Selection and evaluation of three interventional procedures for achalasia based on long-term follow-up

AIM: To determine the best method out of the three types of interventional procedure for achalasia based on a longterm follow-up.METHODS: The study cohort was comprised of 133 patients of achalasia. Among them, 60 patients were treated under fluoroscopy with pneumatic dilation (group A), 8 patients with permanent uncovered or antireflux covered metal stent dilation (group B), and 65 patients with temporary partially covered metal stent dilation (group C).RESULTS: One hundred and thirty dilations were performed on the 60 patients of group A (mean 2.2 times per case).The mean diameter of the strictured cardia was 3.3±2.1 mm before dilation and 10.6±3.8 mm after dilation. The mean dysphagia score was 2.7±1.4 before dilation and 0.9±0.3after dilation. Complications in group A were chest pain (n=30), reflux (n=16), and bleeding (n=6). Thirty-six patients (60 %) in group A exhibited dysphagia relapse during a 12-month follow-up, and 45 patients (90 %) out of 50 exhibited dysphagia relapse during a 36-month followup. Five uncovered and 3 antireflux covered expandable metal stents were permanently placed in the 8 patients of group B. The mean diameter of the strictured cardia was 3.4±1.9 mm before dilation and 19.5±1.1 mm after dilation.The mean dysphagia score was 2.6±1.3 before dilation and 0.4±0.1 after dilation. Complications in group B were chest pain (n=6), reflux (n＝5), bleeding (n=3), and hyperplasia of granulation tissue (n=3). Four patients (50 %) in group B exhibited dysphagia relapse during a 12-month followup, and 2 case (66.7 %) out of 3 patients exhibited dysphagia relapse during a 36-month follow-up. Sixty-five partially covered expandable metal stents were temporarily placed in the 65 patients of group C and withdrawn after 3-7 days via gastroscopy. The mean diameter of the strictured cardia was 3.3±2.3 mm before dilation and 18.9±3.5 mm after dilation. The mean dysphagia score was 2.4±1.3 before dilation and 0.5±0.2 after dilation. Complications in group C were chest pain (n=26), reflux (n=13), and bleeding (n=8).6 patients (9.2 %) out of 65 exhibited dysphagia relapse during a 12-month follow-up, and 8 patients (14.5 %) out of 55 exhibited dysphagia relapse during a 36-month followup. All the stents were inserted and withdrawn successfully.The follow-up in groups A-C lasted 12-96 months.CONCLUSION: Temporary partially covered metal stent dilation is one of the best methods with interventional procedure for achalasia in terms of long-term follow-up.

Visible light induced photodegradation of organic pollutants on nitrogen and fluorine co-doped TiO_2 photocatalyst

The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.

Methylation profile of the promoter CpG islands of 14 “drug-resistance”genes in hepatocellular carcinoma

AIM: To establish the DNA methylation patterns of the promoter CpG islands of 14 'drug-resistance' genes in hepatocellular carcinoma (HCC).METHODS: The methylation specific polymerase chain reaction in conjunction with sequencing verification was used to establish the methylation patterns of the 14 genes in the liver tissues of four healthy liver donors, as well as tumor and the paired non-cancerous tissues of 30 HCC patients.RESULTS: While 11 genes (ATP-binding cassette, sub-family G (WHITE), member 2(ABCG2), activating transcription factor (ATF2), beta-2-microglobulin (B2M), deoxycytidine kinase(DCK, occludin (OCLN, v-raf-1 murine leukemia viral oncogene homolog (RAF/), ralA binding protein 1 (RALBP1),splicing factor (45 kD) (SPF45), S-phase kinase-associated protein 2 (p45) (SKP2), tumor protein p53 (Li-Fraumeni syndrome) (TP53) and topoisomerase (DNA) II beta (TOP2B) maintained the unmethylated patterns, three genes displayed to various extents the hypermethylation state in tumor tissues in comparison with the normal counterparts. The catalase (CAT) was hypermethylated in tumor and the neighboring non-cancerous tissue of one case (3.3%). Both glutathione S-transferase pi (GSTp/) (80%, 24/30 in tumor and 56.7%,17/30 in the paired non-cancerous tissues) and cystic fibrosis transmembrane conductance regulator, ATP-binding cassette (sub-family C, member 7) (CF-FR) (77%, 23/30 in tumor and 50%, 15/30 in the paired non-cancerous tissues) genes were prevalently hypermethylated in HCC as well as their neighboring non-cancerous tissues. No significant difference in the hypermethylation occurrence was observed between the HCC and its neighboring non-cancerous tissues.CONCLUSION: Hypermethylation of promoter CpG islands of both CF-FR and GSTpigenes occurs prevalently in HCC,which may correlate with the low expression of these two genes at the mRNA level and has the profound etiological and clinical implications. It is likely to be specific to the early phase of HCC carcinogenesis.

Temporary partially-covered metal stent insertion in benign esophageal stricture

AIM: To study the therapeutic efficacy of temporary partiallycovered metal stent insertion on benign esophageal stricture.METHODS: Temporary partially-covered metal stent was inserted in 83 patients with benign esophageal stricture. All the patients had various dysphagia scores.RESULTS: Insertion of 85 temporary partially-covered metal stents was performed successfully in 83 patients with benign esophageal stricture and dysphagia was effectively remitted in all the 83 cases. The dysphagia score was 3.20±0.63(mean±SD) and 0.68±0.31 before and after stent insertion,and 0.86±0.48 after stent removal. The mean diameter of the strictured esophageal lumen was 3.37±1.23 mm and 25.77±3.89 mm before and after stent insertion, and 16.15±2.96 mm after stent removal. Follow-up time was from 1 week to 96 months (mean 54.26±12.75 months). The complications were chest pain (n=37) after stent insertion,and bleeding (n=12) and reflux (n=13) after stent removal.CONCLUSION: Temporary partially-covered metal stent insertion is one of the best methods for treatment of benign esophageal stricture.

Comparison of different intervention procedures in benign stricture of gastrointestinal tract

AIM:To determine the most effective intervention procedure by evaluation of mid and long-term therapeutic efficacy in patients of stricture of the gastrointestinal tract (GTT). METHODS:Different intervention procedures were used to treat benign stricture of GIT in 180 patients including pneumatic dilation (group A,n=80),permanent (group B, n=25) and temporary (group C,n=75) placement of expandable metallic stents. RESULTS:The diameters of the strictured GIT were significantly greater after the treatment of all procedures employed (P<0.01).For the 80 patients in group A,160 dilations were performed (mean,2.0 times per patient). Complications in group A included chest pain (n=20),reflux (n=16),and bleeding (n=6).Dysphagia relapse occurred in 24(30%) and 48 (60%) patients respectively during 6-and- 12 momth follow-up periods in group A.In group B,25 uncovered or partially covered or antireflux covered expandable metallic stents were placed permantly, complications included chest pain (n=10),reflux (n=15), bleeding (n=3),and stent migration (n=4),and dysphagia relapse occurred in 5 (20%) and 3 patients (25%) during the 6-and-12 month follow-up periods,respectively.In group C,the partially covered expandable metallic stents were temporarily placed in 75 patients and removed after 3 to 7 days via gastroscope,complications including chest pain (n=30),reflux (n=9),and bleeding (n=12),and dysphagia relapse occurred in 9 (12%) and 8 patients (16%) during the 6-and-12 month follow-up periods,respectively.The placement and withdrawal of stents were all successfully performed.The follow-up of all patients lasted for 6 to 96 months (mean 45.3±18.6 months). CONCLUSION:The effective procedures for benign GIT stricture are pneumatic dilation and temporary placement of partially-covered expandable metallic stents.Temporary placement of partially-covered expandable metallic stents is one of the best methods for benign GIT strictures in mid and long-term therapeutic efficacy.

Complications of stent placement for benign stricture of gastrointestinal tract

AIM:To observe the frequent complications of stent placement for stricture of the gastrointestinal tract and to find proper treatment.METHODS:A total number of 140 stents were inserted in 138 patients with benign stricture of the gastrointestinal tract.The procedure was cornpleted under fluoroscopy in all of the patients.RESULTS:Stents were successfully placed in all the 138 patients.Pains occurred in 23 patients (16.7%),slight or dull pains were found in 21 patients and severe chest pain in 2 respectively.For the former type of pain,the patients receivedonly analgesia or even no treatment,while peridural anesthesics was conducted for the latter condition. Reflux occurred in 16 of these patients (11.6%) after stent placement.It was managed by common antireflux procedures. Gastrointestinal bleeding occurred in 13 patients (9.4%),and was treated by hemostat.Restenosis of the gastrointestinal tract occurred in 8 patients (5.8%),and was apparently associated with hyperplasia of granulation tissue.In 2 patients,the second stent was placed under X-ray guidance.The granulation tissue was removed by cauterization through hot-node therapy under gastroscope guidance in 3 patients,and surgical reconstruction was performed in another 3 patients. Stent migration occurred in 5 patients (3.6%),and were extracted with the aid of a gastroscope.Food-bolus obstruction was encountered in 2 patients (1.4%) and was treated by endoscope removal.No perforation occurred in all patients.CONCLUSION:Frequent complications after stent placement for benign stricture of the gastrointestinal tract include pain,reflux,bleeding,restenosis,stent migration and food-bolus obstruction.They can be treated by drugs,the second stent placement or gastroscopic procedures according to the specific conditions.

Engineering tropane biosynthetic pathway in Hyoscyamus niger hairy root cultures

Scopolamine is a pharmaceutically important tropane alkaloid extensively used as an anticholinergic agent.Here,we report the simultaneous introduction and overexpression of genes encoding the rate-limiting upstream enzyme pu-trescine N-methyltransferase(PMT)and the downstream enzyme hyoscyamine6β-hydroxylase(H6H)of scopolamine biosynthesis in transgenic henbane(Hyoscyamus niger)hairy root cultures.Transgenic hairy root lines expressing both pmt and h6h produced significantly higher(P<0.05)levels of scopolamine compared with the wild-type and transgenic lines har-boring a single gene(pmt or h6h).The best line(T 3 )produced411mg/liter scopolamine,which was over nine times more than that in the wild type(43mg/liter)and more than twice the amount in the highest scopolamine-producing h6h single-gene transgenic line H 11 (184mg/liter).To our knowledge,this is the highest scopolamine content achieved through genetic engi-neering of a plant.We conclude that transgenic plants harboring both pmt and h6h possessed an increased flux in the tropane alkaloid biosynthetic pathway that enhanced scopolamine yield,which was more efficient than plants harboring only one of the two genes.It seems that the pulling force of the downstream enzyme(the faucet enzyme)H6H plays a more important role in stimulating scopolamine accumulation in H.niger whereas the functioning of the upstream enzyme PMT is increased propor-tionally.This study provides an effective approach for large-scale commercial production of scopolamine by using hairy root culture systems as bioreactors.

The cell cycle related apoptotic susceptibility to arsenic trioxide is associated with the level of reactive oxygen species

Double staining flow cytometry was performed using 7-amino actinomycin D and 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate,to detect the level fluctuation of reactive oxygen species (ROS) during the cell cycle of normal NB4 cells. Our results showed that NB4 cells possessed higher level of ROS in G2/M phase than in G1 and S phases. Double staining flow cytometry,with TdT mediated dUTP nick end labeling (Tunel) and propidium iodide (PI),indicated that As2O3 (2 μM) could induce apoptosis in NB4 cells prevailingly from G2/M phase,and this efficacy was enhanced upon co-administration of 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) (2.5 μM) which could produce the endogenous ROS. These results suggested that different ROS level in different cell cycle phases of NB4 cells might determin the selective induction of G2/M apoptosis and the cells' susceptibility to apoptosis by As2O3.

Screening on oil-decomposing microorganisms and application in organic waste treatment machine

As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing rate by Y3 was higher than that by each separate individual strain, indicating a synergistic effect of the two bacteria. Under the conditions that T=25—40℃,pH=6—8, HRT(Hydraulic retention time)=36 h and the oil concentration at 0.1%, Y3 yielded the highest decomposing rate of 95.7 %. Y3 was also applied in an organic waste treatment machine and a certain rate of activated bacteria was put into the stuffing. A series of tests including humidity, pH, temperature, C/N rate and oil percentage of the stuffing were carried out to check the efficacy of oil-decomposition. Results showed that the oil content of the stuffing with inoculums was only half of that of the control. Furthermore, the bacteria were also beneficial to maintain the stability of the machine operating. Therefore, the bacteria mixture as well as the machines in this study could be very useful for waste treatment.

The altered DNA methylation pattern and its implications in liver cancer

DNA methylation is the most intensively studied epigenetic phenomenon, disturbances of which result in changes ingene transcription, thus exerting drastic imparts onto biological behaviors of cancer. Both the global demethylation andthe local hypermethylation have been widely reported in all types of tumors, providing both challenges and opportunitiesfor a better understanding and eventually controlling of the malignance. However, we are still in the very early stage ofinformation accumulation concerning the tumor associated changes in DNA methylation pattern. A number of excellentrecent reviews have covered this issue in depth. Therefore, this review will summarize our recent data on DNA methy-lation profiling in cancers. Perspectives for the future direction in this dynamic and exciting field will also be given.

OPTIMIZATION APPROACH FOR HYBRID ELECTRIC VEHICLE POWERTRAIN DESIGN

According to bench test results of fuel economy and engine emission for thereal power-train system of EQ7200HEV car. a 3-D performance map oriented quasi-linear model isdeveloped for the configuration of the powertrain components such as internal combustion engine,traction electric motor, transmission, main retarder and energy storage unit. A genetic algorithmbased on optimization procedure is proposed and applied for parametric optimization of the keycomponents by consideration of requirements of some driving cycles. Through comparison of numericalresults obtained by the genetic algorithm with those by traditional optimization methods, it isshown that the present approach is quite effective and efficient in emission reduction and fueleconomy for the design of the hybrid electric car powertrain.

Nonlinear control for a class of hydraulic servo system

The dynamics of hydraulic systems are highly nonlinear and the system may be subjected to non-smooth and discontinuous nonlinearities due to directional change of valve opening, friction, etc. Aside from the nonlinear nature of hydraulic dynamics, hydraulic servo systems also have large extent of model uncertainties. To address these challenging issues, a robust state-feedback controller is designed by employing backstepping design technique such that the system output tracks a given signal arbitrarily well, and all signals in the closed-loop system remain bounded. Moreover, a relevant disturbance attenuation inequality is satisfied by the closed-loop signals. Compared with previously proposed robust controllers, this paper's robust controller based on backstepping recursive design method is easier to design, and is more suitable for implementation.

Follow-up evaluation for benign stricture of upper gastrointestinal tract with stent insertion

AIM: To determine the best mothod for benign stricture of the upper gastrointestinal tract (UGIT) with stent insertion by follow-up evaluation.METHODS: A total of 110 stents insertions were performed in 110 cases of benign stricture of the UGIT. Permanent (group A) and temporary (group B) placement of an expandable metal stent in 30 cases and 80 cases respectively. All cases were completed under fluoroscopy.RESULTS: In group A, 30 uncovered or antireflux covered or partially covered expandable metal stents were placed permanently. In group A, 5 cases (16.7 %) in 3-months, 5 cases (20.0 %) in 6-months, 6 cases (25 %) in the 1st year,6 cases (50 %) in the 3rd year, and 4 cases (80 %) in the 5th year exhibited dysphagia relapse. In group B, a partiallycovered expandable metal stent was temporarily placed in each patient and removed after 3-7 days via gastroscopy.Follow-up data in this group showed that 8 cases (7.5 %) in 3-months, 9 cases (12.0 %) in 6-months, 10 cases (15.4 %) in the 1st year, 6 cases (20 %) in the 3rd year, and 3 cases (25 %) in the 5th year exhibited dysphagia relapse. The placement and withdrawal of all stents were all performed successfully. The follow-up of all cases lasted for 3-99 months (mean 41.6±19.7 months).CONCLUSION: The best mothod for benign stricture of UGIT with stent insertion is temporary placement of a partially-covered expandable metal stent.

A non-invasive method for gastrointestinal parameter monitoring

AIM: To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract.METHODS: The authors developed a miniature, multifunctional gastrointestinal monitoring system, which comprises a set of indigestible biotelemetry capsules and a data recorder.The capsule, after ingested by patients, could measure pressure, temperature and pH value in the gastrointestinal tract and transmit the data to the data recorder outside the body through a 434 MHz radio frequency data link. After the capsule passed out from the body, the data saved in the recorder were downloaded to a workstation via a special software for further analysis and comparison.RESULTS: Clinical experiments showed that the biotelemetry capsules could be swallowed by volunteers without any difficulties. The data recorder could receive the radio frequency signals transmitted by the biotelemetry in the body. The biotelemetry capsule could pass out from the body without difficulties. No discomfort was reported by any volunteer during the experiment. In vivo pressure and temperature data were acquired.CONCLUSION: A non-invasive method for monitoring 24-h gastrointestinal parameters was proposed and tested by the authors. The feasibility and functionality of this method are verified by laboratory tests and clinical experiments.

Cloning and molecular characterization of a novel lectin gene from Pinellia ternata

The full-length cDNA of Pinellia ternata agglutinin (PTA) was cloned from inflorescences using RACE-PCR. Through comparative analysis of PTA gene (pta) and its deduced amino acid sequence with those of other Araceae species, pta was found to encode a precursor lectin with signal peptide and to have extensive homology with those of other Araceae species. PTA was a heterotetrameric mannose-binding lectin with three mannose-binding boxes like lectins from other Araceae and Amaryllidaceae species. Southern blot analysis of the genomic DNA revealed that pta belonged to a low-copy gene family. Northern blot analysis demonstrated that pta constitutively expressed in various plant tissues including root, leaf, stem and inflorescence. The pta cDNA sequence encoding for mature PTA protein was cloned into pET-32a plasmid and the resulting plasmid, pET-32a-PTA containing Trx-PTA fusion protein, was investigated for the expression in E. coli BL21. SDS-PAGE gel analysis showed that the Trx-PTA fusion protein was successfully expressed in E. coli BL21 when induced by IPTG. Artificial diet assay revealed that PTA fusion protein had significant levels of resistance against peach potato aphids when incorporated into artificial diet at 0.1% (w/v). The cloning of the pta gene will enable us to further test its effect in depth on aphids by transferring the gene into crop plants.

超空泡回转体减阻特性研究(英文)

Drag reduction characteristics of supercavitating body of revolution was researched numerically with a bubble two-phase flow model embodied in commercial CFD code Fluent 6.0.The work included the effects of body shape on drag coefficient and supercavity sizes; supercavity control; drag coefficient Cd as a function of cavitation number; and the effect of the ratio of length L to diameter D on drag reduction rate. Research on drag reduction mechanism of supercavitation shows that supercavitation can reduce not only the friction drag coefficient but also the pressure drag coefficient. There may be a best combination among body shape, the ratio L/D, cavitation number, engineering feasibility and so on, which makes the drag reduction ratehighest.

Biological nitrogen removal with enhanced phosphate uptake in (AO)2SBR using single sludge system

Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed stable phosphorus and nitrogen removal performance, and average removals for COD, TN and TP were 90%, 91% and 96%, respectively. The conditions of pH 7.5—8.0 and temperature 32℃ were found detrimental to nitrite oxidation bacteria but favorable to ammonia oxidizers, and the corresponding specific oxygen uptake rates(SOUR) for phase 1 and 2 of nitrification process were 0.7 and 15 mgO 2/(gVSS·h) in respect, which led to the nitrite accumulation in aerobic phase of(AO)2 SBR. Respiratory tests showed that 40 mgNO 2-N/L did not deteriorate the sludge activity drastically, and it implied that exposure of sludge to nitrite periodically enabled the biomass to have more tolerance capacity to resist the restraining effects from nitrite. In addition, batch tests were carried out and verified that denitrifying phosphorus accumulation organisms(DPAOs) could be enriched in a single sludge system coexisting with nitrifiers by introducing an anoxic phase in an anaerobic-aerobic SBR, and the ratio of the anoxic phosphate uptake capacity to aerobic phosphate uptake capacity was 45%. It was also found that nitrite(up to 20 mgNO 2-N/L) was not inhibitory to anoxic phosphate uptake and could serve as an electron acceptor like nitrate, but presented poorer efficiency compared with nitrate.

Re-activation characteristics of preserved aerobic granular sludge

In some industrial plants, wastewater was intermittently or seasonally generated. There may be periods during which wastewater treatment facilities have to be set into an idle phase over several weeks. When wastewater was generated again, the activated sludge flocs may have disintegrated. In this experiment, re-activation characteristics of aerobic granular sludge starved for 2 months were investigated. Specific oxygen utilization rate(SOUR) was used as an indicator to evaluate the metabolic activity of the sludge. The results revealed that aerobic granular sludge could be stored up to two months without running the risk of losing the integrity of the granules and metabolic potentials. The apparent color of aerobic granules stored at room temperature gradually turned from brownish-yellowish to gray brown. They appeared brownish-yellowish again 2 weeks after re-activation. The velocity and strength of granules after 2-month idle period could be fully restored about 3 weeks after re-activation. Metabolic activity, however, dropped to 15 8 mg O_2/(g MLVSS·h), i.e. 74 % reduction after 2 months of storage. After restarting the reactor, it took 2 weeks that SOUR of up to 48 5 mg O_2 /(g MLVSS·h) was achieved. A stable effluent COD concentration of less than 150 mg/L was achieved during the re-activation process.

Methylation profiling of twenty four genes and the concordant methylation behaviours of nineteen genes that may contribute to hepatocellular carcinogenesis

To determine the possible role of the epigenetic mechanisms in carcinogenesis of the hepatocellular carcinoma, we methylation-profiled the promoter CpG islands of twenty four genes both in HCC tumors and the neighboring non-cancerous tissues of twenty eight patients using the methylation-specific PCR (MSP) method in conjunction with the DNA sequencing. In comparison with the normal liver tissues from the healthy donors, it was found that while remained unmethylated the ABL, CAV, EPO, GATA3, LKB1, NEP, NFL, NIS and p27^(KIP1) genes, varying extents of the HCC specific hypermethylation were found associated with the ABO, AR, CSPG2, cyclin al, DBCCR1, GALR2, IRF7, MGMT, MT1A, MYOD1, OCT6, p57^(KIP2), p73, WT1 genes, and demethylation with the MAGEA1 gene, respectively. Judged by whether the hypermethylated occurred in HCC more frequently than in their neighboring normal tissues, the hypermethylation status of the AR, DBCCR1, IRF7, OCT6, and p73 genes was considered as the event specific to the late stage, while that the rest that lacked such a distinguished contrast, as the event specific to the early stage of HCC carcinogenesis. Among all the clinical pathological parameters tested for the association with, the hypermethylation of the cyclin al gene was more prevalent in the non-cirrhosis group (P=0.021) while the hypermethylated p16^(INK4a) gene was more common in the cirrhosis group (P=0.017). The concordant methylation behaviors of nineteen genes, including the four previously studied and their association with cirrhosis has been evaluated by the best subgroup selection method. The data presented in this report would enable us to shape our understanding of the mechanisms for the HCC specific loss of the epigenetic stability of the genome, as well as the strategy of developing the novel robust methylation based diagnostic and prognostic tools.

Waves induced by a submerged moving dipole in a two-layer fluidof finite depth

The waves induced by a moving dipole in a two-fluid system are analytically and experimentally investigated. The velocity potential of a dipole moving horizontally in the lower layer of a two-layer fluid with finite depth is derived by superposing Greens functions of sources (or sinks). The far-field waves are studied by using the method of stationary phase. The effects of two resulting modes, i.e. the surface- and internal-wave modes, on both the surface divergence field and the interfacial elevation are analyzed. A laboratory study on the internal waves generated by a moving sphere in a two-layer fluid is conducted in a towing tank under the same conditions as in the theoretical approach. The qualitative consistency between the present theory and the laboratory study is examined and confirmed.