A real-time prostate cancer detection technique using needle insertion force and patient-specific criteria during percutaneous intervention

In this article, the authors present a novel real-time cancer detection technique by using needle insertion forces in conjunction with patient-specific criteria during percutaneous interventions. Needle insertion experiments and pathological analysis were performed for developing a computer-aided detection (CAD) model. Backward stepwise regression method was performed to identify the statistically significant patient-specific factors. A baseline force model was then developed using these significant factors. The threshold force model that estimated the lower bound of the cancerous tissue forces was formulated by adding an adjustable classifier to the baseline force model. Trade-off between sensitivity and specificity was obtained by varying the threshold value of the classifier, from which the receiver-operating characteristic (ROC) curve was generated. Sequential quadratic programming was used to optimize the CAD model by maximizing the area under the ROC curve (AUC) using a set of model-training patient data. When the CAD model was evaluated using an independent set of model-validation patient data, an AUC of 0.90 was achieved. The feasibility of cancer detection in real time during percutaneous interventions was established.

Enhanced Field Emission from Argon Plasma-Treated Ultra-sharp alpha-Fe(2)O(3) Nanoflakes

Hematite nanoflakes have been synthesized by a simple heat oxide method and further treated by Argon plasmas. The effects of Argon plasma on the morphology and crystal structures of nanoflakes were investigated. Significant enhancement of field-induced electron emission from the plasma-treated nanoflakes was observed. The transmission electron microscopy investigation shows that the plasma treatment effectively removes amorphous coating and creates plenty of sub-tips at the surface of the nanoflakes, which are believed to contribute the enhancement of emission. This work suggests that plasma treatment technique could be a direct means to improve field-emission properties of nanostructures.

Morphology-controlled synthesis and a comparative study of the physical properties of SnO2 nanostructures: from ultrathin nanowires to ultrawide nanobelts

Controlled synthesis of one-dimensional materials, such as nanowires and nanobelts, is of vital importance for achieving the desired properties and fabricating functional devices. We report a systematic investigation of the vapor transport growth of one-dimensional SnO(2) nanostructures, aiming to achieve precise morphology control. SnO(2) nanowires are obtained when SnO(2) mixed with graphite is used as the source material; adding TiO(2) into the source reliably leads to the formation of nanobelts. Ti-induced modification of crystal surface energy is proposed to be the origin of the morphology change. In addition, control of the lateral dimensions of both SnO(2) nanowires (from approximately 15 to approximately 115 nm in diameter) and nanobelts (from approximately 30 nm to approximately 2 microm in width) is achieved by adjusting the growth conditions. The physical properties of SnO(2) nanowires and nanobelts are further characterized and compared using room temperature photoluminescence, resonant Raman scattering, and field emission measurements.

Ferroelectric transistors with nanowire channel: toward nonvolatile memory applications

We report the fabrication and characterization of ZnO nanowire memory devices using a ferroelectric Pb(Zr(0.3)Ti(0.7))O(3) (PZT) film as the gate dielectric and the charge storage medium. With a comparison to nanowire transistors based on SiO(2) gate oxide, the devices were evaluated in terms of their electric transport, retention, and endurance performance. Memory effects are observed as characterized by an eminent counterclockwise loop in I-V(g) curves, which is attributed to the switchable remnant polarization of PZT. The single-nanowire device exhibits a high (up to 10(3)) on/off ratio at zero gate voltage. Our results give a proof-of-principle demonstration of the memory application based on a combination of nanowires (as channels) and ferroelectric films (as gate oxide).

Multifunctional CuO nanowire devices: p-type field effect transistors and CO gas sensors

We report the properties of a field effect transistor (FET) and a gas sensor based on CuO nanowires. CuO nanowire FETs exhibit p-type behavior. Large-scale p-type CuO nanowire thin-film transistors (10(4) devices in a 25 mm(2) area) are fabricated and we effectively demonstrate their enhanced performance. Furthermore, CuO nanowire exhibits high and fast response to CO gas at 200 degrees C, which makes it a promising candidate for a poisonous gas sensing nanodevice.

A novel gas sensor based on field ionization from ZnO nanowires: moderate working voltage and high stability

We report a kind of gas sensor using ZnO nanowires as the field ionization anode. The sharp tips of nanowires generate very high electric fields at relatively low voltages. The sensors show good sensitivity and selectivity. Moreover, the detection limitation of the field ionization based ZnO nanowire gas sensors is about 5%. More importantly, a sensor with ZnO nanowires as the anode exhibits an impressive performance with respect to stability and anti-oxidation behavior, which are significantly better than those of carbon nanotubes (CNTs) as electrodes. Therefore, the simple, low-cost, sensors described here could be deployed for a variety of applications.

Controlling the growth of ZnO quantum dots embedded in silica by Zn/F sequential ion implantation and subsequent annealing

We report the formation of embedded ZnO quantum dots (QDs) by Zn and F ion sequential implantation and subsequent annealing. Optical absorption and photoluminescence spectrum measurements, transmission electron microscopy bright field images and selected area electron diffraction patterns indicate that ZnO QDs were formed after annealing in air or vacuum at temperatures higher than 500 °C. Atomic force microscopy images show a comparatively flat surface of the annealed samples, which indicates that only very few Zn atoms are evaporated to the surfaces. The formation of ZnO QDs during the thermal annealing can be attributed to the direct oxidization of Zn nanoparticles by the oxygen molecules in the substrate produced during the implantation of F ions. The quality of ZnO QDs increases with the increase of annealing temperature.

Favorable response to human adipose tissue-derived mesenchymal stem cells in steroid-refractory acute graft-versus-host disease

There is no consistently effective therapy for patients with steroid-refractory acute graft-versus-host disease (GVHD). Various alternative approaches have been tested, including antithymocyte globulin, mycophenolate mofetil (MMF), pentostatin, and monoclonal antibodies; however, they have only been modestly successful. The purpose of our study was to evaluate the efficacy of human adipose-tissue-derived mesenchymal stem cells (AMSC) as salvage therapy for steroid-refractory acute GVHD. Six patients with steroid-refractory grades III-IV acute GVHD received IV infusions of AMSC. The AMSC dose was 1.0x10(6)/kg. No side effects were noted after the AMSC infusions. Five patients were treated once and one patient twice. Two patients received AMSC from haplo-identical family donors and four from unrelated mismatched donors. Acute GVHD disappeared completely in five of six patients, four of whom are alive after a median follow-up of 40 months (range, 18-90 months) after the initiation of AMSC therapy. All four surviving patients are in good clinical condition and in remission of their hematological malignancy. Two patients died-one with no obvious response to AMSC died of multiorgan failure and one a relapse of leukemia. These results suggested that AMSC is a promising treatment for severe steroid-resistant acute GVHD.

Low-temperature synthesis and photocatalytic properties of ZnO nanotubes by thermal oxidation of Zn nanowires

A low-cost and catalyst-free two-step approach has been developed to produce ZnO nanotubes (ZNTs) by simple thermal oxidation of Zn nanowires under 20 Pa at a low temperature of 400 °C. The growth mechanism of ZNTs is discussed in detail. The formation of these tubular structures is closely linked to the oxidation pressure and temperature, which involves a process consisting of the deposition of Zn nanowires, cracking of the Zn nanowires and sublimation of the Zn cores, and subsequent oxidation to ZNTs. The optical properties were studied by using Raman and photoluminescence spectra, where a strong green emission related to the single ionized oxygen vacancy appears. The photocatalytic activity measurement indicates an enhanced photocatalytic activity of the prepared ZNTs due to their high surface-to-volume ratios and abundant oxygen vacancies near the surfaces of the ZNTs. This type of high surface area structural ZNTs could find promising potential for optoelectronic and environmental applications.

[Separation and identification of chlorogenic acid and related impurities by high performance liquid chromatography-tandem mass spectrometry]

A method using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established for analysis and identification of chlorogenic acid along with its related impurities. A Gemini C18 HPLC column (4.6 mm x 150 mm,5 microm) was used with acetonitrile-water ( containing 0.1% formic acid) (8:92, v/v) as mobile phase. Eight related impurities of chlorogenic acid were identified and their structures were determined by using online HPLC-MS/MS and photodiode array detector (DAD). The method is quick, simple and can be used directly to identify the structure of unknown trace substances in the sample of chlorogenic acid.

Echocardiographic risk stratification for early surgery with endocarditis: a cost-effectiveness analysis

BACKGROUND

Despite widespread acceptance of echocardiography for diagnosis of infective endocarditis, few investigators have evaluated its utility as a risk-stratification tool to aid therapeutic decision-making.

METHODS

A decision tree and Markov analysis model were constructed using published and institutional data to estimate the cost-effectiveness of an echocardiographic risk-stratification strategy for infective endocarditis. The models compared surgery for high-risk patients based on clinical factors ("standard care") and surgery for high-risk patients based on echocardiographic findings ("echocardiography-guided").

RESULTS

The cost per patient for standard care and echocardiography-guided strategies was $47,766 and $53,669, respectively. The expected quality-adjusted life years (QALY) for standard care and echocardiography-guided strategies were 5.86 years and 6.10 years, respectively. Compared with standard care, the echocardiography-guided strategy cost an additional $23,867 per QALY saved. In one-way sensitivity analyses, the incremental cost of this strategy remained <$50,000/QALY across a broad range of scenarios. Baseline stroke risk had the greatest effect on cost-effectiveness. For populations with stroke risk less than 3.65%, the echocardiography-guided strategy was not cost-attractive (ICER >$50,000/QALY). At stroke risk between 3.65% and 14%, the ICER for the echocardiography-guided strategy was attractive (<$50,000 /QALY). The echocardiography-guided strategy became economically dominant at any baseline stroke risk greater than 18.3%.

CONCLUSION

Echo-guided risk stratification for early surgery in patients with large vegetations is a cost-attractive treatment strategy for IE, as it improves outcome for an incremental cost <$50,000/QALY.

Field emission of GaN-filled carbon nanotubes: high and stable emission current

Field electron emission of GaN-filled carbon nanotubes, grown by microwave plasma enhanced chemical vapor deposition, was investigated. The detailed structural characterization shows that the filled nanotube has a GaN-core/C-shell structure, in which the GaN wire corresponds to a wurtzite structure. The field emission properties of the GaN-filled carbon nanotubes have been achieved with high and stable emission current. It is attributed to the unique cable-like structure, which makes the GaN-core/C-shell composite mechanically solid and chemically stable. This study suggests the GaN-filled carbon nanotube as an ideal candidate for future high-current and high-power field emitter applications.

Effects of velocity modulation during surgical needle insertion

Precise interstitial intervention is essential for many medical diagnostic and therapeutic procedures. But accurate insertion and placement of surgical needle in soft tissue is quite challenging. The understanding of the interaction between surgical needle and soft tissue is very important to develop new devices and systems to achieve better accuracy and to deliver quality treatment. In this paper we present the effects of velocity (linear, rotational, and oscillatory) modulation on needle force and target deflection. We have experimentally verified our hypothesis that needle insertion with continuous rotation reduces target movement and needle force significantly. We have observed little changes in force and target deflection in rotational oscillation (at least at lower frequency) of the needle.

Tumor Detection in vivo with Optical Spectroscopy

Ultrasound induced blood stasis has been observed for a long time, but to date most experimental observations have been in vitro. In this paper we discuss a possible diagnostic use for this previously undesirable effect of ultrasound - tumor detection in vivo. We demonstrate that, using optical spectroscopy, effects of ultrasound can be used to differentiate tumor from non-tumor in murine tissue. Finally, we propose a novel diagnostic algorithm that quantitatively differentiates tumor from non-tumor with maximum specificity 0.83, maximum sensitivity 0.79, and area under ROC curve 0.90.

In vivo Optical Spectroscopy of Acoustically Induced Blood Stasis

Ultrasound-induced blood stasis has been observed for more than thirty years. Most of the literature has been focused on the health risks associated with this phenomenon and methods employed to prevent stasis from occurring during ultrasound imaging. To date, experimental observations have been either in vitro or invasive. The current work demonstrates ultrasound- induced blood stasis in murine tumor and nontumor tissue, observed through noninvasive measurements of optical spectroscopy, and discusses possible diagnostic uses for this previously undesirable effect of ultrasound.

Establishment and properties of fetal dermis-derived mesenchymal stem cell lines: plasticity in vitro and hematopoietic protection in vivo

Human mesenchymal stem cells (hMSCs) are excellent candidates for ex vivo gene transfer and cell therapy in various systems. However, hMSCs are mortal somatic cells, and thus invariably enter an irreversible growth arrest after a finite number of cell divisions in culture. It has been proposed that this is due to telomere shortening. In this study, pGRN145 plasmid containing human telomerase reverse transcriptase (hTRT) was introduced into fetal dermis-derived hMSCs. Single-cell clones positive for telomerase activity and hTRT mRNA were selected and expanded. Single-cell-derived hTRT(+) cells could be expanded rapidly in vitro and passaged up to 70 doublings without showing senescence. FACScan flow cytometer showed that hTRT(+) cells were positive for CD29, CD44, CD105, and CD166, while CD31, CD45, CD34, vWF, and HLA-DR were negative. Under suitable conditions, hTRT(+) cells have the ability of multiple lineage differentiation, including bone, fat, and nerve. Furthermore, transplantation of hTRT(+) cells could protect NOD/SCID mice from lethal irradiation. Thus, these cells may be an ideal cell source for promoting hematopoietic recovery after radiotherapy.