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Funding Information: This research was supported in part by the National Natural Science Foundation of China under Grant No. 61901136, the National Key Research and Development Program of China under Grant No. 2021YFC2801204, the Ph.D. Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities under Grant No. 3072021GIP0507, and the China Scholarship Council under Grant No. 202006680029. The authors would like to thank the Acoustic Research Laboratory of the National University of Singapore for providing the snapping shrimp noise. The authors also thank Mandar Chitre, the head of the Acoustic Research Laboratory, for his helpful comments to improve the manuscript. Publisher Copyright: © 2022 Acoustical Society of America. Detecting the presence or absence of a known signal is an important aspect of underwater acoustic (UWA) communications as it is a vital first step to process the received data. The influence of impulsive noise and multipath propagation on detection are both considered in this paper. Many robust detectors have been designed to cope with impulsive noise, but they tend to ignore the impact of multipath propagation, which may decrease the detection probability. To emphasize the role of multipath channel, we propose two-stage detection methods. In the first stage, the channel is estimated based on robust orthogonal matching pursuit, while in the second stage, detectors that use the channel estimation from the first stage, namely augmented log-likelihood ratio detector and augmented pseudo-correlation detector, are developed. The former detector is parametric and the latter one is non-parametric. The improved performance is demonstrated in simulated multipath channel and actual UWA channel with both simulated noiseand recorded snapping shrimp noise, indicating that the proposed detectors are resistant to impulsive noise. It is also shown that the use of multipath information helps to improve the detection performance.

Dual-cylinder driving columns of a hydraulic support are required to be synchronous, with the purpose of guaranteeing the support balance and providing the roof an enough force. In addition, pipelines connecting cylinders with electro-hydraulic servo-valve have a significance influence on synchronization. Taking the length of pipelines into account, the mathematical model of a dual-cylinder driven hydraulic support is built, and the displacement–force coupling characteristic caused by the shared pump is tackled by a decoupling compensator. Following that, an adaptive sliding-mode synchro-position control strategy (ASSC) is designed based on an improved sliding mode reaching law and an adaptive law is developed to restrain the uncertainties resulted from the sub-system after decoupling. The experimental results obtained from the joint simulation platform and practical system show that the proposed controller can effectively reduce the synchronization error between two column positions and has better control performance than the PI and fuzzy PID controllers.

A possible N–C bond formation directly from N2 and CH4 mediated by heteronuclear metal cluster anions CoTaC2− at room temperature was identified.

Inspired by information processing and communication in nature based on molecular recognition and structural diversity, ongoing efforts aim to development of artificial molecular or nano-systems for sensing, logic computing, and even data storage and safety. However, due to their preparation/functionalization shortcomings (laborious and time-consuming), poor flexibility and compatibility, and limited paradigm, it is still a big challenge whether simple molecules can be used to achieve comprehensive and universal applications from sensing to information storage and protection. Herein, we for the first time demonstrated a molecular paradigm-computer-like "basic input output system (BIOS)" which can realize "plug-and-play" sensing, information encoding, molecular cryptography, and steganography based on a simple artificial molecule (p-nitrophenol, PNP). Based on its molecular recognition and inherent chemical identities, PNP was utilized for colorimetric detection of multiple metal ions (Hg

Various sensing platforms based on molecular or nanosystems are widely exploited through molecular diversity and specific recognition. However, it is extremely challenging to develop systems with tunable sensing ability and utilize the systems as information carriers/covers for communication and safety. Herein, DNA nanosensing systems based on cobalt oxyhydroxide (CoOOH) nanosheets were constructed for tunable detection and valence distinction of metal ions, molecular crypto-steganography, and information coding. CoOOH nanosheets absorb fluorescence-labeled single-stranded DNA with different bases and lengths, resulting in fluorescence quenching. The binding priority of bases with CoOOH nanosheets was guanine (G) > cytosine (C) > adenine (A) ≈ thymine (T) and the short chain excelled long chain. Due to the differences in the interaction among CoOOH, DNA, metal ions and variability of DNA bases, various DNA−CoOOH nanosystems have significantly different selective response patterns (that is selectivity) to metal ions and tunable linear ranges to Fe3+, Hg2+, Cr3+. Interestingly, by utilizing their molecular diversity, recognition, selective patterns, DNA−CoOOH sensing systems can be served as doubly cryptographic and steganographic systems to implement information encoding, encryption, and hiding and to reversely improve the selectivity of metal ions. This study provides an idea and platform for adjustable detection and valence distinction of metal ions, and gives a set of “molecular programming languages” for designing intelligent programmable sensing and molecular information communication and safety systems.

Dinitrogen activation/fixation is one of the most important and challenging subjects in synthetic as well as theoretical chemistry. In this study, the adsorption reactions of N2 onto TaCn– (n = 1–4) cluster anions have been investigated by means of mass spectrometry in conjunction with density functional theory calculations. Following the experimental results that only TaC4– was observed to adsorb N2, theoretical calculations predicted that the TaC4– reaction system (TaC4– + N2 → TaC4N2–) has a negligible barrier on the approach of N2 molecule while insurmountable barriers are located on the reaction pathways of TaC1–3–/N2 reaction systems. The natural bond orbital and molecular orbital analysis indicated that the more positive charge on the metal center of TaC1–4– would facilitate the initial approach of the nonpolar N2 molecule, and the appropriate frontier orbital of TaC1–4– with proper symmetry (π-type 5d orbital) which can match up well with the π* antibonding orbital of the N2 molecule with less σ r...

It is experimentally challenging to generate nano-sized metal oxide clusters with significant intensity as well as to resolve a single hydrogen atom by mass spectrometry (TOF-MS). Herein, the high-resolution tandem time-of-flight mass spectrometer is home-made and the experimental apparatus is capable to perform the reactivity study of nano-sized vanadium oxide clusters. The formation and distribution of nano-sized vanadium oxide cluster anions V x O y − ( x up to 70) were analyzed and the photoreaction of alkene attached complex V 40 O 101 C 2 H 4 − (or V 40 O 101 C 3 H 6 − ) was studied. Larger V x O y − cluster anions can be generated typically under higher O 2 concentration and the intensity proportion (%) of vanadium oxide cluster with a certain oxygen-deficiency value Δ (Δ= 2 y -5 x -1 for V x O y − ) in each V x series is nearly invariant. In photoreaction of V 40 O 101 C 2 H 4 − (or V 40 O 101 C 3 H 6 − ), the transfer of two oxygen atoms from V 40 O 101 − to C 2 H 4 (or C 3 H 6 ) and the generation of V 40 O 99 − dominants the channel. The mass resolution of the primary TOF-MS for V 40 O 101 − (∼1.5 nm) is up to 13002. The mass resolution of the secondary TOF-MS for photoreaction is calculated to be about 4530 to resolve parent (V 40 O 101 C 2 H 4 − ) and daughter ions (V 40 O 99 − ).

Joaquim AF, Lee NJ, Lehman RA Jr, Tumialan LM, Riew KD (2020) Osteolysis after cervical disc arthroplasty. Eur Spine J. https://doi.org/10.1007/s00586-020-06578-2 Article PubMed Google Scholar Li Z, Kuhn G, von Salis-Soglio M, Cooke SJ, Schirmer M, Muller R, Ruffoni D (2015) In vivo monitoring of bone architecture and remodeling after implant insertion: the different responses of cortical and trabecular bone. Bone 81:468–477. https://doi.org/10.1016/j.bone.2015.08.017 Article PubMed Google Scholar Kurcz B, Lyons J, Sayeed Z, Anoushiravani AA, Iorio R (2018) Osteolysis as it pertains to total hip arthroplasty. Orthoped Clin North Am 49(4):419–435. https://doi.org/10.1016/j.ocl.2018.06.001 Article Google Scholar Wu TK, Liu H, Wang BY, He JB, Ding C, Rong X, Yang Y, Huang KK, Hong Y (2020) Incidence of bone loss after Prestige-LP cervical disc arthroplasty: a single-center retrospective study of 396 cases. Spine J Off J North Am Spine Soc 20(8):1219–1228. https://doi.org/10.1016/j.spinee.2020.05.102 Article Google Scholar Download references Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu, 610041, Sichuan, China Ting-kui Wu, Junbo He, Bei-yu Wang & Hao Liu West China School of Medicine, Sichuan University, No. 37 Guo Xue Rd, Chengdu, 610041, China Qing-yu Liu You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar Correspondence to Hao Liu. The authors declare that they have no conflict of interest. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Reprints and Permissions Wu, T., Liu, Q., He, J. et al. Letter to the Editor concerning “Osteolysis after cervical disc arthroplasty” by Joaquim AF, et al. (Eur Spine J; [2020]: doi: 10.1007/s00586-020–06,578-2). Eur Spine J (2020). https://doi.org/10.1007/s00586-020-06606-1 Download citation Received: 04 September 2020 Revised: 04 September 2020 Accepted: 15 September 2020 Published: 25 September 2020 DOI: https://doi.org/10.1007/s00586-020-06606-1

Dinitrogen activation/fixation is one of the most important and challenging subjects in synthetic as well as theoretical chemistry. In this study, the adsorption reactions of N

The reactivity of closed-shell gas phase cluster anions AuTi3O7- and AuTi3O8- with methane under thermal collision conditions was studied by mass spectrometric experiments and quantum chemical calculations. Methane activation was observed with the formation of AuCH3 in both cases, while the formation of formaldehyde was also identified in the reaction system of AuTi3O8-. The cooperative effect of the separated Au+ and O2- ions on the clusters induces the cleavage of the first C-H bond of methane. Further activation of the second C-H bond by a peroxide ion O22- leads to the formation of formaldehyde. This study shows that closed-shell species on metal oxides can be reactive enough to facilitate thermal H-CH3 bond cleavage and the subsequent conversion.

V5O12CH4(+) and V5O13CH4(+) clusters are generated from interactions of pregenerated V5O12(+) and V5O13(+) with CH4 in a fast flow reactor, respectively. The two adsorption complexes are then characterized by collision-induced dissociation (CID) and infrared photodissociation (IRPD) methods. The CID studies indicate that CH4 is molecularly adsorbed on V5O12(+) and V5O13(+). Each of the IRPD spectra of V5O12CH4(+) and V5O13CH4(+) has a broad red band located around 2770 cm(-1) and a narrow blue band located around 2990 cm(-1). The red and blue bands have large and small red shifts with respect to the symmetric and antisymmetric C-H stretch vibrations of free CH4, respectively. Density functional theory calculations are carried out for the structures and vibrational frequencies of V5O12(+) and V5O12CH4(+). The computed results suggest that the anharmonicity including Fermi resonance should be taken into account to interpret the observed IRPD spectrum. In V5O12CH4(+), the CH4 unit adsorbs on the 3-fold coordinated V(5+) site with an η(2) configuration. The stretch of the two C-H bonds close to the V(5+) ion is associated with the red band and the stretch of the other two C-H bonds is associated with the blue band. This study may shed light on the nature of methane adsorption onto vanadium pentoxide surfaces.

Laser ablation generated AuC3H(-) anions were skimmed into a time-of-flight mass spectrometer (TOF-MS) and selected with a mass gate. Photoelectron spectra of AuC3H(-) were recorded using the velocity map imaging technique at several photon energies. The experimental spectra, quantum chemistry calculations, and Franck-Condon simulations suggest that the AuC3H(-) cluster has four structure isomers, including one unexpected structure of [C═C═C-Au-H](-). When AuC3H(-) is compared with C3H2(-), introduction of gold into the hydrocarbon system results in the much lower isomerization barriers.

Middle ear adenoma (MEA) is a rare benign tumour. Here we report a case of MEA in a 39-year-old man with hearing loss. Some significant histopathological features of MEA and neuroendocrine differentiation identified by immunohistochemistry are described. The tumour showed remarkable and rare degenerative histological characteristics. There were a few tumour cells which were covered by degenerated tissue. Consequently, following frozen biopsy, the tumour was misdiagnosed as chronic ear inflammation. No recurrence was seen in this patient after 45 months of follow-up; regular clinical and radiological follow-up is necessary since recurrence is possible. A literature review for MEA is presented and this type of tumour is discussed clinically, microscopically and immunohistochemically. The differential diagnosis and associated treatment are described.

To evaluate the magnetic resonance (MR) findings of bile duct tumor thrombi (BDTT) and intraductal growing-type cholangiocarcinoma (IDG-type CC), especially focusing on the distal segment of intrabiliary tumors.Twenty-nine cases of hepatocellular carcinoma with BDTT and 17 cases of IDG-type CC were available for retrospective review. The following MR findings were evaluated: presence of necrosis and T1-weighted (T1W) hyperintense signal on the surface of the distal segment of intrabiliary tumors, bile duct wall thickening adjacent to the tumor, dilation of bile duct of the tumor-bearing segment, location and maximum diameter of intraductal mass, and presence of a hepatic parenchymal mass.There was significant difference in T1W hyperintense signal on the surface of the distal segment of intrabiliary tumors between BDTT and IDG-type CC (P.05). The T1W hyperintense signal detected in BDTT was identified as bile layering (9/25) or hemobilia (16/25) pathologically. For the diagnosis of BDTT, the sensitivity and specificity of T1W hyperintense signal was 86.2% and 100%, respectively. There was significant difference in necrosis at the distal end of intrabiliary tumors and presence of hepatic parenchymal mass between BDTT and IDG-type CC (P.05). However, no statistical significance was found in bile duct dilation, the absence of wall thickening, the location of intraductal mass, or the maximum diameter of intrabiliary mass between the two groups (P.05).The T1W hyperintense signal on the distal segment of intrabiliary mass was because of concentrated bile deposits or hemobilia. The sign of T1W hyper signal on the distal segment is valuable to differentiate BDTT and IDG-type CC.

To investigate the clinicopathologic features of bile duct tumor thrombus (BDTT) occurrence after treatment of primary small hepatocellular carcinoma (sHCC).A total of 423 patients with primary sHCC admitted to our hospital underwent surgical resection or local ablation. During follow-up, only six patients were hospitalized due to obstructive jaundice, which occurred 5-76 mo after initial treatment. The clinicopathologic features of these six patients were reviewed.Six patients underwent hepatic resection (n = 5) or radio-frequency ablation (n = 1) due to primary sHCC. Five cases had an R1 resection margin, and one case had an ablative margin less than 5.0 mm. No vascular infiltration, microsatellites or bile duct/canaliculus affection was noted in the initial resected specimens. During the follow-up, imaging studies revealed a macroscopic BDTT extending to the common bile duct in all six patients. Four patients had a concomitant intrahepatic recurrent tumor. Surgical re-resection of intrahepatic recurrent tumors and removal of BDTTs (n = 4), BDTT removal through choledochotomy (n = 1), and conservative treatment (n = 1) was performed. Microscopic portal vein invasion was noted in three of the four resected specimens. All six patients died, with a mean survival of 11 mo after BDTT removal or conservative treatment.BDTT occurrence is a rare, special recurrent pattern of primary sHCC. Patients with BDTTs extending to the common bile duct usually have an unfavorable prognosis even following aggressive surgery. Insufficient resection or ablative margins against primary sHCC may be a risk factor for BDTT development.

AIM: To retrospectively analyze the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of primary clear cell carcinoma of the liver (PCCCL) and compare the imaging appearances of PCCCL and common type hepatocellular carcinoma (CHCC) to determine whether any differences exist between the two groups. METHODS: Twenty cases with pathologically proven PCCCL and 127 cases with CHCC in the Second Affiliated Hospital of Sun Yat-sen University were included in this study. CT or MRI images from these patients were retrospectively analyzed. The following imaging findings were reviewed: the presence of liver cirrhosis, tumor size, the enhancement pattern on dynamic contrast scanning, the presence of pseudo capsules, tumor rupture, portal vein thrombosis and lymph node metastasis. RESULTS: Both PCCCL and CHCC were prone to occur in patients with liver cirrhosis, the association rate of liver cirrhosis was 80.0% and 78.7%, respectively (P > 0.05). The mean sizes of PCCCL and CHCC tumors were (7.28 ± 4.25) cm and (6.96 ± 3.98) cm, respectively. Small HCCs were found in 25.0% (5/20) of PCCCL and 19.7% (25/127) of CHCC cases. No significant differences in mean size and ratio of small HCCs were found between the two groups (P = 0.658 and 0.803, respectively). Compared with CHCC patients, PCCCL patients were more prone to form pseudo capsules (49.6% vs 75.0%, P = 0.034). Tumor rupture, typical HCC enhancement patterns and portal vein tumor thrombosis were detected in 15.0% (3/20), 72.2% (13/18) and 20.0% (4/20) of patients with PCCCL and 3.1% (4/127), 83.6% (97/116) and 17.3% (22/127) of patients with CHCC, respectively. There were no significant differences between the two groups (all P > 0.05). No patients with PCCCL and 2.4% (3/127) of patients with CHCC showed signs of lymph node metastasis (P > 0.05). CONCLUSION: The imaging characteristics of PCCCL are similar to those of CHCC and could be useful for differentiating these from other liver tumors (such as hemangioma and hepatic metastases). PCCCLs are more prone than CHCCs to form pseudo capsules.

The aim of this study was to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of dermatofibrosarcoma protuberans (DFSP), with a view to improving the diagnosis of this kind of tumor. A total of 27 cases of histopathologically confirmed DFSP were analyzed retrospectively. Of these, 18 patients underwent a CT scan and 9 patients underwent an MRI. All patients underwent unenhanced and contrast-enhanced examinations; 1 patient underwent multiphrase CT enhancement examination. Imaging characteristics, including location, shape, size, number, edge, and attenuation or intensity of each lesion, both unenhanced and contrast enhanced, were analyzed. Of the 27 cases, 24 were solitary, 2 had 2 nodules, and 1 had multiple confluent tumors. The lesion with multiple confluent tumors was ill defined and irregular; the other lesions were oval or round, well-defined nodules or masses. The unenhanced CT images showed 19 homogenous isodense lesions. There was no calcification in any of the patients. The contrast-enhanced CT images showed intermediate and marked nonhomogeneous enhancement in 13 lesions, intermediate homogeneous enhancement in 4 lesions, and a mild heterogeneous enhancement in 2 lesions. MR T1-weighted images revealed 1 ill-defined and 9 well-defined homogeneous isointense lesions. T2-weighted images showed homogeneous hyperintensity to the muscles in 6 lesions, 3 mild hyperintense lesions with hypointense lesions, and 1 mixed, mild hyperintense and isointense lesion. Contrast-enhanced T1-weighted images demonstrated intermediate and marked nonhomogeneous enhancement in 9 lesions and intermediate homogeneous enhancement in 1 lesion. DFSP is characterized by a subcutaneous well-defined soft tissue nodule or mass on plain CT/MR scans, and shows intermediate-to-marked enhancement on contrast-enhanced CT/MR scans. The imaging findings for DFSP are nonspecific, but may help to define the diagnosis in an appropriate clinical setting.

To report the occurrence of lower extremity avascular abnormalities in 124 cases of recovered severe acute respiratory syndrome (SARS) health care workers of four hospitals in Guangzhou and preliminary investigate the correlation with the treatment of steroid.124 health care workers with recovered SARS from four hospitals in Guangzhou were examined with MR imaging of the lower extremity including bilateral hips and knees. In 124 health care workers, 38 cases have not treated with steroid, while 86 cases have treated with varied dosage. The imaging protocol was consisted of screening and full examination. Coronal T1-weighted imaging and short tau inversion recovery sequence were defined as the screening examination. The full examination was defined as images from the screening examination plus three additional imaging sequences: transverse and coronal T2-weighted imaging and short tau inversion recovery sequence.In 86 health care workers, 5 cases were found positive in the lower extremity. Osteonecrosis was found in 3 cases. One was involved in bilateral femoral head, and another was unilateral femoral head, and the remaining one was bilateral femoral heads and unilateral femoral condyle and tibial condyle. Bilateral femoral and tibial marrow edema were found in one case. Femoral infarction with significant calcification occurred in one health care worker. Logistic regression analysis indicated that the presence of avascular abnormalities was related with maximum daily dosage.Osteonecrosis definitely exists in the minority of health care workers with recovered SARS in Guangzhou, who had treated with steroid. The maximum daily dosage of steroid may significantly influence on the occurrence of avascular abnormalities.

To retrospectively analyze the imaging features of hepatic focal nodular hyperplasia (FNH) in children on dynamic contrast-enhanced multi-slice computed tomography (MSCT) and computed tomography angiography (CTA) images.From September 1999 to April 2012, a total of 218 cases of hepatic FNH were confirmed by either surgical resection or biopsy in the Sun Yat-sen Memorial Hospital of Sun Yat-sen University and the Cancer center of Sun Yat-sen University, including 12 cases (5.5%) of FNH in children (age ≤ 18 years old). All the 12 pediatric patients underwent MSCT. We retrospectively analyzed the imaging features of FNH lesions, including the number, location, size, margin, density of FNH demonstrated on pre-contrast and contrast-enhanced computed tomography (CT) scanning, central scar, fibrous septa, pseudocapsule, the morphology of the feeding arteries and the presence of draining vessels (portal vein or hepatic vein).All the 12 pediatric cases of FNH had solitary lesion. The maximum diameter of the lesions was 4.0-12.9 cm, with an average diameter of 5.5 ± 2.5 cm. The majority of the FNH lesions (10/12, 83.3%) had well-defined margins. Central scar (10/12, 83.3%) and fibrous septa (11/12, 91.7%) were commonly found in children with FNH. Central scar was either isodense (n = 7) or hypodense (n = 3) on pre-contrast CT images and showed progressive enhancement in 8 cases in the equilibrium phase. Fibrous septa were linear hypodense areas in the arterial phase and isodense in the portal and equilibrium phases. Pseudocapsule was very rare (1/12, 8.3%) in pediatric FNH. With the exception of central scars and fibrous septa within the lesions, all 12 cases of pediatric FNH were homogeneously enhanced on the contrast-enhanced CT images, significantly hyperdense in the arterial phase (12/12, 100.0%), and isodense in the portal venous phase (7/12, 58.3%) and equilibrium phase (11/12, 91.7%). Central feeding arteries inside the tumors were observed on CTA images for all 12 cases of FNH, whereas no neovascularization of malignant tumors was noted. In 9 cases (75.0%), there was a spoke-wheel shaped centrifugal blood supply inside the tumors. The draining hepatic vein was detected in 8 cases of pediatric FNH. However, the draining vessels in the other 4 cases could not be detected. No associated hepatic adenoma or hemangioma was observed in the livers of the 12 pediatric cases.The characteristic imaging appearances of MSCT and CTA may reflect the pathological and hemodynamic features of pediatric FNH. Dynamic multi-phase MSCT and CTA imaging is an effective method for diagnosing FNH in children.

Non-hepatocellular carcinoma (non-HCC) with macroscopic bile duct tumor thrombus (BDTT) formation is rare, few radiological studies have been reported. In this case report, we retrospectively analyzed the imaging findings of three cases of non-HCC with macroscopic BDTT on dynamic enhanced multislice computed tomography (MSCT) scan. One case of primary hepatic carcinosarcoma was presented as a solitary, large well-defined tumor with significant necrotic changes. One case of liver metastasis from colon cancer was presented as a lobulated, large ill-defined tumor. One case of intraductal oncocytic papillary neoplasm involved the entire pancreas, presented as a cystic and solid mass with multilocular changes (the individual loculi were less than 5.0 mm in diameter). The bile duct was dilated due to expansible growth of the BDTT in all three patients. The BDTT was contiguous with hepatic or pancreatic tumor, and both of them showed the same enhancement patterns on dynamic contrast-enhanced computed tomography scan: early enhancement in the hepatic arterial phase and a quick wash-out of contrast agent in the portal and equilibrium phases. Macroscopic BDTT in non-HCC patient is rare, dynamic enhanced MSCT scan may be valuable in the diagnosis of non-HCC with BDTT.