Lamellar Fluctuations Melt Ferroelectricity.

We consider a standard Ginzburg-Landau model of a ferroelectric whose electrical polarization is coupled to gradients of elastic strain. At the harmonic level, such flexoelectric interaction is known to hybridize acoustic and optic phonon modes and lead to phases with modulated lattice structures that precede the state with spontaneously broken inversion symmetry. Here, we use the self-consistent phonon approximation to calculate the effects of thermal and quantum polarization fluctuations on the bare hybridized modes to show that such long-range modulated order is unstable at all temperatures. We discuss the implications for the nearly ferroelectric SrTiO_{3} and KTaO_{3}, and we propose that these systems are melted versions of an underlying modulated state that is dominated by nonzero momentum thermal fluctuations except at the very lowest temperatures.

[The stability and repeatability of radiomics features based on lung diffusion-weighted imaging].

Objective: To evaluate the feasibility, robustness and reproducibility of radiomics features derived from lung diffusion-weighted imaging (DWI). Methods: Thirty patients with pulmonary nodules/masses who underwent magnetic resonance imaging examination in the Department of Radiology, the First Affiliated Hospital of Guangzhou Medical University, from January 4 2019 to May 5 2019, including 16 males and 14 females, aged from 27 to 69 (57±11) years, were prospectively collected. Planar echo imaging (EPI) -DWI and fast spin-echo (TSE) -DWI scans were performed under free-breathing conditions. Each scan was repeated at an interval of 5 minutes, and the corresponding apparent diffusion coefficient (ADC) maps were reconstructed. Each DWI and ADC sequence (a total of eight groups of images) were manually segmented by two radiologists, and a total of 396 radiomics features in 6 categories were extracted from each group of images. Consistency correlation coefficient (CCC) and dynamic range (DR) were used to evaluate the robustness of features between two scans, and stable features were defined as both CCC values and DR values ≥0.85. Intra-observer and interobserver reproducibility were evaluated by intra-group correlation coefficient (ICC), and ICC values≥0.75 was considered to be good reproducibility. Results: Regardless of EPI or TSE technique, the number of robust features extracted fromDWI (TSE: n=197, EPI: n=169) were higher than that of the corresponding ADC (TSE: n=126, EPI: n=148). The proportion of robust features of TSE-DWI、EPI-DWI、TSE-ADC、EPI-ADC was 49.7% (197/396), 42.7% (169/396), 31.8% (126/396) and 37.4% (148/396), respectively. Of the 396 features, 54 (13.6%) of them demonstrated great robustness (CCC and DR≥0.85) and interobserver and interobserver reproducibility (ICC≥0.75) across all sequences. Conclusions: Radiomics features derived from lung DWI showed robustness and reproducibility. Different sequences and different feature clusters have different proportions of stable features, and some features have good robustness and reproducibility between different scans, different observers, and even different sequences.

[Value of radiomics model based on dynamic contrast-enhanced magnetic resonance imaging in differentiation fat-poor angiomyolipoma from alpha-fetoprotein-negative hepatocellular carcinoma in the background of non-cirrhotic liver].

Objective: To explore the value of radiomics model based on dynamic contrast-enhanced magnetic resonance imaging (MRI) in differentiation fat-poor angiomyolipoma (fp-AML) from alpha-fetoprotein-negative hepatocellular carcinoma (n-HCC) in the background of non-cirrhotic liver. Methods: The complete data of 121 patients from Guangdong Provincial People's Hospital, Zhongshan Hospital Affiliated to Fudan University and Sun Yat-sen University Cancer Center with hepatic fp-AML and n-HCC confirmed by pathology from October 2010 to July 2020 were retrospectively analyzed. Among them, 75 were males and 46 were females, aged from 23 to 80 (55±12) years. A total of 93 patients from Zhongshan Hospital Affiliated to Fudan University were divided into the training cohort (n=75) and internal test cohort (n=18) according to entry time, and the patients of other 2 hospitals were divided into external test cohort (n=28). The radiomics features were extracted from the preoperative triple-phase contrast-enhanced images. The feature selection algorithm based on Joint Mutual Information Maximisation (JMIM) was used to extract the optimal feature subset, and support vector machine (SVM) was used to build the radiomics model. The diagnostic performance of radiomics model was evaluated using the receiver operating characteristic (ROC) curve, and was compared with that of two radiologists. Results: In the internal cohort, the area under the curve (AUC) for the differential diagnosis between fp-AML and n-HCC of the radiomics model was 0.819 (with an accuracy of 72.2%), outperforming than radiologist 1 with 10 years of diagnostic experience (AUC=0.542, P=0.029) and radiologist 2 with 2 years of diagnostic experience (AUC=0.375, P=0.004). In the external cohort, the AUC of the radiomics model was 0.772 (with and accuracy of 71.4%), which was comparable to that of radiologist 1 (AUC=0.661, P=0.442) and better than that of radiologist 2 (AUC=0.400, P=0.008). Conclusion: The radiomics model based on dynamic contrast-enhanced MRI is of high accuracy for preoperatively differentiating hepatic fp-AML from n-HCC in the noncirrhotic liver.

[Promoting the application of federated learning in medical imaging artificial intelligence].

Medical image-based artificial intelligence (AI) systems have shown great potential in assisting disease diagnosis and treatment. However, the challenges, such as data silos, privacy security and standardization, seriously impedes the application of AI in disease diagnosis and treatment. By integrating federated learning technology and FAIR data principle, it is possible to resolve the aforementioned obstacles. Then, it is able to maximize the value of multicenter data to develop a more efficient and accurate disease diagnosis and treatment AI systems, and promote the clinical application of medical image-based AI systems in the field of disease diagnosis and treatment.

Identifying pulmonary nodules or masses on chest radiography using deep learning: external validation and strategies to improve clinical practice.

AIM: To test the diagnostic performance of a deep learning-based system for the detection of clinically significant pulmonary nodules/masses on chest radiographs. MATERIALS AND METHODS: Using a retrospective study of 100 patients (47 with clinically significant pulmonary nodules/masses and 53 control subjects without pulmonary nodules), two radiologists verified clinically significantly pulmonary nodules/masses according to chest computed tomography (CT) findings. A computer-aided diagnosis (CAD) software using a deep-learning approach was used to detect pulmonary nodules/masses to determine the diagnostic performance in four algorithms (heat map, abnormal probability, nodule probability, and mass probability). RESULTS: A total of 100 cases were included in the analysis. Among the four algorithms, mass algorithm could achieve a 76.6% sensitivity (36/47, 11 false negative) and 88.68% specificity (47/53, six false-positive) in the detection of pulmonary nodules/masses at the optimal probability score cut-off of 0.2884. Compared to the other three algorithms, mass probability algorithm had best predictive ability for pulmonary nodule/mass detection at the optimal probability score cut-off of 0.2884 (AUCMass: 0.916 versus AUCHeat map: 0.682, p<0.001; AUCMass: 0.916 versus AUCAbnormal: 0.810, p=0.002; AUCMass: 0.916 versus AUCNodule: 0.813, p=0.014). CONCLUSION: In conclusion, the deep-learning based computer-aided diagnosis system will likely play a vital role in the early detection and diagnosis of pulmonary nodules/masses on chest radiographs. In future applications, these algorithms could support triage workflow via double reading to improve sensitivity and specificity during the diagnostic process.

Correlation between composition, microstructure, and emission properties in Nd-doped Si-rich Si oxynitride films: investigation into the nature of the sensitizer.

Rare earth (RE) ions doped in Si-based materials, compatible with Si technology, are promising compounds with regards to optical communication and energy conversion. In this article, we show the emission properties of Nd-doped Si-rich Si oxynitride (Nd-SRSON) films, and their dependence on the dangling bond density and the nature of the sensitizer. These films were prepared by reactive magnetron sputtering and post-annealing. The film composition, microstructure, and emission properties were investigated as a function of deposition parameters and annealing temperatures. Both Fourier transform infrared (FTIR) and ellipsometry spectroscopy measurements have confirmed that the sample composition (Si/N ratio) can be carefully tuned by varying the ratio of reactive nitrogen to argon in the sputtering plasma. Moreover, FTIR and x-ray photoelectron spectroscopy measurements demonstrate the existence of both nitrogen and oxygen dangling bonds (N· and O·) in as-deposited samples. These dangling bonds were passivated during annealing. Under non-resonant excitation at 488 nm, the films exhibit a significant photoluminescence (PL) signal from Nd3+ ions demonstrating the occurrence of an effective sensitization of Nd3+ ions in the host matrix. Both PL excitation and ellipsometry results (the energy band gap from new amorphous model) exclude the sensitization by an exciton with energy over the band gap, whereas the presence of Si agglomerates, at the atomic scale, have been identified as effective sensitizers towards Nd3+ ions. This work not only provides knowledge to optimize Si-based materials for favorable emission properties, but also, presents a universal methodology to investigate the nature of sensitizers for RE emitters. This allows one to find correlations between composition, microstructure, and emission properties.

Mutations during the Adaptation of H9N2 Avian Influenza Virus to the Respiratory Epithelium of Pigs Enhance Sialic Acid Binding Activity and Virulence in Mice.

The natural reservoir for influenza viruses is waterfowl, and from there they succeeded in crossing the barrier to different mammalian species. We analyzed the adaptation of avian influenza viruses to a mammalian host by passaging an H9N2 strain three times in differentiated swine airway epithelial cells. Using precision-cut slices from the porcine lung to passage the parental virus, isolates from each of the three passages (P1 to P3) were characterized by assessing growth curves and ciliostatic effects. The only difference noted was an increased growth kinetics of the P3 virus. Sequence analysis revealed four mutations: one each in the PB2 and NS1 proteins and two in the HA protein. The HA mutations, A190V and T212I, were characterized by generating recombinant viruses containing either one or both amino acid exchanges. Whereas the parental virus recognized α2,3-linked sialic acids preferentially, the HA190 mutant bound to a broad spectrum of glycans with α2,6/8/9-linked sialic acids. The HA212 mutant alone differed only slightly from the parental virus; however, the combination of both mutations (HA190+HA212) increased the binding affinity to those glycans recognized by the HA190 mutant. Remarkably, only the HA double mutant showed a significantly increased pathogenicity in mice. In contrast, none of those mutations affected the ciliary activity of the epithelial cells which is characteristic for virulent swine influenza viruses. Taken together, our results indicate that shifts in the HA receptor affinity are just an early adaptation step of avian H9N2 strains; further mutational changes may be required to become virulent for pigs.IMPORTANCE Swine play an important role in the interspecies transmission of influenza viruses. Avian influenza A viruses (IAV) of the H9N2 subtype have successfully infected hosts from different species but have not established a stable lineage. We have analyzed the adaptation of IAV-H9N2 virus to target cells of a new host by passaging the virus three times in differentiated porcine respiratory epithelial cells. Among the four mutations detected, the two HA mutations were analyzed by generating recombinant viruses. Depending on the infection system used, the mutations differed in their phenotypic expression, e.g., sialic acid binding activity, replication kinetics, plaque size, and pathogenicity in inbred mice. However, none of the mutations affected the ciliary activity which serves as a virulence marker. Thus, early adaptive mutation enhances the replication kinetics, but more mutations are required for IAV of the H9N2 subtype to become virulent.

Skin whitening capability of shikimic acid pathway compound.

OBJECTIVE: To examine the skin whitening capabilities of shikimic acid pathway compounds and find the most effective molecule to be used as the active ingredient for skin whitening products. MATERIALS AND METHODS: Skin whitening is the practice of using chemical substances to lighten skin tone by the lessening the concentration of melanin. The whitening efficacy of shikimic acid pathway compounds was evaluated. Eight compounds in the shikimic acid pathway were chosen for this study: benzoic acid, p-coumaric acid, vanillic acid, syringic acid, quinic acid, shikimic acid, orcinol monohydrate, and phenyl pyruvic acid. We measured the tyrosinase inhibitory capacity of the compounds in the animal model of zebrafish and also evaluated the compounds' anti-oxidant activities using the DPPH radical scavenging, and ABTS+ free radical scavenging tests. Compounds' cytotoxicity effects were also evaluated. RESULTS: Amongst eight shikimic acid pathway compounds used in this study, shikimic acid was the most potent tyrosinase-inhibitor and the most efficient compound to be used as an active ingredient for skin whitening. Shikimic acid revealed a good radical scavenging activity (RAS) with low cell toxicity. CONCLUSIONS: Promising results obtained in this study may open a new window of opportunity to introduce another compound to be used in the skin-whiting cosmetics industry.

Determination of patellar ligament and anterior cruciate ligament geometry using MRI.

Ligament geometry is crucial to surgical treatment success in anterior cruciate ligament (ACL) injury. This study aimed to optimize the MRI technique to elucidate the geometry of the patellar ligament (PL) and ACL in vivo. A 1.5-T superconducting MRI system with a special surface coil and fast spin echo was used to acquire high-resolution T1-weighted images (H-T1WI) of the ACL. The sagittal plane angle was 10° to 15° towards the inner side of the vertical line of the tangent line axis of the femoral intercondylar fossa. The H-T1WI images of the PL were centered at the lower margin of the patella and the center of the tibial tuberosity. The lengths of the PL and ACL were measured using a Radworks 5.1 workstation. ACL and PL lengths were compared between left and right knees and between genders, and left PL length measurements obtained separately by three doctors underwent correlation analysis. The quality of the images satisfied the clinical measurement requirements. The duration of sagittal image acquisition was 2 min and 25 s. The average PL length was 42.20 ± 4.21 and 40.15 ± 4.00 mm, and the average ACL length was 36.98 ± 4.12 and 35.80 ± 4.67 mm, in male and female subjects, respectively. The intraclass correlation coefficients of the PL lengths obtained by the three specialists were greater than 0.997. This MRI technique provides highly stable and repeatable in vivo data of PL and ACL geometry relevant to ACL reconstruction surgery with PL grafts.

Imaging, clinical and pathological features of salivary gland adenolymphoma.

OBJECTIVE: Adenolymphoma (Warthin's tumor) is a common salivary gland benign tumors with poor diagnosis and ranking second after the parotid tumors. Presently, a rising tendency of the incidence of adenolymphoma has been noted. The aim of this study was to investigate the clinical, pathological and imaging features of this tumor. PATIENTS AND METHODS: 24 cases of confirmed adenolymphoma were retrospectively analyzed with clinical features, pathological data and CT imaging. RESULTS: Among 24 cases, 22 (91.7%) patients were male, two patients were female, 23 (95.8%) patients were more than 50 years old; 38 lesions were found in 24 patients including isolated lesions in 16 patients (66.7%), and multiple lesions in 8 patients (33.3%). 81.6% adenolymphoma lesions (31/38) were located in the posterior and inferior quadrant. The shapes of lesions were more oval or round, well-circumscribed, homogeneous (n=26) or inhomogeneous (n=12) with high density. 27 lesions were demonstrated with enhancement after contrast enhancement and 10 lesions showed small vessels penetrating through or surrounding the mass. CONCLUSIONS: Adenolymphoma of the parotid (Warthin tumor) should be first considered by the clinical data including age, gender, location and imaging manifestations of the lesions.

Efficacy of endoscopic stapled transanal rectal resection for the treatment of rectocele.

OBJECTIVE: The objective of the study was to determine the efficacy of endoscopic stapled transanal rectal resection for the treatment of rectocele. PATIENTS AND METHODS: For this purpose, the data were collected from 61 patients with severe rectocele that underwent endoscopic stapled transanal rectal resection within the time period from April 2010 to April 2012. The pre- and post-operative Longo's obstructed defecation syndrome (ODS) were compared. The reduction of the rectocele was assessed by defecography on visit and from patients' satisfaction obtained through following up. RESULTS: We found that the postoperative Longo's ODS was significantly lower than the preoperative value (p < 0.01); and defecography showed that the rectocele was significantly reduced or disappeared. Furthermore, 57 of the 61 (93.4%) patients expressed their satisfaction at follow up. CONCLUSIONS: The endoscopic stapled transanal rectal resection can be recommended as the treatment of choice for rectocele since it is an easy-to-perform procedure that has satisfactory short and mid to long-term therapeutic efficacy.

Occurrence and assessment of treatment efficiency of nonylphenol, octylphenol and bisphenol-A in drinking water in Taiwan.

Occurrence and methods for the removal of nonylphenolic compounds in drinking water have been gaining increased attention due to their widespread presence in natural water and the potential health risks from the consumptions of drinking water. The purpose of this study was to assess the occurrence of nonylphenol (NP), octylphenol (OP), and bisphenol-A (BPA) in water sources and treated water in Taiwan, to evaluate the treatment efficiencies of these compounds in both the conventional (coagulation, sedimentation, filtration and chlorination) and advanced treatment processes. The treatment efficiencies of these chemicals were assessed based on their concentrations in water sources, and the results were verified with laboratory simulated treatment processes. A survey of NP, OP, and BPA in 11 Taiwanese water sources showed that all of them could be identified in most of the sampled sources, and that higher concentrations of NP were found when the raw water was contaminated by domestic wastewater. However, higher treatment efficiency could be observed when the NP concentration in water source is high. Laboratory simulation studies of conventional treatment processes showed that chlorination played an important role in the degradation of NP in raw water. Treatment efficiencies of 60%-90% were achieved for NP removal when sufficient chlorine dosages were applied to satisfy chlorine demands. However, results also showed that conventional coagulation and rapid filtration processes were less effective in the reduction of phenolic compounds in water.

Factors affecting peritoneal dialysis selection in Taiwanese patients with chronic kidney disease.

BACKGROUND: Taiwan has the highest incidence and prevalence of end-stage renal disease (ESRD) in the world with 55,499 ESRD patients on long-term dialysis. Nevertheless, 90.96% of these patients are managed on maintenance haemodialysis (HD), with only 9.03% enrolled in a peritoneal dialysis (PD) programme. AIM: The study aim was to identify the factors affecting Taiwanese patient's selection of PD in preference to HD for chronic kidney disease. METHODS: A cross-sectional research design was utilized with 130 chronic renal failure (CRF) patients purposively selected from outpatient nephrology clinics at four separate Taiwan hospitals. Logistic regression was used to identify the main factors affecting the patient's choice of dialysis type. RESULTS: Single-factor logistic regression found significant differences in opinion related to age, education level, occupation type, disease characteristics, lifestyle modifications, self-care ability, know-how of dialysis modality, security considerations and findings related to the decisions made by medical personnel (P < 0.05). Moreover, multinomial logistic regression after adjustment for interfering variables found that self-care ability and dialysis modality know-how were the two main factors affecting the person's selection of dialysis type. CONCLUSIONS: Self-care ability and the person's knowledge of the different types of dialysis modality and how they function were the major determinants for selection of dialysis type in Taiwan based on the results from this study. The results indicate that the education of CRF patients about the types of dialysis available is essential to enable them to understand the benefits or limitations of both types of dialysis.

Determination of apparent diffusion coefficient to quantitatively study partial hepatic ischemia reperfusion injury in a rabbit model.

BACKGROUND: Animal models of partial hepatic ischemia-reperfusion injury (IRI) have potential benefits for decision making and clinical management after liver transplantation or massive hepatic resection. We evaluated changes in apparent diffusion coefficient (ADC) in rabbits with partial hepatic IRI using 3.0 T magnetic resonance diffusion-weighted imaging (DWI). METHODS: Rabbits underwent 60 minutes of left lobar ischemia followed by 0.5, 2, 6, 12, 24, or 48 hours of reperfusion (n = 6 each). DWI spin echo-echo planar imaging (SE-EPI) was performed with b values of 50, 100, 200, 300, 500, and 600 s/mm(2). RESULTS: There was a significant difference between the ADCs at 0.5 hour and sham groups when b values were <300 s/mm(2) and between the six hour and sham groups with b = 50 and 100 s/mm(2). The ADC values were lower in the 24-hour group with b values of 50, 100, 200, and 300 s/mm(2) (all P < .01) but significantly increased in the 48-hour group when b = 500 and 600 s/mm(2) compared with the sham group (all P < .01). ADC did not change significantly in the 2-hour and 12-hour groups compared with the control group. CONCLUSIONS: In this study 3.0 T DWI dynamically monitored the pathological processes of liver IRI, revealing the microvascular disorder with a perfusion-sensitive ADC at the lower b values (<300 s/mm(2)), particularly in the early stages.

α-Catulin knockdown induces senescence in cancer cells.

Cellular senescence functions as a tumor suppressor that protects against cancer progression. α-Catulin, an α-catenin-related protein, is reported to have tumorigenic potential because it regulates the nuclear factor-κB (NF-κB) pathway, but little is known about its clinical relevance and the mechanism through which it regulates cancer progression. Here, we found that α-catulin mRNA levels were significantly upregulated in cancer cell lines and clinical oral squamous cell carcinomas, which positively correlated with tumor size (P=0.001) and American Joint Committee on Cancer (AJCC) stage (P=0.004). α-Catulin knockdown in the OC2 and A549 cancer cell lines dramatically decreased cell proliferation and contributed to cellular senescence, and inhibited OC2 xenograft growth. Mechanistic dissection showed that α-catulin depletion strongly induced the DNA-damage response (DDR) in both cell lines, via a p53/p21-dependent pathway in A549 cells, but a p53/p21-independent pathway in OC2 cells carrying mutant p53. Global gene expression analysis revealed that α-catulin knockdown altered cell-cycle regulation and DDR pathways at the presenescent stage as well as significantly downregulate several crucial genes related to mitotic chromosome condensation, DDR and DNA repair systems, which suggests that its depletion-induced cellular senescence might be caused by chromosome condensation failures, severe DNA damage and impaired DNA repair ability. Our study provides evidence that α-catulin promotes tumor growth by preventing cellular senescence and suggests that downregulating α-catulin may be a promising therapeutic approach for cancer treatment.

Alkene hydroboration: hot intermediates that react while they are cooling.

Non-TST behavior has recently attracted a great deal of attention. If such behavior is general, then the standard way in which synthetic chemists rationalize and predict reactivity and selectivity would be at least partially invalid. The work in this article was inspired by recent results which highlighted a departure from the predictions of TST for rationalization of the regiochemical outcome of the hydroboration reaction mechanism, suggesting that the isomeric product ratios arise because of nonstatistical dynamical effects (J. Am. Chem. Soc. 2009, 131, 3130-3131). We suggest, based on new calculations using a weak collision RRKM-Master Equation (ME) model, an alternative interpretation of the experimental results which preserves a statistical reaction model. While it is a common assumption that all intermediates and transition states along the reaction path are in thermal equilibrium with solvent, our ME results show that hot intermediates may react while they are undergoing stepwise relaxation through weak collisions, even in solution. To our knowledge, this work represents the first application of master equation methodology to a solution phase thermal reaction in organic chemistry that cannot be otherwise explained using conventional TST. Explicit modeling of solvent and solute dynamics is often prohibitively expensive; however, the master equation offers a computationally tractable model with considerable predictive power that may be utilized to investigate whether stepwise collisional relaxation is prevalent in other polyatomic systems.

Temperature dependent kinetics (195-798 K) and H atom yields (298-498 K) from reactions of (1)CH(2) with acetylene, ethene, and propene.

The rate coefficients for the removal of the excited state of methylene, (1)CH(2) (a(1)A(1)), by acetylene, ethene, and propene have been studied over the temperature range 195-798 K by laser flash photolysis, with (1)CH(2) being monitored by laser-induced fluorescence. The rate coefficients of all three reactions exhibit a negative temperature dependence that can be parametrized as k((1)CH(2)+C(2)H(2)) = (3.06 +/- 0.11) x 10(-10) T ((-0.39+/-0.07)) cm(3) molecule(-1) s(-1), k((1)CH(2)+C(2)H(4)) = (2.10 +/- 0.18) x 10(-10) T ((-0.84+/-0.18)) cm(3) molecule(-1) s(-1), k((1)CH(2)+C(3)H(6)) = (3.21 +/- 0.02) x 10(-10) T ((-0.13+/-0.01)) cm(3) molecule(-1) s(-1), where the errors are statistical at the 2sigma level. Removal of (1)CH(2) occurs by chemical reaction and electronic relaxation to ground state triplet methylene. The H atom yields from the reactions of (1)CH(2) with acetylene, ethene, and propene have been determined by laser-induced fluorescence over the temperature range 298-498 K. For the reaction with propene, H atom yields are close to the detection limit, but for acetylene and ethene, the fraction of H atom production is approximately 0.88 and 0.71, respectively, at 298 K, rising to unity by 398 K, with the balance of the reaction with acetylene presumed to be electronic relaxation. Experimental constraints limit studies to a maximum of 1 Torr of bath gas; master equation calculations using an approach that allows treatment of intermediates with deep energy wells have been carried out to explore the role of collisional stabilization for the reaction of (1)CH(2) with acetylene. Stabilization is calculated to be insignificant under the experimental conditions, but does become significant at higher pressures. Between pressures of 100 and 1000 Torr, propyne and allene are formed in similar amounts with a slight preference for propyne. At higher pressures propyne formation becomes about a factor two greater than that of allene, and above 10(5) Torr (300 < T (K) < 600) cyclopropene formation starts to become significant. The implications of temperature-dependent (1)CH(2) relaxation on the roles of (1)CH(2) in chemical mechanisms for soot formation are discussed.

Migration of a swallowed toothpick into the liver: the value of multiplanar CT.

Foreign body ingestion is not an uncommon problem encountered in clinical practice. However, the associated complication of bowel perforation and migration of the foreign body to the liver is rare. We report two cases of hepatic foreign bodies identified intra-operatively as toothpicks, with the alimentary tract being the presumed origin.

Lesser sac herniation through a defect in the transverse mesocolon: CT findings.

We herein report a case of lesser sac herniation through a defect in the transverse mesocolon. In addition to CT signs suggestive of bowel obstructions, there are some characteristic CT findings in this extremely rare type of internal herniation, which include clustering of distended jejunal segments directly compressing the pancreas, displacement of the stomach anterolaterally, displacement of the transverse colon anteriorly and a normal appearance around the foramen of Winslow.