Strain-invariant stretchable radio-frequency electronics.

Wireless modules that provide telecommunications and power-harvesting capabilities enabled by radio-frequency (RF) electronics are vital components of skin-interfaced stretchable electronics1-7. However, recent studies on stretchable RF components have demonstrated that substantial changes in electrical properties, such as a shift in the antenna resonance frequency, occur even under relatively low elastic strains8-15. Such changes lead directly to greatly reduced wireless signal strength or power-transfer efficiency in stretchable systems, particularly in physically dynamic environments such as the surface of the skin. Here we present strain-invariant stretchable RF electronics capable of completely maintaining the original RF properties under various elastic strains using a 'dielectro-elastic' material as the substrate. Dielectro-elastic materials have physically tunable dielectric properties that effectively avert frequency shifts arising in interfacing RF electronics. Compared with conventional stretchable substrate materials, our material has superior electrical, mechanical and thermal properties that are suitable for high-performance stretchable RF electronics. In this paper, we describe the materials, fabrication and design strategies that serve as the foundation for enabling the strain-invariant behaviour of key RF components based on experimental and computational studies. Finally, we present a set of skin-interfaced wireless healthcare monitors based on strain-invariant stretchable RF electronics with a wireless operational distance of up to 30 m under strain.

Tuberculosis of Cystic Duct Lymph Node Associated with Cholecystitis.

Tuberculosis of the cystic duct lymph node is very rare. Only four cases have been reported in the literature. This paper presents the case of a young male patient with a tuberculous cystic duct lymph node and chronic cholecystitis, who was diagnosed with cystic duct stones and a gall bladder polyp preoperatively.

Tunable Young's Moduli of Soft Composites Fabricated from Magnetorheological Materials Containing Microsized Iron Particles.

This study experimentally investigates the field-dependent Young's moduli of soft composites, which are fabricated from two different magnetic-responsive materials; magnetorheological elastomer (MRE) and magnetorheological fluid (MRF). Four factors are selected as the main factors affecting Young's modulus of soft composites: the amount of MRF, the channel pattern, shore hardness and carbonyl iron particle (CIP) concentration of the MRE layer. Five specimens are manufactured to meet the investigation of four factors. Prior to testing, the scanning electron microscopy (SEM) image is taken to check the uniform dispersion of the carbonyl iron particle (CIP) concentration of the MRE layer, and a magnetic circuit is constructed to generate the effective magnetic field to the specimen fixed at the universal tensile test machine. The force-displacement curve is directly measured from the machine and converted to the stress-strain relationship. Thereafter, the Young's modulus is determined from this curve by performing linear regression analysis with respect to the considered factors. The tunability of the Young's moduli of the specimens is calculated based on the experimental results in terms of two performance indicators: the relative percentage difference of Young's modulus according to the magnetic field, and the normalized index independent of the zero-field modulus. In the case of the relative percentage difference, the specimens without MRF are the smallest, and the ones with the highest CIP concentration are the largest. As a result of comparing the normalized index of each factor, the change in shore hardness and channel pattern have little effect on the tunability of Young's moduli, and the amount of MRF injected and CIP concentration of MRE have a large effect. The results of this study are expected to provide basic guidelines for fabricating soft composites whose field-dependent Young's moduli can be tuned by several factors with different effects.

Field-Dependent Stiffness of a Soft Structure Fabricated from Magnetic-Responsive Materials: Magnetorheological Elastomer and Fluid.

A very flexible structure with a tunable stiffness controlled by an external magnetic stimulus is presented. The proposed structure is fabricated using two magnetic-responsive materials, namely a magnetorheological elastomer (MRE) as a skin layer and a magnetorheological fluid (MRF) as a core to fill the void channels of the skin layer. After briefly describing the field-dependent material characteristics of the MRE and MRF, the fabrication procedures of the structure are provided in detail. The MRE skin layer is produced using a precise mold with rectangular void channels to hold the MRF. Two samples are produced, namely with and without MRF, to evaluate the stiffness change attributed to the MRF. A magnetic field is generated using two permanent magnets attached to a specialized jig in a universal tensile machine. The force-displacement relationship of the two samples are measured as a function of magnetic flux density. Stiffness change is analyzed at two different regions, namely a small and large deformation region. The sample with MRF exhibits much higher stiffness increases in the small deformation region than the sample without MRF. Furthermore, the stiffness of the sample with MRF also increases in the large deformation region, while the stiffness of the sample without MRF remains constant. The inherent and advantageous characteristics of the proposed structure are demonstrated through two conceptual applications, namely a haptic rollable keyboard and a smart braille watch.

3D-Printed Soft Structure of Polyurethane and Magnetorheological Fluid: A Proof-of-Concept Investigation of its Stiffness Tunability.

In this study, a soft structure with its stiffness tunable by an external field is proposed. The proposed soft beam structure consists of a skin structure with channels filled with a magnetorheological fluid (MRF). Two specimens of the soft structure are fabricated by three-dimensional printing and fused deposition modeling. In the fabrication, a nozzle is used to obtain channels in the skin of the thermoplastic polyurethane, while another nozzle is used to fill MRF in the channels. The specimens are tested by using a universal tensile machine to evaluate the relationships between the load and deflection under two different conditions, without and with permanent magnets. It is empirically shown that the stiffness of the proposed soft structure can be altered by activating the magnetic field.

Successful Conservative Management of Hepatic Portal Venous Gas due to Anastomosis Leakage After a Sigmoidectomy.

In past decades, hepatic portal venous gas (HPVG) has rarely been reported, and the mortality rate has been very high. In most cases, surgical intervention was needed. Presently, abdominal computed tomography can be conveniently used to diagnose HPVG, which has various underlying causes and benign courses. We present the case of a patient with HPVG due to anastomosis leakage after a sigmoidectomy for diverticulitis; the patient was cured with conservative management.

Spontaneous Bleeding from a Short Gastric Artery after Vomiting Successfully Treated without Surgery.

Spontaneous bleeding from a short gastric artery in the absence of pre-disposing trauma is reported very rarely. To the best of our knowledge, the published literature includes only 14 cases. Young men comprise almost all of the patients, and were induced by vomiting or gagging. The patients usually required emergent surgery. Our patient, a 32-year-old man, was diagnosed with spontaneous hemoperitoneum due to short gastric artery tearing after a few instances of vomiting. We managed him conservatively including fluid, vitamin K and antifibrinolytic agent without surgery.

Expression of the Cancer Stem Cell Markers CD44 and CD133 in Colorectal Cancer: An Immunohistochemical Staining Analysis.

PURPOSE: The aim of this study was to assess the expressions of CD44 and CD133 in colorectal cancer tissue by using immunohistochemical staining and to analyze the clinical significance of the expressions related to other clinicopathological data and survival results. METHODS: One hundred sixty-two patients with a biopsy-proven colorectal adenocarcinoma who were operated on between January 1998 and August 2004 were enrolled in this study. Immunohistochemical staining for CD44 and CD133 was performed on primary colorectal cancer tissue, metastatic lymph nodes, and synchronous and metachronous metastatic tumor tissues if available. RESULTS: CD44 expression was stronger in the primary tumor than in metastatic lymph nodes (P < 0.001), and CD133 expression tended to be stronger in primary tumor than in metastatic lymph nodes (P = 0.057). No significant correlation was found between the CD44 and the CD133 expressions. The cases with recurrence showed low expression of CD44 (P = 0.017). CD133 expression was lower in cases with elevated CA 19-9 serum levels (P = 0.028) and advanced T stage (P = 0.038). Multivariate analysis proved that low expression of CD44 was an independent prognosis factor for short disease-free survival (P = 0.028). CONCLUSION: Low CD44 expression was correlated with increased tumor recurrence and short disease-free survival, and low CD133 expression was associated with advanced tumor stage. We suggest that further studies be performed to evaluate whether the immunohistochemical method for determining the CD44 and the CD133 expressions is appropriate for exploring cancer stem-cell biology in patients with colorectal cancer.

Long-Term Clinical Outcome of Clostridium difficile Infection in Hospitalized Patients: A Single Center Study.

BACKGROUND/AIMS: Antibiotic usage and increasingly aging populations have led to increased incidence of Clostridium difficile infection (CDI) in worldwide. Recent studies in Korea have also reported increasing CDI incidence; however, there have been no reports on the long-term outcomes of CDI. We therefore investigated the long-term clinical outcomes of patients with CDI, including delayed recurrence, associated risk factors and mortality. METHODS: Hospitalized patients diagnosed with CDI at Seoul Paik Hospital between January 2007 and December 2008 were included. Their medical records were retrospectively investigated. 'Delayed recurrence' was defined as a relapse 8 weeks after a successful initial treatment. Multivariate logistic regression analysis was performed to identify risk factors for the delayed recurrence. Kaplan-Meier curves were used to analyze mortality rates. RESULTS: A total of 120 patients were enrolled; among them, 87 were followed-up for at least 1 year, with a mean follow-up period of 34.1±25.1 months. Delayed recurrence was observed in 17 patients (19.5%), and significant risk factors were age (over 70 years, P=0.049), nasogastric tube insertion (P=0.008), and proton pump inhibitor or H2-blocker treatments (P=0.028). The 12- and 24-month mortality rates were 24.6% and 32.5%, respectively. No deaths were directly attributed to CDI. CONCLUSIONS: Delayed recurrence of CDI was not rare, occurring in 19.5% of the study population. Although CDI-related mortality was not reported, 2-year (32.5%) mortality rate of CDI patients implies that a CDI diagnosis may predict severe morbidity and poor prognosis of the underlying disease.

Prognostic value of the distance of proximal resection margin in patients who have undergone curative gastric cancer surgery.

BACKGROUND: We conducted this retrospective study to analyze the relationship between the distance of the proximal resection margin (PRM) and the pattern of recurrence in patients with gastric cancer who underwent curative gastrectomy. METHODS: In our series, there were 774 patients who underwent curative gastrectomy for gastric adenocarcinoma. Thus, we classified our clinical series of patients into the distal gastrectomy group (n = 529) and the total gastrectomy group (n = 245). The clinical pathologic data and PRM distance were collected. Univariate and multivariate analyses were performed to evaluate association between PRM distance and locoregional recurrence. RESULTS: The mean distance of the PRM was 4.03 cm in the total gastrectomy group. The distance of the PRM had a significant correlation with advanced T-stage, advanced N-stage,vascular invasion,lymphatic invasion, neural invasion, histological undifferentiation, greater tumor size, and the upper third of the tumor location. On multivariate analysis, tumor recurrence showed only the independent prognostic factor N-stage (P <0.023). The mean distance of the PRM was 6.4 cm in the distal gastrectomy group. The distance of the PRM had a significant correlation with the advanced T-stage, advanced N-stage, younger age, vascular invasion, histological undifferentiation, greater tumor size, and the middle third of tumor location. On multivariate analysis, tumor recurrence showed three independent prognostic factors, N-stage (P <0.001), vascular invasion (P = 0.009), and lower third tumor location (P = 0.035). The total gastrectomy of locoregional recurrence was related to N-stage (P = 0.039), and the distal gastrectomy of locoregional recurrence was related to T-stage (P = 0.021). Study on the disease-free survival, PRM distance, and locoregional recurrence was not statistically relevant in both the total and distal gastrectomy group (P = 0.565 and P = 0.584, respectively). CONCLUSIONS: Our results indicate that a sufficient resection margin is not the absolute factor associated with the rate of survival and recurrence, although it is a key prognostic factor. The locoregional recurrence had no significant correlation with the distance of the PRM after curative gastrectomy.

[Prognostic significance of Ki-67 expression in patients undergoing surgical resection for gastrointestinal stromal tumor].

BACKGROUND/AIMS: Assessment of malignant potential in gastrointestinal stromal tumor (GIST) is still problematic. The maximum tumor diameter and the mitotic index are generally used as an index of malignancy of GISTs. The Ki-67 labeling index has recently been used as an index of cell growth. The aim of this study was to investigate the prognostic value of Ki-67 in GIST. METHODS: We retrospectively reviewed the medical records of 32 patients with GIST who underwent surgical resection at Inje University Seoul Paik Hospital. We analyzed their Ki-67 expression, histologic finding, and prognosis. RESULTS: According to the tumor size and mitotic count, 4 patients were classified as very low risk, 9 patients as low risk, 14 patients as intermediate risk and 5 patients as high risk. The average Ki-67 index was 5.56±4.48%. The median follow-up duration was 35.72±29.04 months, and local/distant recurrences were observed in 6 (18.7%) patients. The overall cumulative disease free survival rates in patients with Ki-67 index ≤5% at 1 year, 2 years, and 5 years were 100%, 100%, and 86%, respectively. The overall cumulative disease free survival rates in patients with Ki-67 index >5% were at 1 year, 2 years, and 5 years were 82.1%, 70.3%, and 46.9%, respectively. There was significant relationship between elevated Ki-67 and disease free survival rate (p=0.007). CONCLUSIONS: Our study suggests that Ki-67 index >5% confers a higher risk of relapse in patients with GIST. Future work should focus on standardization of Ki-67 assessment and specification of its role in making treatment decisions.

Inflammation-based score (Glasgow prognostic score) as an independent prognostic factor in colorectal cancer patients.

PURPOSE: This study was conducted to evaluate the systemic inflammatory response in colorectal cancer patients, and to estimate the usefulness of the Glasgow prognostic score (GPS) as a prognostic factor. METHODS: Patients with biopsy-proven colorectal adenocarcinoma who were operated between April 2005 and December 2008 were enrolled in this study. The GPS was estimated based on the measurement of CRP and serum albumin level. The GPS was compared with other clinicopathological factors. Univariate and multivariate analyses were performed to evaluate the factors affecting cancer-specific survival. RESULTS: GPS was significantly higher in patients with anemia, thrombocytosis, a high neutrophil to lymphocyte ratio, tumor of the colon, and large tumor. Patient age, gender, serum CEA level, tumor gross appearance, TNM stage, and tumor differentiation were not related with the GPS. In univariate analysis, hemoglobin, CEA, gross appearance of tumor, TNM stage, tumor differentiation, and GPS were associated with cancer-specific survival. In multivariate analysis, TNM stage (III or IV : I or II; hazard ratio [HR], 12.322; P = 0.015), tumor differentiation (poorly differentiated : well or moderately differentiated; HR, 3.112; P = 0.021), and GPS (GPS 2 : GPS 0 or 1; HR, 5.168; P = 0.003) were identified as independent prognostic factors in colorectal cancer. CONCLUSION: Our study showed that the GPS was an independent variable from tumor stage and a good and convenient prognostic factor in colorectal cancer patients.

SH3RF2 functions as an oncogene by mediating PAK4 protein stability.

SH3RF (SH3-domain-containing RING finger protein) family members, SH3RF1-3, are multidomain scaffold proteins involved in promoting cell survival and apoptosis. In this report, we show that SH3RF2 is an oncogene product that is overexpressed in human cancers and regulates p21-activated kinase 4 (PAK4) protein stability. Immunohistochemical analysis of 159 colon cancer tissues showed that SH3RF2 expression levels are frequently elevated in cancer tissues and significantly correlate with poor prognostic indicators, including increased invasion, early recurrence and poor survival rates. We also demonstrated that PAK4 protein is degraded by the ubiquitin-proteasome system and that SH3RF2 inhibits PAK4 ubiquitination via physical interaction-mediated steric hindrance, which results in the upregulation of PAK4 protein. Moreover, ablation of SH3RF2 expression attenuates TRADD (TNFR-associated death domain) recruitment to tumor necrosis factor-α (TNF-α) receptor 1 and hinders downstream signals, thereby inhibiting NF-κB (nuclear factor-kappaB) activity and enhancing caspase-8 activity, in the context of TNF-α treatment. Notably, ectopic expression of SH3RF2 effectively prevents apoptosis in cancer cells and enhances cell migration, colony formation and tumor growth in vivo. Taken together, our results suggest that SH3RF2 is an oncogene that may be a definitive regulator of PAK4. Therefore, SH3RF2 may represent an effective therapeutic target for cancer treatment.

Inflammatory myofibroblastic tumor mimicking hepatocellular carcinoma with dense lipiodol uptake.

Inflammatory myofibroblastic tumor (IMT) of the liver is a very rare lesion that has radiologic similarity with malignant liver tumor. Differential diagnosis of IMT from a malignant lesion of the liver is very important because surgical resection is not mandatory for IMT. Lipiodol computed tomography is a very sensitive and specific diagnostic tool for hepatocellular carcinomas (HCC). Herein, we describe a case of IMT that had dense lipiodol uptake in the tumor and mimicked HCC. To our knowledge, previously, only one case of IMT with dense lipiodol retention has been reported.

Hepatic paraganglioma and multifocal gastrointestinal stromal tumor in a female: Incomplete Carney triad.

The Carney triad (CT) describes the coexistence of multiple neoplasms including gastrointestinal stromal tumors (GISTs), extra-adrenal paraganglioma and pulmonary chondroma. At least two neoplastic tumors are required for diagnosis. In most cases, however, CT is incomplete. We report a case of an incomplete CT in a 34-year-old woman with a multifocal GIST and non-functional paraganglioma of the liver. Preoperative evaluation with a gastrofiberscope and abdominal computed tomography revealed multiple gastric tumors resembling GISTs and a single liver lesion which was assumed to have metastasized from the gastric tumors. The patient underwent total gastrectomy and partial hepatectomy. Histologic findings confirmed multiple gastric GISTs and paraganglioma of the liver. We report a case of a patient with incomplete expression of CT.

Clinical significance of preoperative inflammatory parameters in gastric cancer patients.

PURPOSE: Chronic inflammation induces cancer and cancer induces local tissue damage with systemic inflammation. Therefore, the aim of this study is to investigate the potential relationship between the severity of inflammation and prognosis in cancer patients. MATERIALS AND METHODS: This study enrolled 220 patients from January 2002 to December 2006 who underwent gastric surgery. We evaluated the relationship between preoperative inflammatory parameters (erythrocyte sedimentation rate, neutrophil-to-lymphocyte ratio) and other clinicopathological factors. Survival outcomes were compared according to the extent of inflammation. RESULTS: Significant elevation of erythrocyte sedimentation rate was related with old age, increased neutrophil-to-lymphocyte ratio, decreased hemoglobin, increased carcinoembryonic antigen, increased tumor size and advanced TNM stage. Neutrophil-to-lymphocyte ratio was significantly correlated with old age, increased erythrocyte sedimentation rate and advanced TNM stage. In the univariate analysis, elevated erythrocyte sedimentation rate and increased neutrophil-to-lymphocyte ratio had significantly poorer survival than those without elevation (all P<0.05). However, the multivariate analysis failed to prove erythrocyte sedimentation rate and neutrophil-to-lymphocyte ratio as independent prognostic factors. CONCLUSIONS: The elevation of erythrocyte sedimentation rate and neutrophil-to-lymphocyte ratio were correlated with poor prognosis in the univariate analysis and there was a strong correlation between inflammatory parameters (erythrocyte sedimentation rate and neutrophil-to-lymphocyte ratio) and tumor progression. Thus, erythrocyte sedimentation rate and neutrophil-to-lymphocyte ratio are considered useful as follow-up factors.

Carcinosarcoma of the stomach: a case report.

Carcinosarcoma is a rare malignant, biphasic tumor comprised of carcinoma and sarcoma components. In the gastrointestinal tract, carcinosarcoma is most frequently seen in the esophagus and rarely in the stomach. We report a 51-year-old female patient with 2-month-history of epigastric pain and dyspepsia. Endoscopic finding revealed a huge ulcerative lesion that infiltrated from the antrum to the mid-body. An endoscopically taken biopsy revealed poorly differentiated malignant round cell neoplasm. After the palliative subtotal gastrectomy, immunohistochemical studies showed two positive reactions for the epithelial marker and mesenchymal marker. Based on the above findings, the patient was diagnosed with gastric carcinosarcoma. The immunohistochemical analysis is a critical method in making an accurate diagnosis of carcinosarcoma.

Ileo-pelvic anastomosis and augmentation cystoplasty for treatment of encrusted pyelitis in a transplanted kidney.

Infection stones are more likely to form after urinary diversion as the result of urinary stasis. To prevent urinary stasis due to encrusted pyelitis in a transplanted kidney, we describe an alternative a surgical treatment: ileo-pelvic anastomosis. In our patient with a transplanted kidney, the ileal conduit had previously been anastomosed end-to-side owing to renal tuberculosis with an atrophied bladder; the transplanted ureter was anastomosed to the ileum in the left lower abdomen with an ileal conduit on the opposite side. Routine check-up revealed hydronephrosis with infected pyelitis and ureteritis in the transplanted kidney. We performed ileo-pelvic end-to-end anastomosis to prevent urinary stasis by lengthening the ileal conduit and performed augmentation cystoplasty to support the atrophied bladder following tuberculosis. We suggest that this approach may be useful in similar cases.