Air travel choice, online meeting and passenger heterogeneity - An international study on travellers' preference during a pandemic.

This study empirically identifies business travellers' preferences during the COVID-19 pandemic across different regions. A stated preference study was conducted during April to June 2021 on respondents in the U.S., the city of Shanghai in mainland China and Hong Kong. Generalised mixed multinomial logit (GMXL) models are estimated incorporating attributes of travel characteristics, severity levels of the pandemic, and health control measures at the airport. When an online meeting is inapplicable, respondents from Shanghai and Hong Kong highly value heath control measures, and are not sensitive to the time spent at airport health checkpoints. In comparison, U.S. respondents are averse to the time spent for health check, the reporting of personal information, travel history, symptoms, and the requirements of compulsory mask wearing and onsite sample testing. However, when online meeting is applicable, all the respondents show no appreciation for health control measures, while the U.S. respondents are twice more averse to the time spent at airport health checkpoints. Online meeting reduces the intention of international business travel amid the pandemic for passengers in Shanghai and Hong Kong, but imposes no significant effects on U.S. travellers. Such significant heterogeneity in traveller preference partly explains the different recovery patterns observed in various aviation markets, and justifies individualized travel arrangements and service priority in fulfilling pandemic control requirements across different regions. Our study also suggests that there are commonly accepted areas for global cooperation such as the sharing of vaccination record, and the option of online meeting calls for convenient travel arrangements amid pandemic to all countries.

Polyphenols and Alkaloids in Byproducts of Longan Fruits (Dimocarpus Longan Lour.) and Their Bioactivities.

The longan industry produces a large amount of byproducts such as pericarp and seed, resulting in environmental pollution and resource wastage. The present study was performed to systematically evaluate functional components, i.e., polyphenols (phenolics and flavonoids) and alkaloids, in longan byproducts and their bioactivities, including antioxidant activities, nitrite scavenging activities in simulated gastric fluid and anti-hyperglycemic activities in vitro. Total phenolic and total flavonoid contents in pericarp were slightly higher than those in seeds, but seeds possessed higher alkaloid content than pericarp. Four polyphenolic substances, i.e., gallic acid, ethyl gallate, corilagin and ellagic acid, were identified and quantified using high-performance liquid chromatography. Among these polyphenolic components, corilagin was the major one in both pericarp and seed. Alkaloid extract in seed showed the highest DPPH radical scavenging activity and oxygen radical absorbance capacity. Nitrite scavenging activities were improved with extract concentration and reaction time increasing. Flavonoids in seed and alkaloids in pericarp had potential to be developed as anti-hyperglycemic agents. The research result was a good reference for exploring longan byproducts into various valuable health-care products.

A hierarchical hub location model for the integrated design of urban and rural logistics networks under demand uncertainty.

This paper contributes to the integrated design issue of urban and rural logistics networks under demand uncertainty. A hierarchical hub location model is proposed, which minimizes the expected total system cost by optimizing the locations, number and capacities of "urban-town‒village" hierarchical logistics hubs. The interactions among the logistics hubs and among the hub‒and‒spoke connections, as well as the hub capacity constraints are explicitly considered in the presence of logistics demand uncertainty. A demand scenario‒based branch‒and‒Benders‒cut algorithm is developed to solve the proposed model. A case study of Jiangling urban‒rural region in Hubei province of China is conducted for the illustration of the model and solution algorithm. The results generated by the proposed algorithm are benchmarked against those obtained by GUROBI solver and the practical scheme being currently implemented in the region. The results showed that the proposed methodology can greatly improve the efficiency of the urban‒rural logistics system in terms of expected total system cost. It is important to explicitly model the demand uncertainty, otherwise a significant decision bias may emerge. The proposed algorithm outperforms the GUROBI solver in terms of problem size solved and computational time.

The effect of online meeting and health screening on business travel: A stated preference case study in Hong Kong.

This study quantifies the effects of health control measures at the airport on passenger behaviour related to business travel. A stated preference survey was conducted over potential air travellers in Hong Kong in the context of COVID-19 pandemic. Panel latent class models were estimated to understand passenger preference toward new travel requirements given the applicability of online meeting. Online meeting is applicable in cases where it is a good substitute of air travel and achieves the same outcomes of a trip, and inapplicable otherwise. Empirical results indicate that traveller subgroups are affected in different ways. When an online meeting is inapplicable, nearly 75% of the respondents prefer to travel for business and undertake health screenings. These passengers (identified as "captive" business travellers) perceive such measures necessary to lower health related risks during air travel. As such, they are willing to spend up to 21 to 38 min on the health control measures such as vaccination record requirements and test involving sample collection. When an online meeting is applicable, the share of "choice" business travellers is about 45%, among whom the attitudes towards health control measures become more averse. The average weighted willingness-to-pay for the time saved at health checkpoints increase significantly. The aviation industry thus faces a "double-hit" problem: operation costs will increase due to pandemic control measures, and the resultant inconvenience, extra time and costs further reduces travel demand. Unlike previous short pandemics, business travel is likely to suffer with an extended decline until the pandemic is fully controlled. These identified challenges call for financial and operational support to help the aviation industry reach a sustainable "new normal". The high value of time saved at check points also justifies investments that make the pandemic control and health measures efficient and smooth. Travellers' time spent on airport health control should be within 20 min to avoid substantial negative impacts on business travel demand.

Distribution and characterization of higher chlorinated benzenes in outdoor dust collected from a fast developing city in North China.

Five higher chlorinated benzenes (CBs), include hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and three isomers of tetrachlorobenzens, were analyzed in 20 outdoor dust samples collected from a fast developing city, Xinxiang. Only HCB was detected in all outdoor dust samples. The dominate part of the CBs residue in most samples was HCB and the mean HCB concentration (4.13 ng/g dry weight) in this study was in the range of global background soil HCB levels (ranging from 0.010 to 5.20 ng/g dry weight). The higher ratios of HCB/PeCB in the outdoor dust samples in the present study indicate that pesticide application may be an important source of HCB in China.

[Characteristics of Dissolved Organic Matter in Overlying Water During Algal Bloom Decay].

In this study, indoor simulation experiments were performed to elucidate the effects of migration and transformation of dissolving organic matter (DOM) during the decay of algal blooms. Based on ultraviolet-visible spectra (UV-vis) and excitation-emission matrix spectroscopy (EEMs), spectral characterizations of dissolved organic matter (DOM) in overlying water were evaluated with analyses of the physical and chemical indexes, variation in dissolved organic carbon (DOC), and variation in dissolved inorganic carbon (DIC). Results showed that at the early stage of decay, a large amount of organic matter was released, and dissolved oxygen (DO) decreased sharply. With the extension of reaction time, DOC gradually changed into DIC, which further changed the oxidation-reduction and acid-base characteristics of the water. UV-vis spectra showed that a large amount of DOM was released with high aromaticity and a high degree of humification, and the released DOM was gradually degraded. With the application of parallel factor analysis in excitation-emission matrix spectroscopy (EEM-PARAFAC), three fluorescence components were analyzed:refractory humic-like substances (C1), protein-like tryptophan substances (C2) produced by algae, and fulvic-like substances (C3) related to microbial activities. Most protein-like tryptophan substances were degraded into fulvic-like substances by microorganisms during the decaying process. Heterotrophic microorganisms promoted the release of algae-derived DOM and accelerated the degradation of DOM. The DOM born during algae blooms decaying process was eventually converted into humic-like substance, which was difficult to be degraded. We analyzed correlations of water quality, UV-vis spectrum, and EEMs parameters. Results showed that ORP was positively correlated (P<0.05) with DO. There was a significant negative correlation (P<0.05) between pH and DOC, which was consistent with the trend of the transformation to from DOC to DIC; C1 was positively correlated (P<0.05) with Fn355; and C2 was significantly positively correlated (P<0.05) with DOC and Fn280; C3 was positively correlated (P<0.05) with FI, BIX and ß:α. The variation trend of these spectral parameters was consistent with that of DOM components. In summary, with the analyses of water quality characteristics and spectral characteristics of DOM in overlying water during algae blooms decaying process, it was expected that our results could contribute to the further exploration of the dynamic migration and transformation of lake DOM and the changes of carbon cycling.

[Synergistic Mechanism of Interferon alpha-1b, Interleukin-2 and Thalidomide for Immune Regulation in Patients with Acute Myeloid Leukemia].

OBJECTIVE: To explore the synergistic immunomodulatory mechanism of interferon alpha-1b, interleukin-2 and thalidomide (ITI) regimen on patients with acute myeloid leukemia (AML). METHODS: Sixty eight untreated de novo or relapsed or refractory or maintenance therapy patients with AML admitted in the Affiliated Cancer Hospital of Zhengzhou University and the other 11 medical units from March 2016 to May 2019 were treated with ITI regimen. Peripheral blood specimen per patient was collected into EDTA-K3 anticoagulation vacuum tube before the administration of ITI and 3 months after the treatment; peripheral blood lymphocyte subsets and perforin and Granzyme B expression were analyzed by using flow cytometry; the levels of VEGF, IFN-γ, TNF-α and IL-6 in the plasma were detected by using a cytometric bead array. Thirty-five healthy subjects from the hospital physical examination centre were selected as normal controls. RESULTS: The ratio of CD4+/CD8+ T cells, the percentage of NK cells, the expression of perforin and Granzyme B of NK cells in the peripheral blood of patients with hematological malignancies were lower than those of healthy controls. The level of VEGF, IL-6 and TNF-α in the peripheral plasma were higher than those of the healthy control group, and the difference was statistically significant. The level of IFN-γ was lower, and the difference was not statistically significant. The ratio of CD4+/CD8+ T cells, the percentage of NK cells, the expression of Granzyme B and Perforin of NK cells in peripheral blood were higher after the therapy of thalidomide combined with rhIFNα-1b for 3 months as compared with those before treatment of ITI, the level of the IFN-γ in peripheral plasma was higher while that of VEGF was lower, the difference was statistically significant; after treatment, the ratio of CD3+ CD4+ and CD3+ CD8+ lymphocytes and the level of TNF-α in peripheral blood were higher those that before treatment, IL-6 was lower, while the difference was not statistically significant. CONCLUSION: The ITI regimen can raise the ratio of CD4+/CD8+ T cells and the percentage of natural killer cells, also, can enhance the generation of perforin and granzyme B and the concentration of IFN-γ as well as inhibit the generation of VEGF, suggesting that these activities may enhance the antitumour capacity of patients with AML.

[Effect of Nutrient Loadings on the Regulation of Water Nitrogen and Phosphorus by Vallisneria natans and Its Photosynthetic Fluorescence Characteristics].

Submerged macrophytes are an important component of aquatic ecosystems. During the growing period, submerged macrophytes can absorb nitrogen and phosphorus nutrients to reduce pollution loadings. Shoots of submerged macrophytes can also promote the adhesion of suspended substances in water, reducing the turbidity. The release of nutrients in sediments can be suppressed by its root system, and the resuspension of sediments caused by disturbance of winds and waves can also be resisted. The role of submerged macrophytes in ecological restoration of eutrophic lakes has attracted widespread attention. In 1960, the submerged plants Vallisneria natans and Potamogeton malaianus had been the dominant species in East Taihu. However after 2002, Nymphoides peltatum, Elodea nattalii, P. malaianus, etc. have gradually taken over the dominant roles along with significant elevations of nitrogen and phosphorus levels. Nutrients in water are not the only key factors causing eutrophication of water bodies; the nutrient source for submerged plant growth affect both the purification efficiency and the photosynthetic characteristics of submerged macrophytes. Excessive nitrogen and phosphorus concentrations can inhibit the photosynthetic physiological activities of submerged macrophytes, affecting the succession of aquatic vegetation. In addition, under high nutrient conditions, the competition from periphytic algae and planktonic algae may also directly poison submerged macrophytes, leading to its degradation and disappearance. Systematic studies on the regulation and photosynthetic fluorescence response mechanism of submerged macrophytes to varied nutrient loadings are helpful in revealing their relationships. The seedlings of submerged macrophyte V. natans were transplanted in a laboratory mesocosm to study the effect of nutrient loadings on its regulation of water nitrogen and phosphorus. Three nitrogen and phosphorus loadings from low, medium, and high levels derived from nitrate, ammonium, and phosphate were setup as the aquatic medium for the plant growth. Twelve harvests were carried out to determine the evolution of nutrient removal performance of V. natans. Its photosynthetic fluorescence characteristics were measured by a pulse-amplitude modulated fluorometer (Diving-PAM). Results showed that the nitrogen and phosphorus adsorption abilities of V. natans were gradually enhanced with the increase of nutrient concentrations in the range of TN ≤ 12 mg·L-1 and TP ≤ 1.0 mg·L-1. In the treatment of high nutrient concentrations (TN=12 mg·L-1 and TP=1.0 mg·L-1), the removal rates of nitrogen and phosphorus reached more than 95%. V. natans preferentially absorbed ammonium nitrogen when its concentration was high. The medium nutrient concentrations (TN:8-12 mg·L-1 and TP:0.6-1.0 mg·L-1) did not significantly affect the Fv/Fm ratio of leaves. However, the low nutrient concentrations (TN=3 mg·L-1 and TP=0.3 mg·L-1) could improve the Fv/Fm ratio of leaves and were beneficial for the growth of V. natans. The inhibition of photosynthetic activity and light tolerance were enhanced with the increase in nutrient concentrations. The photosynthetic activity of V. natans gradually recovered with no significant changes in the capacity for light harvesting, when the nutrient concentrations gradually decreased in the water. Our results indicate that the high nitrogen and phosphorus loadings indeed hamper the photosynthetic capacity, which may subsequently restrain the maintenance of the dominance of V. natans in the submerged macrophyte communities.

[Therapeutic effects of photocatalytic nano-TiO2on human nasopharyngeal carcinoma xenografts in nude mice].

OBJECTIVE: To study the therapeutic effect of photocatalytic nano-TiO2 on nasopharyngeal carcinoma xenograft in nude mice and underlying mechanism. METHODS: Nude mice bearing human nasopharyngeal carcinoma xenograft were randomly divided into six groups: nano-TiO2 + UV irradiation (with gradient concentration of nano-TiO2); nano-TiO2 alone and UV irradiation alone and blank control. The nano-TiO2 suspension was injected into xenografts, and 24 h after UV light with the wave length of 330 - 400 nm, all the xenografts were removed and sectioned for HE staining. Ultrastructure and apoptosis of tumor cells in the xenografts were observed by transmission electron microscope (TEM). The expression of Caspase-3 was examined immunohistochemical staining and the apoptosis was detected with TUNEL. RESULTS: Pathological analysis showed significant inflammatory responses (grade II and III) with local necrosis occurred in tumor tissues after nano-TiO2 photodynamic therapy, but not in the negative control and blank control. TEM showed the nano-TiO2 particles entered into the cytoplasm and the nucleus of tumor cells and many tumor cells had morphological changes for apoptosis. Significant positive expression of Caspase-3 and TUNEL-positive cells were found in the the xenografts with the treatments of nano-TiO2 + UV irradiation compared to control (P < 0.01), which were enhanced with the increases in nano-TiO2 concentration (P < 0.01). CONCLUSION: Photocatalytic nano-TiO2 can inhibit the growth of nasopharyngeal carcinoma xenograft in nude mice by inducing Caspase-3 expression and apoptosis in the tumor cells.

[Pathological features and clinical managements of nasopharyngeal angiofibroma].

OBJECTIVE: To study the pathological features of nasopharyngeal angiofibroma (NA) and the principles for clinical managements. METHODS: Thirty-five patients with NAs were treated in First Affiliated Hospital of Fujian Medical University from Oct. 1981 to May 2007. The pathological changes, sites of origin, causes of intraoperative bleeding and the experiences of managements were retrospectively analysed. Using Fish stage: 6 cases were in stage I, 8 cases were in stage II, 17 cases were in stage III, 4 cases were stage IV. Two cases via endoscopic surgery, 2 cases via palatal approach, 19 cases via midfacial degloving approach, 9 cases via lateral rhinotomy approach, 3 cases via craniofacial combined approach. RESULTS: In nasal cavity and paranasal sinus, the tumor was covered by squamous or columnar epithelium. The tumor extensions such as in pterygopalatine fossa and infratemporal fossa were covered by fibrous pseudocapsule. All cases of this series originated in the lateral wall of posterior portion of the nasal cavity. Fifteen of thirty-five cases confidentially originated near sphenopalatine foramen. Large and thick vessels in the pedicle region were the exact sites of serious intraoperative bleeding. Thirty-one cases were totally removed. Four cases were subtotal resected. Visual loss revealed in 6 cases, 4 cases visual acuity improved postoperatively. Three cases revealed postoperative dry eye due to surgical involvement of the sphenopalatine ganglion. CONCLUSIONS: nasopharyngeal angiofibroma is covered by epithelium or pseudo-capsule, it does not infiltrate the surrounding tissue. Dissecting along the surface of tumor might decrease bleeding and facilitate removal of tumor. An ideal surgical management should be done according to actually size and image examination, to the greatest extent keeping normal facial appearance. Attention should be paid to the complications such as visual loss and dry eye.

[Prognostic significance of peripheral blood cell and bone marrow megakaryocyte counts in patients with idiopathic thrombocytopenic purpura].

To clarify the prognostic contribution of peripheral blood cell and bone marrow megakaryocyte counts in patients with idiopathic thrombocytopenic purpura, a series of data of 299 ITP patients including the counts of peripheral white blood cells and platelets, their increase potentials after treatment and the megakaryocytic counts on the bone marrow smears at diagnosis as well were collected and retrospectively analyzed to correlate with the disease development. The results showed that peripheral white blood cell and platelet counts at diagnosis were not associated with the prognosis, but positively associated with the increment of platelet counts after treatment. The cure rate reached up to 94.9% in the group with the platelet level restored to 100 x 10(9)/L in two weeks of therapy. The numerous megakaryocyte counts in bone marrow at diagnosis indicated good prognosis that the cure rate was up to 86.1% when the counts were more than 100 per 1.5 x 3 cm of smear. In conclusion, bone marrow examination on the quantity and quality of megakaryocyte would be critical for diagnosis and evaluation of the prognosis. Consecutive platelet counts during therapy is useful to estimate the disease development.

[Plasma soluble interleukin-2 receptor level in patients with idiopathic thrombocytopenic purpura and its clinical significance].

To investigate contribution of soluble interleukin-2 receptor (SIL-2R) to the clinical progress of idiopathic thrombocytopenic purpura (ITP), SIL-2R levels were measured in the plasma of 34 patients and 34 normal controls with double antibody sandwich ELISA. The cohort consisted of 12 patients with chronic ITP, 15 with acute ITP and 7 with ITP in remission. The results showed that the mean SIL-2R level of chronic ITP group was significantly higher than those of both the control and acute ITP group (P < 0.001 and P < 0.01, respectively). The SIL-2R level of 7 cases in remission, however, was not significantly different from that of normal controls. Furthermore, the plasma levels were dramatically lowered in patients responsive to VLAP regimen (vincristine, L-imidazole, antaisu and prednisone), and those were not evidently decreased in unresponsive patients. It was concluded that T cell activation may play a role in the development of ITP, and further, the level of plasma SIL-2R might predict the prognosis of ITP.

Huge lobulated juvenile angiofibroma: sites of extension and selection of procedures for management.

OBJECTIVE: To review and report our experiences in the management of huge lobulated juvenile angiofibroma (JNA). MATERIALS AND METHODS: From 1980 to 2001, 11 cases were diagnosed and treated in our department. Their clinical manifestations and the results of treatment were analyzed and evaluated, with particular attention to the anatomic sites of extension and the selection of choices for appropriate treatment. RESULTS: Owing to extranasopharyngeal extension, 6 to 12 different anatomic sites were occupied by each tumour, including the cheek (9 tumours) and middle cranial fossa (3 tumours). To remove these tumours, a transantral approach via midfacial degloving was usually used, with or without another incision and approach combined. When the middle cranial fossa is extensively involved by a tumour lobe, it should first be exposed and managed through a transtemporal-extradural or intradural approach. The internal carotid artery and cavernous sinus can be controlled distally. JNAs in 9 cases were resected completely without recurrence after following up for 1 to 22 years. The other 2 JNAs with large intracranial extension and serious intraoperative bleeding were removed subtotally. CONCLUSION: A huge JNA might occupy multiple anatomic sites, and the transantral approach via midfacial degloving is recommended as the best choice for its removal, with another incision and approach combined, if necessary.