Formation and functionalization of Ge-nanoparticles in ZnO.

Semiconductor nanocrystals are often proposed as a viable route to improve solar energy conversion in photovoltaics and photoelectrochemical systems. Embedding the nanocrystals in, e.g. a transparent and conducting electrode of a solar cell will promote the photon absorption and subsequent transfer of the generated charge carriers from the nanocrystal, and thereby enhance the function of the electrode. This can be accomplished by embedding a semiconducting nanocrystal with a small bandgap in a transparent conducting oxide (TCO), which is commonly utilized as electrode in new generation solar cells. Here, we demonstrate the incorporation, formation, and functionalization of germanium (Ge) nanocrystals in zinc oxide utilizing ion implantation, where post implantation annealing at 800 °C results in diamond cubic Ge nanocrystals with sizes between 2 and 20 nm. Photoluminecence spectra show a distinct emission around 0.7 eV arising from the Ge nanocrystals, and with additional emission features up to 1.15 eV due to quantum confinement, demonstrating a novel functionalization and tunability of the TCO electrode.

Role of temperature in de-mixing absorbance spectra composed of compound electrolyte solutions.

This work is focused on the role of temperature in the de-mixing of absorbance spectra measured in mixed aqueous Na2SO4 and NaNO3 solutions. First, the influence of temperature on the absorbance spectrum of demineralized water was determined. Second, the absorbance spectra of five separate electrolytes (NaNO2, NaNO3, CaCl2, K2CO3, and NaOH) at three temperatures (4°C, 25°C, and 50°C) for concentrations ranging from 0.0625 M to 0.5 M were examined. These five electrolytes show similar temperature dependencies. Finally, absorbance spectra of mixed solutions were investigated at temperatures of 5°C, 15°C, 25°C, 35°C, and 45°C for concentrations ranging from 0.0625 M to 0.5 M per electrolyte in the mixture. The spectral window from 650 to 1100 nm was utilized to observe the ionic and temperature influences on the vibrational modes of the OH bond in the solvent molecules. The effects of dissolving Na2SO4 and NaNO3 are nonlinearly cumulative at lower temperatures indicating extended alteration of the water structure beyond the first hydration shell. A similar trend was observed for a mixture of Na2CO3 and NaCl. Furthermore, it was found that higher temperatures are better for recovering the separate component absorption signatures of an electrolyte mixture. The near-infrared spectral regime is well suited for integrated sensing, and therefore these results can help in designing an integrated sensor to identify inorganic species in water.

Optical properties of ZnFe2O4 nanoparticles and Fe-decorated inversion domain boundaries in ZnO.

The maximum efficiency of solar cells utilizing a single layer for photovoltaic conversion is given by the single junction Shockley-Queisser limit. In tandem solar cells, a stack of materials with different band gaps contribute to the conversion, enabling tandem cells to exceed the single junction Shockley-Queisser limit. An intriguing variant of this approach is to embed semiconducting nanoparticles in a transparent conducting oxide (TCO) solar cell front contact. This alternative route would enhance the functionality of the TCO layer, allowing it to participate directly in photovoltaic conversion via photon absorption and charge carrier generation in the nanoparticles. Here, we demonstrate the functionalization of ZnO through incorporation of either ZnFe2O4 spinel nanoparticles (NPs) or inversion domain boundaries (IDBs) decorated by Fe. Diffuse reflectance spectroscopy and electron energy loss spectroscopy show that samples containing spinel particles and samples containing IDBs decorated by Fe both display enhanced absorption in the visible range at around 2.0 and 2.6 eV. This striking functional similarity was attributed to the local structural similarity around Fe-ions in spinel ZnFe2O4 and at Fe-decorated basal IDBs. Hence, functional properties of the ZnFe2O4 arise already for the two-dimensional basal IDBs, from which these planar defects behave like two-dimensional spinel-like inclusions in ZnO. Cathodoluminescence spectra reveal an increased luminescence around the band edge of spinel ZnFe2O4 when measuring on the spinel ZnFe2O4 NPs embedded in ZnO, whereas spectra from Fe-decorated IDBs could be deconvoluted into luminescence contributions from bulk ZnO and bulk ZnFe2O4.

Lung cancer mimicking left atrial mass.

Cardiac involvement in lung cancer is found in up to 25% of autopsy cases. However, despite the considerable mortality and morbidity associated with cardiac metastasis, antemortem diagnosis is unusual. A rare case of lung cancer presenting as a left atrial mass is reported.

Can algae-based technologies be an affordable green process for biofuel production and wastewater remediation?

Algae is a well-known organism that its characteristic is prominent for biofuel production and wastewater remediation. This critical review aims to present the applicability of algae with in-depth discussion regarding three key aspects: (i) characterization of algae for its applications; (ii) the technical approaches and their strengths and drawbacks; and (iii) future perspectives of algae-based technologies. The process optimization and combinations with other chemical and biological processes have generated efficiency, in which bio-oil yield is up to 41.1%. Through life cycle assessment, algae bio-energy achieves high energy return than fossil fuel. Thus, the algae-based technologies can reasonably be considered as green approaches. Although selling price of algae bio-oil is still high (about $2 L-1) compared to fossil fuel's price of $1 L-1, it is expected that the algae bio-oil's price will become acceptable in the next coming decades and potentially dominate 75% of the market.

Interface phenomena in magnetron sputtered Cu2O/ZnO heterostructures.

The interface between ZnO and Cu2O has been predicted to be a good candidate for use in thin film solar cells. However, the high predicted conversion efficiency has yet to be fully realized experimentally. To explore the underlying causes of this we investigate the interface between ZnO and Cu2O in magnetron sputtered samples. Two different sample geometries were made: In the first set thin layers of ZnO were deposited on Cu2O (type A), while in the second set the order was reversed (type B). Using x-ray photoelectron spectroscopy (XPS), an intermediate CuO layer was identified regardless of the order in which the Cu2O and ZnO layers were deposited. The presence of a CuO layer was supported by transmission electron microscopy (TEM) results. Changes in the electron hole screening conditions were observed in CuO near the interface with ZnO, manifested as changes in the relative peak-to-satellite ratio and the degree of asymmetric broadness in the Cu 2p peak. The suppression of the Cu 2p satellite characteristic of CuO may cause the CuO presence to be overlooked and cause errors in determinations of valence band offsets (VBOs). For the type A samples, we compare four different approaches to XPS-based determination of VBO and find that the most reliable results are obtained when the thin CuO layer and the altered screening conditions at the interface were taken into account. The VBOs were found to range between 2.5 eV and 2.8 eV. For the B type samples a reduction of the Cu 2p-LMM Auger parameter was found as compared to bulk Cu2O, indicative of quantum confinement in the Cu2O overlayer.

Long-term orthognathic surgical outcomes in Treacher Collins patients.

INTRODUCTION: Treacher Collins syndrome is a rare disorder characterized by several orofacial findings including malar deficiency and hypoplastic mandibles. These patients often require a combined orthodontic-orthognathic approach to correct their malocclusion. This is most often characterized by a short posterior vertical height and an anterior open bite. Orthognathic correction often requires Le Fort I and bilateral sagittal split osteotomies. No long-term stability results have been reported after bimaxillary surgery in Treacher Collins patients. METHODS: A retrospective review of all Treacher Collins patients evaluated for orthognathic surgery by a single surgeon from 1993 to 2007 was performed. Patients were divided into groups who required surgery and those who did not. Part I analyzed the cephalometric differences between the surgical (S) and nonsurgical (NS) groups. Part II of the study assessed the preorthodontic treatment (T1), preoperative (T2), immediate postoperative (T3), and 1-year postoperative (T4) cephalometric measurement variables to determine the net surgical movement (T3 - T2) and relapse (T4 - T3). RESULTS: Twenty-two patients met the inclusion criteria, of which 11 had occlusal relationships requiring orthognathic surgery. Nine out of 11 chose to have surgery. At baseline, surgical patients exhibited a statistically significant retruded maxilla as measured by SNA and midface length compared to the NS group. In addition, the S group also had an increased gonial angle. There were significant movements in all maxillary and mandibular measurements. There was a significant relapse in the palatal plane angle when the maxilla was anteriorly impacted, with a 2.8-mm average relapse of the advancement. Relapse of the counterrotation movement of the mandible was identified, but this was not significant. Relapse did not affect the final occlusal result, which may have been compensated with postsurgical orthodontic treatment. CONCLUSION: Bimaxillary orthognathic surgery in the Treacher Collins patients may be performed safely with long-term dental and skeletal stability.

Environmentally friendly power generator based on moving liquid dielectric and double layer effect.

An electrostatic power generator converts mechanical energy to electrical energy by utilising the principle of variable capacitance. This change in capacitance is usually achieved by varying the gap or overlap between two parallel metallic plates. This paper proposes a novel electrostatic micro power generator where the change in capacitance is achieved by the movement of an aqueous solution of NaCl. A significant change in capacitance is achieved due to the higher than air dielectric constant of water and the Helmholtz double layer capacitor formed by ion separation at the electrode interfaces. The proposed device has significant advantages over traditional electrostatic devices which include low bias voltage and low mechanical frequency of operation. This is critical if the proposed device is to have utility in harvesting power from the environment. A figure of merit exceeding 10000(10(8)µW)/(mm(2)HzV(2)) which is two orders of magnitude greater than previous devices, is demonstrated for a prototype operating at a bias voltage of 1.2 V and a droplet frequency of 6 Hz. Concepts are presented for large scale power harvesting.

A diverging gynecological template for radioactive interstitial/intracavitary implants of the cervix.

The Syed-Neblett perineal template has been in use at our institution since 1984. We have occasionally encountered problems in inserting the needles through the peripheral rows of the template and have seen significant convergence of the needles cephalad to the template. To solve these problems we have modified the Syed-Neblett template. In the new design, the entrance holes are closer together than in the original template, but they are angled so as to achieve a more compact design while maintaining a dose distribution close to that of the Syed-Neblett design. We have seen significantly fewer clinical problems with this design. In addition, a smaller number of needles achieve the same dose distribution; this simplifies their visualization on radiographs.

Acquisition of oral phencyclidine self-administration in rhesus monkeys: effect of sex.

RATIONALE: There are increasing reports of sex differences in the etiology of drug abuse in humans. A nonhuman primate model is useful for examining sex as a variable in drug abuse. OBJECTIVES: To determine whether there are sex differences in the acquisition of oral phencyclidine (PCP) self-administration and to compare the effect of altered feeding conditions on drug self-administration in male and female monkeys. METHODS: Acquisition of orally delivered PCP was studied using 7 female and 11 male adult rhesus monkeys. Initially, the monkeys were not food restricted, and they were given access to water under concurrent fixed-ratio (FR) 1 schedules during daily 3-h sessions. Each lip-contact response on a drinking spout resulted in a 0.3 ml liquid delivery. After baseline levels of water intake were obtained for 5 days, water was replaced with PCP (0.125 mg/ml) at both drinking spouts. Body weights were then reduced to 85% of free-feeding weights, and the monkeys were fed 30 min before the session began. The FR value was increased from 1 to 2, 4, and 8, at both drinking spouts. As a final step in the procedure, water and PCP were concurrently available at the two spouts under FR 8 schedules. Acquisition of PCP-reinforced behavior was considered to have occurred if PCP intake was consistently greater than water intake. RESULTS: Lip-contact responses and liquid deliveries were not significantly different between the females and males throughout the acquisition period, but there was a significant increase in responding and decrease in liquid intake as FR increased, and a significant increase in PCP consumption due to food restriction that did not differ in males and females. On a milligram per kilogram basis, female monkeys consumed nearly twice as much PCP as the males; however, this effect was not significant. The females showed significantly higher PCP than water intake while the males consumed approximately equal amounts of PCP and water. Of the seven females, 100% met the acquisition criterion of significantly greater PCP than water intake, while only 36.4% of the males met the criterion. CONCLUSION: These results concur with previous rat studies and indicate that female monkeys are more likely than males to acquire drug-reinforced behavior.

Adenosquamous carcinoma of the cervix: prognosis in stage IB.

The outcome of women with adenosquamous carcinoma of the cervix has been a controversial issue. To assess the prognostic significance of this cell type, the medical records of 29 patients with stage IB primary adenosquamous carcinoma of the cervix were reviewed. Twenty-six had cervical tumors measuring 3 cm or less. With a median follow-up of 60 months, the overall disease-free 5-year survival was 85%. Pelvic lymph node metastases were found in three of 19 patients (16%) with stage IB, and periaortic lymph nodes were negative in eight. A log-likelihood chi 2 test comparing lymphatic spread, recurrence rate, and 5-year disease-free survival in patients with stage IB disease and tumors less than 3 cm versus a similar group of 58 patients with pure squamous cell carcinoma of equivalent stage and comparable size treated during the same time disclosed no significant differences in any of the indicators analyzed. We conclude that stage IB adenosquamous carcinoma of the cervix does not differ in its metastatic potential or outcome from the more common pure squamous cell carcinoma.

Treatment of malaria in Vietnam with oral artemisinin.

In this study, 638 patients with either Plasmodium falciparum or P. vivax malaria were treated with artemisinin (qinghaosu) that was isolated and formulated into tablets and capsules in Vietnam. In all cases, artemisinin treatment resulted in a rapid clearance of parasitemia and fever. Recrudescence rates were highest in those groups receiving treatment for five or less days (50%), but were between 10% and 23% for those groups receiving the drug for 5-10 days. A low recrudescent rate (9.5%) was also found when patients were treated with a combination of artemisinin for three days and tetracycline for five days. Thus, artemisinin represents a useful and economically feasible component of the malaria control program in Vietnam.

Dose distribution around a 3.0-mm type 6702 I-125 seed.

The 3M Company recently produced a special version of the type 6702 seed for use in animal studies of ocular melanoma. The seed consists of a single I-125 impregnated ion exchange resin sphere encapsulated in a 3.0-mm-long titanium cylinder, as opposed to the normal 4.5-mm cylinder containing from three to five resin spheres. Monte Carlo simulations and measurements show that the dose distribution around the 3-mm capsule differs in places by up to 10% from that of the 4.5-mm seed. In addition, the two seed types differ by 12% in the ratio of dose in tissue along the transverse seed axis to apparent activity. These differences must be taken into account when using these seeds.

Evaluation of a computerized antimicrobial susceptibility system with bacteria isolated from animals.

The BIOMIC is a computerized system used to calculate the minimal inhibitory concentration (MIC) of an antimicrobial agent from a zone of inhibition generated by a disk diffusion test. This system was developed using bacterial pathogens of human origin. This study investigated the use of the BIOMIC system for determining MICs for bacterial pathogens from animals. The MICs generated by the BIOMIC system were compared with the MICs generated using a broth microdilution testing method. A total of 663 drug-organism combinations was tested. These combinations included 3 species of gram-positive bacteria, 5 species of gram-negative bacteria, and the antimicrobial agents ampicillin, gentamicin, cephalothin, ciprofloxacin, enrofloxacin, trimethoprim/sulfamethoxazole, tetracycline, and erythromycin. Overall, the MICs generated by the BIOMIC system correlated with the broth microdilution MICs for 72% of the total drug-organism combinations tested. The Pseudomonas aeruginosa strains tested showed the highest agreement between the 2 systems, with 100% for all antibacterial agents tested, whereas Pasteurella haemolytica, Pasteurella multocida, and enterococci showed the least agreement (76%, 57%, and 47%, respectively). Among these organisms, trimethoprim-sulfa showed the least agreement (31%) and ciprofloxacin showed the greatest (91%). These results indicate that the BIOMIC system could be a useful tool in veterinary medicine for producing quantitative antimicrobial susceptibility results. However, it is currently unreliable for some drug-bacteria combinations. This discrepancy possibly could be corrected by modification of the software using data points generated by a large-scale study.

Improved gas exchange performance of the intravascular oxygenator by active blood mixing.

The intravascular oxygenator and carbon dioxide removal device (IVOX; CardioPulmonics, Salt Lake City, UT) has been shown to perform 30% of the gas exchange in animals and patients with acute respiratory failure. Among the factors that limit gas exchange is the mass transfer resistance in the blood phase. To determine if a reduction in mass transfer resistance by mixing venous blood can enhance the O2 transfer and CO2 removal by IVOX, a right atrium-pulmonary artery venovenous bypass circuit was used in sheep to model the adult vena cava. A size 9 IVOX (894 fibers with 0.41 m2 surface area, n = 5) was incorporated in the bypass circuit and the blood flow controlled by a roller pump ranging from 1 to 4 l/min. An intra-aortic balloon was placed near the shaft of the IVOX and pulsated at the rate adjusted to best improve CO2 removal (100-120 bpm). O2 transfer and CO2 removal were measured with balloon pulsation on and off at different flow rates. Results showed that blood mixing by pulsation of the balloon caused a 25-49% increase in O2 transfer by IVOX, and this increase remained relatively constant throughout the full flow range. CO2 removal was also increased by up to 35%, but at flows between 3.5 and 4 l/min, the effect of mixing was diminished. It is concluded that reduction in the mass transfer resistance by blood mixing improves gas exchange. Because O2 is more diffusion limited, it is more dependent upon mixing of blood for gas exchange than CO2. More design improvements to incorporate active mixing may further enhance the gas exchange performance of IVOX.

Modification of agricultural waste/by-products for enhanced phosphate removal and recovery: potential and obstacles.

There is a growing trend to employ agricultural waste/by-products (AWBs) as the substrates for the development of phosphate biosorbents. Nevertheless, due to the lack of anion binding sites, natural AWBs are usually inefficient in phosphate decontamination. Consequently, modification plays a vital role in improving phosphate sorption's property of raw AWBs. This review paper evaluates all existing methods of modification. The literatures indicate that modification can significantly improve phosphate removal ability of AWBs by retaining phosphate ion onto modified AWBs principally via ion exchange (electrostatic interaction) and ligand exchange mechanisms. So far, little work has been done on the beneficial use of modified AWBs for the phosphorus recovery from aqueous solutions. The poor recyclability of modified AWBs could be responsible for their limited application. Hence, further study is essential to search for novel, cost-effective, and green methods of modification.

Analysis of factors influencing aspiration risk following chemoradiation for oropharyngeal cancer.

Our aim was to identify risk factors for aspiration following concurrent chemoradiation for oropharyngeal cancer. 46 patients with locally advanced oropharyngeal carcinoma underwent concurrent chemoradiation at our institution. All patients underwent modified barium swallow to assess dysphagia severity and to determine the need for continued tube feedings after treatment. Dysphagia severity was graded as 1-7. There were 5 Grade 2, 11 Grade 3, 5 Grade 4, 5 Grade 5, 10 Grade 6 and 10 Grade 7 scores. 25 patients (54%) developed aspiration (5 trace, 20 severe). The aspiration rate for T1-T2 and T3-T4 tumours was 31% and 67%, respectively (p = 0.03). There was no statistical difference in the aspiration rate between the base of the tongue and tonsillar carcinoma (p = 0.23). Despite anatomical organ preservation, most patients with locally advanced oropharyngeal carcinoma had moderate to severe dysphagia after chemoradiation. Patients with large tumours had a significant risk of developing aspiration following treatment.

Temporal aggregate size distributions from simulation of platelet aggregation and disaggregation.

A modification of the Smoluchowski collision theory for platelet aggregation is proposed with additional kinetic terms to accommodate observed disaggregation behavior. This model, consisting of a set of coupled, nonlinear, first-order differential equations, approximates size distributions with time for normal human platelets in plasma after the addition of a stimulus. Parameters controlling the kinetics of the formation and breakup of aggregates are numerically investigated. The aggregation coefficient, predominant during the aggregation phase, is strongly dependent on both time and aggregating agent doses. For the disaggregation phase, the disaggregation rate constants are a function of aggregate size, with a time-dependent disaggregation coefficient. Numerical results generated by the model are compared with experimental volume-size distribution curves from the literature.

Mitomycin-C/5-FU and radiation therapy for locally advanced uterine cervical cancer.

To assess the feasibility and effectiveness of combined therapy on locally advanced cervical cancer, we entered 38 patients into a study. The patients were treated with mitomycin-C (10 mg/m2) on Days 1 and 30 and 5-FU (1000 mg/m2) on Days 1 to 4 and Days 30 to 33. In 5 weeks 4500-5000 cGy was given concurrently, followed by radioactive implants. Twenty-six patients had an early-stage disease (IB-IIB) and twelve had a late-stage disease (IIIB-IVA). Eighty-seven percent (33/38) of the patients had a tumor measuring 5 cm or more. The other 5 patients with a tumor size under 5 cm had biopsy-proven positive pelvic nodes; 2 of these 5 patients had a pretherapy hysterectomy. Tumor response, complete (CR) vs partial (PR), was assessed in 36 patients 3 months after completion of therapy. A CR was noted in 80% (29/36) of the patients. The PR status conferred a detrimental effect on the pelvic disease control (PDC), disease-free survival (DFS), and survival (S) while late stage correlated with the development of distant metastases (DM) and a poor DFS. PDC was obtained in 93% (27/29) of the patients who had a CR, as compared to only 43% (3/7) of those with a PR (P = 0.0228). The DFS and S rates were 59 and 77% for patients with a CR and 21 and 19% for those with a PR; respective P values were 0.0340 and 0.0002. Eleven percent (3/26) of the patients with an early stage developed DM, as compared to 50% (6/12) of those with late stage, (P = 0.0016). The DFS rates were 80 and 37% for patients with an early and late stage, respectively (P = 0.0141). Four patients developed transient neutropenia and one had transient thrombocytopenia. The second dose of mitomycin-C was omitted in 4 patients due to persistent neutropenia in 3 and to transfusion-related hepatitis in 1. Two percent (5/21) of the patients who had a staging laparotomy developed wound dehiscence. Three patients developed non-cancer-related small bowel obstruction requiring surgery. We concluded that this combined regimen was well tolerated. Although it was effective in controlling the cancer in the pelvis, this regimen failed to control DM in late-stage patients.

Plasmodium falciparum: mutation pattern in the dihydrofolate reductase-thymidylate synthase genes of Vietnamese isolates, a novel mutation, and coexistence of two clones in a Thai patient.

Pyrimethamine and cycloguanil resistance of Plasmodium falciparum has been linked to mutations in the dihydrofolate reductase (dhfr) portion of the dhfr-ts gene. In this paper, the DNA sequence of the dhfr-ts gene of 50 isolates from Vietnam and 2 clones (T9/94 and T9/96) isolated from a malaria patient from Thailand have been analyzed. A comparison between these isolates and clones showed differential mutation patterns. Forty-eight isolates were found to consist of mutations associated with Pyr. A novel leucine mutation at position 140 was found in the isolate VP8 and in clone T9/94. The isolate VP8 and the clone T9/94 were found to also have the characteristic changes at positions 16 (Val) and 108 (Thr) that have been found in cycloguanil-resistant isolates. The isolate VP35 was shown to be resistant to both antifolates, while the clone T9/96 was found to be sensitive to both antifolates and to have a sequence identical to that of wild-type dhfr-ts. The two clones from a single patient showed the coexistence of resistant and sensitive clones in the absence of treatment by antifolates. Since cycloguanil resistance seems to be rare in Vietnam, cycloguanil alone or in combination with other antimalarial agents might be an alternative for treatment and prophylaxis, even in areas with high resistance to pyrimethamine.