Comparing the effects of 5% albumin and 6% hydroxyethyl starch 130/0.4 on coagulation and inflammatory response when used as priming solutions for cardiopulmonary bypass

AIM

This prospective, randomized and controlled trial compares the use of human albumin (HA) and hydroxyethyl starch (HES) 130/0.4 in the priming solution for a non-biocompatible cardiopulmonary bypass (CPB) circuit. The effects of each substance on coagulation, postoperative blood loss and pro-inflammatory activities were examined.

METHODS

Thirty-six adult patients undergoing mitral valvular heart surgery were randomly assigned to either the HA or HES group; 500 mL of 5% HA or 6% HES 130/0.4 were added to the priming solution of the CPB circuit for each group, respectively. Coagulation variables were measured perioperatively; these variables included thromboelastographic (TEG) parameters and pro-inflammatory markers such as interleukin (IL)-6, IL-8 and tumor necrotic factor (TNF)-a. Postoperative blood loss and transfusion requirements were also assessed.

RESULTS

There were no significant intergroup differences in the coagulation variables (including TEG parameters), serum concentrations of IL-6, IL-8 and TNF-a, and blood loss or transfusion requirements. TEG parameters, which indicate the speed of solid clot formation and the strength of the fibrin clot, decreased up to 4 hours after CPB in both groups. Serum concentrations of IL-6, IL-8 and TNF-a were higher up to 12 hours after surgery compared to baseline values in both groups. Hemoglobin levels and platelet counts were lower up to 12 hours after surgery compared to baseline values in both groups.

CONCLUSION

HES 130/0.4 was comparable to albumin as a component of the priming solution for a non-biocompatible CPB circuit. The two substances showed similar effects on coagulation variables, blood loss and pro-inflammatory activities in adult patients undergoing mitral valvular heart surgery.

Silicon enhances natural enemy attraction and biological control through induced plant defences

Silicon (Si) is known to have a role in constitutive plant defence against arthropod pests, and recent work has illustrated involvement in induced plant defences. The present tri-trophic study tested the hypothesis that Si increases natural enemy attraction to pest-infested plants and improves biological control. Cucumber plants treated with potassium silicate (Si+) and untreated control plants (Si-) were maintained in separately vented glasshouse compartments. Y-tube olfactometer studies showed that adult Dicranolaius bellulus were significantly more attracted to Si+ plants upon which Helicoverpa armigera larvae had fed compared with Si-, pest-infested plants. Predators were not significantly more attracted to Si+ plants when comparing uninfested cucumbers. In a field experiment, we placed H. armigera-infested and uninfested Si+ and Si- cucumber plants in a lucerne stand. Removal rates of H. armigera egg baits showed predation was greater for Si+ infested plants than for other treatments. Results suggest that Si applied to plants with a subsequent pest infestation increases the plants' attractiveness to natural enemies; an effect that was reflected in elevated biological control in the field.

Comparison of mechanical rigidity between plate augmentation leaving the nail in situ and interlocking nail using cadaveric fracture model of the femur

Thirteen matched pairs of cadaveric femurs were placed into two groups. In each group, a transverse fracture was created at a point 70% distal between the lesser trochanter and the adductor tubercle. One femur out of each matched pair was then stabilised with an interlocking intramedullary nail (nail only group) and the other femur was stabilised with plate augmentation after interlocking intramedullary nailing (plate augmentation group). The bending load to promote 5-mm displacement showed statistically significant differences between the plate augmentation group (mean 843.36 ± 409.13 N) and the nail only group (mean 315.02 ± 219.80 N) (p = 0.001). Torsional torque at the angle of 15 degrees showed statistically significant differences between the two groups; a mean of 2.09 ± 0.53 N·m for the plate augmentation group and a mean of 0.63 ± 0.46 N·m for the nail only group (p = 0.0001). We found a 2.6-fold increase in bending stiffness and a 3.3-fold increase in torsional stiffness in plate augmentation leaving a nail in situ compared to interlocking nailing only in the distal third fracture of femur.

Inhibition of Orientia tsutsugamushi infection by a truncated recombinant 56-kDa outer membrane protein

AIMS

The objective of this study was to evaluate recombinant 56-kDa outer membrane protein as a potential inhibitor to infection from Orientia tsutsugamushi.

METHODS AND RESULTS

The 56-kDa protein was cloned and expressed in an Escherichia coli system, and the degree of target cell attachment to immobilized 56-kDa protein was measured in a cell adhesion assay. The results showed that the 56-kDa protein has an ability to attach HeLa cells. Furthermore, treatment of target cells with a truncated 56-kDa 1-418 (amino acid residues) protein inhibited target cell infection by O. tsutsugamushi, demonstrated with an indirect immunofluorescence antibody assay.

CONCLUSIONS

The truncated 56-kDa protein (a.a. 1-418) plays an important role in O. tsutsugamushi infection, and the 56-kDa protein could be useful and effective in the inhibition of O. tsutsugamushi attachment and infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

The attachment of the 56-kDa protein to target cells was directly determined by in vitro adherence test, and the invasion of target cells by O. tsutsugamushi was inhibited by treating the target cells with a truncated 56-kDa protein.

Outcomes after repeated resection for recurrent pulmonary metastases from colorectal cancer

BACKGROUND

It remains controversial whether metastasectomy is still feasible in patients with pulmonary recurrence from colorectal cancer, after initial metastasectomy. The aim of this study was to evaluate outcomes of repeated metastasectomy in these patients.

MATERIALS AND METHODS

From 1995 to 2007, 202 patients had received a pulmonary metastasectomy from colorectal cancer at our institution. Over a median follow-up of 28.9 months, 48 patients received second metastasectomy (29 wedge resections, 5 segmentectomies, 13 lobectomies, and 1 completion pneumonectomy). The median disease-free interval was 9.6 months. Among these 48 patients, 28 showed pulmonary recurrence again and of those, 10 patients received third metastasectomy (two wedge resections, two segmentectomies, four lobectomies, and two completion pneumonectomies).

RESULTS

There was no postoperative mortality. Of the 48 patients who underwent second metastasectomy, overall and disease-free 5-year survivals were 79% and 49%, respectively, after second operation. Of the 10 patients who received third metastasectomy, overall survival was 78% at 5 years after last operation.

CONCLUSIONS

Repeated resection after initial metastasectomy can be carried out safely and provides long-term survival in patients with recurrent pulmonary metastasis from colorectal cancer. Our findings indicate that close follow-up for the early detection of recurrence and parenchyma-saving resection can improve the results after repeated resection.

Relationship between echocardiographic index of ventricular filling pressure and intraoperative haemodynamic changes during off-pump coronary bypass surgery

BACKGROUND

The ratio of mitral velocity to early-diastolic velocity of the mitral annulus (E/e') is an indicator of diastolic function representing acute loading conditions of the left ventricle. We tested the efficacy of E/e' as a predictor of haemodynamic derangement during off-pump coronary artery bypass surgery (OPCAB), when heart displacement causes loading changes.

METHODS AND RESULTS

Fifty patients with left ventricular (LV) ejection fraction >or= 50% were divided into two groups; E/e'<8 (normal LV filling pressure, n=25) and >15 (increased LV filling pressure, n=25). Haemodynamic measurements were recorded after induction of anaesthesia, during grafting, and after sternum closure. Patients' characteristics and operative data were similar between the groups. Cardiac index and mixed venous oxygen saturation were significantly lower during grafting and after sternum closure in the E/e'>15 group, compared with E/e'<8 group and with the baseline values. The E/e'>15 group required significantly longer ventilation time and length of stay in the intensive care unit.

CONCLUSIONS

Even in patients with preserved systolic LV function, patients with E/e'>15 were more prone to undergo a significant decrease in cardiac output during OPCAB, which did not return to baseline level after completion of grafting. Whether this finding is associated with increased morbidity and mortality should be validated.

Effect of low-dose ketamine on inflammatory response in off-pump coronary artery bypass graft surgery

BACKGROUND

Off-pump coronary artery bypass graft surgery (OPCAB) is still associated with a marked systemic inflammatory response. The aim of this study was to investigate whether pre-emptive, low dose of ketamine, which has been reported to have anti-inflammatory activity in on-pump coronary artery bypass surgery, could reduce inflammatory response in low-risk patients undergoing OPCAB.

METHODS

In this prospective randomized-controlled trial, 50 patients with stable angina and preserved myocardial function undergoing OPCAB were randomly assigned to receive either 0.5 mg kg(-1) of ketamine (Ketamine group, n=25) or normal saline (Control group, n=25) during induction of anaesthesia. Inflammatory markers including C-reactive protein (CRP), interleukin (IL)-6, tumour necrosis factor-alpha (TNF-alpha), and cardiac enzymes were measured previous to induction (T1), 4 h after surgery (T2), and the first and second days after the surgery (T3 and T4).

RESULTS

There were no significant intergroup differences in the serum concentrations of the CRP, IL-6, and TNF-alpha and cardiac enzymes. Pro-inflammatory markers and cardiac enzymes, except TNF-alpha, were all increased after the surgery compared with baseline values in both groups.

CONCLUSIONS

Low-dose ketamine administered during anaesthesia induction did not exert any evident anti-inflammatory effect in terms of reducing the serum concentrations of pro-inflammatory markers in low-risk patients undergoing OPCAB.

Heteropolymorphism of mitochondrial NADH dehydrogenase subunit 3 gene for the population analysis of chum salmon, Oncorhynchus keta

Mitochondrial DNAs (mtDNAs) has been frequently used as genetic markers for the population genetic studies. In this study we used chum salmon (Oncorhynchus keta) from Korea, Japan andAmerica, and compared their mitochondrial NADH dehydrogenase subunit 3 (ND3) genes by DNA sequence analysis. Sequence variation was studied in the ND3 among total 11 individuals from three populations. The ND3 gene was amplified by PCR targeting parts of cytochrome oxidase III gene (COIII) and NADH dehydrogenase subunit 4L gene (ND4L). ND3 gene sequence, encoded 752 bps, presented some genetic variation in the chum salmon populations. The observed nucleotide variations inferred the distinct genetic differentiation of American salmons from Korean and Japanese chum salmons. Six sites of single nucleotide polymorphism (SNP) were explored in the ND3 locus. Denaturing gradient gel electrophoresis analysis also showed a clear heterogenous band in American salmons compared to Asian salmons.

Effect of kimchi powder level and drying methods on quality characteristics of breakfast sausage

This study was conducted to determine the effect of the addition of kimchi powder on the quality characteristics of meat batter and breakfast sausage. Breakfast sausages were supplemented with freeze dried kimchi powder (FKP) or hot air dried kimchi powder (HKP) at levels of 1% (FKP-1 and HKP-1) or 2% (FKP-2 and HKP-2). The emulsion stability, cooking yield, and apparent viscosity in meat batters improved with increments of kimchi powder (p<0.05). Increased levels of kimchi powder in breakfast sausage decreased the L(∗) value, pH, and springiness, and increased the a(∗) value, b(∗) value, hardness, chewiness, and gumminess (p<0.05). Sensory evaluations indicated that a higher overall acceptability was attained when the kimchi powder was added to breakfast sausage at a level of 2%.

B cell lineage contributions to antiviral host responses

B cell responses are a major immune protective mechanism induced against a large variety of pathogens. Technical advances over the last decade, particularly in the isolation and characterization of B cell subsets by multicolor flow cytometry, have demonstrated the multifaceted nature of pathogen-induced B cell responses. In addition to participation by the major follicular B cell population, three B cell subsets are now recognized as key contributors to pathogen-induced host defenses: marginal zone (MZ) B cells, B-1a and B-1b cells. Each of these subsets seems to require unique activation signals and to react with distinct response patterns. Here we provide a brief review of the main developmental and functional features of these B cell subsets. Furthermore, we outline our current understanding of how each subset contributes to the humoral response to influenza virus infection and what regulates their differential responses. Understanding of the multilayered nature of the humoral responses to infectious agents and the complex innate immune signals that shape pathogen-specific humoral responses are likely at the heart of enhancing our ability to induce appropriate and long-lasting humoral responses for prophylaxis and therapy.

A single institutional experience of thymic epithelial tumours over 11 years: clinical features and outcome and implications for future management

Thymic epithelial tumours (TETs), the most common tumour of the anterior mediastinum, are epithelial neoplasms of the thymus with a wide spectrum of morphologic features. We retrospectively analysed clinical features of TET and the correlation of World Health Organisation (WHO) histologic classification and Masaoka staging system with different treatment modalities in 195 patients, from 1995 to 2005. According to the Masaoka's staging system, there were 78 (40.0 %) patients with stage I, 38 (19.5%) with stage II, 41 (21.0%) with stage III, 38 (19.5%) with stage IV. All patients were reclassified according to the WHO criteria as follows: Type A (n=9, 4.6%), AB (n=37, 18.9%), B1 (n=29, 14.8%), B2 (n=48, 24.6%), B3 (n=40, 20.5%), C (n=32, 16.4%). There was a fairly good correlation between Masaoka staging and WHO histotype (P<0.05). However, in multivariate analysis, the tumour stage and WHO histotype were two independent factors separately for predicting overall survival (P<0.001, P<0.001, respectively). Thus, both Masaoka stage and WHO histotype should be considered in risk stratification of therapy for TET patients. Patients with completely resected types B2, B3 and C and adjuvant radiotherapy (n=57) had more favourable disease-free and overall survival as compared with those without adjuvant treatment (n=20) (P=0.015, 0.015, respectively). Given that the predominant sites of recurrence after surgery was pleura/pericardium and lung, and the fact that complete resection was a significant influential factor for survival at log–rank test, an active investigation of newer treatment strategies such as neoadjuvant treatment to improve the resectability and development of optimal adjuvant treatment modality is a high priority especially for those with high-risk for recurrence or in patients with advanced stage disease.

Helicobacter pylori eradication for low-grade gastric mucosa-associated lymphoid tissue lymphoma is more successful in inducing remission in distal compared to proximal disease

A series of studies has shown that Helicobacter pylori eradication induces remission in most patients with low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, there have been few reports about the effect of bacterial treatment on the gastric MALT lymphoma in Korea, a well-known H. pylori endemic area. A total of 111 H. pylori-infected patients were prospectively enrolled in Seoul National University Hospital and 99 among them were completely followed up according to our protocol. After H. pylori eradication, tumoural response was evaluated by endoscopy and histopathology every 2–3 months till complete remission (CR) and every 6 months after achieving CR. Median follow-up period was 41 months (range, 11–125 months). Helicobacter pylori was successfully eradicated in all 99 patients and CR was obtained in 84 (84.8%) of 99 patients. The median time to reach CR was 3 months and 94% of CR is in continuous complete remission. Five patients with CR relapsed after 10–22 months without the evidence of H. pylori reinfection. Cumulative recurrence rate was 2.3, 7.7 and 9.3% at 1, 2 and 3 years, respectively. Tumours were mainly located in distal stomach (67.7%) and tumours in distal stomach were associated with more favourable response than those in proximal stomach (P=0.001). Majority of patients with low-grade gastric MALT lymphoma treated by exclusive H. pylori eradication have a favourable long-term outcome, offering a real chance of cure. Tumour location could be a predictive factor for remission following H. pylori eradication.

Pulmonary cavitary mass containing a mural nodule: differential diagnosis between intracavitary aspergilloma and cavitating lung cancer on contrast-enhanced computed tomography

AIM

The objective of this study was to identify whether there were any significant differences in the computed tomography (CT) findings of an intracavitary aspergilloma and a cavitating lung cancer containing a mural nodule.

MATERIALS AND METHODS

The CT and histopathological findings of 12 patients (male:female ratio 3:9; aged 51-76 years) with cavitating lung cancer containing a mural nodule and 26 patients (male:female ratio 14:12; aged 29-72 years) with intracavitary aspergilloma were retrospectively reviewed.

RESULTS

The mural nodules within cavitating lung cancer were more enhanced (p<0.001) and showed a nondependent location more frequently (p=0.012) than those of intracavitary aspergillomas. The cavitary walls were thicker in cavitating lung cancer (mean 5.8mm thick) than those in intracavitary aspergillomas (mean 2.6mm thick; p=0.035). Adjacent bronchiectasis and volume decrease of the involved lobe were observed more frequently in intracavitary aspergillomas than in cavitating lung cancers (p<0.001 and p=0.008, respectively).

CONCLUSION

Whether a mural nodule within a cavitary lesion is contrast-enhanced or not is one of the most important features in making a differential diagnosis between an intracavitary aspergilloma and a cavitating lung cancer. Assessment of dependent location of a mural nodule within the cavity and wall thickness of the cavity itself can also be helpful for differentiation.

Phosphorus recovery by mesoporous structure material from wastewater

This study was designed to investigate the fundamental aspects of a possible removal of phosphorous from wastewater by using the mesoporous structure materials for wastewater reuse. The zirconium sulphate with mesoporous structure as a new type of ion exchangers was synthesised by hydrothermal reaction. From the results of X-ray diffraction and transmission electron microscope, it was discovered that the synthesised material had hexagonal mesoporous structure with a pore size of approximately 40-50A. Experimental results showed that the zirconium sulphate with mesoporous structure had very high sorption capacity for the phosphorus. The novel ion exchange occurred between PO4(3-) and SO4(2-), OH-. The amount of phosphate ions exchanged into the solid was as great as 3.4 mmol/g-ZS. Furthermore, it is possible to obtain a higher removal efficiency than other ion exchange media and adsorbents.

The prevalence and risk factors associated with isolated untreated systolic hypertension in Korea: the Korean National Health and Nutrition Survey 2001

Although isolated systolic hypertension (ISH) increases the risk of coronary heart disease and stroke, more than any other hypertension subtype, the prevalence and risk factors associated with ISH in the Korean population are not known. The 2001 Korean National Health and Nutrition Survey was a cross-sectional and nationally representative survey conducted in 2001. The prevalence of ISH by age and body mass index (BMI) was examined in 6601 Korean adults over 20 years of age. After adjusting for age, 4.32+/-0.32% of Korean adults had ISH, 5.28+/-0.37% had isolated diastolic hypertension and 5.82+/-0.36% had systolic/diastolic hypertension. The overall prevalence of ISH was found to increase directly with advancing age and increasing BMI. Although the ISH was found to be more common in men overall (4.81+/-0.50% in men, 4.12+/-0.37% in women), it was more common in women over 70 years of age. Independent variables associated with risk for ISH included advanced age, BMI, triglyceride (TG) levels, monthly income and alcohol intake. However, gender, fasting blood glucose, total cholesterol and high-density lipoprotein cholesterol levels, residential area, education level and smoking were found not to be significantly associated with ISH risk. The findings of the present study demonstrate that the prevalence of untreated ISH in Korea was lower than in Western countries. Age, BMI, TG levels, monthly income and alcohol intake were associated with ISH.

Impact of hemoglobin on survival of cervical carcinoma patients treated with concurrent chemoradiotherapy is dependent on lymph node metastasis findings by magnetic resonance imaging

The objective of this study was to confirm whether hemoglobin (Hb) levels during chemoradiotherapy are associated with survival in patients with locally advanced cervical carcinoma and to assess impact of the Hb level on survival according to lymph node (LN) metastasis. A retrospective review of 85 cervical carcinoma patients treated with concurrent chemoradiotherapy was conducted. The stage of disease ranged between FIGO stage IB and stage IVA. Disease-free and overall survivals were evaluated by univariate and multivariate analyses. After median follow-up of 35.7 months, 24 patients developed recurrence of disease and 14 patients died from their disease. Stage, LN metastasis, and squamous cell carcinoma antigen and Hb levels during chemoradiation were correlated significantly with survival (P < 0.05). Maintenance of Hb above 10.0 g/dL was associated with better survival (P < 0.05). However, no such benefits were observed in patients with LN metastasis by magnetic resonance imaging (MRI). Multivariate Cox regression hazard model showed that Hb levels during chemoradiation were an independent prognostic factor in patients without LN metastasis by MRI. Maintenance of Hb during chemoradiation is of benefit in cervical carcinoma patients without LN metastasis but not with LN metastasis by MRI.

Evaluation of a MF membrane system composed of pre coagulation-sedimentation and chlorination for water reuse

In this research, we investigated the variation of transmembrane pressure and permeate water quality in pre-coagulation and sedimentation with iron based coagulant, and chlorination of feed water for PVDF (Polyvinylidene fluoride) based MF membrane filtration. NaCIO was fed to the membrane module at a dosage of 0.5 mg/L and maintained during filtration. To observe the effect of raw water, three types of raw and processed waters, including river surface water, coagulated water and coagulated-settled water, were employed. In the case of river surface water, the transmembrane pressure increased abruptly in 500 hours operation. On the contrary, no significant increase in transmembrane pressure was observed for coagulated water and coagulated-settled water for 1200 hours operation. The turbidity of permeate was lower than the detection limit for all applied waters. The removal efficiency for humic substances in coagulated water and coagulated-settled water was approximately ten times higher than that in surface river water. And, the removal efficiency for TOC and DOC was approximately two times higher than that in surface river water. From the results of the operation, it can be observed that it is possible to maintain stable operation at 0.9 m(3)/m(2)-day filtration flux through a combination of pre-coagulation and pre-chlorination. However, the water quality of permeate was the best when the pre-coagulation-sedimentation process was combined with pre-chlorination. With respect to fouling reduction and operation efficiency increase in membrane filtration, the pre-coagulation/sedimentation process is a promising alternative.

A case of recurrent ameloblastoma developing in an autogenous iliac bone graft 20 years after the initial treatment

A case of recurrent ameloblastoma developing in an autogenous iliac bone graft 20 years after radical resection of primary mandibular ameloblastoma is presented. This case showed extensive bony resorption extending throughout the auto-grafted bone. Seeding to the graft bone was suspected as a cause of the recurrence in the iliac bone graft because wide destruction of the graft bone was observed without any prior signs and symptoms of intraoral mucosa. Consequently, extensive resection of bone as well as adjacent soft tissue was performed. Persistent follow-up examination is essential for management of ameloblastoma.

Plate augmentation leaving the nail in situ and bone grafting for non-union of femoral shaft fractures

We reviewed 15 patients with femoral non-union after interlocking intramedullary nailing treated with plate augmentation and bone grafting with the nail in situ. The mean time from primary nailing to plate augmentation and bone grafting was 10 months. At the time of presentation, the patients had undergone an average of 1.6 operations from the time of their original injury. To achieve stability of the fracture, we applied an AO plate on the lateral aspect of the femur. The retained nail maintained alignment of the fracture, and plating did not require an extensive surgical approach. In all patients, there was visible motion at the fracture site; however, the motion disappeared after plate augmentation. All patients achieved radiological solid union at an average of 7.2 months.

Performance evaluation of physicochemical processes for biologically pre-treated livestock wastewater

The use of a combination of biological and physicochemical methods is a promising technique to reduce highly concentrated pollutants in livestock wastewater: firstly, biodegradable organic matters, nitrogen and a part of phosphorus should be removed in a biological treatment process and then residual non-biodegradable organic matters, color and phosphorus be eliminated by physicochemical methods. In this study, therefore, the integrations of chemical coagulation, activated carbon adsorption, Fenton oxidation and ozonation were evaluated to provide an appropriate post-treatment process for biologically pre-treated livestock wastewater. With applying a single method such as coagulation and Fenton oxidation, a yellowish brown color and COD still remained. According to the experimental result, the quality of treated wastewater including color was enough to be discharged after chemical coagulation followed by ozonation or Fenton oxidation process. Among these, ozonation was the most effective technology for decolorization. Neither simple biological nor physicochemical process provides an adequate treatability for the sufficient depletion of organics and decolorization when treating livestock wastewater. Considering only the removal efficiency, the integration of Fenton oxidation and ozonation would be an efficient alternative as a post-treatment.

Pilot-testing an alternative on-site wastewater treatment system for small communities and its automatic control

The pilot test of a new alternative for small wastewater treatment system has been conducted for two years. It consists of a hybrid bioreactor and the expert system including the programmable logic controller and human-machine interface. In order to monitor its status, the real-time data was transferred from the remote station to the central station via a wireless local area network. More efficient and stable performances were observed at automatic operating mode compared with the manual. On an average, COD, SS, T-N and T-P concentrations in the effluent from the hybrid bioreactor were less than 14, 7, 12 and 0.9 mg/L, respectively. According to the result from laboratory experiments, the quality of treated wastewater with chemical coagulation process followed by sand filtration was enough to be utilized again if a final disinfection step is included.

Traveling wave solutions for a one-dimensional crawling nematode sperm cell model

In this paper, we proved that the one-dimensional crawling nematode sperm cell model proposed by Mogilner and Verzi (2003) supports traveling wave solutions if there is no disassembly of unbundled filaments in the cell. Uniqueness of traveling wave is established under additional assumptions and numerical examples are also given in the paper. Mathematical methods used include dynamical system techniques, implicit function theorem and global bifurcation theory.