cssi/SciSciGPT-SciSciNet huggingface dataset:
Chemical factors influencing the rates and sequences of silica phase transitions: Effects of organic constituents

Abstract Dissolved organic matter affects the solution chemistry, hence silica recrystallization reactions, in laboratory experiments. In the presence of organic matter, the reaction rates of silica phase transitions (opal-A to opal-CT) are reduced, and the opal-CT phase produced is more “ordered” (lower d(101) spacing) than that in the absence of organic materials. The degree of this decrease in d(101) spacing depends on the solution properties of the organic materials used in the experiments. The lower the pH of a solution and the higher its organic alkalinity, the slower the formation rate of opal-CT and the lower the d(101) spacing of the opal-CT phase that forms.
A Multi-Gate MOSFET Compact Model Featuring Independent-Gate Operation

A compact model for multi-gate MOSFETs with two independently-biased gates is presented. The core model is verified against TCAD simulations without the use of any fitting parameters. Real device effects such as short channel effects and body doping effects are captured. The use of the model is demonstrated through two simulation examples: (1) Back-gate dynamic feedback of FinFET SRAM cells and (2) Tuning of device variations through back gate biasing.
The design of a new spiking neuron using dual work function silicon nanowire transistors

A new spike neuron cell is designed using vertically grown, undoped silicon nanowire transistors. This study presents an entire design cycle from designing and optimizing vertical nanowire transistors for minimal power dissipation to realizing a neuron cell and measuring its dynamic power consumption, performance and layout area. The design cycle starts with determining individual metal gate work functions for NMOS and PMOS transistors as a function of wire radius to produce a 300 mV threshold voltage. The wire radius and effective channel length are subsequently varied to find a common body geometry for both transistors that yields smaller than 1 pA OFF current while producing maximum drive currents. A spike neuron cell is subsequently built using these transistors to measure its transient performance, power dissipation and layout area. Post-layout simulation results indicate that the neuron consumes 0.397 µW to generate a +1 V and 1.12 µW to generate a −1 V output pulse for a fan-out of five synapses at 500 MHz; the power dissipation increases by approximately 3 nW for each additional synapse at the output for generating either pulse. The neuron circuit occupies approximately 0.27 µm2.
Naturally occurring cross-links in yeast chromosomal DNA

Abstract Chromosome-size yeast DNA molecules with a number average molecular weight (Mn) of 3–4 x 10 8 were isolated from sucrose gradients after sedimentation of lysed yeast spheroplasts. Resedimentation showed that the molecules were isolated without introducing appreciable single-strand or double-strand breaks. The presence of crosslinks in these molecules was suggested by the observation that the apparent Mn in alkali was greater than expected for separated single strands. Since cross-linked molecules would have strands which fail to separate upon denaturation, this was tested more directly. Neutralization of alkaline denaturing conditions resulted in up to 70% of the intact molecules rapidly reforming duplex structures, as shown by equillibrium banding in CsCl. Experiments with larger E. coli DNA molecules (Mn = 5.2 x 10 8 ) indicated that the conditions used were sufficient to denature completely molecules of this size. Results of enzyme treatments suggest that the cross-links are not RNA or protein. Experiments with density-labeled yeast DNA molecules showed that the rapid reformation of duplex DNA is not the consequence either of a bimolecular reaction between separated DNA strands or of intrastrand renaturation. The data indicate that when the yeast DNA molecules are completely denatured, the strands fail to separate. Hence they must be cross-linked. Experiments with sheared DNA show that there are a small number of crosslinks, one to four, per molecule.
Relationships between lake transparency, thermocline depth, and sediment oxygen demand in Arctic lakes

The burial of organic matter within lake sediments can be a significant component of landscape carbon cycling. Whether organic matter deposited in lake sediments is sequestered or mineralized depends on factors limiting the decomposition rate of organic matter, such as temperature and the availability of oxygen. In stratified lakes, the distribution of temperature and oxygen is determined by the depth of the thermocline, and therefore sediment organic matter burial should be sensitive to changes in thermocline depth. Using a survey of more than 30 lakes over 3 years in the Alaskan Arctic, we found that thermocline depth during the summer was positively correlated with water transparency. Furthermore, using sediment incubations from 3 lakes, we found that variation in sediment oxygen demand is primarily affected by variation in temperature and the availability of oxygen with limited effect of the source of the sediments. Because variation in temperature and oxygen concentration in stratified lakes is mainly determined by the depth of thermocline, these results indicate that changes in transparency can have indirect effects on the rate of organic matter mineralization in lakes. A reduction in thermocline depth that results from decreased lake transparency may decrease the breakdown of sediment organic matter and increase the storage of organic carbon in lake sediments.
Comparison of the accuracy of computerized videokeratography and keratometry for use in intraocular lens calculations

Abstract We compared the accuracy of keratometry and computerized videokeratography (CVK) for use in intraocular lens calculations. We studied 48 eyes of 45 patients having phacoemulsification and posterior chamber lens implantation. Computerized videokeratography was performed with the EyeSys Corneal Analysis System™ (ECAS™). Using the SRK II, SRK/T, and Holladay formulas, we evaluated predictive accuracy calculated with keratometric values and four values derived from ECAS measurements. For each formula, the use of one of the CVK parameters resulted in lower mean absolute errors between actual and predicted postoperative refractive errors and higher percentages of cases with power prediction errors
Mechanism of reduction of mitral regurgitation with vasodilator therapy

Abstract Acute mitral regurgitation was produced in six open chest dogs by excising a portion of the anterior valve leaflet. Electromagnetic flow probes were placed in the left atrium around the mitral anulus and in the ascending aorta to determine phasic left ventricular filling volume, regurgitant volume and stroke volume. The systolic pressure gradient was calculated from simultaneously measured high fidelity left atrial and left ventricular pressures. The effective mitral regurgitant orifice area was calculated from Gorlin's hydraulic equation. Infusion of nitroprusside resulted in a significant reduction in mitral regurgitation. No significant change occurred in the systolic pressure gradient between the left ventricle and the left atrium because both peak left ventricular pressure and left atrial pressure were reduced. The reduction of mitral regurgitation was largely due to reduction in the size of the mitral regurgitant orifice. Reduction of ventricular volume rather than the traditional concept of reduction of impedance to left ventricular ejection may explain the effects of vasodilators in reducing mitral regurgitation.
Control-Affine Neural Network Approach for Nonminimum-Phase Nonlinear Process Control

Abstract The design of controllers for nonlinear, nonminimum-phase processes is very challenging and remains as one of the more difficult control research problems. Most currently available control algorithms rely implicitly or explicitly upon an inverse of the process. Linear control methods for nonminimum-phase processes are typically based on a decomposition of the process into a minimum-phase and a nonminimum-phase part, and subsequent inversion of the minimum-phase component. A similar scheme for nonlinear systems is still an open problem. In this work, an internal model control strategy employing a minimum-phase model is proposed. The minimum-phase model is first-order, minimum-phase and control-affine but statically equivalent to the original process. Because the model is identified directly from input-output data, a first principles model of the process is not required. The inverse of the process is obtained through analytical inversion of the process model. The proposed control scheme is applied to a van de Vusse reactor and a complex continuous stirred tank bioreactor.
TWO-PLASMA MODEL FOR LOW CHARGE STATE INTERPLANETARY CORONAL MASS EJECTION OBSERVATIONS

Recent ACE/SWICS observations have revealed that ~5% of all in situ observed interplanetary coronal mass ejections include time periods with very low charge state ions found to be associated with prominence eruptions. It was also shown that these low charge state ions are often observed concurrently with very high charge state ions. But, the physical process leading to these mixed charge states is not known and could be caused by either the mixing of plasmas of different temperatures or by non-local freeze-in effects as discussed by Gruesbeck. We provide a detailed and multi-stage analysis that excludes this latter option. We therefore conclude that time periods of very low charge states are the heliospheric remnants of plasmas born in prominences. We further conclude that the contemporaneously observed low and very high charge states are an indication of mixing of plasmas of different temperatures along magnetic field lines, suggesting that silicon and iron are depleted over carbon and oxygen in the cold, prominence-associated plasma. This represents the first experimental determination of elemental composition of prominence-associated plasma.
Clinical Applications of Diffusion Tensor Imaging

Advancements in diffusion-weighted imaging during the past decade have led to the use of diffusion tensor imaging to further characterize the structural integrity of neural tissue and to noninvasively trace neuronal tracts in the brain and spine. This has led to many clinical applications that have aided in surgical planning for brain and spinal cord tumors and has increased the diagnostic potential of magnetic resonance imaging in disorders such as multiple sclerosis, Alzheimer disease, and traumatic brain injury.
Progress and obstacles in the development of an AIDS vaccine

Generating an effective AIDS vaccine remains a high priority. Are we any closer to reaching this goal? How might we overcome virus variability and generate a vaccine that elicits protective humoral and cellular immune responses at mucosal surfaces as well as systemically? Recent experimental observations suggest approaches to immunization that might finally result in at least a partially effective vaccine against infection with HIV-1. In particular, advances in our understanding of the contribution of vaccine-elicited cellular immunity to protecting memory CD4+ T cells from virus-mediated destruction provide rational strategies for the development of this vaccine. This is therefore an ideal time to review our current understanding of HIV-1 and its control by the immune system, as well as the remaining problems that must be solved to facilitate the development of an effective vaccine against AIDS.
What is the role of portion control in weight management

Systematic studies have shown that providing individuals with larger portions of foods and beverages leads to substantial increases in energy intake. The effect is sustained over weeks, supporting the possibility that large portions have a role in the development of obesity. The challenge is to find strategies to effectively manage the effects of portion size. One approach involves teaching people to select appropriate portions and to use tools that facilitate portion control. Although tools such as portion-control plates have been shown in several randomized trials to improve weight loss, limited data are available on whether education and tools lead to long-term changes in eating behavior and body weight. Another approach is to use preportioned foods (PPFs) to add structure to meals and minimize decisions about the amount of food to eat. A number of randomized controlled trials have demonstrated the efficacy of both liquid meal replacements and solid PPFs for weight loss and weight loss maintenance, but it is not known if they lead to better understanding of appropriate portions. Although portion control is important for weight management, urging people simply to ‘eat less’ of all foods may not be the best approach as high-energy-dense foods disproportionately increase energy intake compared with those lower in energy density. A more effective strategy may be to encourage people to increase the proportion of foods low in energy density in their diets while limiting portions of high-energy-dense foods. If people lower the energy density of their diet, they can eat satisfying portions while managing their body weight.
Delayed primary closure after sternal wound infection

Infected median sternotomy is a major complication of cardiac operations. Over a 30-month period, 25 sternal wound infections were treated at a single institution. Twenty-four (2.7%) followed 883 operations with cardiopulmonary bypass, and 1 followed median sternotomy for a noncardiac procedure. Twenty-one of the 25 patients survived to sternal closure. Eighteen patients were treated with delayed primary closure and 3 with pectoralis muscle flaps. Fifteen patients (83%) had an uneventful postoperative course after delayed primary closure. In 2 patients reoperation was required for sternal dehiscence, and in 1 patient a superficial wound infection developed, which was treated with local wound care. In all 18 patients the sternum eventually healed. Criteria for delayed primary closure included clean tissue surfaces without purulent debris, the absence of pockets of purulent drainage, and negative wound cultures obtained 24 hours before closure. The average time from operation to sternal incision and drainage was 11 days (range, five to 59 days). Delayed primary closure was performed nine days after incision and drainage (range, five to 27 days). The average hospital stay was 24 days after sternal incision and drainage (range, nine to 85 days). Cultures from specimens taken at the time of sternal incision and drainage were positive in all patients. Wound cultures were positive at the time of sternal closure in 5 patients. Wound complications developed in 2 of these 5 patients. Delayed primary closure has many of the advantages of classic methods, but fewer complications. Results are comparable, while allowing simpler wound care and less cosmetic deformity. Delayed primary closure is an acceptable alternative in the treatment of sternal wound infections.
Measurements of Airborne Influenza Virus in Aerosol Particles from Human Coughs

Influenza is thought to be communicated from person to person by multiple pathways. However, the relative importance of different routes of influenza transmission is unclear. To better understand the potential for the airborne spread of influenza, we measured the amount and size of aerosol particles containing influenza virus that were produced by coughing. Subjects were recruited from patients presenting at a student health clinic with influenza-like symptoms. Nasopharyngeal swabs were collected from the volunteers and they were asked to cough three times into a spirometer. After each cough, the cough-generated aerosol was collected using a NIOSH two-stage bioaerosol cyclone sampler or an SKC BioSampler. The amount of influenza viral RNA contained in the samplers was analyzed using quantitative real-time reverse-transcription PCR (qPCR) targeting the matrix gene M1. For half of the subjects, viral plaque assays were performed on the nasopharyngeal swabs and cough aerosol samples to determine if viable virus was present. Fifty-eight subjects were tested, of whom 47 were positive for influenza virus by qPCR. Influenza viral RNA was detected in coughs from 38 of these subjects (81%). Thirty-five percent of the influenza RNA was contained in particles >4 µm in aerodynamic diameter, while 23% was in particles 1 to 4 µm and 42% in particles <1 µm. Viable influenza virus was detected in the cough aerosols from 2 of 21 subjects with influenza. These results show that coughing by influenza patients emits aerosol particles containing influenza virus and that much of the viral RNA is contained within particles in the respirable size range. The results support the idea that the airborne route may be a pathway for influenza transmission, especially in the immediate vicinity of an influenza patient. Further research is needed on the viability of airborne influenza viruses and the risk of transmission.
Solid state fault interruption devices in medium voltage microgrid distribution systems with distributed energy resources

The solid state fault interruption device (SSFID) is used for the purpose of quickly isolating sections of power networks under permanent faults. The SSFID is tested for performance by simulation in a simulated medium voltage system. A comparison with the conventional breaker is presented in response to system faults in the presence of wind power plants and other distributed energy resources. The SSFID appears to be a superior alternative to the contemporary mechanical circuit breaker in isolating faulted sections. However, some high transients may appear on the network because of the operation of the device.
Microstructure of RuO2 layer as diffusion barrier between Al and Si substrate

Abstract The microstructure of samples consisting of a 40 nm thick RuO 2 film reactively sputtered on a Si 〈 111 〉 substrate and covered with 20 nm of Al (〈 Si 〉/RuO 2 / Al) is investigated by high-resolution cross-sectional electron microscopy. The depth distributions of elements are studied by Rutherford backscattering spectrometry and electron probe microanalysis. In the as-deposited sample, the RuO 2 /Al interface is sharp, but a thin (3 nm) SiO 2 layer is observed at the 〈 Si 〉/RuO 2 interface. After annealing at temperatures ranging from 450 to 700°C for 1–6 h, that layer remains unchanged, but a crystalline compound layer forms at the RuO 2 /Al interface. No diffusion of Si and Al into RuO 2 is detectable. The possible mechanisms for the barrier characteristics are discussed. We believe that the presence of the thin SiO 2 layer and the formation of an additional compound layer is intimately related to the good barrier performance of RuO 2 .
Active sub-Rayleigh alignment of parallel or antiparallel laser beams.

We measure and stabilize the relative angle of parallel and antiparallel laser beams to 5?nrad?Hz resolution by comparing the phases of radio frequency beat notes on a quadrant photodetector. The absolute accuracy is 5.1 and 2.1??rad for antiparallel and parallel beams, respectively, which is more than 6 and 16 times below the Rayleigh criterion.
Sodium-selective liquid ion-exchanger microelectrodes for intracellular measurements

The sodium-selective ligand 1,1,1-tris[1(1)-(2(1)-oxa-4(1)-oxo-5(1)-aza-5(1)-methyl)dodecanyl]propane dissolved in 3-nitro-o-xylene containing a small amount of the lipophilic anion tetrachlorophenyl borate was used as a liquid ion-exchanger in sodium-selective microelectrodes. The microelectrodes gave rapid, stable responses that were linear functions of the logarithm of sodium activity. They were tested under conditions approximating those to be expected in the cell interior, and the results indicated that they can be used to measure intracellular sodium activity without significant interference from intracellular potassium.
Supporting Science Learning through Science Literacy Objectives for English Language Learners

The author provides information on how science teachers can write science literacy objectives that help English language learners (ELLs) develop the scientific literacy needed for academic success in the science classroom. The article offers suggestions on how teachers can determine the vocabulary, language functions, and sentence structures that their students need to engage in critical thinking in science. An approach for collaboration with students' English as a second language (ESL) teacher is discussed.
The Story of Jonah on a Magical Amulet

THE WORDS of Jesus in Matt. I2.39-4I gave the story of Jonah an important place among Christian symbols, establishing it as a type of the resurrection of the Christ, and, through him, of all mankind. Its influence upon Christian thought is attested by the church writers from Justin on (Dial. 107-8). Tertullian supports the doctrine of resurrection in the flesh by various scriptural texts, among them the deliverance of Jonah, saying: ". .. quod Ionas devoratus a belua maris, in cuius alvo naufragia digerebantur, triduo post incolomis expuitur . . . cuinam fidei testimonium signant, nisi qua credi oportet haec futurae integritatis esse documenta?" Similarly Augustine, "Ut quid enim exceptus est ventre beluino et die tertio redditus nisi ut significaret Christum de profundo inferni die tertio rediturum?" 1 Other examples could be cited; but the literary allusions to the story of Jonah are few as compared to the works of art that deal with it. More than two hundred such representations on frescoes, sculptures, and small objects were known to Dom H. Leclercq, whose comprehensive article leaves little for later gleaners to gather in.2 The scenes depicted, whether together or singly, are almost always the swallowing of Jonah by the sea monster, the disgorging, and Jonah's rest under the shade of the gourd. Works of art that have to do with the story of Jonah are scantily represented in American collections. In the Metropolitan Museum there is a small, crude, and much damaged sculpture, which was published by Dr. Walter Lowrie in 1901; the work is in marble, partly in relief, partly in the round, and is probably not earlier than the fourth century.3 It shows a ship sailing to right with a crew of four men, a helmsman, almost completely destroyed, and
Na-K-ATPase and transepithelial sodium transport in the toad

Abstract 1. 1. Studies have been conducted using the isolated toad skin and urinary bladder preparations in an attempt to evaluate the relationship between sodium, potassium activated adenosinetriphosphatase (Na-K-ATPase) system and transepithelial sodium transport. 2. 2. In both the skin and bladder, ouabain showed no significant inhibitory effect on the Na-K-ATPase activity at 23°C, while it exerted a potent inhibition of the active sodium transport at this temperature. On the other hand, at 37°C, both the Na-K-ATPase activity and the sodium transport were strongly inhibited by the glycoside. 3. 3. The inhibitory effect of ouabain on the sodium transport was reduced as potassium concentration in the serosal bathing medium was increased. 4. 4. There was no apparent correlation between the magnitude of sodium transport and the Na-K-ATPase activity of the skin regardless of whether the skin was treated with vasopressin (ADH), ouabain, or both ADH and ouabain. 5. 5. These results emphasize the difficulty associated with correlating sodium transport across epithelia with activity of Na-K-ATPase in a subcellular fraction.
Optimal communication channel utilization for matrix transposition and related permutations on binary cubes

Abstract We present optimal schedules for permutations in which each node sends one or several unique messages to every other node. With concurrent communication on all channels of every node in binary cube networks, the number of element transfers in sequence for K elements per node is K 2 , irrespective of the number of nodes over which the data set is distributed. For a succession of s permutations within disjoint subcubes of d dimensions each, our schedules yield min ( K 2 +(s−1)d,(s+3)d, K 2 +2d) exchanges in sequence. The algorithms can be organized to avoid indirect addressing in the internode data exchanges, a property that increases the performance on some architectures. For message-passing communication libraries, we present a blocking procedure that minimizes the number of block transfers while preserving the utilization of the communication channels. For schedules with optimal channel utilization, the number of block transfers for a binary d -cube is d . The maximum block size for K elements per node is ⌈ K (2d) ⌉.
Histopathological changes in distal tracheal mucosa in beagle puppies.

Summary Direct effects of the tracheotomy tube and cuff on glottic, subglottic and tracheal mucosa have been well described. Little work has been done on the effects of tracheotomy on the distal tracheobronchial tree. Ten beagle puppies underwent tracheotomy and were sacrificed at 18, 24, 36, 48 and 72 h. The trachea was studied for changes in cilia, epithelium, submucosal reaction and mucous production at the level of the tracheostome, tracheotomy tube tip, carina and right mainstem bronchus. Severe changes of epithelial erosion and ulceration with submucosal inflammatory reaction were noted as early as 18 h and persisted through 24 h. Some resolution of inflammation and progression to squamous metaplasia were seen at 36, 48 and 72 h. Changes in mucous gland activity varied widely. The traumatic effects of tracheotomy on normal tracheal anatomy and physiology and their clinical implications are discussed.
Clinical utility of intraoperative frozen section diagnosis in head and neck surgery: A quality assurance perspective

The technical and professional issues that affect the clinical utility of intraoperative frozen section diagnosis in head and neck surgery are addressed from a quality assurance perspective. The most common reasons for sampling errors and interpretive errors are discussed. We offer several recommendations for head and neck surgeons and pathologists which will optimize the clinical utility of intraoperative frozen section consultation.
An Optimal Scaling Method

Many areas of systems deal with sets of nonlinear functions that can be handled more effectively if proper scaling is performed. When working with m functions and n variables, (m + n) scaling factors are used. A variety of approaches to scaling are reviewed. A method for establishing a scaling array for nonlinear functions is given. The array consists of m rows and (n + 1) columns, with the scaling factor for the (n + 1)-st column constrained to be unity. A particular approach to scaling, introduced by Hamming, is generalized to include weighting factors and target values for array entries. The minimum of the resulting scaling performance measure is characterized by sets of linear equations. A numerical procedure for solving for the optimal scaling factors is given for the general case, and closed-form solutions are obtained for a special case. Numerical examples are used to demonstrate benefits of the use of target values and weighting factors.
Needs of Persons With Serious Mental Illness Following Discharge From Inpatient Treatment: Patient and Family Views

Patients with serious mental illnesses often struggle with persistent symptoms that interfere with daily functioning in the community. The first days and weeks following inpatient treatment for an acute episode may be a critical time for patients to connect with the recommended community follow-up. Residual symptoms may interfere with their ability to access and benefit from these services to meet their needs. A descriptive study was conducted to explore perceptions of patients and families of patients' needs, functioning, coping and social support in the first 4 weeks after inpatient treatment. Results suggested that these patients had residual symptoms after discharge that interfered with functioning despite the availability of follow-up services. Patients identified unmet needs related to their illness. Family members identified concerns related to the lack of improvement in their ill relatives over time. Patients expressed satisfaction with care and felt supported by their families. Both patients and families seemed to lack a thorough understanding of goals for follow-up care.
EFFECTS OF MINOCYCLINE ON SPATIAL LEARNING, HIPPOCAMPAL NEUROGENESIS AND MICROGLIA IN AGED AND ADULT MICE

Age-related priming of microglia and release of inflammatory cytokines, such as interleukin-1β (IL-1β) and interleuekin-6 (IL-6) have been associated with deficits in cognitive function. The present study assessed whether treatment with minocycline could improve spatial cognition in aged mice, and whether these improvements in behavior were associated with reduced microglia activation and an enhancement in hippocampal neurogenesis. Adult (3 months) and aged (22 months) male BALB/c mice received minocycline in their drinking water or control mice received distilled water for 20 days. Mice received BrdU to label dividing cells on days 8–17. Spatial learning was measured using the water maze. Immunohistochemistry was conducted to measure number of BrdU positive neurons and number and size of microglia by detection of Iba-1 in the dentate gyrus molecular layer. Further, hippocampal samples were collected to measure changes in IL-1β, IL-6, and CD74 expression. The data show that aged mice have increased hippocampal expression of IL-1β, IL-6, and CD74 relative to adults. Minocycline treatment significantly improved acquisition of the water maze in aged mice but not adults. Minocycline reduced the average size of Iba-1 positive cells and total Iba-1 counts, but did not affect hippocampal cytokine gene expression. Minocycline increased neurogenesis in adults but not aged mice. Collectively, the data indicate that treatment with minocycline may recover some aspects of cognitive decline associated with aging, but the effect appears to be unrelated to adult hippocampal neurogenesis.
Studies of a reactive histidine of diphosphopyridine nucleotide-linked isocitrate dehydrogenase from bovine heart☆

Abstract Diphosphopyridine nucleotide-linked isocitrate dehydrogenase from bovine heart was inactivated at neutral pH by bromoacetate and diethyl pyrocarbonate and by photooxidation in the presence of methylene blue or rose bengal. Inactivation by diethyl pyrocarbonate was reversed by hydroxylamine. Loss of activity by photooxidation at pH 7.07 was accompanied by progressive destruction of histidine with time; loss of 83% of the enzyme activity was accompanied by modification of 1.1 histidyl residues per enzyme subunit. The pH-rate profiles of inactivation by photooxidation and by diethyl pyrocarbonate modification showed an inflection point around pH 6.6, in accord with the p K a for a histidyl residue of a protein. Partial protection against inactivation by photooxidation or diethyl pyrocarbonate was obtained with substrate (manganous isocitrate or magnesium isocitrate) or ADP; the combination of substrate and ADP was more effective than the components singly. As demonstrated by differential enzyme activity assays between pH 6.4 and pH 7.5 with and without 0.67 m m ADP, modification of the reactive histidyl residue of the enzyme caused a preferential loss of the positive modulation of activity by ADP. The latter was particularly apparent when substrate partially protected the enzyme against inactivation by rose bengal-induced photooxidation.
Dysfunction of Natural Killer Activity in a Family with Chronic Fatigue Syndrome

Abstract A family was identified with 5 of 6 siblings and 3 other immediate family members who had developed chronic fatigue syndrome (CFS) as adults. All 8 met criteria for the CFS case definition as recommended by the Centers for Disease Control and Prevention. Sixty-eight blood samples were obtained over a period of 2 years from 20 family members (8 affected, 12 unaffected) and 8 normal controls. All blood samples were tested for NK activity in 4-h51Cr-release assays and for the number of circulating CD3–CD56+and CD3–CD16+by flow cytometry. NK activity of the affected immediate family members (cases,n= 8) was significantly lower (P= 0.006, two-sided) than that of the concurrently tested normal controls. The results for unaffected family members were intermediate between these two groups, and the pairwise comparison of unaffected family members to either cases or controls showed no statistically significant difference (P= 0.29, two-sided). No differences were seen between the groups in the absolute number of CD3–CD56+or CD3–CD16+lymphocytes in the peripheral blood. Familial CFS was associated withpersistentlylow NK activity, which was documented in 6/8 cases and in 4/12 unaffected family members. In the family with 5 of 6 siblings who had documented CFS, 2 of their offspring had pediatric malignancies. Low NK activity in this family may be a result of a genetically determined immunologic abnormality predisposing to CFS and cancer.
Incremental Maxwell Garnett formalism for homogenizing particulate composite media

Based on the Maxwell Garnett (MG) formalism for homogenizing particulate composite media, an incremental MG (IMG) formalism is developed. Whereas the MG formalism is suitable for dilute composite media, the IMG formalism is phenomenologically valid even for dense composite media because it homogenizes incrementally over a succession of several intermediate dilute composite media. IMG algorithms are presented for the simple dielectric-in-dielectric, as well as the complicated bianisotropic-in-bianisotropic composite media. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 276–279, 1998.
Partial characterization of phospholipase C activity in normal, psoriatic uninvolved, and lesional epidermis.

Abstract Arachidonic acid (AA), the precursor of prostaglandins and leukotrienes, can be directly liberated from membrane phospholipids by phospholipase A 2 or indirectly by phospholipase C. One or both of these enzymes may be responsible for the increased content of AA found in psoriatic lesional epidermis. Keratome biopsies were obtained from normal and psoriatic individuals. After homogenization and sonication, a 10,000 g supernatant was used as the enzyme source. The activities of both phospholipase A 2 and C were assayed in each sample using phosphatidylcholine and phosphatidylinositol, respectively, as substrates. Phospholipase A 2 activity was found to be significantly higher than normal in both uninvolved and lesional psoriatic epidermis. In contrast, phospholipase C activity was significantly higher than normal in only the psoriatic plaque on the basis of wet weight ( p p = 0.01), and DNA ( p = 0.004) content. Phospholipase C activity in pmol diacylglycerol formed/min/μg DNA was: normal 4.96 ± 0.80, n=13; uninvolved 7.29 ± 1.06, n=18; plaque 14.44 ± 2.50, n=18. Analysis (pH profile, calcium requirement, substrate specificity, and saturation kinetics) of pooled epidermal extracts showed no inherent differences in phospholipase C from normal and psoriatic epidermis, suggesting either a higher concentration or the presence of an activated form of the enzyme in psoriatic plaque. Since phospholipase C activity, in contrast to phospholipase A 2 activity, is elevated only in lesional epidermis, it is possible that this enzyme contributes to AA accumulation observed in this tissue.
Microscale fracture measurements with application to comminution

Abstract Indentation fracture is widely used in the ceramics and hard-metals industries for the measurement of material fracture toughness. Particular advantages unique to this technique are the relative ease of performing tests, the small quantity of material required, the low cost and ready availability of equipment, and the simplicity of sample preparation. We have applied this technique successfully to the measurement of fracture toughness of geological materials and measurements have been made on a number of samples. These measurements have been correlated with experimental results from particle breakage tests under impact conditions. The very small volume of material involved in the indentation test makes the technique useful as a microstructural probe. It can be used to measure the relative fracture resistance of different portions of a mineral composite. This is done by measuring the total extent of the surface expression of cracking produced by a micro-indenter using image analysis procedures. Measurements in a number of mineralogical materials showed that the amount of fracturing in the vicinity of a grain boundary is more extensive than in the bulk of the grain, and that in some materials, fracture along the grain boundary dominates over propagation into the adjacent grain. These effects could have significant implications for mineral liberation.
From status to delinquent offenses: Escalation?

Abstract An important issue in juvenile justice today is whether the juvenile court should maintain or abandon its present legal jurisdiction over status offenders. Arguments in favor of retaining such jurisdiction are often based on the relatively untested assumption of career “escalation”—the idea that juvenile misbehaviors, if left untreated, will increase in seriousness with age from status offenses to more serious forms of delinquency. However, our analysis of self-reported surveys from a national panel of boys indicates that patterns of juvenile misbehaviors are more likely to be stable or constant over time than to increase in seriousness. The policy implications of these findings are discussed.
Estimation of Substituent Group Electronic Influence from Molecular Connectivity Delta Values

An estimation of the relative electronegativities of atoms in their valence state is presented, based upon counts of valence and sigma electrons other than those bonding with hydrogen. This Kier/Hall valence state electronegativity is linearly related to the Mulliken-Jaffe' electronegativity. This estimation is extended to include group electronegativities. Groups, treated as benzene ring substituents, are evaluated in terms of their electronic influence on a benzene ring. This influence is partitioned into electronegativity equalization effects through sigma and pi orbital interactions plus lone pair orbital pressure on the ring pi system. A simple summation of these three influences, calculated very easily from structure, is found to be well correlated with the Hammett values for 25 common substituents for both para and meta position values. The present treatment deals with first row elements.
Compact, power-efficient architectures using microvalves and microsensors, for intrathecal, insulin, and other drug delivery systems

Abstract This paper describes a valve-regulated architecture, for intrathecal, insulin and other drug delivery systems, that offers high performance and volume efficiency through the use of micromachined components. Multi-drug protocols can be accommodated by using a valve manifold to modulate and mix drug flows from individual reservoirs. A piezoelectrically-actuated silicon microvalve with embedded pressure sensors is used to regulate dosing by throttling flow from a mechanically-pressurized reservoir. A preliminary prototype system is demonstrated with two reservoirs, pressure sensors, and a control circuit board within a 130 cm3 metal casing. Different control modes of the programmable system have been evaluated to mimic clinical applications. Bolus and continuous flow deliveries have been demonstrated. A wide range of delivery rates can be achieved by adjusting the parameters of the manifold valves or reservoir springs. The capability to compensate for changes in delivery pressure has been experimentally verified. The pressure profiles can also be used to detect catheter occlusions and disconnects. The benefits of this architecture compared with alternative options are reviewed.
Effects of urine composition on epithelial Na+ channel‐targeted protease activity

We examined human urinary proteolytic activity toward the Epithelial Sodium Channel (ENaC). We focused on two sites in each of alpha and gamma ENaC that are targets of endogenous and exogenous proteases. We examined the effects of ionic strength, pH and urinary H+-buffers, metabolic intermediates, redox molecules, and large urinary proteins. Monoatomic cations caused the largest effect, with sodium inhibiting activity in the 15–515 mEq range. Multivalent cations zinc and copper inhibited urinary proteolytic activity at concentrations below 100 μmol/L. Similar to sodium, urea caused a 30% inhibition in the 0–500 mmol/L range. This was not observed with acetone and ethanol. Modulating urinary redox status modified activity with H2O2 stimulated and ascorbate inhibited activity. Minimal effects (<10%) were observed with caffeine, glucose, several TCA cycle intermediates, salicylic acid, inorganic phosphate, albumin, creatinine, and Tamm–Horsfall protein. The cumulative activity of ENaC-cleaving proteases was highest at neutral pH, however, alpha and gamma proteases exhibited an inverse dependence with alpha stimulated at acidic and gamma stimulated at alkaline pH. These data indicate that ENaC-targeting urinary proteolytic activity is sensitive to sodium, urea and pH and changes in these components can modify channel cleavage and activation status, and likely downstream sodium absorption unrelated to changes in protein or channel density.
Contributions of the 1838-1842 U.S. Exploring Expedition

The years 1988–1992 mark the 150th anniversary of the U.S. Exploring Expedition, one of the first scientific missions undertaken by the United States to explore the oceans of the world. It circumnavigated the world and mapped large portions of the coast of Antarctica, the islands of the central Pacific Ocean, and the northwest Pacific coast of North America. The explorers were the first to sight land on the Antarctic continent. The eastern Antarctic coastline was mapped by the expedition and later named Wilkesland in honor of the commander of the U.S. Exploring Expedition. The expedition mapped most of the island groups in the central Pacific Ocean, eliminating the confusion over the number and position of islands in this region. The important legacies from the expedition include the establishment of the U.S. National Museum (Smithsonian Museum) to house the collections of the cruise and the establishment of the United States as an internationally recognized scientific leader in the area of botanical, zoological, and marine studies, and as a leader and contributor to international ocean-going expeditions.
Response and recovery of a subalpine stream following a catastrophic flood

The July 15, 1982, Lawn Lake flood in Rocky Mountain National Park, Colorado, was caused by the failure of a 79-yr-old earthen dam. Peak discharges of the flood far exceeded naturally occurring flows, and it caused severe channel disturbance along most of Roaring River and some parts of Fall River. This study documents the geomorphic response of a 5-km reach of Fall River in the 5 yr following the flood. In 1983, the first year after the Lawn Lake flood, snowmelt flows were well above average. These high flows together with very high sediment yields from Roaring River resulted in significant geomorphic changes on reaches of Fall River downstream. During the 1983 snowmelt runoff, ∼15.5 x 106 kg of bed-load sediment was eroded from the upper part of the study area. These loads were at least 1,000 times higher than before the Lawn Lake flood. Most of this sediment was then deposited in a highly sinuous reach of Fall River in the lower part of the study area. This reach had not been much affected by the Lawn Lake flood, but sedimentation during the period of high flow in 1983 completely filled in the channel, resulting in the formation of a continuous 2.3-km-long depositional zone. In 1984, sediment yield from Roaring River declined dramatically, and this trend continued for the next 3 yr. By 1987, the bed-load sediment yield in the upper reaches of Fall River was only about 0.4 x 106 kg/yr. The decline in sediment loads resulted in progressive erosion and recovery of the original channel of Fall River in the depositional zone reach. Recovery in the upstream part of the depositional zone was complete by 1985. Recovery in the downstream part of the depositional zone took longer because of the continued supply of sediment and because the sediment was mobile less of the time. As of 1987, about 80% of the material initially stored in the sedimentation zone had been eroded. Bed-load sediment yields at a sampling site 1 km downstream of the terminus of the depositional zone ranged from 5 x 106 to 11 x 106 kg/yr, but showed no significant decline over the 5-yr study period. The average rate of bed-load transport through this reach was at least 100 times greater than before the Lawn Lake flood, but few discernible channel changes resulted from the higher loads.
Seismic performance of electric transmission network under component failures

Dealing with the transmission network of electric power systems, this paper identifies the sequential failures of receiving station components under a severe earthquake. Such failures progressively degrade the power network performance, potentially leading to a network blackout. Hence, in this paper, these components are incorporated into the network systems analysis taking their seismic vulnerability into consideration in the form of fragility curves for the evaluation of the network performance under seismic conditions. Specifically, most critical to the operation of transmission network, transformers, disconnect switches, circuit breakers and buses are integrated into the systems analysis, exploring the possibility of progressive failures of these components. The scenarios of these component failures can make it possible to estimate quantitatively direct cost of damage, emergency repair and restoration, and duration of power interruption and attendant economic losses and societal disruption. Copyright © 2006 John Wiley & Sons, Ltd.
Synchronizing computer clocks using Kalman filters

I have used the Kalman Filter algorithm to improve the link between the Internet Time Servers operated by the National Institute of Standards and Technology (NIST) and the primary atomic clock ensemble in Boulder, which realizes UTC(NIST) and which is used as the reference for the time servers. The Kalman algorithm is better able to separate the contributions of multiple noise sources such as the fluctuations in the asymmetry of the channel delay and the statistical fluctuations in the clock used as the internal reference for the time server. This improved separation has made it possible to compensate to some extent for the lower-quality telephone circuits that are often used as the links for synchronizing the time servers to the atomic clock ensemble.
X Chromosome Inactivation and Epigenetic Responses to Cellular Reprogramming

Reprogramming somatic cells to derive induced pluripotent stem cells (iPSCs) has provided a new method to model disease and holds great promise for regenerative medicine. Although genetically identical to their donor somatic cells, iPSCs undergo substantial changes in the epigenetic landscape during reprogramming. One such epigenetic process, X chromosome inactivation (XCI), has recently been shown to vary widely in human female iPSCs and embryonic stem cells (ESCs). XCI is a form of dosage compensation whose chief regulator is the noncoding RNA Xist. In mouse iPSCs and ESCs, Xist expression and XCI strictly correlate with the pluripotent state, but no such correlation exists in humans. Lack of XIST expression in human cells is linked to reduced developmental potential and an altered transcriptional profile, including upregulation of genes associated with cancer, which has therefore led to concerns about the safety of pluripotent stem cells for use in regenerative medicine. In this review, we describe how different states of XIST expression define three classes of female human pluripotent stem cells and explore progress in discovering the reasons for these variations and how they might be countered.