near infrared (NIR) spectroscopy to identify motor and sensory fascicles. Using 12 adult Beagle dogs which were anesthetised generally and sacrificed, canalis vertebraliswere opened and both anterior and posterior roots were harvested from the first lumbar vertebrae to the second sacral vertebrae (L1–S2). A total of 126 anterior roots and 126 posterior roots were collected. NIR diffuse reflectance spectra were measured using a Fourier transform near infrared (FT-NIR) spectrometer fitted with a fibre-optic probe. The average spectrum of each sample was used for further analysis. There were no clear differences from the spectra between the anterior and posterior root samples. Original spectral data were transformed to second derivative spectral data. Soft independent modelling of class analogy (SIMCA) was employed to identify the anterior and posterior roots based upon differences in their spectral features. SIMCA models correctly classified 79–100% for the anterior and posterior roots and mean 83.7%. This study demonstrated that NIR spectroscopy in combination with pattern recognition methods (SIMCA) could be used to classify the anterior and posterior roots. This result suggests that NIR spectroscopy may provide a rapid, correct, non-destructive, low-cost means to quickly differentiate motor and sensory fascicles in mixed nerves.

The aim of this study was to determine the feasibility of using near infrared (NIR) spectroscopy to identify motor and sensory fascicles. Using 12 adult Beagle dogs which were anesthetised generally and sacrificed, canalis vertebralis were opened and both anterior and posterior roots were harvested from the first lumbar vertebrae to the second sacral vertebrae (L_1–S_2). A total of 126 anterior roots and 126 posterior roots were collected. NIR diffuse reflectance spectra were measured using a Fourier transform near infrared (FT-NIR) spectrometer fitted with a fibre-optic probe. The average spectrum of each sample was used for further analysis. There were no clear differences from the spectra between the anterior and posterior root samples. Original spectral data were transformed to second derivative spectral data. Soft independent modelling of class analogy (SIMCA) was employed to identify the anterior and posterior roots based upon differences in their spectral features. SIMCA models correctly classified 79–100% for the anterior and posterior roots and mean 83.7%. This study demonstrated that NIR spectroscopy in combination with pattern recognition methods (SIMCA) could be used to classify the anterior and posterior roots. This result suggests that NIR spectroscopy may provide a rapid, correct, non-destructive, low-cost means to quickly differentiate motor and sensory fascicles in mixed nerves.

Sutures penetrate tissues to close wounds. This process leads to inflammatory responses, prolongs healing time, and increases operation complexity. It becomes even worse when sutures are applied to stress‐sensitive and fragile tissues. By bonding tissues via forming covalent bonds, some medical adhesives are not convenient to be used by surgeons and have side effects to the tissues. Here egg albumen adhesive (EAA) is reported with ultrahigh adhesive strength to bond various types of materials and can be easily used without any chemical and physical modifications. Compared with several commercial medical glues, EAA exhibits stronger adhesive property on porcine skin, glass, polydimethylsiloxane. The EAA also shows exceptional underwater adhesive strength. Finally, wound closure using EAA on poly(caprolactone) nanofibrous sheet and general sutures is investigated and compared in a rat wound model. EAA also does not show strong long‐term inflammatory response, suggesting that EAA has potential as a medical glue, considering its abundant source, simple fabrication process, inherent nontoxicity, and low cost. Egg albumen adhesive (EAA)is formed by simply adding raw egg albumen powder to water. EAA exhibits outstanding adhesion strength on pigskin tissues, polydimethylsiloxane, and glass substrates especially. EAA on nanofibrous mesh shows reliable biocompatibility and biodegradability, and great wound closure performance. EAA also has exceptional underwater adhesive strength when combined with Vaseline.