bluuebunny/crossref_metadata_2025 huggingface dataset:
Local suffering and the global discourse of mental health and human rights: An ethnographic study of responses to mental illness in rural Ghana
Authors: Read Ursula M , Adiibokah Edward , Nyame Solomon
Published: October 2009

Background

The Global Movement for Mental Health has brought renewed attention to the neglect of people with mental illness within health policy worldwide. The maltreatment of the mentally ill in many low-income countries is widely reported within psychiatric hospitals, informal healing centres, and family homes. International agencies have called for the development of legislation and policy to address these abuses. However such initiatives exemplify a top-down approach to promoting human rights which historically has had limited impact at the level of those living with mental illness and their families.

Methods

This research forms part of a longitudinal anthropological study of people with severe mental illness in rural Ghana. Visits were made to over 40 households with a family member with mental illness, as well as churches, shrines, hospitals and clinics. Ethnographic methods included observation, conversation, semi-structured interviews and focus group discussions with people with mental illness, carers, healers, health workers and community members.

Results

Chaining and beating of the mentally ill was found to be commonplace in homes and treatment centres in the communities studied, as well as with-holding of food ('fasting'). However responses to mental illness were embedded within spiritual and moral perspectives and such treatment provoked little sanction at the local level. Families struggled to provide care for severely mentally ill relatives with very little support from formal health services. Psychiatric services were difficult to access, particularly in rural communities, and also seen to have limitations in their effectiveness. Traditional and faith healers remained highly popular despite the routine maltreatment of the mentally ill in their facilities.

Conclusion

Efforts to promote the human rights of those with mental illness must engage with the experiences of mental illness within communities affected in order to grasp how these may underpin the use of practices such as mechanical restraint. Interventions which operate at the local level with those living with mental illness within rural communities, as well as family members and healers, may have greater potential to effect change in the treatment of the mentally ill than legislation or investment in services alone.
Modeling the effect of multiple sets of mesoscale fractures in porous rock on frequency-dependent anisotropy
Authors: Chapman Mark
Published: October 2009

This study models the seismic response of porous rock containing two fracture sets with different orientations, sizes, and connectivities. Modeling demonstrates frequency-dependent anisotropy controlled by two characteristic frequencies that are defined by fluid mobility and the length scales of the fractures. Fracture-related dispersion and attenuation typically occur over a wider frequency band than is seen in the case of a single fracture set. When one set of fractures is modeled as being sealed, the azimuthal variation of velocity and attenuation can be different, with the azimuth of minimum attenuation coinciding with the strike direction of the open fracture set. The results should support attempts to differentiate between open and closed fractures on the basis of seismic measurements.
Poroelastic analysis of amplitude-versus-frequency variations
Authors: Ren Haitao , Goloshubin Gennady , Hilterman Fred J.
Published: October 2009

Although significant advancement has occurred in the interpretation of seismic amplitude-variation-with-offset (AVO) anomalies, a theory is lacking to guide the interpretation of frequency-dependent seismic anomalies. Using analytic equations and numerical modeling, we have investigated characteristics of the normal-incident reflection coefficient (NI) as a function of frequency at an interface between a nondispersive medium and a patchy-saturated dispersive medium. Because of velocity dispersion, the variation of NI magnitude is divided into three general classes. These classes are (1) low-frequency dim-out reservoirs, in which NI magnitude decreases toward lower frequencies; (2) phase-shift reservoirs, in which NI is a small negative value at low frequencies but becomes positive at higher frequencies; and (3) low-frequency bright-spot reservoirs, in which NI magnitude increases toward lower frequencies. This classification could provide insight for frequency-dependent seismic interpre-tation.
Phase II, Randomized, Controlled, Double-Blinded Trial of Weekly Elesclomol Plus Paclitaxel Versus Paclitaxel Alone for Stage IV Metastatic Melanoma
Authors: O'Day Steven , Gonzalez Rene , Lawson David , Weber Robert , Hutchins Laura , Anderson Clay , Haddad Jonathan , Kong Steven , Williams Anthony , Jacobson Eric
Published: October 2009

Purpose

Elesclomol is a novel, small-molecule, oxidative stress inducer believed to exert selective cytotoxicity by increasing intracellular concentrations of reactive oxygen species, which results in cell death via mitochondrial apoptosis. We evaluated whether the addition of elesclomol to weekly paclitaxel could improve efficacy in patients with stage IV metastatic melanoma.

Patients and Methods

We randomly assigned patients with metastatic melanoma, measurable disease, and one or fewer prior chemotherapy regimens to elesclomol 213 mg/m2plus paclitaxel 80 mg/m2(E + P) or to paclitaxel 80 mg/m2alone at a 2:1 ratio; regimens were given as a 1-hour intravenous infusion weekly, during 3 of every 4 weeks until disease progression per Response Evaluation Criteria in Solid Tumors or death occurred. Patients who experienced progression were unblended, and patients on paclitaxel alone were permitted to cross over to E + P. The primary efficacy end point was progression-free survival (PFS); secondary end points were response rate (RR), toxicity, and overall survival (OS; analyzed post hoc).

Results

At 21 US sites, 53 patients were randomly assigned to E + P, and 28 patients were randomly assigned to paclitaxel. The addition of elesclomol to paclitaxel yielded a doubling of median PFS (112 v 56 days) and a 41.7% risk reduction for disease progression/death (hazard ratio, 0.583; P = .035). Respective RRs for the E + P and paclitaxel groups were 15% and 3%; median OS was 11.9 v 7.8 months. Of patients on paclitaxel alone, 19 (68%) of 28 crossed over to E + P after they experienced progression. Weekly E + P was well tolerated.

Conclusion

E + P resulted in a statistically significant doubling of median PFS, with an acceptable toxicity profile and encouraging OS. A multinational, phase III trial (SYMMETRY) of E + P compared with paclitaxel alone in metastatic melanoma has closed.
Achievement of at Least Very Good Partial Response Is a Simple and Robust Prognostic Factor in Patients With Multiple Myeloma Treated With High-Dose Therapy: Long-Term Analysis of the IFM 99-02 and 99-04 Trials
Authors: Harousseau Jean-Luc , Avet-Loiseau Herve , Attal Michel , Charbonnel Catherine , Garban Frederic , Hulin Cyrille , Michallet Mauricette , Facon Thierry , Garderet Laurent , Marit Gerald , Ketterer Nicolas , Lamy Thierry , Voillat Laurent , Guilhot Francois , Doyen Chantal , Mathiot Claire , Moreau Philippe
Published: October 2009

Purpose

The prognostic impact of complete response (CR) achievement in multiple myeloma (MM) has been shown mostly in the context of autologous stem-cell transplantation. Other levels of response have been defined because, even with high-dose therapy, CR is a relatively rare event. The purpose of this study was to analyze the prognostic impact of very good partial response (VGPR) in patients treated with high-dose therapy.

Patients and Methods

All patients were included in the Intergroupe Francophone du Myelome 99-02 and 99-04 trials and treated with vincristine, doxorubicin, and dexamethasone (VAD) induction therapy followed by double autologous stem-cell transplantation (ASCT). Best post-ASCT response assessment was available for 802 patients.

Results

With a median follow-up of 67 months, median event-free survival (EFS) and 5-year EFS were 42 months and 34%, respectively, for 405 patients who achieved at least VGPR after ASCT versus 32 months and 26% in 288 patients who achieved only partial remission (P = .005). Five-year overall survival (OS) was significantly superior in patients achieving at least VGPR (74% v 61% P = .0017). In multivariate analysis, achievement of less than VGPR was an independent factor predicting shorter EFS and OS. Response to VAD had no impact on EFS and OS. The impact of VGPR achievement on EFS and OS was significant in patients with International Staging System stages 2 to 3 and for patients with poor-risk cytogenetics t(4;14) or del(17p).

Conclusion

In the context of ASCT, achievement of at least VGPR is a simple prognostic factor that has importance in intermediate and high-risk MM and can be informative in more patients than CR.
Mobile Phone Use and Risk of Tumors: A Meta-Analysis
Authors: Myung Seung-Kwon , Ju Woong , McDonnell Diana D. , Lee Yeon Ji , Kazinets Gene , Cheng Chih-Tao , Moskowitz Joel M.
Published: October 2009

Purpose

Case-control studies have reported inconsistent findings regarding the association between mobile phone use and tumor risk. We investigated these associations using a meta-analysis.

Methods

We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library in August 2008. Two evaluators independently reviewed and selected articles based on predetermined selection criteria.

Results

Of 465 articles meeting our initial criteria, 23 case-control studies, which involved 37,916 participants (12,344 patient cases and 25,572 controls), were included in the final analyses. Compared with never or rarely having used a mobile phone, the odds ratio for overall use was 0.98 for malignant and benign tumors (95% CI, 0.89 to 1.07) in a random-effects meta-analysis of all 23 studies. However, a significant positive association (harmful effect) was observed in a random-effects meta-analysis of eight studies using blinding, whereas a significant negative association (protective effect) was observed in a fixed-effects meta-analysis of 15 studies not using blinding. Mobile phone use of 10 years or longer was associated with a risk of tumors in 13 studies reporting this association (odds ratio = 1.18; 95% CI, 1.04 to 1.34). Further, these findings were also observed in the subgroup analyses by methodologic quality of study. Blinding and methodologic quality of study were strongly associated with the research group.

Conclusion

The current study found that there is possible evidence linking mobile phone use to an increased risk of tumors from a meta-analysis of low-biased case-control studies. Prospective cohort studies providing a higher level of evidence are needed.
Cediranib, an Oral Inhibitor of Vascular Endothelial Growth Factor Receptor Kinases, Is an Active Drug in Recurrent Epithelial Ovarian, Fallopian Tube, and Peritoneal Cancer
Authors: Matulonis Ursula A. , Berlin Suzanne , Ivy Percy , Tyburski Karin , Krasner Carolyn , Zarwan Corrine , Berkenblit Anna , Campos Susana , Horowitz Neil , Cannistra Stephen A. , Lee Hang , Lee Julie , Roche Maria , Hill Margaret , Whalen Christin , Sullivan Laura , Tran Chau , Humphreys Benjamin D. , Penson Richard T.
Published: October 2009

Purpose

Angiogenesis is important for epithelial ovarian cancer (EOC) growth, and blocking angiogenesis can lead to EOC regression. Cediranib is an oral tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptor (VEGFR) -1, VEGFR-2, VEGFR-3, and c-kit.

Patients and Methods

We conducted a phase II study of cediranib for recurrent EOC or peritoneal or fallopian tube cancer; cediranib was administered as a daily oral dose, and the original dose was 45 mg daily. Because of toxicities observed in the first 11 patients, the dose was lowered to 30 mg. Eligibility included ≤ two lines of chemotherapy for recurrence. End points included response rate (via Response Evaluation Criteria in Solid Tumors [RECIST] or modified Gynecological Cancer Intergroup CA-125), toxicity, progression-free survival (PFS), and overall survival (OS).

Results

Forty-seven patients were enrolled; 46 were treated. Clinical benefit rate (defined as complete response [CR] or partial response [PR], stable disease [SD] > 16 weeks, or CA-125 nonprogression > 16 weeks), which was the primary end point, was 30%; eight patients (17%; 95% CI, 7.6% to 30.8%) had a PR, six patients (13%; 95% CI, 4.8% to 25.7%) had SD, and there were no CRs. Eleven patients (23%) were removed from study because of toxicities before two cycles. Grade 3 toxicities (> 20% of patients) included hypertension (46%), fatigue (24%), and diarrhea (13%). Grade 2 hypothyroidism occurred in 43% of patients. Grade 4 toxicities included CNS hemorrhage (n = 1), hypertriglyceridemia/hypercholesterolemia/elevated lipase (n = 1), and dehydration/elevated creatinine (n = 1). No bowel perforations or fistulas occurred. Median PFS was 5.2 months, and median OS has not been reached; median follow-up time is 10.7 months.

Conclusion

Cediranib has activity in recurrent EOC, tubal cancer, and peritoneal cancer with predictable toxicities observed with other TKIs.
Phase II Study of Cisplatin Plus Etoposide and Bevacizumab for Previously Untreated, Extensive-Stage Small-Cell Lung Cancer: Eastern Cooperative Oncology Group Study E3501
Authors: Horn Leora , Dahlberg Suzanne E. , Sandler Alan B. , Dowlati Afshin , Moore Dennis F. , Murren John R. , Schiller Joan H.
Published: October 2009

Purpose

To investigate the efficacy and safety of bevacizumab plus cisplatin and etoposide in patients with extensive-stage disease, small-cell lung cancer (ED-SCLC).

Patients and Methods

In this phase II trial, 63 patients were treated with bevacizumab 15 mg/kg plus cisplatin 60 mg/m2 and etoposide 120 mg/m2, which was followed by bevacizumab alone until death or disease progression occurred. The primary end point was the proportion of patients alive at 6 months without disease progression (ie, progression-free survival [PFS]). Secondary end points included overall survival (OS), objective response rate, and toxicity. Correlative studies were performed to explore the relationship between baseline and changes in plasma vascular endothelial growth factor (VEGF), soluble cell adhesion molecules (ie, vascular cell adhesion molecule [VCAM], intercellular cell adhesion molecule [ICAM], and E-selectin) and basic fibroblast growth factor and outcome.

Results

The 6-month PFS was 30.2%, the median PFS was 4.7 months, and OS was 10.9 months. The response rate was 63.5%. The most common adverse event was neutropenia (57.8%). Only one patient had grade 3 pulmonary hemorrhage. Patients who had high baseline VCAM had a higher risk of progression or death compared with those who had low baseline VCAM levels. No relationships between outcome and any other biomarkers were seen.

Conclusion

The addition of bevacizumab to cisplatin and etoposide in patients with ED-SCLC results in improved PFS and OS relative to historical controls who received this chemotherapy regimen without bevacizumab. This regimen appears to be well tolerated and has minimal increase in toxicities compared with chemotherapy alone. Baseline VCAM levels predicted survival, but no other relationships among treatment, biomarkers, and outcome were identified.
Differences in endoplasmic-reticulum quality control determine the cellular response to disease-associated mutants of proteolipid protein
Authors: Roboti Peristera , Swanton Eileithyia , High Stephen
Published: October 2009

Missense mutations in human PLP1, the gene encoding myelin proteolipid protein (PLP), cause dysmyelinating Pelizaeus-Merzbacher disease of varying severity. Although disease pathology has been linked to retention of misfolded PLP in the endoplasmic reticulum (ER) and induction of the unfolded protein response (UPR), the molecular mechanisms that govern phenotypic heterogeneity remain poorly understood. To address this issue, we examined the cellular response to missense mutants of PLP that are associated with distinct disease phenotypes. We found that the mild-disease-associated mutants, W162L and G245A, were cleared from the ER comparatively quickly via proteasomal degradation and/or ER exit. By contrast, the more `aggressive' A242V mutant, which causes severe disease, was significantly more stable, accumulated at the ER and resulted in a specific activation of the UPR. On the basis of these findings, we propose that the rate at which mutant PLP proteins are cleared from the ER modulates disease severity by determining the extent to which the UPR is activated.
Structural Reverse and its Significance to Oil and Gas Accumulation in Ordos Block in Neogene
Authors: Zhao Hongge , Liu Chiyang , Wang Jianqiang , Gui Xiaojun , Yue Leping , Weng WangFei , Liang Meiyan
Published: October 2009

Ordos Block is considered as a rather stable basin in Cenozoic by most researchers. The result of our study is different from this opinion. Before the Cenozoic, tectonic movement directions are uplifted in the eastern part and sunk in the western part of the basin. The oldest Cenozoic strata which deposit in the east part of Ordos Basin are Neogene red clays. They appear on both Pre-Tertiary and Post-Mesozoic geological maps of Ordos Basin. According to fission track dating data from various researchers, structural unconformity contacts, paleo-current directions and regional environment, the western part of Ordos Block have become structural uplift. The red clay strata have not been observed there. The eastern Ordos Block had a wide distribution of red clay which sedimented from west to east on the Lower Cretaceous, Middle Jurassic Anding Formation, Zhiluo Formation, Early-Mid Jurassic Yan'an Formation and Late Triassic Yanchang Formation, respectively. Therefore, we concluded that there existed a structural sinking event in the eastern part of the basin. The event occurred since the red clay sedimentation. In this stage, the red clay showed about 8 Ma by magnetostratigraphy dating. We name this tectonic movement direction change as structural reverse. It is supposed that the reverse time which the west basin turned from the depression since Mesozoic to thrust and uplift is also in 8Ma or so. The structural reverse times of the eastern and western basin are synchronous. It began in 8 Ma and continued after that. The structural reverse had great significance to the fluid deposits such as oil and gas in Ordos Basin.
Managing Project Failure Risk Through Contingent Contracts in Procurement Auctions
Authors: Chen Jianqing , Xu Lizhen , Whinston Andrew
Published: October 2009

Procurement auctions are sometimes plagued with a chosen supplier's failing to accomplish a project successfully. The risk of project failure is considerable, especially when the buyer has inadequate information about suppliers ex ante and the project can only be evaluated at the end. To manage such uncertainty, a model of competitive procurement and contracting for a project is presented in this paper. We study a setting in which suppliers differ in both the costs to fulfill the project and the types reflecting their success probabilities. To screen suppliers, the buyer invites suppliers to specify a two-dimensional bid composed of the proposed cost and a penalty payment if the delivered project fails to meet the requirements. We find that a quasi-linear scoring rule can effectively separate suppliers regarding their types. We then study the efficient and optimal design of the scoring rule. The efficient design internalizes the inferred information on suppliers' type and essentially ranks suppliers based on the expected total cost to the buyer. In the optimal design, the buyer may or may not under-reward suppliers' high success probability, depending on the balance between suppliers' success probabilities and the associated cost distributions. Interestingly, it is always optimal for the buyer to possibly award the project to suppliers with low success probability to promote the competition, even when the difference in suppliers' success probabilities is huge. We show that, compared to standard auctions, the procurement auctions with contingent contracts can significantly improve both social welfare and the buyer's payoff.
Severe Apnea in an Infant Exposed to Lamotrigine in Breast Milk
Authors: Nordmo Elisabet , Aronsen Lena , Wasland Kristin , Småbrekke Lars , Vorren Solveig
Published: October 2009

Objective:

To report a case of severe apnea in an infant exposed to lamotrigine through breast-feeding.

Case Summary:

A 16-day-old infant developed several mild episodes of apnea that culminated in a severe cyanotic episode requiring resuscitation. A thorough examination at the hospital gave no evidence of underlying diseases that could explain the reaction. The mother had used lamotrigine in increasing doses throughout pregnancy, and at the time of the apneic episodes, she used 850 mg/day. The infant was fully breast-fed, and the neonatal lamotrigine serum concentration was 4.87 μg/mL at the time of admission. Breast-feeding was terminated, and the infant fully recovered.

Discussion:

Although there are several reports on extensive passage of lamotrigine into breast milk, this is the first published report of a serious adverse reaction in a breast-fed infant. Lamotrigine clearance increases throughout pregnancy, and maternal dose increases are often necessary to maintain therapeutic effect. After delivery, clearance rapidly returns to preconception levels, enhancing the risk of adverse reactions in both mothers and breast-fed infants if the dose is not sufficiently reduced. In this case, the dose was slowly reduced after delivery, and the maternal lamotrigine serum concentration more than doubled in the week before the neonatal apneic episodes. A high lamotrigine concentration was detected in the breast milk, and the neonatal lamotrigine serum concentration was in the upper therapeutic range. The neonatal lamotrigine elimination half-life was approximately twice that seen in adults. The Naranjo probability scale indicated a probable relationship between apnea and exposure to lamotrigine through breast-feeding in this infant.

Conclusions:

Infants can be exposed to clinically relevant doses of lamotrigine through breast-feeding. Individual risk/benefit assessment is important, and close monitoring of both mother and child is advisable, especially during the first 3 weeks postpartum.
Fospropofol: A New Sedative–Hypnotic Agent for Monitored Anesthesia Care
Authors: Moore Gina D , Walker Alyssa M , MacLaren Robert
Published: October 2009

Objective:

To summarize the published clinical data on fospropofol, critically review the safety and efficacy information, and provide pertinent information for formulary review.

Data Sources:

Data were collected from searches of MEDLINE (1966–June 30, 2009), EMBASE (1974–June 30, 2009), bibliographies of manuscripts, and www.fda.gov . Key search terms included fospropofol, Lusedra, Aquavan, sedative–hypnotic, and monitored anesthesia care.

Study Selection and Data Extraction:

All Phase 1, Phase 2, and Phase 3 clinical trials studying the safety and efficacy of fospropofol were reviewed.

Data Synthesis:

Fospropofol is a water-soluble prodrug of propofol, a potent sedative–hypnotic agent. Propofol is highly lipophilic and is formulated in lipid-containing solvents, which have known disadvantages, including pain on injection, narrow therapeutic window with the potential to cause deep sedation, high lipid intake during long-term sedation, and risk of infection resulting from bacterial contamination. Due to its water solubility, fospropofol eliminates some of the known lipid emulsion–associated disadvantages of propofol and provides a more predictable peak onset of activity and more gradual recovery to a full state of consciousness. The pharmacokinetic and pharmacodynamic profiles of fospropofol make it an attractive agent for sedation for procedures of short duration. Unfortunately, the number of patients studied has been relatively small and the amount of safety data is limited. Of concern are reports of hypoxemia and hypotension; these reports are limited in number, but the episodes are serious and may require acute intervention. Although fospropofol holds promise for procedural sedation, due to limited safety data, the Food and Drug Administration has limited approval of fospropofol to monitored anesthesia care in patients undergoing diagnostic or therapeutic procedures.

Conclusions:

Fospropofol is a viable addition to the class of sedative–hypnotic agents due to the minimization of unwanted adverse effects of propofol and maintenance of a favorable pharmacokinetic profile facilitating sedation, anxiolysis, and rapid recovery. However, there are limited safety data to justify its use without the presence of dedicated anesthesia personnel.
Terahertz Pulsed Spectroscopy as a New Tool for Measuring the Structuring Effect of Solutes on Water
Authors: Kaun N. , Baena J. R. , Newnham D. , Lendl B.
Published: October 2009

Absorption spectra of aqueous solution of “chaotropes” (structure maker) and “kosmotropes” (structure breaker) have been recorded in the mid-infrared (MIR) and terahertz (THz) spectral region. A different impact of the two groups of solutes on the absorption spectrum of water was found in the recorded THz spectra. A concentration-dependent increased absorption across the investigated THz spectral region (0.04–2 THz, 1.3–66 cm−1, respectively) has been recorded for all studied chaotropic solutions, whereas the opposite has been obtained for kosmotrope containing solutions. In the case of ionic solutes a further increase in absorption towards higher frequencies was measured. The distinction between chaotrope and kosmotrope solutes was, as expected, also possible in the MIR spectral region. Depending on the structure-forming effect of the solute the OH stretch vibration of the water (around 3400 cm−1) was slightly shifted. A red shift has been observed for solution of kosmotropes, whereas a blue shift was observed in the case of solutions containing chaotropes. Compared to the MIR spectral region the structure influencing effect of solutes can be more efficiently studied in the THz spectral region, which provides information from interactions between neighboring water molecules.
Nanoliter Serum Sample Analysis by Mid-Infrared Spectroscopy for Minimally Invasive Blood-Glucose Monitoring
Authors: Diessel Edgar , Kamphaus Peter , Grothe Klaus , Kurte Roland , Damm Uwe , Heise H. Michael
Published: October 2009

The aim of this study was to demonstrate that mid-infrared spectroscopy is able to quantify glucose in a serum matrix with sample volumes well below 1 μL. For this, we applied mid-infrared attenuated total reflectance (ATR) or transmission-based spectroscopic methods to glucose quantification in microsamples of dry-film sera, either undiluted or diluted 10 times in distilled water. The sample series spanned physiological glucose concentrations between 50 and 600 mg/dL and volumes of 80, 8, and 1 nL. Calibration was carried out using multivariate partial least-squares (PLS) modeling with spectral data between 1180 and 940 cm−1. Best performance was achieved in the ATR experiments. For raw ATR spectra, the optimum standard error of prediction (SEP) of 13.3 mg/dL was obtained for the 8 nL sample series with subsequent 10-fold dilution. With respect to the coefficient of variation of the glucose assay, CVpred, we obtained a value of 3% for the 80 nL volume samples with spectral preprocessing using matrix protein absorption bands as an internal standard, 4% for the 8 nL samples, and 6% for the 1 nL samples with raw data. Spectral standardization resulted in significant improvement, especially for the 80 nL volume sample series. By contrast, the accuracy of the glucose assay for the 1 nL sample volume series could not be improved either by internal standardization or by considering the dry film areas for normalization, which we attribute to varying topographies of the dry films.
Dual Layer and Multilayer Enhancements from Silver Film over Nanostructured Surface-Enhanced Raman Substrates
Authors: Li Honggang , Cullum Brian M.
Published: October 2009

Novel dual layer and multilayer silver film over nanostructure (SFON) substrates have been developed that provide surface-enhanced Raman scattering (SERS) signal enhancements of greater than 1000% compared to conventional single layer SFON substrates. These substrates provide signal enhancement factors of 3.8 × 105 and greater for a variety of SERS active analytes. Substrate preparation is accomplished by vapor depositing a thick (∼100 nm) layer of silver on top of an underlying layer of alumina nanoparticles, followed by deposition of additional layers of silver with silver oxide layers between them. Unlike previous dual layer silver island based substrates that have been developed, these substrates do not rely on achieving an optimal morphology via deposition of silver. Instead, these substrates rely on the roughness being provided by the original under-layer, providing enhanced substrate homogeneity and more reproducible signals than either silver island substrates or colloidal substrates. In addition, the signal enhancement gives these substrates extended lifetimes compared to conventional single layer SFON substrates. Finally, this study also shows that geometric surface structure and surface roughness factors play little or no role in this enhancement process, allowing for this multilayer fabrication process to be applied to many different types of substrates achieving similar or even greater results.
Spectroscopic Characterization of Two Different Microwave (2.45 GHz) Induced Argon Plasmas at Atmospheric Pressure
Authors: García M. C. , Yubero C. , Calzada M. D. , Martínez-Jiménez M. P.
Published: October 2009

A surface-wave-sustained discharge created by using a surfatron device in a tube open to the atmosphere can be used to maintain a microwave (2.45 GHz) plasma at atmospheric pressure at powers of less than 300 W. The TIA ( Torche à Injection Axiale) is a device also producing a plasma that, moreover, permits us to work at high power (higher than 200 W and up to 1000 W). A study of the departure from the thermodynamic equilibrium existing in the argon plasmas created by both devices has been done by using optical emission spectroscopy techniques in order to characterize them and to evaluate their possible advantages when they are used for applied purposes.
Standard Reference Material 2036 Near-Infrared Reflection Wavelength Standard
Authors: Choquette Steven J. , Duewer David L. , Hanssen Leonard M. , Early Edward A.
Published: October 2009

Standard Reference Material 2036 (SRM 2036) is a certified transfer standard intended for the verification and calibration of the wavelength/wavenumber scale of near-infrared (NIR) spectrometers operating in diffuse or trans-reflectance mode. SRM 2036 Near-Infrared Wavelength/Wavenumber Reflection Standard is a combination of a rare earth oxide glass of a composition similar to that of SRM 2035 Near-Infrared Transmission Wavelength/Wavenumber Standard and SRM 2065 Ultraviolet–Visible–Near-Infrared Transmission Wavelength/Wavenumber Standard, but is in physical contact with a piece of sintered poly(tetrafluoroethylene) (PTFE). The combination of glass contacted with a nearly ideal diffusely reflecting backing provides reflection–absorption bands that range from 15% R to 40% R. SRM 2036 is certified for the 10% band fraction air wavelength centroid location, 10%B, of seven bands spanning the spectral region from 975 nm to 1946 nm. It is also certified for the vacuum wavenumber 10%B of the same seven bands in the spectral region from 10 300 cm−1 to 5130 cm−1 at 8 cm−1 resolution. Informational values are provided for the locations of thirteen additional bands from 334 nm to 804 nm.
Subsurface Probing in Diffusely Scattering Media Using Spatially Offset Raman Spectroscopy
Authors: Matousek P. , Clark I. P. , Draper E. R. C. , Morris M. D. , Goodship A. E. , Everall N. , Towrie M. , Finney W. F. , Parker A. W.
Published: October 2009

We describe a simple methodology for the effective retrieval of Raman spectra of subsurface layers in diffusely scattering media. The technique is based on the collection of Raman scattered light from surface regions that are laterally offset away from the excitation laser spot on the sample. The Raman spectra obtained in this way exhibit a variation in relative spectral intensities of the surface and subsurface layers of the sample being investigated. The data set is processed using a multivariate data analysis to yield pure Raman spectra of the individual sample layers, providing a method for the effective elimination of surface Raman scatter. The methodology is applicable to the retrieval of pure Raman spectra from depths well in excess of those accessible with conventional confocal microscopy. In this first feasibility study we have differentiated between surface and subsurface Raman signals within a diffusely scattering sample composed of two layers: trans-stilbene powder beneath a 1 mm thick over-layer of PMMA (poly(methyl methacrylate)) powder. The improvement in contrast of the subsurface trans-stilbene layer without numerical processing was 19 times. The potential applications include biomedical subsurface probing of specific tissues through different overlying tissues such as assessment of bone quality through skin, providing an effective noninvasive means of screening for bone degeneration, other skeletal disease diagnosis, and dermatology studies, as well as materials and catalyst research.
Comparison of Methods for Transfer of Calibration Models in Near-Infared Spectroscopy: A Case Study Based on Correcting Path Length Differences Using Fiber-Optic Transmittance Probes in In-Line Near-Infrared Spectroscopy
Authors: Sahni Narinder Singh , Isaksson Tomas , Næs Tormod
Published: October 2009

This article addresses problems related to transfer of calibration models due to variations in distance between the transmittance fiber-optic probes. The data have been generated using a mixture design and measured at five different probe distances. A number of techniques reported in the literature have been compared. These include multiplicative scatter correction (MSC), path length correction (PLC), finite impulse response (FIR), orthogonal signal correction (OSC), piecewise direct standardization (PDS), and robust calibration. The quality of the predictions was expressed in terms of root mean square error of prediction (RMSEP). Robust calibration gave good calibration transfer results, while the other methods did not give acceptable results.
A General Model-Based Approach to Two-Dimensional Infrared Correlation Spectroscopy Incorporating the Global Phase Angle
Authors: Morita Shin-Ichi , Shanmukh Saratchandra , Ozaki Yukihiro , Dluhy Richard A.
Published: October 2009

We describe a theoretical framework for a model-based approach to two-dimensional correlation spectroscopy that is generally applicable to any arbitrary model function. The method is based on the correlation between spectral data and a set of model waveforms with a varying correlation index, the global phase angle Θ. When experimental spectral intensity variations are expressed as sinusoidal, exponential, Lorentzian, or quadratic functions, the proposed approach allows us to estimate the quantitative values of the target parameters in those expressions. In addition, this method enables us to assess the sequential order in a series of bands undergoing non-identical intensity changes in a dynamic data set. We present both simulated and experimentally obtained data that illustrate that the deviations from linearity of the absorption band intensity waveforms are clearly detected and can be quantitatively estimated using quadratic functions.
Inverse Spatially Offset Raman Spectroscopy for Deep Noninvasive Probing of Turbid Media
Authors: Matousek Pavel
Published: October 2009

A new type of highly sensitive spatially offset Raman spectroscopy (SORS) developed for deep noninvasive probing of stratified turbid media is described. The technique, termed inverse SORS, permits much greater depths to be interrogated than those accessible with the conventional SORS approach. This is achieved by enhancing the sensitivity of the technique through the elimination of spectral distortions inherent to the conventional SORS methodology. The method also permits the use of higher laser powers in applications where intensity limits exist, such as when probing human tissue in vivo. In addition, the new approach possesses a much higher degree of flexibility, enabling on-the-spot tailoring of experimental conditions such as the magnitude and number of spatial offsets to individual samples. The scheme uses a reverse SORS geometry whereby Raman light is collected through fibers at the center of the probe and laser radiation is delivered to the sample through a beam in the shape of a ring. The method is demonstrated on a layered powder sample and several practical examples of its uses, presented for the first time, are also given. Potential applications include disease diagnosis, noninvasive probing of pharmaceutical products and chemicals through packaging, probing of polymers, biofilms or paints, and homeland security screening.
Multivariate Curve Resolution of Synchronous Fluorescence Spectra Matrices of Fulvic Acids Obtained as a Function of pH
Authors: Da Silva Joaquim C. G. Esteves , Tauler Romá
Published: October 2009

Synchronous fluorescence spectra (excitation wavelength range between 280 and 510 nm and wavelength interval of 25 nm) of three samples of fulvic acids (FA) were obtained as a function of the pH, in the range from 2.0 to 10.5, and as a function of the FA concentration, in the range from 20 to 180 mg/L. FA were obtained from composted livestock materials (lsFA), composted sewage sludge (csFA), and Laurentian soil (laFA). Three-dimensional spectral matrices were obtained (wavelength, pH, and FA concentration) and multivariate curve resolution (MCR) was used to calculate spectra and fluorescence intensity profiles for the detected components. Cluster analysis of the calculated spectra showed the existence of similar and unique fluorescent properties in the three FA samples. Some of the calculated fluorescence intensity profiles have a shape compatible with acid–base species distribution diagrams, which allowed pKa values to be estimated, namely, a well-defined acid–base equilibrium with pKa 5.7 ± 0.2 (lsFA), 6.9 ± 0.4 (csFA), and 5.5 ± 0.2 (laFA); and other acid–base systems not well defined with pKa at about 3.0 and 8.6. Other spectral variations revealed the existence of inner-filter effects or self-quenching as the concentration of FA increases.
Fiber-Optic Surface Plasmon Resonance Sensors in the Near-Infrared Spectral Region
Authors: Masson Jean-Francois , Kim Yoon-Chang , Obando Louis A. , Peng Wei , Booksh Arl S.
Published: October 2009

The sensitivity of fiber-optic surface plasmon resonance (SPR) sensors was improved by a factor of at least thirteen for aqueous solutions by modifying the tip geometry to allow interrogation of the surface plasmon (SP) band in the near-infrared (NIR) region. This was achieved by tuning the angle at the distal end of the SPR sensor to a dual taper of 71° and 19°. Using a low numerical aperture (NA) fiber-optic sensor, NA = 0.12, is necessary to obtain a functional SPR sensor working in the NIR region. Theoretical simulations using the Maxwell equations demonstrated that even higher enhancement is theoretically possible while maintaining a narrow spectral feature upon the excitation of the SP bands on gold surfaces. The manufacture of the SPR sensors yields good agreement between theoretical simulations and experimental observations. To investigate the properties of these fiber-optic SPR-NIR sensors, sucrose solutions ranging from 0 to 15 × 10−3 in mole fraction were utilized. The increased sensitivity of the fiber-optic SPR sensors, when used to monitor biomarkers, would yield lower detection limits. The smaller sensing area, compared to planar or other fiber-optic SPR sensors, combined with an improvement of the sensitivity, would yield a dramatic reduction of the absolute amount detected by biosensors.
Nondestructive Identification of Arsenic and Cobalt Minerals from Cobalt City, Ontario, Canada: Arsenolite, Erythrite, and Spherocobaltite on Pararammelsbergite
Authors: Kloprogge J. T. , Duong L. V. , Weier M. , Martens W. N.
Published: October 2009

A Ni-Co-As ore sample from Cobalt City, Ontario, Canada, was examined with scanning electron microscopy and energy dispersive X-ray analysis. In addition to cobaltian pararammelsbergite with variable cobalt content, for which Cobalt City is the type locality, and erythrite, one new mineral was observed for this locality. Well-formed crystals of arsenolite, As2O3, were found embedded in what appears to be fibrous spherocobaltite, CoCO3. Additional information was obtained by Raman microscopy, confirming the identification of the arsenolite. Both are considered to be secondary minerals formed by exposure to air resulting in oxidation and the formation of secondary carbonates.
Development of a Planar Array Infrared Reflection Spectrograph for Reflection—Absorption Spectroscopy of Thin Films at Metal and Water Surfaces
Authors: Kim Young Shin , Snively Christopher M. , Rabolt John F. , Chase D. Bruce
Published: October 2009

Planar array infrared (PA-IR) spectroscopy offers several advantages over Fourier transform infrared (FT-IR) methods, including ultrafast speed (< 100 μs temporal resolution) and excellent sensitivity. However, obtaining spectra in the range of 1800 to 1000 cm−1 of films at the air–water interface remains difficult due to the poor IR reflectivity of water, the extremely low concentration of the thin film on the water subphase, and the interference of water bands. In this study, we report a new planar array infrared reflection spectrograph (PA-IRRS), which has several advantages over conventional approaches. This instrument can record sample and reference spectra simultaneously with an instrumental setup that is the same as that of a single-beam instrument by splitting the incident infrared beam into two sections on a plane mirror (H) or a water trough. With this design, the instrument can accommodate large infrared accessories, such as a water trough, without a loss of infrared beam intensity. Water bands can be subtracted to obtain a high-quality spectrum for poly(L-lactic acid) Langmuir film on the water subphase with a resolution of about 6 cm−1 in 10.8 s. Hence, this PA-IRRS system has great potential for investigating the time-resolved dynamics of a broad range of Langmuir films, such as cellular membranes or biopolymers, on the water subphase.
Calibration of Probe Volume in Fluorescence Correlation Spectroscopy
Authors: Gao Yi , Zhong Zhenming , Geng M. Lei
Published: October 2009

In fluorescence correlation spectroscopy (FCS), an accurate evaluation of the probe volume is the basis of correct interpretation of experimental data and solution of an appropriate diffusion model. Poor fitting convergence has been a problem in the determination of the dimensional parameters, the beam radius, ω, and the distance along the optical axis of the probe volume, l. In this work, the instability of fitting during the calibration process is investigated by examining the χ2 surfaces. We demonstrate that the minimum of χ2 in the ω dimension is well defined for both converging and diverging data. The difficulty of fitting comes from the l dimension. The uncertainty in l could be significantly larger than that in ω, as determined by F-statistics. A modified calibration process is recommended based on examining two data treatment methods, combining several short data sets into a single long run and averaging the correlation functions of several short data sets. It is found that by using the mean of several converging correlation functions from short data sets instead of a long time correlation, more stable and consistent dimensional parameters are extracted to define the probe volume.
Two-Dimensional Attenuated Total Reflection Infrared and Near-Infrared Correlation Study of the Structure of Butyl Alcohol/Water Mixtures
Authors: Wojtków Dagmara , Czarnecki Mirosław A.
Published: October 2009

The effect of temperature on attenuated total reflection infrared (ATR-IR) and near-infrared (NIR) transmission spectra of pure butan-1-ol, butan-2-ol, 2-methyl-propan-1-ol, 2-methyl-propan-2-ol, and mixtures with a small water content (XH2O ≤ 0.1) have been examined. The spectra were analyzed using a two-dimensional (2D) correlation approach. Two kinds of correlation analysis were performed: IR–IR and NIR–NIR homo-correlation and IR–NIR hetero-correlation. Our results reveal that the addition of small to moderate amounts of water does not destroy the structure of alcohol. The presence of water stabilizes the structure of alcohols and this effect is more evident for sec-butanol and tert-butanol. The ATR-IR spectra provide information on the most associated species, whereas absorption of the smaller associates and the free OH group is hardly seen. On the contrary, in the NIR spectra the absorption of the free OH groups dominates. The ability of resolution enhancement in the hetero-correlation asynchronous spectra is reduced as compared to that in the homo-correlation spectra. On the other hand, peaks may appear in the hetero-correlation synchronous spectra that are not observed in the homo-correlation contour plots. The positions of the synchronous peaks were used for evaluation of anharmonicity constants. These values for the free OH group do not depend on the experimental conditions. In contrast, the anharmonicity constants for the bonded OH groups determined from the spectra of pure alcohols may significantly differ from those obtained from diluted solutions.
Some Insights about 1,6-Diphenyl-1,3,5-hexatriene—Lipid Supramolecular Assemblies by Steady-State Fluorescence Measurements
Authors: Caudron E. , Zhou J. Y. , England P. , Ollivon M. , Prognon P.
Published: October 2009

1,6-Diphenyl-1,3,5-hexatriene (DPH) is the most widely proposed molecular probe for the post-column fluorescence derivatization of lipids after liquid chromatography separation. This kind of detection consists of a supramolecular combination of DPH and eluted lipids. The detection is optimally performed in a mainly aqueous environment (over 80% v/v) because the weak fluorescence of DPH in water is drastically enhanced upon formation of supramolecular assemblies with lipids. In the present study, and in order to obtain better spectroscopic insights into the nature of these supramolecular assemblies, two different lipids were tested, 1,2,3-tridodecanoylglycerol (LLL) as a model triglyceride (nonpolar lipid) and dimyristoylphosphatidylcholine (DMPC) as a model phosphatidylcholine (charged amphiphilic lipid). Stoichiometry and association constants were determined on the basis of the variation of fluorescence intensity in the presence of various concentrations of lipids. LLL60–DPH2 and DMPC200–DPH2 complexes were identified with association constants as high as K2 = (5.8 × 0.5) × 1013 M−2 and (17.3 × 2.0) × 1013 M−2 for LLL and DMPC, respectively. The fluorescence intensity of DPH in the presence of LLL is greater than in the presence of DMPC. An attempt to characterize the insertion mode of DPH in the lipidic supramolecular assemblies is also made.