Experimental study on the atomization characteristics and dust removal efficiency of a fan-shaped nozzle for purifying working environment.

The inadequacy of the existing research in characterizing the atomization performance of the whole atomization field by the local region at nozzle axis hinders the improvement of dust removal performance of a spray system, especially for fan-shaped nozzles with large atomization angle. To solve this inadequacy, 88 measuring points were designed in this study to reveal the spatial distribution characteristics of atomization parameters of a fan-shaped pressure atomization nozzle using a 3D Fiber Phase-Doppler Anemometer. Moreover, the atomization performance and dust removal performance of the whole atomization field under different spray pressures were characterized. The results showed that the spatial distribution of atomization parameters in the axis and radial direction of the nozzle was inhomogeneous. As the axial distance from the nozzle outlet increased, the average droplet size showed a trend of first decreasing and then increasing, the proportion of the droplet of 15-70 µm showed a trend of first increasing and then decreasing, while the average droplet velocity and droplet flux showed a decreasing trend. In addition, the spray orientation was perpendicular to gravity, and the atomization field was parallel to gravity, resulting in a significant difference in the average droplet size between the upper region and the axis. Compared with the upper and lower regions, the atomization effect at the axis was superior, manifested by higher average droplet velocity and droplet flux, indicating that characterizing nozzle atomization performance with atomization parameters at the axis will lead to overestimation. The increase of spray pressure can improve atomization performance and dust removal efficiency to a certain extent, but the improvement effect had a limit. The atomization field can be divided into atomization region, expansion region and contraction region, and the expansion region was considered as an effective dust removal region. These findings provide reference for the design and operation of a spray system.

Correlation between the quality of cartilage repair tissue and patellofemoral osteoarthritis after matrix-induced autologous chondrocyte implantation at three-year follow-up: a cross-sectional study.

PURPOSE: To investigate whether the quality of cartilage repair tissue is associated with patellofemoral osteoarthritis (PFOA) at a three year follow-up after matrix-induced autologous chondrocyte implantation (MACI). METHODS: This retrospective study included 32 patients who underwent MACI between October 2014 and May 2018 at our institute. The Lysholm score and Visual Analog Scale (VAS) score were assessed. The magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 score and T2* relaxation time of repair tissue were used to evaluate cartilage repair tissue quality. A modified MRI Osteoarthritis Knee Score (mMOAKS) was used to evaluate PFOA. RESULTS: Compared with pre-operative scores, the final Lysholm score (50.71 ± 2.22 vs 89.70 ± 1.18; t = 15.5, P < 0.0001) and VAS score (4.67 ± 0.47 vs 0.92 ± 0.64; t = 22.62, P < 0.0001) were improved at 3 years after MACI. At the three year follow-up, the mean MOCART 2.0 score was 61.56 ± 18.11, and the T2* relaxation time of the repair tissue was significantly lower than that in the healthy control region (24.11 ± 6.38 vs 34.39 ± 1.33, t = - 8.635, P < 0.0001). The mean mMOAKS score was 9.16 ± 4.51. On univariate analysis, the MOCART 2.0 score and T2* relaxation time were negatively associated with the mMOAKS score. CONCLUSION: MACI can lead to significant pain relief and restoration of knee joint function, and good quality cartilage repair tissue was a protective factor against PFOA at the three year follow-up.

Correlation between the subchondral bone marrow lesions and cartilage repair tissue after matrix-associated autologous chondrocyte implantation in the knee: a cross-sectional study.

BACKGROUND: The contribution of the subchondral bone in the development and progression of osteoarthritis (OA) has long been recognized, but its role in cartilage repair procedures has only recently attracted more attention. PURPOSE: To explore the correlation between the cartilage repair tissue (RT) and the subchondral bone marrow lesions (BMLs) after matrix-associated autologous chondrocyte implantation (MACI) in the knee joint. MATERIAL AND METHODS: A total of 30 patients who underwent MACI in the knee from January 2015 to June 2018 and follow-up magnetic resonance imaging (MRI) scan were recruited in this study. The MRI results of cartilage RT were evaluated using T2* relaxation time. Subchondral BMLs were also qualitatively evaluated by use of the two-dimensional proton density-weighted fat-suppressed (2D-PD-FS) and three-dimensional dual-echo steady-state (3D-DESS) sequences. RESULTS: The univariate analysis displayed a significant negative correlation between subchondral BMLs and cartilage RT (P < 0.01). In the minimally adjusted model (only age, sex, and body mass index [BMI] adjusted), the results did not show obvious changes (ß = -6.54, 95% confidence interval [CI] = -10.99 to -2.09; P = 0.008). After adjustment for the full models (age, sex, BMI, defect size, combined injury, and preoperative duration of symptoms adjusted), the connection was also detected (ß = -6.66, 95% CI -11.82 to -1.50; P = 0.019). CONCLUSION: After MACI, the subchondral BMLs are significantly correlated with cartilage RT-T2* relaxation time. The role of subchondral bone in cartilage repair procedures should not be underestimated.

Infection Control against COVID-19 in Departments of Radiology.

The COVID-19 epidemic, which is caused by the novel coronavirus SARS-CoV-2, has spread rapidly to become a world-wide pandemic. Chest radiography and chest CT are frequently used to support the diagnosis of COVID-19 infection. However, multiple cases of COVID-19 transmission in radiology department have been reported. Here we summarize the lessons we learned and provide suggestions to improve the infection control and prevention practices of healthcare workers in departments of radiology.

Corona Virus International Public Health Emergencies: Implications for Radiology Management.

The outbreak of 2019 novel coronavirus (2019-nCoV) pneumonia was reported in Wuhan, Hubei Province, China in December 2019 and has spread internationally. This article discusses how radiology departments can most effectively respond to this public health emergency.

A retrospective comparative study of arthroscopic fixation in acute Rockwood type IV acromioclavicular joint dislocation: single versus double paired Endobutton technique.

BACKGROUND: Rockwood type IV acromioclavicular joint (ACJ) dislocation is a trauma usually needs surgical treatment. Paired EndoButton technique (PET) is used in treating such condition. However, the effect of using different types of PET (single versus double PET) for fixation remains controversial. This study aims to evaluate and compare the efficacy of single and double PET and to provide a suitable option for the surgeons. METHODS: We retrospectively reviewed the charts of patients with acute Rockwood type IV ACJ dislocation who had undergone arthroscopic fixation using single or double PET fixation between March 2009 and March 2015. Seventy-eight consecutive patients identified from chart review were picked and were divided into the single and double PET group with 39 cases in each group. The indexes of visual analog scale score (VAS) for pain, the radiographs of the affected shoulder at different time points of the follow-up, the time of return to activities and sports, the constant functional score, and the Karlsson acromioclavicular joint (ACJ) score, were assessed in a minimum of 2 years postoperation. RESULTS: The average coracoclavicular (CC) and acromioclavicular (AC) distances of the affected joints in the double PET group were significantly smaller than those of the single PET group 2 years postoperation (P < 0.05). The average AC and CC distances in the healthy shoulder joints were significantly smaller than those of the affected joints in the single PET group (P < 0.05); however, these values were not significantly different from those of the affected joints in the double PET group (P > 0.05). The mean VAS pain score was not significantly different, while significant difference was found for the number and times of cases return to activities and sports, constant functional score, and Karlsson ACJ score (P < 0.05) between the two groups. Therefore, the double PET group has better outcome than the single PET group. Complications including redislocation, button slippage, erosion, or AC joint instability occurred in the single PET group, while the complication in the double PET group was rare. CONCLUSIONS: Compared with the single PET, the double PET group achieved better outcome with less complications in arthroscopically treating acute Rockwood type IV ACJ dislocation.

Placement of Double Tunnels in ACL Reconstruction Using Bony Landmarks Versus Existing Footprint Remnant: A Prospective Clinical Study With 2-Year Follow-up.

BACKGROUND: The outcomes of double-bundle anterior cruciate ligament reconstruction (DB-ACLR) are becoming controversial. One of the main reasons for the controversy is the techniques for bone tunnel placement. The common technique to place the bone tunnels is to use bony landmarks, while a new approach uses footprint remnants. PURPOSE: To investigate if placement of double tunnels using bony landmarks produces the same clinical results as that of using existing footprint remnants. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: A total of 72 male patients were randomly divided into 2 groups of 36 patients each: (A) DB-ACLR tunnel placement using the footprint remnant procedure (EF group) and (B) DB-ACLR tunnel placement using the bony landmark procedure (BL group). All patients were evaluated before and after surgery. Outcomes were measured by KT-2000 arthrometer side-to-side difference, pivot-shift test, and Tegner, Lysholm, and International Knee Documentation Committee (IKDC) scores. Second-look arthroscopic evaluations were performed in 59 cases (28 and 31 cases in the EF and BL groups, respectively). RESULTS: The mean follow-up time was 36.9±4.8 months. Postoperative 3-dimensional computed tomography scans showed that bone sockets were variable on both femoral and tibial sides in the EF group and almost consistent in the BL group. All of the evaluation indexes were significantly improved postoperatively in both groups. There were no revision cases in the EF group and 2 in the BL group. The EF group showed a faster range of motion (ROM) recovery (at 0° to 120°) than did the BL group. At final follow-up, there was no significant difference between the EF and BL groups in Tegner score (5.88±1.39 vs 5.16±1.76; P=.058) or pivot-shift test (34 vs 32; P=.067). The EF group had a larger proportion of patients with IKDC grade A (normal) (33 vs 24; P<.020), smaller side-to-side difference (0.68±0.38 mm vs 1.23±0.61 mm; P<.001), higher Lysholm score (91.29±4.90 vs 88.71±5.09; P=.032), and better second-look arthroscopic evaluations for graft quality in the anteromedial (P=.034), posterolateral (P=.015), and combined bundles (P=.029) compared with the BL group. CONCLUSION: Although both techniques provided satisfactory clinical results, DB-ACLR using the existing footprint remnant for tunnel placement showed better functional results with respect to faster ROM recovery, higher subjective outcome scores, and better arthroscopic second-look with no revision cases.

[Value of magnetic resonance imaging in preoperative staging of endometrial carcinoma according to International Federation of Gynecology and Obstetrics (2009) staging criteria].

OBJECTIVE: To analyze the magnetic resonance imaging (MRI) features of endometrial carcinoma and their value in endometrial carcinoma staging according to the International Federation of Gynecology and Obstetrics (FIGO 2009) staging criteria. METHODS: Fifty-four patients with pathologically confirmed endometrial carcinoma and complete clinical data underwent preoperative MRI examination. According to FIGO 2009 staging criteria of endometrial carcinoma, the MRI features of the tumor lesions were evaluated for assessment of myometrial invasion and cervical involvement and preoperative staging. RESULTS: The 54 cases included 27 stage Ia cases, 9 stage Ib cases, 10 stage II cases, 5 stage III cases, and 3 stage IV cases. The total lesion display rate by MRI was 94% (51/54). With an isointensity or hypo-intensity on T1WI, the tumor lesions showed a moderate hyper-intensity on T2WI. In enhanced MRI scanning, the lesions showed a moderate heterogeneous enhancement, which had a lower intensity than the marked enhancement of the myometrium. Combination of T2WI and T1WI in fat suppression sequence enhanced scan had a diagnostic accuracy of 91% (49/54) for myometrial invasion, and the sensitivity, specificity and accuracy of MRI for detecting cervical involvement were 77%, 89%, and 83%, respectively. The accuracy of preoperative MRI-based staging of endometrial carcinoma was 89% (48/54), showing no significant difference from the results of postoperative FIGO 2009 staging and pathological examination (P>0.05). CONCLUSION: MRI has a high accuracy in the diagnosis, evaluation of myometrial and cervical invasion depth, and preoperative staging of endometrial carcinoma, and serves as an important modality in assisting clinical decisions on the optimal therapeutic protocols and in prognostic estimation.