Geophysical imaging reveals topographic stress control of bedrock weathering

Bedrock fracture systems facilitate weathering, allowing fresh mineral surfaces to interact with corrosive waters and biota from Earth's surface, while simultaneously promoting drainage of chemically equilibrated fluids. We show that topographic perturbations to regional stress fields explain bedrock fracture distributions, as revealed by seismic velocity and electrical resistivity surveys from three landscapes. The base of the fracture-rich zone mirrors surface topography where the ratio of horizontal compressive tectonic stresses to near-surface gravitational stresses is relatively large, and it parallels the surface topography where the ratio is relatively small. Three-dimensional stress calculations predict these results, suggesting that tectonic stresses interact with topography to influence bedrock disaggregation, groundwater flow, chemical weathering, and the depth of the "critical zone" in which many biogeochemical processes occur.

Effect of combination radioimmunotherapy (RAIT) and chemoimmunotherapy on therapeutic response and toxicity in xenograft models of human pancreatic carcinoma: First experimental studies

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Background: Preclinical and early clinical data with RAIT involving a 90Y-labeled antibody to a pancreatic mucin antigen (hPAM4, clivatuzumab tetraxetan) have shown promising therapeutic activity in combination with gemcitabine. Selective targeting of therapeutic drugs using antibody-drug conjugates (ADC) might be useful in pancreatic cancer therapy.

Methods: ADCs composed of SN-38 coupled to an internalizing anti-TROP-2 antibody, an antigen found on many epithelial cancers, or to the non-internalizing anti-mucin humanized IgG, were prepared (6 SN-38/IgG). Nude mice bearing s.c. Capan-1 or BxPC3 xenografts (∼0.35 cm3) were given multiple ADC doses (twice weekly, 4 weeks) or appropriate controls of a non-targeting IgG-SN-38 conjugate or irinotecan. Other groups of animals were treated with the ADC conjugates and RAIT, using RAIT at 60% and 100% of its MTD. The endpoint was time to progress to 3.0 cm3 (TTP), with animals monitored up to 22 weeks.

Results: ADCs alone were each able to inhibit tumor growth significantly compared to untreated animals. The specificity of the effect was a dose-dependent and related to antigen saturation at higher doses. When ADC was combined with RAIT, TTP improved significantly and more animals were tumor-free. An effective ADC dose could be combined even with RAIT given at its MTD, achieving enhanced efficacy with minimal additional toxicity. ADC + RAIT treatments were best when RAIT was given 1-2 weeks before, the same day, or within 1 week after the ADC treatment, but delaying RAIT for 2 weeks after ADC treatment reduced efficacy. The same anti-pancreatic mucin antibody, hPAM4, could be used in the combination treatment both as RAIT and as an ADC without losing effectiveness.

Conclusions: These studies show the feasibility of using ADC for the treatment of pancreatic cancer, and for combining antibody drug- and radionuclide-targeted therapeutics for improved efficacy with minimal toxicity. Supported in part from NCI grant R01 CA115755.

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Risk factors for treatment failure in patients with prosthetic joint infections

A retrospective, observational cohort study was conducted to describe the incidence, clinical and microbiological findings and to evaluate risk factors for treatment failure associated with prosthetic joint infections (PJIs). We retrospectively reviewed the medical records of all patients undergoing total knee or total hip prosthesis implantation in our institution between 1994 and 2008. Our institution is a 1950-bed tertiary care university hospital and referral centre. A total of 93 patients with PJIs was identified although only 68 patients had undergone prosthesis implantation at our hospital. The overall infection rate was 0.63%. The most common organisms isolated were Gram positive (76.5%), including meticillin-resistant staphylococci. Two-stage arthroplasty was performed in 48 (51.6%) patients, and debridement and retention of the prosthesis in 34 (36.5%) patients. When 43 patients followed up for more than two years after treatment were included in treatment outcome analysis, the overall treatment failure rate was 41.8% (18/43). Staphylococcus aureus infection was the only clinical variable associated with treatment failure (odds ratio: 11.9; 95% confidence interval: 1.07e133.9; P = 0.044), after adjustment for the other variables. In conclusion, S. aureus was the most common pathogen isolated in patients with PJI, and an independent risk factor for treatment failure in patients with PJI.

Risk factors for treatment failure in patients with prosthetic joint infections

A retrospective, observational cohort study was conducted to describe the incidence, clinical and microbiological findings and to evaluate risk factors for treatment failure associated with prosthetic joint infections (PJIs). We retrospectively reviewed the medical records of all patients undergoing total knee or total hip prosthesis implantation in our institution between 1994 and 2008. Our institution is a 1950-bed tertiary care university hospital and referral centre. A total of 93 patients with PJIs was identified although only 68 patients had undergone prosthesis implantation at our hospital. The overall infection rate was 0.63%. The most common organisms isolated were Gram positive (76.5%), including meticillin-resistant staphylococci. Two-stage arthroplasty was performed in 48 (51.6%) patients, and debridement and retention of the prosthesis in 34 (36.5%) patients. When 43 patients followed up for more than two years after treatment were included in treatment outcome analysis, the overall treatment failure rate was 41.8% (18/43). Staphylococcus aureus infection was the only clinical variable associated with treatment failure (odds ratio: 11.9; 95% confidence interval: 1.07-133.9; P=0.044), after adjustment for the other variables. In conclusion, S. aureus was the most common pathogen isolated in patients with PJI, and an independent risk factor for treatment failure in patients with PJI.

One hundred questions of importance to the conservation of global biological diversity

We identified 100 scientific questions that, if answered, would have the greatest impact on conservation practice and policy. Representatives from 21 international organizations, regional sections and working groups of the Society for Conservation Biology, and 12 academics, from all continents except Antarctica, compiled 2291 questions of relevance to conservation of biological diversity worldwide. The questions were gathered from 761 individuals through workshops, email requests, and discussions. Voting by email to short-list questions, followed by a 2-day workshop, was used to derive the final list of 100 questions. Most of the final questions were derived through a process of modification and combination as the workshop progressed. The questions are divided into 12 sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management and restoration, terrestrial ecosystems, marine ecosystems, freshwater ecosystems, species management, organizational systems and processes, societal context and change, and impacts of conservation interventions. We anticipate that these questions will help identify new directions for researchers and assist funders in directing funds.

Gamma-ray spectroscopy at the limits: first observation of rotational bands in 255Lr

The rotational band structure of 255Lr has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, 255Lr is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2-[521] and 7/2-[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.

Estimation of mass transport parameters of gases for quantifying CH4 oxidation in landfill soil covers

Methane (CH(4)), which is one of the most abundant anthropogenic greenhouse gases, is produced from landfills. CH(4) is biologically oxidized to carbon dioxide, which has a lower global warming potential than methane, when it passes through a cover soil. In order to quantify the amount of CH(4) oxidized in a landfill cover soil, a soil column test, a diffusion cell test, and a mathematical model analysis were carried out. In the column test, maximum oxidation rates of CH(4) (V(max)) showed higher values in the upper part of the column than those in the lower part caused by the penetration of O(2) from the top. The organic matter content in the upper area was also higher due to the active microbial growth. The dispersion analysis results for O(2) and CH(4) in the column are counter-intuitive. As the upward flow rate of the landfill gas increased, the dispersion coefficient of CH(4) slightly increased, possibly due to the effect of mechanical dispersion. On the other hand, as the upward flow rate of the landfill gas increased, the dispersion coefficient of O(2) decreased. It is possible that the diffusion of gases in porous media is influenced by the counter-directional flow rate. Further analysis of other gases in the column, N(2) and CO(2), may be required to support this hypothesis, but in this paper we propose the possibility that the simulations using the diffusion coefficient of O(2) under the natural condition may overestimate the penetration of O(2) into the soil cover layer and consequently overestimate the oxidation of CH(4).

Out-of-pocket costs of AIDS care in China: are free antiretroviral drugs enough?

Financial access to HIV care and treatment can be difficult for many people in China, where the government provides free antiretroviral drugs but does not cover the cost of other medically necessary components, such as lab tests and drugs for opportunistic infections. This article estimates out-of-pocket costs for treatment and care that a person living with HIV/AIDS in China might face over the course of one year. Data comes from two treatment projects run by Médecins Sans Frontières in Nanning, Guangxi Province and Xiangfan, Hubei Province. Based on the national treatment guidelines, we estimated costs for seven different patient profiles ranging from WHO Clinical Stages I through IV. We found that patients face significant financial barriers to even qualify for the free ARV program. For those who do, HIV care and treatment can be a catastrophic health expenditure, with cumulative patient contributions ranging from approximately US$200-3939/year in Nanning and US$13-1179/year in Xiangfan, depending on the patient's clinical stage of HIV infection. In Nanning, these expenses translate as up to 340% of an urban resident's annual income or 1200% for rural residents; in Xiangfan, expenses rise to 116% of annual income for city dwellers and 295% in rural areas. While providing ARV drugs free of charge is an important step, the costs of other components of care constitute important financial barriers that may exclude patients from accessing appropriate care. Such barriers can also lead to undesirable outcomes in the future, such as impoverishment of AIDS-affected households, higher ARV drug-resistance rates and greater need for complex, expensive second-line antiretroviral drugs.

Positive impact of radiation dose on disease free survival and locoregional control in postoperative radiotherapy for squamous cell carcinoma of esophagus

The effect of total radiation dose (TRD) on the outcome of patients with postoperative radiotherapy (RT) for squamous cell carcinoma of esophagus was assessed. Sixty-seven patients with esophagectomy, followed by postoperative RT for squamous cell carcinoma of esophagus from June 1984 through February 2001, were retrospectively reviewed. Of these, 13 patients were excluded. No patient had chemotherapy. Patients were classified into two groups based on TRD delivered: TRD of less than 50 Gy (Group A, n = 16) and at least 50 Gy (Group B, n = 38). Follow-up duration of all patients ranged from 4 to 140 months (median, 14). Median TRD of Group A and B were 45 Gy (range, 45-48.6) and 54 Gy (range, 50-59.6), respectively. Median overall survival (OS) and disease-free survival (DFS) of all patients were 15 and 10 months, respectively. Although the TRD of 50 Gy or higher was marginally significant for improved OS (hazard ration [HR] 0.559, P = 0.066), it was statistically significant for improved DFS (HR 0.398, P = 0.011), and locoregional recurrence-free survival (HR 0.165, P = 0.001) with multivariate analysis. Three patients in group A and two in group B experienced a complication of grade 3 or higher. Our study suggests a positive impact of TRD of 50 Gy or higher on DFS and locoregional control, with acceptable morbidity in postoperative RT for patients with squamous cell carcinoma of esophagus. According to the present analysis, TRD should be at least 50 Gy in postoperative RT alone setting.