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Implant infection is one of the most common and serious complications in orthopedics, and it is also an important reason for the failure of implant surgery. When bacteria form a biofilm on the implant surface, it is extremely difficult to be eliminated and attracts more bacteria and fungi. A large number of studies have shown that the use of surface modification technology can effectively reduce the adhesion and accumulation of pathogenic bacteria, thereby preventing peri-implant infection. The formation process of bacterial biofilm on the surface of orthopedic implants and the antibacterial mechanism of metal antibacterial agents were first analyzed. Then, some of the most widely used metal-based inorganic antibacterial coatings at home and abroad and their related preparation processes were reviewed, the problems and improvement methods in the application of these coatings were also discussed, and the development direction of inorganic antibacterial coatings in the future was prospected, such as synergistic antibacterial coatings and bone-promoting antibacterial coatings.

In order to obtain films with better mechanical properties and fracture toughness, the (TiAlCrZrNb)- Six-N (x=0, 4%, 8%, 12% and 16%) high entropy ceramic nanocomposite films with different Si contents were deposited on Si substrate by magnetron sputtering technology. The effects of Si doping on the microstructure, mechanical properties! and fracture toughness of the films were investigated by X-ray diffractometry, scanning electron microscopy, high-resolution transmission electron microscopy and Nano indentation apparatus. The results show that the mechanical properties and fracture toughness of the films increase first and then decrease with the addition of Si element, which can be attributed to the formation of nanocomposite structures. When Si content is 4%, (TiAlCrZrNb)-Six-N film has the best comprehensive mechanical properties, and Us maximum hardness and elastic modulus are 22.7 GPa and 192.0 GPa, respectively. In this case, the fracture toughness reaches the best, and the radial crack length C as 6.760 µm, The K1C was 1.77 MPa • m1/2. [ABSTRACT FROM AUTHOR]

Objective·To verify the accuracy and clinical feasibility of fluoroscopic stereophotogrammetric analysis (FSA) technology based on two dimension (2D)-three dimension (3D) registration for early migration detection of aseptic loosening of joint prostheses.Methods·2D-3D registration algorithms centering on the light source and projected object respectively in FSA technology were verified under various working conditions through image synthesis experiments, and the feasibility of clinical application was verified through real model experiments. The image synthesis experiment established a perspective projection environment with the same parameters as the real environment in a virtual environment, the 2D perspective images of the 3D model (bone or prosthesis) during the six degrees of freedom transformation were recorded, and the six degrees of freedom transformation of the 3D model was restored by using different 2D-3D registration algorithms. The error of each registration algorithm was calculated. For real model validation, the migration between bone and prosthesis after joint replacement surgery was simulated with a high precision bone prosthesis migration simulator. The 3D model of the bone or prosthesis was reconstructed by using computed tomograph (CT) images and optical scanning, and the 2D perspective images before and after prosthesis migration were captured by using a fluoroscopy device. The migration of the prosthesis was restored by using FSA technology based on 2D-3D registration, and the error of FSA technology was calculated.Results·The accuracy of the 2D-3D registration algorithm centering on the light source was higher than that of the algorithm centering on the projected object under different working conditions. When the initial registration conditions were favorable, the algorithm centering on the light source reduced the rotation error compared to the algorithm centering on the projected object, with a statistical difference (P=0.021), and the displacement error decreases, with a significant statistical difference (P=0.000). Moreover, algorithms centering on the light sources required lower similarity and fewer registration times to meet clinical application requirements.Conclusion·The accuracy of FSA technology based on 2D-3D registration in early migration detection of artificial joint prostheses meets clinical application requirements. This technology can warn of late aseptic loosening of prostheses by detecting early migration of prostheses after joint replacement surgery, and is expected to be applied to clinical practice through further research.

In order to explore the influence of the thickness of Ni-P transition layer on the preparation of Ni-P-PTFE coating on stainless steel surface. Ni /N-P /Ni-P-PTFE three-layers structure gradient coating was prepared on stainless steel by electroplating combined with electroless plating. Scanning electron microscopy (SEM), X-ray diffraction (XRD), nano indentation, friction and wear tester, scratch tester and contact angle tester were used to characterize and test the microstructure, mechanical properties, adhesion and anti-adhesion property of the gradient coating. The results showed that, with the increased of N-P transition layer deposition time, the transition layer gradually thickened, the PTFE content in N-P-PTFE first decreased and then increased, the hardness and adhesion of N-PTFE coating first increased and then decreased. The maximum values of hardness and adhesion reach to 4.18 GPa and 13.49 N respectively when the N-P deposition time was 20 min. When the N-P deposition time was 25 min,the friction coefficient reached the minimum value of 0.17, and the contact angle between the surface of Ni-P-PTFE coating with water-based and oil-based liquid reached the maximum value of 101.1° and 60.06° respectively. At this time, the Ni-P-PTFE coating showed excellent adhesion resistance. [ABSTRACT FROM AUTHOR]

The dead-time effects of single-phase rectifier causes voltage and current distortions, zero-current clamping effects,etc. To solve the problems, the dead-time and zero-current clamping effects were analyzed, and a novel dead time compensation method of single-phase PWM rectifier was proposed by the observation of grid input voltage based on resonant controller phase-looked loop. The new method avoids the noise of the current detection, so that zero-crossing detection is more accurate, and does not cause the phase delay. Comparative analysis was conducted with traditional dead time compensation method based on the current. The proposed scheme can effectively improve the degree of sinusoidal current waveform, and eliminate the need to detect the direction of the current conventional solutions drawbacks. This algorithm is simple and has a practical value. The simulation and experiment results show that the grid input current total harmonic distortion with grid input voltage observation is lower and compensation effect is better. [ABSTRACT FROM AUTHOR]

The deformation problem in the mask projection stereolithography(MPS) are studied from the two aspects of theoretical analysis and software simulation. A little deflection temperature stress bending differential equation is established, so the quantitative relation between the distortion and the layer number, the temperature difference and the locations are obtained. The ANSYS software is used to simulate the deformation of the solidification process of the bridge parts in the help of the method of elements birth and death. Consequently, the influence of the layer number, the temperature difference and the locations on the deformation are validated, and the reasons why the deformation is produced are expounded. The correctness of the theoretical analysis and the software simulation are checked through the study of the experiment making. [ABSTRACT FROM AUTHOR]

The article discusses a study on the effects of Listeria monocytogenes on ultrastructural of blood-brain barrier in mice by observing ultra-thin slices of blood-brain barrier ultrastructural changes under transmission electron microscope. It states that the blood-brain barrier of the infected mice with listeria monocytogens was completely damaged and vascular permeability was increased that resulted in appearance of inflammatory cells in brain tissue.

Rod-pinch diode is widely used in flash X-ray machines of various voltage levels. Its structure is very simple and the radiation dose is high with a small focal spot. The most important thing in the physics of rodpinch diode is to study the emission state of electrons and ions under different voltage-loading waveforms. At present, the theory of electron explosion emission has been mature, but there is a lack of specific research on the property of plasma emission except that anode plasma is indispensable. Therefore, the study of anode plasma emission of the rod-pinch diode is helpful to deeply understand the influencing factor of plasma on radiation dose. Improving the radiation imaging performance of rod-pinch diode by adjusting plasma emission, like pre-filled rod-pinch diode, PIC and Monte Carlo simulations were used in this paper. PIC simulation was used to obtain the peak current of the rod-pinch diode and the phase space file storing the electron bombarding the anode. The phase space file was used as the input source file of Monte Carlo to obtain the simulated radiation dose of the rod-pinch diode. Three X-ray devices of 450 kV, 1 MV and 4 MV were used to obtain the diode current and radiation dose at 1 m of the rod-pinch diode at the voltage level of 0.45-4 MV. By comparing the simulation result with the experimental result, the correct plasma emission function of the anode rod was obtained. According to the above methods, it is confirmed that the plasma emission function is closely related to the energy and power of electron bombarding the anode rod, and the ion emission function of anode rod with different diameters at the voltage level of 0.45-4 MV is obtained. At the same time, it is found that the position of the electron bombardment anode rod corresponds to the position of plasma emission. It shows that the heat transfer of electron deposition energy on the anode rod cannot be considered in the time range of X-ray emission. After the anode ion emission function obtained in this paper was added to the numerical calculation model, the relative error between the simulated peak current and radiation dose and the real experimental value is within 20%, which can accurately predict the diode current and radiation dose in the flash X-ray experiment. Using this model, the relationship between plasma density and electron bombarding anode rod was studied. Electrons bombarding the side of the anode rod with near grazing incidence and the end face of the anode rod can obtain a higher X-ray radiation dose. Combined with 3D modeling technology, the simulation method can fully evaluate the penetration ability of X-ray in a specific object, to scientifically select the input voltage level in the formal experiment. At the same time, combined with material science and related technology, the model can also be used for the design of a new X-ray diode.

In order to aovid peri-implantitis，Ti-ZnO nanocomposite coatings were prepared on the surface of pure Ti slices by reactive magnetron sputtering.The effects of nano-ZnO content on the microstructure and antibacterial performance of the coatings were studied by means of changing the splicing ratio of Ti target and ZnO target.The microstructure，roughness and wettability of the samples were characterized and measured by scanning electron microscopy (SEM)，X-ray diffraction (XRD)，atomic force microscopy (AFM) and JC2000C1 interfacial tension tester.In addition，the release of Zn ions from the coatings was measured by inductively coupled plasma-mass spectrometry (ICP-MS)，the cytotoxicity of the coatings was tested by CCK-8 method，and the antibacterial performance of the coatings was evaluated by plate colony counting method.Results showed that when the ratio of Ti target to ZnO target was 95 ∶5，the nano-ZnO content in Ti-ZnO coating was the highest，the roughness and contact angle with liquid phase of the coating reached the maximum values of 0.547 nm and 101.25° respectively，the coating had no cytotoxicity and met the standards for biosafety materials，and the antibacterial performance of the coating was the best with an antibacterial rate up to 91.05%.

Objective: To evaluate the effectiveness of three-dimensional (3D) printing artificial vertebral body and interbody fusion Cage in anterior cervical disectomy and fusion (ACCF) combined with anterior cervical corpectomy and fusion (ACDF)., Methods: The clinical data of 29 patients with multilevel cervical spondylotic myelopathy who underwent ACCF combined with ACDF between May 2018 and December 2019 were retrospectively analyzed. Among them, 13 patients were treated with 3D printing artificial vertebral body and 3D printing Cage as 3D printing group and 16 patients with ordinary titanium mesh Cage (TMC) and Cage as TMC group. There was no significant difference in gender, age, surgical segment, Nurick grade, disease duration, and preoperative Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS) score, and Cobb angle of fusion segment between the two groups ( P >0.05). The operation time, intraoperative blood loss, hospitalization stay, complications, and implant fusion at last follow-up were recorded and compared between the two groups; JOA score was used to evaluate neurological function before operation, immediately after operation, at 6 months after operation, and at last follow-up; VAS score was used to evaluate upper limb and neck pain. Cobb angle of fusion segment was measured and the difference between the last follow-up and the immediate after operation was calculated. The height of the anterior border (HAB) and the height of the posterior border (HPB) were measured immediately after operation, at 6 months after operation, and at last follow-up, and the subsidence of implant was calculated., Results: The operation time of 3D printing group was significantly less than that of TMC group ( t =3.336, P =0.002); there was no significant difference in hospitalization stay and intraoperative blood loss between the two groups ( P >0.05). All patients were followed up 12-19 months (mean, 16 months). There was no obvious complication in both groups. There were significant differences in JOA score, VAS score, and Cobb angle at each time point between the two groups ( P <0.05). There was an interaction between time and group in the JOA score ( F =3.705, P =0.025). With time, the increase in JOA score was different between the 3D printing group and the TMC group, and the increase in the 3D printing group was greater. There was no interaction between time and group in the VAS score ( F =3.038, P =0.065), and there was no significant difference in the score at each time point between the two groups ( F =0.173, P =0.681). The time of the Cobb angle interacted with the group ( F =15.581, P =0.000). With time, the Cobb angle of the 3D printing group and the TMC group changed differently. Among them, the 3D printing group increased more and the TMC group decreased more. At last follow-up, there was no significant difference in the improvement rate of JOA score between the two groups ( t =0.681, P =0.502), but the Cobb angle difference of the 3D printing group was significantly smaller than that of the TMC group ( t =5.754, P =0.000). At last follow-up, the implant fusion rate of the 3D printing group and TMC group were 92.3% (12/13) and 87.5% (14/16), respectively, and the difference was not significant ( P =1.000). The incidence of implant settlement in the 3D printing group and TMC group at 6 months after operation was 15.4% (2/13) and 18.8% (3/16), respectively, and at last follow-up were 30.8% (4/13) and 56.3% (9/16), respectively, the differences were not significant ( P =1.000; P =0.264). The difference of HAB and the difference of HPB in the 3D printing group at 6 months after operation and last follow-up were significantly lower than those in the TMC group ( P <0.05)., Conclusion: For patients with multilevel cervical spondylotic myelopathy undergoing ACCF combined with ACDF, compared with TMC and Cage, 3D printing artificial vertebrae body and 3D printing Cage have the advantages of shorter operation time, better reduction of height loss of fusion vertebral body, and maintenance of cervical physiological curvature, the early effectiveness is better.

According to the results of transcriptome sequencing in Moniezia expansa, 10 functional genes which represent different expression patterns in different developmental proglottids were selected, including KIFC1, Kif17, tgf-beta, SmadD, tgf-beta receptor, HSD5, aminopeptidase puromycin, Methionine aminopeptidase 2, transcription factor fork head and Sox transcription factor. A real-time fluorescent quantitative PCR assay was developed for detection of mRNA expression level of these taget genes with its beta-tubulin as an internal control. The results showed that compared to scolex-neck proglottids, the mRNA levels of 2 genes (KIFC1, Kif17) in immature proglottides, 4 genes (KIFC1, Kif17, tgf-beta receptor, and amniopeptidase puromycin) in mature proglottides, and 3 genes (HSD5, tgf-beta receptor, and Methionine aminopeptidase 2) in gravid proglottides were up-regulated (P < 0.01).

Objective: To investigate the effects of minocycline in promoting the survival of pheochromocytoma (PCI2) cells exposed to oxygen glucose deprivation (OGD) and explore the underlying mechanisms., Methods: An in vitro cell model of cerebral ischemia was established by OGD for 6 h in PCI2 cells with pretreatment with minocycline or an ERK1/2 inhibitor. At 24 h after OGD injury, the cells were evaluated for cell viability by MTT assay and expressions of heme oxygenase-I (HO-I) and phospholylated extracellular signal-regulated protein kinase 1/2 (ERK1/2) by Western blotting., Results: The cell viability decreased dramatically following OGD. Pretreatment with minocycline (O.I-IO JJ.mol/L) induced a significant increase in the cell viability after OGD and caused up-regulation of HO-I protein and enhanced ERK1/2 phospholylation, and the effects were especially obvious with 1 JJ.mol/L minocycline and were abolished by inhibition of ERK1/2 activity with UOI26 (IO JJ.mol/L)., Conclusion: Minocycline can protect PCI2 cells against OGD-induced toxicity by up-regulating HO-I protein expression through ERKl/2 signaling pathways.

Objective: To analyze the diversity of bacterial community in rectum of diarrheic calves, and differences with health calves., Methods: 16S rRNA clone libraries were constructed, positive clones were digested by Msp I and Hha I for restriction fragment length polymorphism (RFLP), and then a phylogenetic tree was depicted based on the 16S rRNA sequencing, to confirm the compose of microbe in the diarrheic calf rectum., Results: The positive rate of clone was 98.75% (474/480) in diarrheic calves, the dominant bacteria included Lactobacillus (14%), Enterococcus (10%) and Escherichia (8%). The positive rate of clone was 96.45% (488/506) in health samples, the dominant bacteria included Clostridium (13%), Bifidobacterium (8%), Megasphaera (5%)., Conclusion: Complexity and diversity of bacterial community in rectum in 2 weeks old calves had their own features, and significant increase of Lactobacillus, Enterococcus and Escherichia was found in diarrhea calves.

Objective: to compare the therapeutic effect of posterolateral fusion (PLF), posterior lumbar interbody fusion (PLIF) and posterior circumferential fusion (PCF) for lumbar spondylolisthesis., Methods: from January 2003 to December 2008, 232 patients with lumbar spondylolisthesis treated with pedicle screw fixation and followed for reviewed retrospectively. The patients were divided into three groups based on fusion method: group A (PLF, 66 case), group B (PLIF, 54 case)and group C (PCF, 112 case). The three groups were reviewed and compared for clinical outcome and fusion rate., Results: the mean follow-up period was 21 months (range, 6-60 months). The fusion rate was 80.1% for PLF, 92.5% for PLIF and 93.7% for PCF group (P > 0.05). As to isthmic spondylolisthesis or Meyerding grade degenerative II and III spondylolisthesis, the fusion rate was 60.7% for PLF group, 90% for PLIF group and 93.3% for PCF group (P < 0.05). Compare the fusion rate for PLF group and PLIF+ PCF group (P < 0.05), fusion rate for PLIF group and PCF group (P > 0.05). The rate of excellent and good together was 84.8% in PLF group, 90.7% in PLIF group and 93.6% in PCF group (P > 0.05)., Conclusions: posterior lumbar interbody fusion and posterior circumferential fusion are more consistent with bio-mechanics, have a higher fusion rate, for the treatment of spondylolisthesis they are the preferred surgical approaches.

Objective: To understand whether hepatitis E virus (HEV) was infectious in sheep in Xinjiang., Methods: We used reverse transcription-nested polymerase chain reaction(RT-nPCR) to detect HEVRNA in feces. The feces were collected from sheep with positive anti-HEV antibodies in a sheep farm in Xinjiang Autonomous Region., Results: Six of 54 (11.11%) sheep were positive for HEV RNA. PCR amplification products were cloned, sequenced and analyzed. The homology among HEV of the 6 sheep HEV ORF2 189bp nucleotide amplification sequences was 99.38%-100%. They should belong to the same genotype. They were respectively compared with HEV genotype I, II, III and IV corresponding 189bp nucleotide sequences. The average homology was 78.67%-85.33%, 81.33%-82.67%, 78.67%-84.00% and 84.67%-95.36%. The maximum homology between 6 nucleotide amplification sequences and one sequence of genotype IV was 94.04%-95.36%. Based on sequence of the nucleic acid fragments, a phylogenetic tree was constructed. Six sheep HEV ORF2 189bp nucleotide amplification sequences in this study and bovine HEV, swine HEV and human HEV locate the same evolutionary vine and belong to genotype IV., Conclusion: The finding suggested that infection of HEV probably exists in the sheep group in Xinjiang Autonomous Region and the sheep may be a new animal host except swine in origins of HEV infection.

Objective: To establish the cervicothoracic spine finite element model with three-dimensional finite element method, verify the effectiveness of this model and explore the stress distribution., Methods: DICOM image data of one normal healthy young male volunteer were obtained by spiral CT scan and processed with Mimics software. Datas were imported to ANSYS software to become a 3D entity. Disc structure and the main ligament were added. Disc structure was added using the shell-nuclear unit, representing the annulus fibrosus and nucleus pulposus. Ligament structure was established with 2-node cable element, the beginning and ending points of the ligament and the cross-sectional area were determined in accordance with references. C(6,7) and C7T1 facet joints were definded as the nonliner contact joints with friction coefficient. The lower surface of TI in all the directions was completely fixed in this model. In the model 2.0 Nm pure torque were imposed on C6, and the extension, flexion, axial rotation and lateral bending experiment were conducted. The experimental results were compared with the in vitro biomechanical tests., Results: The cervicothoracic spine finite element model included 169,317 nodes and 106,242 units, and consistent with the in vitro biomechanical tests. The three-dimensional finite element model was in good running under external force., Conclusion: It is a convenient and precise method for physicians to establish the finite element model of the cervicothoracic junction. This method facilitates the computer study on the biomechanical behavior of the local structures of the model under various pressure conditions.

Reverse transcription-nested polymerase chain reaction (RT-nPCR) was used to detect HEV (Hepatitis E virus, HEV) RNA in dung or anus-swab samples collected from the cows with the positive anti-HEV antibodies in dairy farms in Xinjiang Autonomous Region. 7 of 60 (11.67%) cows were positive for HEV RNA in one farm. 1 of 31 (3.23%) cows was positive in the other farm. PCR amplification products were cloned, sequenced and analyzed. The result showed that the homology among the 8 bovine HEV ORF2 189bp nucleotide amplification sequences was 96.3%-100.0%, suggesting the same genotype. Compared with HEV genotype 1, 2, 3 and 4 corresponding 189 bp nucleotide sequences, the average homology was 78.5%-86.4%, 81.7%-83.8%, 79.1%-85.3% and 84.3%-95.8% respectively. The maximum homology between 8 nucleotide amplification sequences and one sequence of genotype 4 was 93.2%-95.8%. Based on the sequence of the nucleic acid fragments, a phylogenetic tree was constructed. It was illustrated that 8 bovine HEV ORF2 189bp nucleotide amplification sequences in this study and human C5 strain, swine swC3, swXJ strain belonged to genotype 4. The finding suggested that infection of HEV probably existed in the cow group in Xinjiang Autonomous Region and the cow might be a new animal host except swine in origin of HEV infection.

Objective: To analyze the different decompression methods to treat cervical spondylosis based on imageological evaluation., Methods: Two hundred and sixty three consecutive patients with cervical spondylosis between Nov. 2004 and Oct. 2007 were involved in this study. Patients were distributed to different operation groups based on the preoperative imageological evaluation, including anterior or posterior decompression methods. The Anterior method is to use the discectomy of one to three segments, autogenous iliac graft or titanium mesh or cage fusion and titanium plate fixation, or subtotal vertebrectomy of one to two segments autogenous iliac graft or titanium mesh fusion and titanium plate fixation, or discectomy plus subtotal vertebrectomy, The posterior expansive single open door laminoplasty and other operation types. All the patients were divided into different groups by the preoperative imageological evaluation, age, sex and course of diseases. Then we collected each group's preoperative and postoperative JOA scores and mean improvement rate to evaluate the postoperative effect by different decompression methods., Results: Two hundred and thirty five patients were followed up with a mean period of 18 months (range, 4 to 36 months). JOA scores of all patients were improved by different degrees after operations. Anterior and posterior decompression methods both can achieve higher mean improvement rates. There were no significant differences in mean improvement rates between anterior groups, and so did male and female (P > 0.05). The effect will decrease as age increases or the course of disease prolongs. Statistical significance existed among the different age groups and between course groups (P < 0.05)., Conclusions: Anterior and posterior decompression methods both can achieve good effect. The key point is to choose the surgical indication correctly, decompress thoroughly, and make the fusion reliable and fixation firm. In regard to the patients' imageological evaluation, the methods should be differentiated. The anterior operation type included discectomy of one to three segments, subtotal vertebrectomy of one to two segments and discectomy plus subtotal vertebra ectomy.

Objective: To characterize hematolysis of Enterococcus from sheep., Methods: Using plate assay (PA), contact hemolysis (CH), supernatant assay (SA), culture hemolysis (CLH) and PCR, we studied hemolysis characteristics of 11 Enterococcus clinical isolates, 30 isolates from healthy sheep, a standard G-Streptococcus and a standard Enterococcus., Results: Rabbit blood and sheep blood were not hemolysising in the 11 clinical isolates analyzed by SA and CH. Of the clinical isolates 63.6% had beta-hemolysis with rabbit blood and 36.4% had ALPHA-hemolysis with sheep blood analyzed by PA and CLH assay. Of the cylA gene 63.6% was detected in clinical isolates, the sequence of cylA gene was 99.3% homologous with cylA of plasmid pAD1 (GenBank accession number: L37110). J-hemolysis had 53.3% in rabbit blood, alpha-hemolysis and beta-hemolysis in sheep blood had 53.3% and 43.3% respectively in 30 healthy sheep initial isolates with PA. Only 6% had hemolytic capacity in rabbit blood after second generations. The cylA gene was not detected in 30 healthy sheep isolates by PCR. Standard Enterococcus strain of alpha-hemolysis of sheep blood had no hemolysis of rabbit blood., Conclusion: The red blood cells could induce enterococci hemolysis secreting in the bacteria growth. The result was different with the Phenotype and the Genotype.

Objective: The purpose of this study is to investigate the effect of cervical spinal posture and prior loading history on spinal compressive strength., Methods: Twelve human cadaver cervical spines were harvested and dissected into 24 motion segments containing 2 vertebrae and the intervertebral discs (C3,4 and C5,6). Compressive loads were applied on so that the effects of 2 loading conditions (dehydrated, superhydrated) and 2 postures (neutral trunk, flexed) could be examined. Dissection techniques and X-rays were used to determine the tissue injuries., Results: Specimens had a lower ultimate compressive strength (P <0.001) in flexed posture than in neutral trunk posture. Under the injury loading in neutral trunk posture, superhydrated specimens had a lower strength (29%, P <0.01) than dehydrated specimens did., Conclusion: The spine may be more prone to injury early in the morning when the discs are at highest level of hydration and the cervical spine is in fully flexed posture.