Author Correction: The importance of Antarctic krill in biogeochemical cycles.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The importance of Antarctic krill in biogeochemical cycles.

Antarctic krill (Euphausia superba) are swarming, oceanic crustaceans, up to two inches long, and best known as prey for whales and penguins - but they have another important role. With their large size, high biomass and daily vertical migrations they transport and transform essential nutrients, stimulate primary productivity and influence the carbon sink. Antarctic krill are also fished by the Southern Ocean's largest fishery. Yet how krill fishing impacts nutrient fertilisation and the carbon sink in the Southern Ocean is poorly understood. Our synthesis shows fishery management should consider the influential biogeochemical role of both adult and larval Antarctic krill.

Krill faecal pellets drive hidden pulses of particulate organic carbon in the marginal ice zone.

The biological carbon pump drives a flux of particulate organic carbon (POC) through the ocean and affects atmospheric levels of carbon dioxide. Short term, episodic flux events are hard to capture with current observational techniques and may thus be underrepresented in POC flux estimates. We model the potential hidden flux of POC originating from Antarctic krill, whose swarming behaviour could result in a major conduit of carbon to depth through their rapid exploitation of phytoplankton blooms and bulk egestion of rapidly sinking faecal pellets (FPs). Our model results suggest a seasonal krill FP export flux of 0.039 GT C across the Southern Ocean marginal ice zone, corresponding to 17-61% (mean 35%) of current satellite-derived export estimates for this zone. The magnitude of our conservatively estimated flux highlights the important role of large, swarming macrozooplankton in POC export and, the need to incorporate such processes more mechanistically to improve model projections.

The potential role of Antarctic krill faecal pellets in efficient carbon export at the marginal ice zone of the South Orkney Islands in spring.

Antarctic krill (Euphausia superba) play a central role in the food web of the Southern Ocean, forming a link between primary production and large predators. Krill produce large, faecal pellets (FP) which can form a large component of mesopelagic particulate organic carbon (POC) fluxes. However, the patchy distribution of krill swarms, highly variable pellet composition, and variable sinking and attenuation rates means that these episodic, but potentially large, carbon fluxes are difficult to sample or model. We measured particle flux and type using Marine Snow Catchers (MSC) in the marginal ice zone near the South Orkneys, Antarctica. Krill FP were the dominant component of the POC flux in the upper 200 m (typically 60-85%). FP sinking velocities measured onboard were highly variable (15-507 m d-1) but overall high, with mean equivalent velocities of 172, 267, and 161 m d-1 at our three stations. The high numbers of krill FP sinking through the mesopelagic suggest that krill FP can be transferred efficiently and/or that rates of krill FP production are high. We compared our direct MSC-derived estimates of krill FP POC flux (33-154 mg C m-2 d-1) and attenuation to estimates of krill FP production based on previous measurements of krill density and literature FP egestion rates, and estimated net krill FP attenuation rates in the upper mesopelagic. Calculated attenuation rates are sensitive to krill densities in the overlying water column but suggest that krill FP could be transferred efficiently through the upper mesopelagic, and, in agreement with our MSC attenuation estimates, could make large contributions to bathypelagic POC fluxes. Our study contrasts with some others which suggest rapid FP attenuation, highlighting the need for further work to constrain attenuation rates and assess how important the contribution of Antarctic krill FP could be to the Southern Ocean biological carbon pump.

Delayed emergence of methamphetamine's enhanced cardiovascular effects in nonhuman primates during protracted methamphetamine abstinence.

BACKGROUND: Methamphetamine abuse is linked with brain abnormalities, but its peripheral effects constitute an integral aspect of long-term methamphetamine use. METHODS: Eight male rhesus monkeys with long histories of intravenous methamphetamine self-administration were evaluated 1 day, and 1, 4, 12, 26, and 52 weeks after their last methamphetamine self-administration session. On test days, isoflurane-anesthetized animals received a 0.35 mg/kg IV methamphetamine challenge. A control group consisted of 10 age and gender matched drug naïve monkeys. Cardiovascular responses to methamphetamine were followed for 2.5h. Echocardiograms were acquired at 3 and 12 months of abstinence and in the control animals. RESULTS: No pre-methamphetamine baseline differences existed among 7 physiological measures across all conditions and controls. As expected, methamphetamine increased heart rate and blood pressure in controls. However, immediately following the self-administration period, the blood pressure response to methamphetamine challenge was reduced when compared to control monkeys. The peak and 150-min average heart rate increases, as well as peak blood pressure increases following methamphetamine were significantly elevated between weeks 12 to 26 of abstinence. These data indicate the development of tolerance followed by sensitization to methamphetamine cardiovascular effects. Echocardiography demonstrated decreased left ventricular ejection fraction and cardiac output at 3 months of abstinence. Importantly, both cardiovascular sensitization and cardiotoxicity appeared to be reversible as they returned toward control group levels after 1 year of abstinence. CONCLUSIONS: Enhanced cardiovascular effects may occur after prolonged abstinence in addicts relapsing to methamphetamine and may underlie clinically reported acute cardiotoxic events.

SU-E-J-157: Simulation and Design of a Real-Time 6D Head Motion Compensation Platform Based on a Stewart Platform Approach.

PURPOSE: Real-time sub-millimeter head motion compensation during frameless SRS delivery has the potential to achieve the accuracy of frame-based SRS while being significantly less invasive. Previously, we demonstrated real-time 6D head motion monitoring using an optical camera, however, at the time we were limited to only 3D (x-y-z) of head motion correction due to mechanical restrictions of the head platform. In this work we investigate the feasibility of using a compact 6D robotic Stewart platform (hexapod) placed under the patient's head to perform both translational and rotational motion compensation in real-time. Benefits of a hexapod approach over a conventional serial kinematics stage include less flex, compactness, high force to weight ratio, and fast response times. METHODS: A hexapod is a parallel robotics device consisting of two platforms connected by six linear actuators oriented at particular angles. To provide accurate motion in 6D, the desired position of the top platform (head) was ascertained using inverse kinematics. MATLAB was used to simulate the six actuator positions for performing motion along x-y-z-phi -theta-psi. Prior recorded 6D human volunteer head motion data was used as an input for simulation of motion compensation. Six Firgelli L12-P linearservo actuators, together with a PCI-7344 motion controller and Labview software, were used for initial construction of a hexapod prototype. RESULTS: The necessary actuator lengths over time were computed for this data, simulating the required 6D movement of the hexapod for motion correction. Simulations on previously collected volunteer data indicate a hexapod system is capable of responding to subject head motion with corrections of precise movements, and solutions to the linear system can be computed at near real-time speeds. CONCLUSIONS: Based on simulated results, it was successfully demonstrated that a hexapod device can compensate for small patient head motions along all six degrees of freedom.

First Report of In-Vitro Boscalid-Resistant Isolates of Alternaria solani Causing Early Blight of Potato in Idaho.

Early blight of potato (Solanum tuberosum) is caused by Alternaria solani and occurs annually to some degree in Idaho. The timing of its appearance and rate of disease progress determine the impact on the potato crop. Though losses rarely exceed 20%, they can be higher and occur in stored potatoes if the disease is not controlled. Early blight is managed mainly by cultural practices such as plant nutrition, water management, and avoidance of plant stress, but also with the use of foliar fungicides. Currently, the main fungicides labeled for control of early blight are in the carboxamide and strobilurin fungicide groups. Development of resistance to some fungicide groups may contribute to the loss of control of early blight. Isolates of A. solani from Idaho potatoes were tested for resistance to boscalid in the carboxamide group. Diseased potato leaves with early blight symptoms were collected from fields near Parma, Rupert, and Aberdeen in southern Idaho in 2009 and 2010 and Bonners Ferry in northern Idaho in 2010. To obtain A. solani isolates from leaves, small pieces of leaf tissue (5 × 5 mm) were taken from the center of early blight lesions and streaked across the surface of a thin layer (3 mm) of water agar. Plates were incubated at 25°C overnight to allow spores to germinate. Single germinated A. solani spores were transferred to acidified potato dextrose agar and incubated in the dark at 25°C. Germinated spores were identified based on spore morphology. Spores of A. solani can be easily distinguished from other Alternaria spp. found on potato because they are ellipsoid to oblong and taper to a long beak that is usually as long as the spore body. The identity of cultures grown from single spores was confirmed by colony and spore morphology. Sensitivity of A. solani isolates to boscalid was determined by the spiral gradient endpoint method (2). For all isolates, the effective concentration for 50% reduction in growth was outside the range of the spiral plate dilution series (i.e., isolates were either completely insensitive or completely sensitive to boscalid). In total, 46 isolates (20 collected in 2009 and 26 collected in 2010) were tested against boscalid. Experiments were carried out twice with 2009 isolates using mycelial strips and conidial suspensions. Experiments with 2010 isolates were carried out three times using only conidial suspensions. Of the isolates from 2009, 15% were insensitive. There was no difference between the use of mycelial strips or conidial suspensions. In 2010, 62% of isolates were insensitive. By location, 72% of isolates from Parma, 73% from Rupert, 63% from Aberdeen, and 44% from Bonners Ferry were insensitive. Resistance to boscalid has been reported in A. alternata isolates from pistachio (1,3). However, to our knowledge, this is the first report of resistance to boscalid in isolates of A. solani on potato. These data suggest that resistance to boscalid is widespread in Idaho, even in areas like Bonners Ferry where potato cultivation is limited. Boscalid insensitivity in vitro may not translate directly to commercial production and currently there is no evidence to suggest that boscalid has failed to control early blight in Idaho. However, the discovery of insensitive isolates suggests that boscalid should be considered at high risk of resistance development. References: (1) H. Avenot et al. Plant Dis. 91:1345, 2007. (2) H. Förster et al. Phytopathology 94:163, 2004. (3) N. Rosenzweig et al. (Abstr.) Phytopathology 93(suppl.):S75, 2003.

First Report of Rhizoctonia solani AG2-2IIIB Infecting Potato Stems and Stolons in the United States.

Rhizoctonia solani is an important pathogen of potato (Solanum tuberosum) causing qualitative and quantitative losses. It has been associated with black scurf and stem canker. Isolates of the fungus are assigned to one of 13 known anastomosis groups (AGs), of which AG3 is most commonly associated with potato disease (2,4). In August 2011, diseased potato plants originating from Rupert, ID (cv. Western Russet) and Three Rivers, MI (cv. Russet Norkotah) were received for diagnosis. Both samples displayed stem and stolon lesions typically associated with Rhizoctonia stem canker. The presence of R. solani was confirmed through isolation as previously described (4) and the Idaho and Michigan isolates were designated J11 and J8, respectively. AG was determined by sequencing the rDNA internal transcribed spacer (ITS) region using primers ITS5 and ITS4 (3). The resulting sequences of the rDNA ITS region of isolates J8 and J11 (GenBank Accession Nos. HE608839 and HE608840, respectively) were between 97 and 100% identical to that of other AG2-2IIIB isolates present in sequence databases (GenBank Accession Nos. FJ492075 and FJ492170, respectively). Koch's postulates were confirmed for each isolate by carrying out the following protocol. Each isolate was cultured on potato dextrose agar for 14 days. Five 10-mm agar plugs were then placed on top of seed tubers (cv. Maris Piper) in 1-liter pots containing John Innes Number 3 compost (John Innes Manufacturers Association, Reading, UK). Pots were held in a controlled environment room at 18°C with 50% relative humidity and watered as required. After 21 days, plants were removed and assessed for disease. Typical Rhizoctonia stem lesions were observed and R. solani was successfully reisolated from symptomatic material. To our knowledge, this is the first report of AG2-2IIIB causing disease on potatoes in the United States. In the United States, AGs 2-1, 3, 4, 5, and 9 have all been previously implicated in Rhizoctonia potato disease (2). AG2-2IIIB should now also be considered a potato pathogen in the United States. Knowledge of which AG is present is invaluable when considering a disease management strategy. AG2-2IIIB is a causal agent of sugar beet (Beta vulgaris) root rot in Idaho (1). Sugar beet is commonly grown in crop rotation with potato and such a rotation could increase the risk of soilborne infection to either crop by AG2-2IIIB. References: (1) C. A. Strausbaugh et al. Can. J. Plant Pathol. 33:210, 2011. (2) L. Tsror. J. Phytopatol. 158:649, 2010. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, Inc., New York, 1990. (4) J. W.Woodhall et al. Plant Pathol. 56:286, 2007.

Use of self-actuating and self-sensing cantilevers for imaging biological samples in fluid.

In this paper, we present a detailed investigation into the suitability of atomic force microscopy (AFM) cantilevers with integrated deflection sensor and micro-actuator for imaging of soft biological samples in fluid. The Si cantilevers are actuated using a micro-heater at the bottom end of the cantilever. Sensing is achieved through p-doped resistors connected in a Wheatstone bridge. We investigated the influence of the water on the cantilever dynamics, the actuation and the sensing mechanisms, as well as the crosstalk between sensing and actuation. Successful imaging of yeast cells in water using the integrated sensor and actuator shows the potential of the combination of this actuation and sensing method. This constitutes a major step towards the automation and miniaturization required to establish AFM in routine biomedical diagnostics and in vivo applications.

Pain experiences of traumatically injured patients in a critical care setting.

BACKGROUND: Little is known about the acute pain experiences of traumatically injured critically ill patients. OBJECTIVES: To describe pain experiences of traumatically injured adults during the first 72 hours of hospitalization. METHODS: Thirty multiply injured adults at a level I trauma center participated in the study. Pain was measured by using the McGill Pain Questionnaire and a visual analog scale. Subjects completed pain measures while at rest in a supine recumbent position and after a turn onto the side. RESULTS: The typical subject was 37 years old, had 4 major blunt trauma injuries, and had received the equivalent of 55.9 mg of morphine during the 24 hours before data collection. Mean at-rest scores were 26.5 on the pain-rating index, 2 on the present pain intensity index, and 34.6 on the visual analog scale. Immediately after the turn, mean scores on the visual analog scale increased from 25 to 48.1 (P = .002). Other pain scores after the turn did not differ significantly from at-rest values. Subjects who turned had lower scores on the visual analog scale at rest (P = .02) and less anxiety (P = .02) than did those who refused to turn. Ninety-six percent reported pain in the injured areas, and 36% reported pain related to biomedical devices. No relationship was found among reported pain and demographic, treatment, or clinical variables. CONCLUSIONS: Additional research is needed on pain at rest and during commonly performed procedures and on improved methods for pain relief in traumatically injured critically ill patients.

The 1,2,4-triazolyl cation: thermolytic and photolytic studies.

The generation of the 1,2,4-triazolyl cation (1) has been attempted by the thermolysis and photolysis of 1-(1,2,4-triazol-4-yl)-2,4,6-trimethylpyridinium tetrafluoroborate (2) and the thermolysis of 1- and 4-diazonium-1,2,4-triazoles, using mainly mesitylene as the trapping agent. Thermolysis of 2 gave mostly 1,2,4-triazole, together with 3-(1,2,4-triazol-4-yl)-2,4,6-trimethylpyridine, 4-(1,2,4-triazol-4-ylmethyl)-2,6-dimethylpyridine, and 4-(2,4,6-trimethylbenzyl)-2,6-dimethylpyridine. Thermolysis of each of the diazonium salts in the presence of mesitylene again gave mainly triazole together with very low yields of 1-(1,2,4-triazol-1-yl)-2,4,6-trimethylbenzene and the corresponding -4-yl isomer in about the same ratio. On the other hand, photolysis of 2 in mesitylene gave mainly 1-(1,2,4-triazol-1-yl)-2,4,6-trimethylbenzene. A photoinduced electron transfer from mesitylene to 2 has been observed and preliminary laser flash photolyses of 2 and the corresponding 2,4,6-triphenylpyridinium salt have been carried out. The observed transients are explained as arising from the first excited states of the pyridinium salts rather than from 1. Ab initio MO calculations are reported and indicate that the predicted electronic ground-state of the triazolyl cation is a triplet state of B1 symmetry with five pi electrons, which corresponds to a diradical cation (1c). Possible mechanisms for the formation of the various products are proposed.

Computer-mediated support group use among parents of children with cancer--an exploratory study.

This study describes aspects of computer group use as a vehicle for self-help by parents of children with cancer. Using an electronic mail system, data were gathered from 73 parents who had participated in online support groups. Most participants were Caucasian, well educated, and reported annual incomes of more than $50,000. The perceived benefits of the computer group involvement were getting information, sharing experiences, receiving general support, venting feelings, gaining accessibility, and using writing. The disadvantages included "noise," negative emotions, large volume of mail, and lack of physical contact and proximity. The findings indicate that computer group use is more common in parents with relatively high socioeconomic status. There are certain advantages and disadvantages of computer group use that need to be recognized and addressed by health professionals and users.

Selection of peptides with semiconductor binding specificity for directed nanocrystal assembly.

In biological systems, organic molecules exert a remarkable level of control over the nucleation and mineral phase of inorganic materials such as calcium carbonate and silica, and over the assembly of crystallites and other nanoscale building blocks into complex structures required for biological function. This ability to direct the assembly of nanoscale components into controlled and sophisticated structures has motivated intense efforts to develop assembly methods that mimic or exploit the recognition capabilities and interactions found in biological systems. Of particular value would be methods that could be applied to materials with interesting electronic or optical properties, but natural evolution has not selected for interactions between biomolecules and such materials. However, peptides with limited selectivity for binding to metal surfaces and metal oxide surfaces have been successfully selected. Here we extend this approach and show that combinatorial phage-display libraries can be used to evolve peptides that bind to a range of semiconductor surfaces with high specificity, depending on the crystallographic orientation and composition of the structurally similar materials we have used. As electronic devices contain structurally related materials in close proximity, such peptides may find use for the controlled placement and assembly of a variety of practically important materials, thus broadening the scope for 'bottom-up' fabrication approaches.

Integrating cancer risk assessment into a community health nursing course.

BACKGROUND: Because the state of Maryland has the fourth highest cancer death rate among the states and the District of Columbia, a community-based hospital identified the need to develop a cancer prevention, screening, and education program for the community at large and the employees. Subsequently, as a prerequisite for graduation, Community Health Nursing Students (CHN) conducted a project with the goal of assessing hospital employee cancer risk status and presenting a hospital-based cancer education program. METHOD: Data regarding employee cancer risk status were gathered using a modified 31-item cancer-risk-assessment guide; risk factors for cancers of the lung, colon-rectum, skin, prostate, breast, and cervix were identified. RESULTS: Overall, the employees were at a high to moderate risk of developing cancers of the cervix, followed by cancers of the skin and breast, and at lowest risk of developing cancer of the lung, followed by cancers of the prostate and colon-rectum. CONCLUSION: The findings provided baseline data for the development of employee-focused cancer education and screening programs.

Mentoring: the ultimate professional relationship.

Mentoring plays a significant role in business, industry, government, education, and healthcare. Mentoring relationships help promote the individual's professional growth and development. Such development involves knowledge and skill acquisition, which is facilitated by interaction with other, more experienced and proficient professionals. The Belcher-Sibbald Continuum of Learning describes the relationship among the concepts of role modeling, networking, preceptoring, and mentoring. Each concept is defined and described as a unique relationship which promotes professional growth and development. In addition, three mentoring/networking relationships in the context of the wound care community are presented to provide insight into this type of relationship.

Modification of calcite crystal growth by abalone shell proteins: an atomic force microscope study.

A family of soluble proteins from the shell of Haliotis rufescens was introduced over a growing calcite crystal being scanned in situ by an atomic force microscope (AFM). Atomic step edges on the crystal surface were altered in shape and speed of growth by the proteins. Proteins attached nonuniformly to the surface, indicating different interactions with crystallographically different step edges. The observed changes were consistent with the habit modification induced by this family of proteins, as previously observed by optical microscopy. To facilitate further studies in this area, AFM techniques and certain AFM imaging artifacts are discussed in detail.

Molecular cloning and characterization of lustrin A, a matrix protein from shell and pearl nacre of Haliotis rufescens.

A specialized extracellular matrix of proteins and polysaccharides controls the morphology and packing of calcium carbonate crystals and becomes occluded within the mineralized composite during formation of the molluscan shell and pearl. We have cloned and characterized the cDNA coding for Lustrin A, a newly described matrix protein from the nacreous layer of the shell and pearl produced by the abalone, Haliotis rufescens, a marine gastropod mollusc. The full-length cDNA is 4,439 base pairs (bp) long and contains an open reading frame coding for 1,428 amino acids. The deduced amino acid sequence reveals a highly modular structure with a high proportion of Ser (16%), Pro (14%), Gly (13%), and Cys (9%). The protein contains ten highly conserved cysteine-rich domains interspersed by eight proline-rich domains; a glycine- and serine-rich domain lies between the two cysteine-rich domains nearest the C terminus, and these are followed by a basic domain and a C-terminal domain that is highly similar to known protease inhibitors. The glycine- and serine-rich domain and at least one of the proline-rich domains show sequence similarity to proteins of two extracellular matrix superfamilies (one of which also is involved in the mineralized matrixes of bone, dentin, and avian eggshell). The arrangement of alternating cysteine-rich domains and proline-rich domains is strikingly similar to that found in frustulins, the proteins that are integral to the silicified cell wall of diatoms. Its modular structure suggests that Lustrin A is a multifunctional protein, whereas the occurrence of related sequences suggest it is a member of a multiprotein family.

Regulation of expression of a cDNA from barley roots encoding a high affinity sulphate transporter.

A cDNA encoding a high-affinity sulphate transporter has been isolated from barley by complementation of a yeast mutant. The cDNA, designated HVST1, encodes a polypeptide of 660 amino acids (M(r) = 72,550), which is predicted to have 12 membrane-spanning domains and has extensive sequence homology with other identified eukaryotic sulphate transporters. The K(m) for sulphate was 6.9 microM when the HVST1 cDNA was expressed in a yeast mutant deficient in the gene encoding for the yeast SUL1 sulphate transporter. The strong pH-dependency of sulphate uptake when HVST1 was expressed heterologously in yeast suggests that the HVST1 polypeptide is a proton/sulphate co-transporter. The gene encoding HVST1 is expressed specifically in root tissues and the abundance of the mRNA is strongly influenced by sulphur nutrition. During sulphur-starvation of barley, the abundance of mRNA corresponding to HVST1, and the capacity of the roots to take up sulphate, both increase. Upon re-supply of sulphate, the abundance of the mRNA corresponding to HVST1, and the capacity of the roots to take up sulphate, decrease rapidly, concomitant with rises in tissue sulphate, cysteine and glutathione contents. Addition of the cysteine precursor, O-acetylserine, to plants grown with adequate sulphur supply, leads to increases in sulphate transporter mRNA, sulphate uptake rates and tissue contents of glutathione and cysteine. It is suggested, that whilst sulphate, cysteine and glutathione may be candidates for negative metabolic regulators of sulphate transporter gene expression, this regulation may be overridden by O-acetylserine acting as a positive regulator.

Education of the advanced practice nurse in oncology.

PURPOSE/OBJECTIVES: To review the education of the advanced practice nurse (APN) with a focus on curriculum and issues related to the oncology specialization. DATA SOURCES: The State-of-the-Knowledge Conference on Advanced Practice in Oncology Nursing, journal articles, monographs, and authors' personal experiences. DATA SYNTHESIS: APN education is a current issue in nursing, as well as in the specialty of oncology nursing. Current trends in the delivery of health care require reform of graduate education in nursing to better prepare APNs to shape and respond to the healthcare needs of the public along the entire cancer care continuum. CONCLUSIONS: APN education remains a dynamic, ever-evolving enterprise. The Oncology Nursing Society (ONS) and the American Cancer Society (ACS) have taken a proactive stand on APN education by revising master's curriculum guidelines and supporting the conference. IMPLICATIONS FOR NURSING PRACTICE: APN education in oncology will be an ongoing area of exploration for both ONS and ACS, as well as for leaders in oncology nursing. Development of graduate, postgraduate, and continuing education programs at the APN level of expertise will support high-quality advanced practice in oncology nursing. The feedback mechanisms among practice, education, and research will provide educational programs that will make a difference in the care of patients with cancer.