Three­dimensional finite element analysis: Anatomical splint fixation for Colles fractures.

With the rapid development of digital research in clinical orthopedics, the efficacy and safety of splint fixation can be better evaluated through biomechanical analysis based on a three-dimensional (3D) finite element model. It is essential to address the current gap in understanding the biomechanical implications of anatomical splint fixation for Colles fractures. By employing advanced 3D finite element analysis, the present study aimed to provide a comprehensive evaluation, offering valuable insights that can contribute to enhancing the effectiveness of anatomical splint fixation in the clinical management of Colles fractures. The 3D finite element models of the forearm and hand were constructed using Mimics 15.0 according to data from computed tomography of a patient with a Colles fracture. After the validity of the model was verified, the corresponding material properties of the models were adjusted to simulate a Colles fracture. Subsequently, the reduction functions, such as radial inclination and ulnar deviation, of the simulated fracture were completed and the mechanical changes of the tissues surrounding the fracture were calculated. Anatomical splints were then placed on the surfaces of the 3D finite element models of Colles fractures at various positions to analyze the changes in the stress cloud diagram, such as for the soft tissue and anatomical splints. In the present study, the constructed 3D finite element models were accurate and valid. The maximum stress of the anatomical splints and soft tissues was 2.346 and 0.106 MPa in pronation, 1.780 and 0.069 MPa in median rotation and 3.045 and 0.057 MPa in supination, respectively. Splint stress reached the highest level in supination and soft tissue stress achieved the highest level in pronation. The peak of splint stress occurred during supination, which contrasts to the peak of soft tissue stress observed in pronation, suggesting splint fixation median rotation can effectively avoid compression of the local soft tissue.

Efficacy of the femoral neck system in femoral neck fracture treatment in adults: A systematic review and meta-analysis.

BACKGROUND: Controversy remains around the available choices for the internal fixation of a femoral neck fracture. The femoral neck system (FNS) was developed in 2018 and has been widely applied since then as it can provide rigid fixation stability with less damage to the bone mass around the fracture. However, no systematic reviews and meta-analyses have investigated the efficacy of the FNS in comparison with that of traditional internal fixation in the treatment of femoral fractures. AIM: To assess the efficacy of the FNS in comparison with that of cannulated compression screws (CCS) in the treatment of femoral fractures through systematic review and meta-analysis. METHODS: Five electronic databases (PubMed, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, and Wanfang) were searched from the earliest publication date to December 31, 2021. Reference Citation Analysis (https://www.referencecitationanalysis.com/) was used to check the results and further analyze the related articles. Controlled trials were included if the FNS was applied for the femoral neck fracture in adults and if it was compared with CCS for the achievement of internal fixation. The measurement outcomes included the required operation time, observed patient's blood loss, extent of fracture healing, patient's Harris Hip score (HHS) at the last follow-up, and records of any complications (such as failure of internal fixation, femoral neck shortness, avascular necrosis of the femoral head, and delayed union or nonunion). RESULTS: Ten retrospective controlled studies (involving 711 participants) were included in this meta-analysis. The meta-analysis showed that compared with CCS, use of the FNS could not decrease the operation time [standardized mean difference (SMD): -0.38, 95% confidence interval (CI): -0.98 to 0.22, P = 0.21, I 2 = 93%), but it could increase the intraoperative blood loss (SMD: 0.59, 95%CI: 0.15 to 1.03, P = 0.009, I 2 = 81%). The pooled results also showed that compared with CCS, the FNS could better promote fracture healing (SMD: -0.97, 95%CI: -1.65 to -0.30, P = 0.005, I 2 = 91%), improve the HHS at the last follow-up (SMD: 0.76, 95%CI: 0.31 to 1.21, P = 0.0009, I 2 = 84%), and reduce the chances of developing femoral neck shortness (OR: 0.29, 95%CI: 0.14 to 0.61, P = 0.001, I 2 = 0%) and delayed union or nonunion (OR: 0.47, 95%CI: 0.30 to 0.73, P = 0.001; I 2 = 0%) in adult patients with femoral neck fractures. However, there was no statistically significant difference between the FNS and CCS in terms of failure of internal fixation (OR: 0.49, 95%CI: 0.23 to 1.06, P = 0.07, I 2 = 0%) and avascular necrosis of the femoral head (OR: 0.46, 95%CI: 0.20 to 1.10, P = 0.08, I 2 = 0%). CONCLUSION: Compared with CCS, the FNS could decrease the chances of developing femoral neck shortness and delayed union or nonunion in adults with femoral neck fractures. Simultaneously, it could accelerate fracture healing and improve the HHS in these patients.

Inkjet classification based on a few letters.

Morphology-based classification of inkjet documents has the characteristics of low cost and high efficiency, but this method usually requires measurement and analysis of a large number of printed characters. This paper proposes a novel method for detecting the source of printed documents using a few printed letters. A dataset containing data pertaining to various inkjet printers, including 27 models of inkjets from HP, Canon, and Epson, and their printed documents were gathered. The specifications of the various brands and models of inkjets are summarised, and the characteristics of the microscopic appearance of the printheads are presented. Principal component analysis (PCA) of the variables was applied to describe the proximity between the specimens, and a two-dimensional kernel density estimation was used to describe the variation between and within printer brands and models. Then, specific cases were simulated by random sampling based on the collected inkjet dataset. Multivariate kernel density estimation was used to estimate the numerator and denominator probability distribution for computing the likelihood ratio (LR). The result of K-nearest neighbour analysis showed classification accuracy as high as 98%. The evaluation of the LR presented a significant result (EER=0, RMEP=0, RMED=0.07). This method helps to find a specific inkjet from even a few letters in the printed document for tactical purposes.

Fourier-transform infrared microspectroscopy of pulmonary edema fluid for postmortem diagnosis of diabetic ketoacidosis.

Determination of the cause of death for diabetic ketoacidosis (DKA), a common and fatal acute complication of diabetes mellitus, is a challenging forensic task owing to the lack of characteristic morphological findings at autopsy. In this study, Fourier-transform infrared (FTIR) microspectroscopy coupled with chemometrics was employed to characterize biochemical differences in pulmonary edema fluid from different causes of death to supplement conventional methods and provide an efficient postmortem diagnosis of DKA. With this aim, FTIR spectra in three different situations (DKA-caused death, other causes of death with diabetes history, and other causes of death without diabetes history) were measured. The results of principal component analysis indicated different spectral profiles between these three groups, which mainly exhibited variations in proteins. Subsequently, two binary classification models were established using an algorithm of partial least squares discriminant analysis (PLS-DA) to determine whether decedents had diabetes and whether the diabetic patients died from DKA. Satisfactory prediction results of PLS-DA models demonstrated good differentiation among these three groups. Therefore, it is feasible to make a postmortem diagnosis of DKA and detect diabetes history via FTIR microspectroscopic analysis of the pulmonary edema fluid.

Catharmus tinctorius volatile oil promote the migration of mesenchymal stem cells via ROCK2/Myosin light chain signaling.

MSC transplantation has been explored as a new clinical approach to stem cell-based therapies for bone diseases in regenerative medicine due to their osteogenic capability. However, only a small population of implanted MSC could successfully reach the injured areas. Therefore, enhancing MSC migration could be a beneficial strategy to improve the therapeutic potential of cell transplantation. Catharmus tinctorius volatile oil (CTVO) was found to facilitate MSC migration. Further exploration of the underlying molecular mechanism participating in the pro-migratory ability may provide a novel strategy to improve MSC transplantation efficacy. This study indicated that CTVO promotes MSC migration through enhancing ROCK2 mRNA and protein expressions. MSC migration induced by CTVO was blunted by ROCK2 inhibitor, which also decreased myosin light chain (MLC) phosphorylation. Meanwhile, the siRNA for ROCK2 inhibited the effect of CTVO on MSC migration ability and attenuated MLC phosphorylation, suggesting that CTVO may promote BMSC migration via the ROCK2/MLC signaling. Taken together, this study indicates that C. tinctorius volatile oil could enhance MSC migration via ROCK2/MLC signaling in vitro. C. tinctorius volatile oil-targeted therapy could be a beneficial strategy to improve the therapeutic potential of cell transplantation for bone diseases in regenerative medicine.

Assessment of signature handwriting evidence via score-based likelihood ratio based on comparative measurement of relevant dynamic features.

This paper extends on previous research on the extraction and statistical analysis on relevant dynamic features (width, grayscale and radian combined with writing sequence information) in forensic handwriting examinations. In this paper, a larger signature database was gathered, including genuine signatures, freehand imitation signatures, random forgeries and tracing imitation signatures, which are often encountered in casework. After applying Principle Component Analysis (PCA) of the variables describing the proximity between specimens, a two-dimensional kernel density estimation was used to describe the variability of within-genuine comparisons and genuine-forgery comparisons. We show that the overlap between the within-genuine comparisons and the genuine-forgery comparisons depends on the imitated writer and on the forger as well. Then, in order to simulate casework conditions, cases were simulated by random sampling based on the collected signature dataset. Three-dimensional normal density estimation was used to estimate the numerator and denominator probability distribution used to compute a likelihood ratio (LR). The comparisons between the performance of the systems in SigComp2011 (based on static features) and the method presented in this paper (based on relevant dynamic features) showed that relevant dynamic features are better than static features in terms of accuracy, false acceptance rate, false rejection rate and calibration of likelihood ratios.

(+)-Cholesten-3-one induces osteogenic differentiation of bone marrow mesenchymal stem cells by activating vitamin D receptor.

In our previous reports, it was revealed that steroids in traditional Chinese medicine (TCM) have the therapeutic potential to treat bone disease. In the present study, an in vitro model of a vitamin D receptor response element (VDRE) reporter gene assay in mesenchymal stem cells (MSCs) was used to identify steroids that enhanced osteogenic differentiation of MSCs. (+)-cholesten-3-one (CN), which possesses a ketone group that is modified in cholesterol and cholesterol myristate, effectively promoted the activity of the VDRE promoter. Phenotypic cellular analysis indicated that CN induced differentiation of MSCs into osteogenic cells and increased expression of specific osteogenesis markers, including alkaline phosphatase, collagen II and Runt-related transcription factor 2. Furthermore, CN significantly increased the expression of osteopontin, the target of the vitamin D receptor (VDR), which indicated that CN may activate vitamin D receptor signaling. Over-expression of VDR or knockdown studies with VDR-small interfering RNA revealed that the pro-differentiation effects induced by CN required VDR. Furthermore, the present study determined that the C-terminal region of the VDR is responsible for the action of CN. Taken together, the present findings demonstrated that CN induced osteogenic differentiation of MSCs by activating VDR. The present study explored the regulation of stem cells by using a series of similar steroids and provided evidence to support a potential strategy for the screening of novel drugs to treat bone disease in the future.

[Gut microbiota and osteoporosis].

OBJECTIVE: The rapidly evolving aging society in China is associated with increased incidences of osteoporosis and fractures, which have become common health problems that threaten the quality of life of the elderly. Gut microbiota colonizing in the human intestinal tract form a mutual symbiotic relationship with the host and play an important role in the metabolism and immune regulation of the host. In recent years increasing studies have demonstrated that gut microbiota not only affect the digestive system but also contribute to the disease conditions involving the immune system, and have a close relationship with the occurrence and progression of osteoporosis. This review summarizes the progress and hotspots in recent researches of the associations among gut microbiota, the immune system, osteoporosis.

Characteristics of electrically injured skin from human hand tissue samples using Fourier transform infrared microspectroscopy.

This technical note describes a method for distinguishing normal skin tissue samples from those electrically injured by Fourier transform infrared microspectroscopy (FTIR MSP). Furthermore, the infrared spectral features of electrically injured cells and tissues were evaluated to identify molecular changes in epidermal cells. In the present study, 20 human hand tissue samples were evaluated macroscopically and histopathologically. The electrically injured skin samples were subdivided into 2 regions [normal cell regions (NCRs) and polarized cell regions (PCRs)] and 14 major spectral absorption bands were selected. The spectral results showed that the band absorbance at 1080, 1126, 1172, 1242, 1307, 1403, 1456, 1541, 2852, 2925, 2957, 3075, and 3300cm(-1) increased significantly both in the stratum and non-stratum corneum of the PCRs in electrically injured skin tissues samples. No significant difference was found between normal skin and the NCR of the electrically injured skin samples. The band absorbance ratios of A1172/A1126, A1456/A1403, and A2925/A2957 were significantly increased, whereas the A1652/A1541 ratio was decreased in the PCR of the stratum corneum and non-stratum corneum. Baseline changes from 4000 to near 1737cm(-1) were observed in the spectra of the electrically injured skin samples, which were interpreted in terms of the pathological process involved in electrical injury. FTIR-MSP presents a useful method to provide objective spectral markers for the assisted diagnosis of electrical marks.

[Effects of Staphylococcus aureus supernatant on expression of various cytokines by neutrophils and retinal pigment epithelium cells].

OBJECTIVE: To evaluate the effects of Staphylococcus aureus supernatant on the levels of interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in co-cultures of neutrophils and retinal pigment epithelium (RPE) cells. METHODS: The co-culture system was established by co-culturing of human RPE cell line D407 and human peripheral blood neutrophils. Bacterium-free supernatant of Staphylococcus aureus ATCC29213 was added to the co-culture system for studying its effects. The volume of bacterium-free supernatant was divided into six groups: negative control, brain-heart infusion control, 50 µl, 100 µl, 250 µl and 500 µl group. The number of neutrophils was divided into four groups: negative control, 1 × 10(4), 5 × 10(4) and 5 × 10(5) group. The supernatants was collected at 6 h, 12 h, 24 h, 48 h and 72 h later and the levels of IL-1ß, TNF-α and IL-6 were measured by ELISA kits. RESULTS: When RPE cells were cultured with different doses of bacterium-free supernatant (0, 50, 100, 250 and 500 µl), the levels of IL-1ß was positively correlated with the volume of bacterium-free supernatant and the duration. The levels of IL-6 were significantly higher than that of the control group in the 500 µl group at 24 h [(23.17 ± 3.16) ng/L vs (7.61 ± 1.53) ng/L] and 48 h [(35.00 ± 4.37) ng/L vs (13.17 ± 3.27) ng/L] duration (P = 0.001 and P = 0.026, respectively). When RPE cells were co-cultured with the bacterium-free supernatant and the neutrophils (1 × 10(4), 5 × 10(4) and 5 × 10(5) cells) for 6 and 12 h, the levels of IL-1ß in the 5 × 10(5) group at both 6 h [(236.62 ± 8.20) ng/L] and 12 h [(447.42 ± 35.13) ng/L] was statistically higher than that in other groups (6 h: P = 0.000, P = 0.000, P = 0.002; 12 h: P = 0.000, P = 0.000, P = 0.000, respectively). The levels of IL-6 in the 5 × 10(5) group [(46.96 ± 2.72) ng/L] was significantly higher than that in the other groups at 12 h (P = 0.000, P = 0.000, P = 0.000, respectively). TNF-α could not be detected in the conditioned media from all cultures. CONCLUSIONS: Both IL-1ß and IL-6 are expressed in the co-cultures of neutrophils and RPE cells with Staphylococcus aureus supernatant. IL-1ß is upregulated at the early stage and the high level is maintained longer than that of IL-6. The virulence factor of bacteria and the neutrophil may play a role in the expression of IL-1ß and IL-6 in the RPE cells.

[Determination of blue ballpoint pen ink by laser ablation inductively coupled plasma mass spectrometry].

To establish an identification method for the forensic analysis of blue ballpoint ink by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), 95 kinds of blue ballpoint pen from different manufacturers were detected. These blue ballpoint pens were classified into 34 groups according to their metal element components, among which, 26 groups can be directly distinguished according to the types of metal element components contained in the ballpoint pen, the other groups can be distinguished by different element response ratios. Meanwhile the examination result on the papers showed that the papers have no impact on the ink handwriting analysis. Experimental results showed that the method's reproducibility is good and precision is less than 10%. This method has better identification ability than traditional identification technology for questioned document. Eighty eight kinds of blue ballpoint pen out of the total 95 selected kinds can be distinguished with this method. The established method is simple, rapid, with good precision, and almost has no damage to the sample. It is particularly suitable for the demand of identification of blue ballpoint pen in forensic science.