Design and evaluation of semicarbazide-embeddedd stationary phases for liquid chromatography.

Semicarbazide, as a derivative of urea, constitutes a great variety of functional molecules for different needs. Herein, novel stationary phases with an incorporated semicarbazide group were proposed. Using aliphatic (docosanoyl, C22) and aromatic (benzoyl, Bz) hydrazides, the semicarbazide-embedded ligands were synthesized before chemical modification of the silica gel, allowing for an accurate interpretation of the chromatographic properties of the corresponding packings. The new stationary phases were water-wettable, due to the presence of highly polar groups. In particular, Bz-semicarbazide (Bz-SCD) stationary phase was sufficiently hydrophilic to run in hydrophilic interaction (HILIC) mode, whilst the C22 (C22-SCD) equivalent, in spite of its reversed-phase nature, was markedly less hydrophobic than the referenced polar-embedded ones. The versatility of C22-SCD was demonstrated with a large selection of analytes, including geometric isomers and standard mixtures of polycyclic aromatic hydrocarbons, sulfonamides, sulfonylurea, substituted ureas, pyridines and carbamates, fat-soluble colorants, antifungal metabolites, angiotensin II receptor blockers and calcium channel blockers.

Predictive Modelling of Overall Survival in Adult Patients with Primary Diffuse Large B-cell Lymphoma of the Breast Using the Surveillance, Epidemiology, and End Results (SEER) Database.

OBJECTIVE: We aimed to identify critical clinical features to develop an accurate webbased prediction model for estimating the overall survival (OS) of primary breast diffuse large Bcell lymphoma (PB-DLBCL) adult patients. METHODS: We first included all PB-DLBCL cases with available covariates retrieved from the Surveillance, Epidemiology, and End Results database. We sequentially performed univariate and multivariate Cox regression approaches to identify the predictors independently associated with prognosis, and all the predictors that passed these tests were then constructed to build a nomogram for predicting 3-, 5-, and 10-year survival rates of patients. The C-index and the receiver operating characteristic curve (ROC) were used to evaluate the prediction discrimination, and the calibration curve was applied to estimate the calibration. RESULTS: A total of PB-DLBCL adult patients were included (median age was 69 with the interquartile range [IQR] of 57-79 years), of which 466 (70%) were randomly allocated to the development cohort, and the remaining cases were collected for validation. Using three identified independent predictors (i.e., age, stage, and radiation), an accurate nomogram for predicting OS was developed and validated. The C-indices of our nomogram were both relatively acceptable, with 0.74 (95% CI: 0.71-0.78) and 0.72 (95% CI: 0.70-0.75) for the development and validation cohorts, respectively. The calibration curves also accurately predicted the prognosis of PB-DLBCL in all cases. In addition, ROC curves showed our nomogram to possess superior predictive ability compared to any single variable. To visually present this prediction model, a convenient webbased tool was implemented based on our prognostic nomogram. CONCLUSION: For patients with PB-DLBCL, a more convenient and accurate web-based prediction model was developed and validated, which showed relatively good performances in both discrimination and calibration during model development and validation. External evaluation and validation are warranted by further independent studies.

Surgical techniques and effectiveness of laparoscopic resection of abdominal wall desmoid-type fibromatosis and defect reconstruction: a single-center retrospective analysis.

PURPOSE: Although the treatment of abdominal wall desmoid-type fibromatosis (DF) has evolved over the past decades, surgical treatment remains an important approach. Previously, surgeries for abdominal DF were mostly performed by laparotomy, which involves massive dissection and significant trauma. Here, we report our single-center experience of the laparoscopic management of abdominal wall DF in young female patients. METHODS: The clinical data of nine patients diagnosed with abdominal wall DF during January 2020-April 2022 at the Qilu Hospital of Shandong University were retrospectively analyzed. All patients underwent laparoscopic resection of abdominal wall DF and immediate abdominal wall reconstruction (AWR) with mesh augmentation via the intraperitoneal onlay mesh (IPOM) technique. RESULTS: Laparoscopic DF resection and AWR were successfully performed in all patients. The mean operation time was 175.56 ± 46.20 min. The width of abdominal wall defect was 8.61 ± 3.30 cm. Full- and partial-thickness myofascial closure and reapproximation were performed in five, two, and two patients, respectively. The average mesh size was 253.33 ± 71.01 cm2. The total and postoperative lengths of hospital stay were 11.00 ± 3.46 and 4.89 ± 2.03 days, respectively. Tumor recurred in one patient after 20 months of the resection. Nonetheless, death, herniation, or bulging were not observed in any patient during a mean follow-up of 16.11 ± 8.43 months. CONCLUSION: Laparoscopic resection of abdominal wall DF and immediate AWR with IPOM mesh reinforcement is safe and reliable for young female patients. Management of such patients should be decided according to the biological behavior, size, and location of tumors.

Progress of Metal Nanomaterial Controllable Preparation by Photoreduction.

Metal nanoparticles (NPs) are widely used in biomedicine, catalysis, environment, electronics, and other fields, which is closely related to its structural form. For this purpose, researchers have been looking for a simple, green, and controllable way to mass produce metal nanomaterials with desired characteristics (shape, size, stability, etc.). Due to the surface plasmon resonance (SPR) effect of metal nanoparticles, photoreduction method can control the morphology of metal nanoparticles well, which is also simple, large-scalable, and energy-saving. This review provides an overview of the photoreduction method for the synthesis of metal nanoparticles and discusses the factors such as the light source, pH value, reagents, and temperature on the morphology of the nanoparticles. Finally, the challenges and development trends in the controlled preparation of nanomaterials are proposed.

Exploring Microeukaryote Community Characteristics and Niche Differentiation in Arid Farmland Soil at the Northeastern Edge of the Tibetan Plateau.

The northeastern edge of the Tibetan Plateau exhibits diverse climate and landform variations, and has experienced substantial recent environmental changes, which may significantly impact local agricultural practices. Understanding the microeukaryote community structure within agricultural soils is crucial for finding out the biological responses to such changes and may guide future agricultural practices. In this study, we employed high-throughput amplicon sequencing to examine 29 agricultural soil samples from seven research areas around the northeastern edge of the Tibetan Plateau. The findings revealed that the predominant biological communities in these soils were characterized by a high abundance of Alveolata, Amoebozoa, and Rhizaria. Ascomycota displayed the highest relative abundance among fungal communities. Moreover, notable distinctions in microeukaryote community composition were observed among the study sites. Co-occurrence network analysis highlighted interactions between the biological communities. Furthermore, our results elucidated that deterministic and stochastic processes exerted diverse influences on the distribution of protozoan and fungal communities. This study provides valuable insight into the microeukaryote structure in the agricultural soils of the northeastern edge of the Tibetan Plateau, shedding light on the intricate relationships between environmental factors, microeukaryote communities, and agricultural productivity.

Probio-X Relieves Symptoms of Hyperlipidemia by Regulating Patients' Gut Microbiome, Blood Lipid Metabolism, and Lifestyle Habits.

Hyperlipidemia is a key risk factor for cardiovascular disease, and it is associated with lipid metabolic disorders and gut microbiota dysbiosis. Here, we aimed to investigate the beneficial effects of 3-month intake of a mixed probiotic formulation in hyperlipidemic patients (n = 27 and 29 in placebo and probiotic groups, respectively). The blood lipid indexes, lipid metabolome, and fecal microbiome before and after the intervention were monitored. Our results showed that probiotic intervention could significantly decrease the serum levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol (P < 0.05), while increasing the levels of high-density lipoprotein cholesterol (P < 0.05) in patients with hyperlipidemia. Probiotic recipients showing improved blood lipid profile also exhibited significant differences in their lifestyle habits after the 3-month intervention, with an increase in daily intake of vegetable and dairy products, as well as weekly exercise time (P < 0.05). Moreover, two blood lipid metabolites (namely, acetyl-carnitine and free carnitine) significantly increased after probiotic supplementation cholesterol (P < 0.05). In addition, probiotic-driven mitigation of hyperlipidemic symptoms were accompanied by increases in beneficial bacteria like Bifidobacterium animalis subsp. lactis and Lactiplantibacillus plantarum in patients' fecal microbiota. These results supported that mixed probiotic application could regulate host gut microbiota balance, lipid metabolism, and lifestyle habits, through which hyperlipidemic symptoms could be alleviated. The findings of this study urge further research and development of probiotics into nutraceuticals for managing hyperlipidemia. IMPORTANCE The human gut microbiota have a potential effect on the lipid metabolism and are closely related to the disease hyperlipidemia. Our trial has demonstrated that 3-month intake of a mixed probiotic formulation alleviates hyperlipidemic symptoms, possibly by modulation of gut microbes and host lipid metabolism. The findings of the present study provide new insights into the treatment of hyperlipidemia, mechanisms of novel therapeutic strategies, and application of probiotics-based therapy.

Ecological sustainability and high-quality development of the Yellow River Delta in China based on the improved ecological footprint model.

Aiming at the traditional ecological footprint model, the improved ecological footprint of the carbon footprint effectively makes up for the singularity of the ecological footprint's consideration of carbon emissions, and plays an important role in promoting high-quality development and ecological sustainability. This paper selects 2015, 2018 and 2020 as important time points for the study, corrects the ecological footprint parameter factors based on net primary productivity (NPP), measures the ecological footprint after the improvement of the carbon footprint, studies the spatial and temporal variation in the ecological footprint at the 100-m grid scale with the support of IPCC greenhouse gas inventory analysis, and analyzes the current ecological conservation status of the Yellow River Delta. Additionally, in the context of a low carbon economy, the decoupling index of carbon emissions and GDP is extended to the evaluation and analysis of high-quality development. The study showed that (1) the ecological footprint of the Yellow River Delta has increased year by year, from 0.721 hm2·person- 1 to 0.758 hm2·person- 1, an average annual increase of 2.9%; the ecological carrying capacity has decreased from 0.40 hm2·person- 1 to 0.31 hm2·person- 1, an overall decrease of 28.59%. (2) The overall ecological deficit of the Yellow River Delta grid is lightly overloaded, with most of the ecological surplus occurring in the northern and eastern parts of the study area and a few moderate and heavy overloads in the center of the core area where there is a lot of built-up land and the area is small and easy to gather. (3) Based on the low-carbon economy analysis, 2015, 2017 and 2020 reach absolute decoupling and are in the ideal scenario. However, in the rest of the years, carbon emissions and economic development are still in a large contradiction, and decoupling has fluctuated and varied greatly in the last six years. The effective combination of ecological footprint and low carbon economy analysis provides an important theoretical basis for improving ecological conservation and achieving high-quality development.

p-Terphenyl-based rigid stationary phases with embedded polar groups for liquid chromatography.

Terphenyls are important building blocks for a wide range of functional molecules. Among the three isomers, p-terphenyl (C18H14) is particularly useful for the construction of optical devices on account of its unique structure. Herein, two rigid stationary phases bearing p-terphenyl as an external moiety and variable embedded carbamate groups (p-TerC with one embedded carbamate group and p-TerC2 with two embedded carbamate group) were presented. The proposed stationary phases were characterized by various means and evaluated in reversed-phase (RP) mode, using different classes of analytes, including polycyclic aromatic hydrocarbons (PAHs), alkylbenzenes, 4-alkylbiphenyls, substituted ureas, sulfonylureas, substituted sulfanilamides and aromatic acids. The comparison with conventional C18, several other polar-embedded aromatic and C18 equivalents indicated p-terphenyl-based stationary phases were featured by multiple retention mechanisms, involving π-π interaction, charge-transfer interaction, hydrogen-bonding and hydrophobic interaction in RP mode. A unusually high specificity to the analytes with linear structures was observed, as exemplified by an irreversible adsorption of tetracene and a readily separation of tetraphene and chrysene. The aliphatic linker used in the proposed stationary phases was an influential factor for retentivity, selectivity and column efficiency. Interestingly, p-TerC2 was operable in normal-phase mode for the separation of certain PAHs through polar-related interactions. The linear, rigid polyphenyl structure of p-terphenyl endowed the new stationary phase with distinctive chromatographic properties, in contrast to those of the preceding counterparts bonded with alkyl and/or polynuclear aromatic moieties.

Duodenal-jejunal bypass increases intraduodenal bile acids and upregulates duodenal SIRT1 expression in high-fat diet and streptozotocin-induced diabetic rats.

BACKGROUND: The mechanisms underlying diabetes remission after duodenal-jejunal bypass (DJB) remain elusive. In DJB surgery, the duodenum is excluded. However, the duodenum has emerged as an important regulator of glucose homeostasis, and elevated duodenal SIRT1 leads to improved hepatic insulin sensitivity. After DJB, bile acids (BAs) in the duodenum are not mixed and diluted by the ingested food. And activation of BA receptors promotes SIRT1 expression in many tissues. We hypothesized that BA-mediated upregulation of SIRT1 may contribute to diabetic control after DJB. AIM: To investigate the surgical effects of DJB on duodenal SIRT1 expression and uncover the potential crosslinks between BAs and SIRT1. METHODS: Twenty diabetic rats were randomly allocated to the sham (n = 10) and DJB (n = 10) groups. Body weight, food intake, fasting blood glucose (FBG), serum and intraduodenal total BA (TBA) levels were measured accordingly. Oral glucose tolerance test (OGTT) and intraperitoneal pyruvate tolerance test (ipPTT) were performed to evaluate the effects of surgeries on systemic glucose disposal and hepatic gluconeogenesis. The key genes of BA signaling pathway in the duodenal mucosa, including farnesoid X receptor (FXR), small heterodimer partner (SHP), and Takeda G-protein-coupled receptor 5 (TGR5) were evaluated by real-time quantitative polymerase chain reaction 8 wk postoperatively. The duodenal SIRT1, AMPK, and phosphorylated AMPK (p-AMPK) levels were evaluated by western blotting. Rat small intestine epithelial IEC-6 cells were treated with GW4064 and INT-777 to verify the effects of BAs on SIRT1 expression in enterocytes. RESULTS: The DJB group exhibited body weight and food intake comparable to those of the sham group at all postoperative time points. The FBG level and area under the curve for the OGTT and ipPTT were significantly lower in the DJB group. The DJB group exhibited higher fasting and postprandial serum TBA levels than the sham group at both 2 and 8 wk postoperatively. At 8 wk after surgery, the DJB group showed higher intraluminal TBA concentration, upregulated mRNA expression of FXR and SHP, and elevated protein expression of SIRT1 and p-AMPK in the descending and horizontal segments of the duodenum. Activation of FXR and TGR5 receptors by GW4064 and INT-777 increased the mRNA and protein expression of SIRT1 and promoted the phosphorylation of AMPK in IEC-6 cells. CONCLUSION: DJB elevates intraduodenal BA levels and activates the duodenal BA signaling pathway, which may upregulate duodenal SIRT1 and further contribute to improved glucose homeostasis after DJB.

Population spatialization at building scale based on residential population index-A case study of Qingdao city.

The study of population spatialization has provided important basic data for urban planning, development, environment and other issues. With the development of urbanization, urban residential buildings are getting higher and higher, and the difference between urban and rural population density is getting larger and larger. At present, most population spatial studies adopt the grid scale, and the population in buildings is evenly divided into various grids, which will lead to the neglect of the population distribution in vertical space, and the authenticity is not strong. In order to improve the accuracy of the population distribution, this paper studied the spatial distribution of population at the building scale, combined the digital surface model (DSM) and the digital elevation model (DEM) to calculate the floor of buildings, and proposed a new index based on the total floor area of residential buildings, called residential population index (RPI). RPI is directly related to the number of people a building can accommodate, so it can effectively estimate the population of both urban and rural areas even if the structure of urban and rural buildings is very different. In addition, this paper combined remote sensing monitoring data with geographic big data and adopted principal component regression (PCR) method to construct RPI prediction model to obtain building-scale population distribution data of Qingdao in 2018, providing ideas for population spatialization research. Through field sampling survey and overall assessment, the results were basically consistent with the actual residential situation. The average error with field survey samples is 14.5%. The R2 is 0.643 and the urbanization rate is 69.7%, which are all higher than WorldPop data set. Therefore, this method can reflect the specific distribution of urban resident population, enhance the heterogeneity and complexity of population distribution, and the estimated results have important reference significance for urban management, urban resource allocation, environmental protection and other fields.

Learning Suction Graspability Considering Grasp Quality and Robot Reachability for Bin-Picking.

Deep learning has been widely used for inferring robust grasps. Although human-labeled RGB-D datasets were initially used to learn grasp configurations, preparation of this kind of large dataset is expensive. To address this problem, images were generated by a physical simulator, and a physically inspired model (e.g., a contact model between a suction vacuum cup and object) was used as a grasp quality evaluation metric to annotate the synthesized images. However, this kind of contact model is complicated and requires parameter identification by experiments to ensure real world performance. In addition, previous studies have not considered manipulator reachability such as when a grasp configuration with high grasp quality is unable to reach the target due to collisions or the physical limitations of the robot. In this study, we propose an intuitive geometric analytic-based grasp quality evaluation metric. We further incorporate a reachability evaluation metric. We annotate the pixel-wise grasp quality and reachability by the proposed evaluation metric on synthesized images in a simulator to train an auto-encoder-decoder called suction graspability U-Net++ (SG-U-Net++). Experiment results show that our intuitive grasp quality evaluation metric is competitive with a physically-inspired metric. Learning the reachability helps to reduce motion planning computation time by removing obviously unreachable candidates. The system achieves an overall picking speed of 560 PPH (pieces per hour).

Comparison of reverse puncture device and overlap in laparoscopic total gastrectomy for gastric cancer.

BACKGROUND: Intracorporeal oesophagojejunostomy is one of the key steps in laparoscopic total gastrectomy (LTG). At present, there is no widely accepted anastomosis technique in oesophagojejunostomy. MATERIALS AND METHODS: We retrospectively studied 63 patients with gastric cancer who underwent LTG. Two types of anastomosis techniques have been applied during LTG: the reverse puncture device (RPD) (28 patients) and overlap (35 patients). RESULTS: A total of 63 patients (51 males and 12 females: mean age = 58 years and mean body mass index [BMI] = 26.3 kg/m2) were enrolled in this study. There were no significant difference in age, BMI, duration of surgery, duration of anastomosis, blood loss, post-operative hospital stay, tumour location, tumour size, degree of tumour differentiation, Borrmann type, total number of lymph nodes, number of positive lymph nodes, hospital stay, hospitalisation costs, intra-operative complications, post-operative complications and prognosis between the RPD group and the overlap group. RPD group showed a significant advantage in terms of the distance between the top border of tumours and the top resection margin (P < 0.001). We further found that the oesophageal lateral negative surgical margin distance of the upper gastric cancer in the RPD group was significantly longer than that in the overlap group (P < 0.001). CONCLUSIONS: Both the RPD and overlap techniques are safe and applicable in LTG. However, RPD has the advantage of obtaining an adequate safe margin compared with that of overlap technique, especially in patients with gastro-oesophageal junction carcinoma.

A carbonylative coupling approach to alkyl stationary phases with variable embedded carbamate groups for high-performance liquid chromatography.

A highly efficient carbonylative coupling method for the preparation of alkyl stationary phases with variable numbers of carbamate groups was established. The effectiveness of such method was verified through elemental analysis, X-ray photoelectron spectroscopy and solid-state 13C nuclear magnetic resonance spectroscopy of three as-synthesized stationary phases bearing different alkyl chains and different numbers of carbamate groups (octadecyl/one carbamate group, C18C; docosyl/three carbamate groups, C22C3; triacontyl/two carbamate groups, C30C2). The comparative evaluation of these stationary phases using a great variety of analytes, including three sets of isomers of alkylbenzenes, two sets of standard mixtures of polycyclic aromatic hydrocarbons (SRM 1647e and 869b), nine polychlorinated biphenyls, fiveteen N-substituted ureas, ten sulfonylureas, five xanthines and some other phytonutrients, revealed their remarkable applicability in reversed-phase liquid chromatography. Notably, the intercalated carbamate groups rendered the resultant stationary phases compatible with 100% aqueous mobile phase. The suppression of silanol activity was positively related to the number of polar groups embedded in the bonded selector, and the smallest peak tailing factor (1.14) for amitriptyline was obtained by C22C3. The molecular shape-related selectivity was found to be more closely related to the length of the selector's aliphatic chain, as supported by the lowest αTBN/BaP value (0.31) by C30C2. These carbamate-embedded alkyl stationary phases constituted another class of polar-embedded stationary phases possessing a single type of functional ligand.

A docosyl-terminated polyamine amphiphile-bonded stationary phase for multimodal separations in liquid chromatography.

A convenient synthetic approach to a linear alkyl-polyamine amphiphilic chromatographic selector was proposed. Successive immobilization of the amphiphile onto silica gel afforded a multimodal stationary phase for high-performance liquid chromatography (HPLC). The as-prepared silica material was studied comparatively with a conventional octadecyl (C18) and an amide-embedded C18 stationary phase. The new uniform docosyl-triamine tandem was featured by an enhanced shape selectivity towards geometric isomers, and a low silanol activity towards alkaline solutes. The presence of multiple amino groups rendered the new adsorbent operable in different modes, such as hydrophilic interaction and ion-exchange modes. The satisfactory performance of the said stationary phase in separating different classes of analytes, including polycyclic aromatic hydrocarbons, flavonoids, tricyclic antidepressants, calcium channel blockers, aromatic acids, inorganic anions, nucleosides and estrogens, revealed its great potential and high adaptability for multipurpose LC utility.

A highly efficient acyl-transfer approach to urea-functionalized silanes and their immobilization onto silica gel as stationary phases for liquid chromatography.

An alternative method for efficient synthesis of urea-functionalized silanes was proposed on the basis of an N, N'-carbonyldiimidazole-mediated acyl-transfer reaction between various amino-containing building blocks. The employment of different parent aminosilanes and alkylamines afforded an array of urea-containing silanes, which were subsequently immobilized onto silica gel to form corresponding urea-embedded alkyl stationary phases for high-performance liquid chromatography. The different substituents on the silicon core of the derivatized silane were found to significantly influence the final chromatographic behaviors. The comparative chromatographic characterization of thus-prepared silica packings with conventional octadecyl (C18) stationary phases revealed that the urea group was beneficial to suppress silanol activity towards basic probes, as well as to increase the water-compatibility of the alkyl stationary phases. The combination of a polar urea moiety and a non-polar long alkyl chain was favorable for an enhanced steric selectivity towards shape-constrained isomers. The polarizability-sensitive feature of such stationary phases made them good candidates for efficient separation of nitro-containing polar substances.

Design and evaluation of polar-embedded stationary phases containing triacontyl group for liquid chromatography.

The present work described two triacontyl-bonded silica adsorbents containing different polar embedded groups (i.e. amide- and carbamate-type) for high performance liquid chromatography, which were prepared by covalent surface modification of silica gel with respective pre-synthesized polar-embedded triacontyl (C30) silane. The acylimidazole-mediated method was used for the first time for the synthesis of amide-type alkyl silane, while the carbamate-type silane was obtained via an improved solvent-free procedure. A conventional C30 stationary phase was also developed on the same silica substrate in the similar manner, which was used as a reference column for comparison of the unique mechanisms facilitated and/or furnished by the polar groups. The successful immobilization of the designed C30 species was confirmed by infrared spectroscopy and elemental analysis. In further comparison with an amide-embedded octadecyl (C18) two other conventional C18 stationary phases of different surface chemistry, detailed chromatographic characterization of the C30 series stationary phases was performed in terms of surface density, hydrophobicity, aromatic selectivity, shape selectivity and water tolerance using a diversified range of analytes, including homologous alkylbenzenes, isomeric polycyclic aromatic hydrocarbons, carotenes, congeners of polychlorobiphenyls, aromatic amines, phenolic compounds, estrogens and nucleosides. A high resemblance between the chromatographic behaviors of the two polar-modified C30 stationary phases was observed, meanwhile they demonstrated noticeable differences from non-polar C30 stationary phase. The polar-embedded C30 phases showed satisfactory performance towards the solutes of interest in the studied conditions. The beneficial synergy of the polar groups and the triacontyl chains enabled these polar-enhanced C30 stationary phases to address challenging separation tasks with high selectivity.

Laparoscopic gastrectomy for early gastric cancer and the risk factors of lymph node metastasis.

Objective: Lymph node metastasis (LNM) is one of the important prognostic factors of early gastric cancer (EGC). Moreover, LNM is also important when choosing therapeutic intervention for EGC patients. The purpose of this study is to explore the risk factors of LNM in EGC and to discuss the corresponding treatment. Design: We retrospectively reviewed the medical records of 253 patients with EGC who underwent surgical therapy in our department between 2012 and 2015. Univariate analysis and Multivariate Cox regression were used to evaluate the independent risk factors of LNM. Results: LNM was present in 38 cases among 253 patients (15%). Univariate analysis showed an obvious correlation between LNM and tumour location, tumour size, depth of invasion, morphological classification, gross type of the lesion and venous invasion. Multivariate analysis indicated that poorly differentiated carcinoma, submucosal cancer, tumour size ≥2 cm and venous invasion were the independent risk factors for LNM. Conclusion: Tumour size, depth of invasion, morphological classification and blood vessel invasion were predictive risk factors for LNM in EGC. We propose that EGC patients with those risk factors should be accepted gastrectomy with LN dissection.

An alternative approach for preparation of amide-embedded stationary phase for reversed-phase liquid chromatography.

Polar-embedded stationary phases are superior to conventional alkyl stationary phases in terms of water-wettability, silanol activity and polar selectivity. A novel method was proposed for efficient preparation of amide-embedded stationary phases bearing extended aliphatic chain and large aromatic ring. The present approach, which simply required isocyanate and desired carboxylic acid, rather than the normal combination of amine/acyl chloride/proton scavenger, produced aromatic pyrenyl amide-embedded (PYE-Amide) and aliphatic docosanyl amide-embedded (C22-Amide) stationary phases. The as-synthesized packing materials were characterized and evaluated in comparison with conventional octadecyl stationary phases in terms of bonding density, aromatic and hydrophobic natures, charge-transfer capability, and selectivity towards isomers of various unsaturated compounds. A high affinity of the unsaturated ligand for the unsaturated solutes, especially the electron-deficient ones, was observed. The PYE-Amide stationary phase exhibited unique aromaticity-dependent shape selectivity, which was beneficial to the resolution of certain geometric isomers of polycyclic arenes. The applicability of such stationary phases was demonstrated by effective separations of estrogens and sulfonamide drugs.

Tuning selectivity via electronic interaction: Preparation and systematic evaluation of serial polar-embedded aryl stationary phases bearing large polycyclic aromatic hydrocarbons.

Aromatic stationary phases showing complementary selectivity to their alkyl counterparts are extremely useful for certain challenging separation tasks. Herein, a series of polar-embedded aryl stationary phases were synthesized from reactive derivatives of large polycyclic aromatic hydrocarbons (PAHs), including anthracene (three-ring, catacondensed), pyrene (four-ring, pericondensed) and triphenylene (four-ring, fully-benzenoid). These PAHs were functionalized with hydroxymethyl group (PAH-CH2OH), then catalytically converted to carbamates (PAH-CH2OC(=O)NH-R) using isocyanate, and finally covalently grafted onto silica to produce corresponding carbamate-embedded PAH stationary phases. To gain insight into the connection and difference among the attached species, the chromatographic behaviors of these new adsorbents were systematically evaluated in terms of surface coverage, hydrophobic and aromatic features, shape selectivity and charge-transfer property, using different classes of analytes, such as alkylbenzenes, PAH congeners and isomeric multi-substituted benzenes, and the results were further compared with conventional octadecyl ones (C18). The relationships between the shape selectivity and the surface chemistry revealed unique behavioral patterns of theses immobilized conjugated ligands, as well as marked differences amongst them, which formed sharp contrast to the case of C18. The effects of temperature and mobile phase compositions on the shape selectivity were further studied. The charge-transfer characteristics demonstrated the great potential of such polar-embedded PAH materials for highly selective separation of electron-deficient compounds through electron donor-acceptor complexation.