Silicon micromachined ultrasonic scalpel for the dissection and coagulation of tissue.

This work presents a planar, longitudinal mode ultrasonic scalpel microfabricated from monocrystalline silicon wafers. Silicon was selected as the material for the ultrasonic horn due to its high speed of sound and thermal conductivity as well as its low density compared to commonly used titanium based alloys. Combined with a relatively high Young's modulus, a lighter, more efficient design for the ultrasonic scalpel can be implemented which, due to silicon batch manufacturing, can be fabricated at a lower cost. Transverse displacement of the piezoelectric actuators is coupled into the planar silicon structure and amplified by its horn-like geometry. Using finite element modeling and experimental displacement and velocity data as well as cutting tests, key design parameters have been identified that directly influence the power efficiency and robustness of the device as well as its ease of controllability when driven in resonance. Designs in which the full- and half-wave transverse modes of the transducer are matched or not matched to the natural frequencies of the piezoelectric actuators have been evaluated. The performance of the Si micromachined scalpels has been found to be comparable to existing commercial titanium based ultrasonic scalpels used in surgical operations for efficient dissection of tissue as well as coaptation and coagulation of tissue for hemostasis. Tip displacements (peak-to-peak) of the scalpels in the range of 10-50 µm with velocities ranging from 4 to 11 m/s have been achieved. The frequency of operation is in the range of 50-100 kHz depending on the transverse operating mode and the length of the scalpel. The cutting ability of the micromachined scalpels has been successfully demonstrated on chicken tissue.

Psychological implications of infertility in women with polycystic ovary syndrome.

BACKGROUND: In polycystic ovary syndrome (PCOS), one of the main features is chronic anovulation associated with lower pregnancy rates. Little is known regarding the psychological aspects associated with infertility in these patients. Therefore, we examined the influence of an unfulfilled wish to conceive on various aspects of psychological functioning in PCOS women. METHODS: Standardized questionnaires assessing quality-of-life (36-item short-form health survey, SF-36), depressiveness (Beck Depression Inventory), emotional distress (Symptom Check List 90, SCL-90-R), sexual satisfaction and self-worth (visual analogue scales), and a questionnaire on the desire for a child (FKW) were administered at the outpatient endocrine clinic to consecutive PCOS patients. RESULTS: Questionnaires from 115 PCOS patients were analysed. The majority (76.1%) worried about remaining childless in the future, and 51.3% reported a current wish to conceive. 23.9% of patients had scores indicating mild to moderate depression, and 25.2% had scores indicating clinically relevant depression. Furthermore, all quality-of-life scores were significantly lower compared with normative data (P < 0.001). Unexpectedly, comparisons of patients with a current unfulfilled desire to conceive to those with no present wish for a child revealed no discernable impact on depressive symptoms, quality-of-life or emotional distress. Reduced sexual satisfaction and self-worth were largely determined by partnership status and not infertility. However for PCOS patients who wished to conceive, the wish for a child was a significantly greater priority when compared with normative data from infertile patients. CONCLUSIONS: PCOS represents a major risk factor for psychosocial and emotional problems, but at least in this sample of PCOS patients, infertility does not appear to constitute a primary determinant of psychological problems.

Obesity, depression, and chronic low-grade inflammation in women with polycystic ovary syndrome.

BACKGROUND AND OBJECTIVE: Women with polycystic ovary syndrome (PCOS) present with multiple risk factors for cardiovascular diseases at a young age, including obesity and chronic low-grade inflammation. Since depression is common in PCOS, this study aimed to address whether depression correlates with indices of chronic low-grade inflammation beyond the association with obesity. METHODS: Serum concentrations of IL-6, the stimulated production of IFN-gamma, TNF-alpha, IL-2, IL-4, IL-5, and IL-10, leukocyte numbers, and hsCRP were analyzed in 57 PCOS patients and 28 healthy women, together with clinical parameters, including body mass index (BMI), testosterone, and insulin resistance (HOMA-IR), and psychological parameters, including Beck Depression Inventory (BDI) and health-related quality-of-life (SF-36) scores. RESULTS: PCOS patients demonstrated significantly increased hsCRP, IL-6, and leukocyte numbers. Group differences in IL-6 and leukocyte numbers, but not hsCRP, disappeared after controlling for BMI. The stimulated production of IFN-gamma, TNF-alpha, IL-2, IL-4, and IL-5 was significantly decreased, irrespective of BMI. In PCOS, hsCRP, IL-6, and leukocyte numbers were correlated with BMI, HDL, diastolic blood pressure, and with insulin resistance. On the other hand, no correlations were found with depression scores or with PCOS-specific endocrine abnormalities. In regression models, BMI was a significant predictor of the key immune markers, and explained a large amount of variance, whereas BDI was not included in either model. CONCLUSIONS: These data confirm that obesity plays a pivotal role in inflammatory processes relevant to cardiovascular risk in women with PCOS. However, even lean PCOS patients may display subtle alterations in specific aspects of immunity. Our findings did not support a correlation of depression with chronic low-grade inflammation in PCOS.

Ionic and acid-base consequences of exposure to increased salinity in the zebra mussel, Dreissena polymorpha.

Dreissena polymorpha, an invasive freshwater bivalve, displays physiological characteristics that reflect its ancestry in brackish water, yet it has limited ability to withstand modest increases in salinity. We examined changes in hemolymph ion concentrations and acid-base variables in mussels transferred to and incubated in 10% artificial seawater (ASW) for 7 days and then returned to pondwater (PW) for a further 7 days. Hemolymph was sampled (10 animals per sample period) every 4 h for the first 24-h incubation and at 72 h and 168 h for both the transfer to 10% ASW and the transfer back to PW. The initial response to transfer to 10% ASW was a rapid attainment of an apparent isoosmotic steady state, with most hemolymph ion concentrations rising and attaining steady state within 12 h. Hemolymph magnesium rose more slowly, and hemolymph calcium declined despite an increase in its concentration in the bathing medium. Hemolymph pH rose significantly during the first 24 h, from 7.96 to 8.25, as a result of increases in bicarbonate; pH subsequently returned to normal through increases in PCO2. When animals were returned to PW after 7 days' incubation in ASW, the response of the major hemolymph ions was largely the reverse of that effected by the transfer to ASW. Hemolymph pH was not altered significantly until after 72 h in PW, when declines in bicarbonate lowered the pH to 7.73. Strong ion difference (SID) was related significantly to hemolymph pH. Hemolymph calcium and magnesium showed a reciprocal relationship throughout both transfer and incubation. Solubility interactions between sulfate and calcium and magnesium may be important in determining calcium availability in solution. The Na/K ratio in hemolymph was maintained within relatively narrow bounds throughout the procedure and may contribute to the mussels' ability to volume-regulate during an osmotic challenge. Overall, the responses of D. polymorpha to modest changes in salinity were largely the result of passive processes.

A new position measurement system for micro-measurements in orthopaedics.

This paper describes both a legacy position measurement system and a new position measurement system developed for use in making accurate position measurements on the order of 1 mum (micro-measurements) specifically related to the evaluation of orthopaedic implants during simulated use. Commercially available components including an off the shelf position sensor and off the shelf data acquisition hardware are integrated with a signal conditioner designed around off the shelf components, and custom written software in the new measurement system. This new system exhibits marked improvements in cost, accuracy, range and ruggedness over the legacy measurement system used for the same purpose, and has been adopted for the evaluation of orthopaedic implants.

Test of a potential link between analytic and nonanalytic category learning and automatic, effortful processing.

The link between automatic and effortful processing and nonanalytic and analytic category learning was evaluated in a sample of 29 college undergraduates using declarative memory, semantic category search, and pseudoword categorization tasks. Automatic and effortful processing measures were hypothesized to be associated with nonanalytic and analytic categorization, respectively. Results suggested that contrary to prediction strong criterion-attribute (analytic) responding on the pseudoword categorization task was associated with strong automatic, implicit memory encoding of frequency-of-occurrence information. Data are discussed in terms of the possibility that criterion-attribute category knowledge, once established, may be expressed with few attentional resources. The data indicate that attention resource requirements, even for the same stimuli and task, vary depending on the category rule system utilized. Also, the automaticity emerging from familiarity with analytic category exemplars is very different from the automaticity arising from extensive practice on a semantic category search task. The data do not support any simple mapping of analytic and nonanalytic forms of category learning onto the automatic and effortful processing dichotomy and challenge simple models of brain asymmetries for such procedures.

Lifting of the degeneracy in semibullvalenes by remote and direct substituents: a quantitative study using variable-temperature carbon-13 NMR spectroscopy.

A series of six 1,5-(ethylmethyl)semibullvalenes (1a <==> 1a', 2 <==> 2', 3 <==>3') and two 4(2)-substituted semibullvalenes (4 <==> 4'), each undergoing Cope equilibria between nondegenerate valence tautomers, was investigated by carbon-13 NMR spectroscopy at a range of temperatures in several different solvents. Gompper's treatment of substituent perturbation was extended, specifically accounting for the effects of the substituents on chemical shifts, to allow the determination of the thermodynamic parameters for these skewed equilibria. These new treatments were used to determine the population difference (f - f ') between the valence tautomers and the perturbation thermodynamic quantities DeltaH(P), DeltaS(P), and DeltaG(P). The slow-exchange limit was reached for the parent 1,5-(ethylmethyl)semibullvalenes 3a <==> 3a' from which it was established that the preferred valence tautomer is 3a with the ethyl group on the cyclopropane ring. Despite considerable effort, the slow-exchange limit could not be reached in any of our other remotely substituted semibullvalenes. Provided that the ethyl group always prefers the cyclopropyl position as in 3a, the 1-ethyl-5-methylsemibullvalenes 1a, 2, and 3 are more stable by DeltaH(P) = 0.7-1.7 kJ mol(-1) than their valence tautomers 1a', 2', and 3'. In the directly substituted semibullvalenes (4 left harpoon ovet right harpoon 4'), the preferred valence tautomers 4a and 4b have the bromine atom or the nitrile group on the vinyl position (C(4)) rather than on the cyclopropane ring (C(2)) and are more stable than 4a' and 4b' by DeltaH(P) = 4.8 and 7.0 kJ mol(-1), respectively.

Kidney function and sulfate uptake and loss in the freshwater bivalve Toxolasma texasensis.

Toxolasma texasensis acclimated to an artificial pondwater (PW) maintained a concentration of SO4 in the blood of about 1-2 mmol l(-1) . The anion transport inhibitor DIDS (5,5'-diisothiocyanatostilbene 2, 2'-disulfonic acid) reduced the uptake of 35SO4 from the bathing medium by 54%. The clearance of polyethylene glycol (PEG) injected into the blood of T. texasensis ranged between 0.8 and 1.3 ml g(-1) dry tissue h(-1), and provided an estimate of renal filtration in PW-acclimated animals. The clearance of radioactive 35SO4 simultaneously injected into the same animal was about 16% of the PEG clearance, suggesting that sulfate was being reabsorbed by the kidney. Para-aminohippuric acid was cleared about 4.6 times faster than PEG, indicating that this organic acid was subjected to secretion in addition to filtration. When the normal osmotic gradient was abolished by acclimating T. texasensis to 10% seawater (SW), the PEG clearance decreased to 0.17 ml g(-1) dry tissue h(-1). Sulfate clearance in animals acclimated to PW or 10% SW was the same. However, in mussels acclimated to 10% SW, the calculated amount of SO4 reabsorbed was significantly reduced relative to mussels acclimated to PW. T. texasensis conserved SO4 when acclimated to PW, and reduced reabsorption when acclimated to the sulfate-rich 10% SW. When mussels acclimated to 10% SW were returned to PW, there was a transient increase in sulfate clearance during the first 8 h because filtration exceeded reabsorption.

Disciplining children: characteristics associated with the use of corporal punishment.

OBJECTIVE: To evaluate the Social Situational Model of Family Violence through an examination of characteristics associated with the use of ordinary and severe corporal punishment as measured by the Parents-Child Conflict Tactics Scales. METHOD: Logistic Regression used to examine the validity of the model using data from a national sample conducted by the Gallup Organizations. RESULTS: Those with fewer resources (lower income, lower educational attainment) were more likely to be use severe corporal punishment. In addition, those who had been more likely to be socialized into the use of violence were also more likely to use severe corporal punishment. CONCLUSIONS: The social situational model of family violence was supported suggesting that increased efforts be made to give these parents the resources they need to implement alternative discipline strategies.

Transient high altitude expressive aphasia.

Transient focal neurological deficits have been described in sojourners to high altitude. We present two cases of transient expressive aphasia in well-acclimatized high altitude climbers. We speculate that this type of transient focal neurological impairment may represent migraine aura, and we discuss other reports of transient focal neurological deficit at high altitude.

Prostaglandin E2-induced up-regulation of c-fos messenger ribonucleic acid is primarily mediated by 3',5'-cyclic adenosine monophosphate in MC3T3-E1 osteoblasts.

The mechanism by which the proto-oncogene, c-fos, is up-regulated in response to PGE2 in the mouse osteoblastic (MC3T3-E1) cell line was investigated using RT-PCR. c-fos messenger RNA up-regulation by dmPGE2 is rapid, starting 10 min post stimulation, and transient. The specific protein kinase A (PKA) inhibitor, H89, inhibited c-fos induction. Moreover, down-regulation of protein kinase C (PKC) activity by chronic TPA treatment had no effect on the induction of c-fos by dmPGE2. We conclude that up-regulation of c-fos by dmPGE2 is primarily dependent on PKA in MC3T3-E1 osteoblasts. In S49 lymphoma wild-type but not S49 cyc- cells, which are deficient in cAMP signaling, dmPGE2 up-regulates c-fos and increases cell growth compared with unstimulated cells. Thus in S49 lymphoma cells, c-fos induction by PGE2 is also dependent on cAMP signaling. The minimal c-fos promoter region required for dmPGE2-induced expression was identified by transfecting c-fos promoter deletion constructs coupled to the chloramphenicol acetyltransferase (CAT) reporter gene into Vero cells. Transfection of a plasmid containing 99 bp c-fos proximal promoter was sufficient to direct c-fos/CAT expression following stimulation with dmPGE2. Because induction of c-fos is mediated by cAMP, these data are consistent with activation of c-fos via the CRE/ATF cis element.

Exploring intra-ethnic diversity among four groups of Hispanic elderly: patterns and levels of service utilization.

This study investigates service use by a sample of 2,135 Hispanic elderly in order to address the issue of the homogeneity or heterogeneity within the older Hispanic population as revealed by the use of formal services. Factor analysis revealed a high degree of homogeneity in the patterns of formal service use among the four Hispanic groups in this study that follows three latent, but distinct, patterns of behavior: the use of federal entitlement programs, in-home services, and senior center services. Although the patterns of service use reflect substantial homogeneity among the Hispanics in this sample, there is a high degree of heterogeneity in the level of service use. Overall, service use was systematically lower among "Other" Hispanic elders and systematically higher among Puerto Rican elders, with somewhat more erratic use among Cuban American and Mexican American elders. Controlling for between-group differences in socio-demographic characteristics did little to reduce relatively systematic between-group differences in levels of service use.

Paracellular Solute Uptake in the Freshwater Bivalves Corbicula fluminea and Toxolasma texasensis.

Two species of freshwater bivalve were exposed to hyperosmotic solutions of various nonelectrolytes to compare the paracellular permeability of their gill epithelia. In Corbicula fluminea, exposure resulted in an elevation of blood solutes that was primarily due to dehydration. After 36 h of exposure, the concentration of Na in the blood decreased precipitously, and the nonelectrolyte accumulated. When lanthanum was added to the solution as a diffusion tracer, its electron-dense precipitate was rarely observed to penetrate the paracellular spaces of the gill epithelial cells in the absence of hyperosmotic stress. In contrast, precipitated lanthanum was commonly observed in the paracellular junctional complexes of the gill in animals that were subjected to hyperosmotic conditions. When the second species, Toxolasma texasensis, was exposed to hyperosmotic solutions of nonelectrolyte, dehydration appeared to be minimal and a seemingly normal concentration of ions was maintained in the blood. This, however, was because of the simultaneous loss of ions and water and a small gain in nonelectrolytes. Longer exposure (12 h or more) produced a precipitous decrease in most blood solutes and an extensive accumulation of nonelectrolyte. More lanthanum precipitate was seen in the paracellular spaces of both control and hyperosmotically stressed T. texasensis than in identically treated C. fluminea. We conclude that the epithelial junctions found in C. fluminea are relatively tight, which probably contributes to the ability of this species to maintain the solute in its body fluid at concentrations higher than are possible in T. texasensis.

Ion Transport in the Freshwater Bivalve Corbicula fluminea.

In freshwater bivalves such as the mussel Corbicula fluminea, uptake of chloride depends on the external concentration of the chloride ion. In C. fluminea, Cl- uptake displayed saturation kinetics both in animals acclimated to pondwater and in those subjected to salt depletion by storage in deionized water. The transport capacity (Jmax) was 7.00 +/- 0.51 {mu}eq g-1 dry tissue h-1 and the transport affinity (Km) was 0.21 +/- 0.08 mM in animals acclimated to pondwater. Animals subjected to salt depletion had a higher rate of Cl- uptake than did animals acclimated to pondwater. After 4 weeks in deionized water, the longer the animals were salt-depleted, the higher their rate of Cl- uptake. Na+ and Cl- transport were independent in pondwater-acclimated C. fluminea. For salt-depleted animals, Cl- transport was Na+-independent, but Na+ transport depended partially on external Cl-. Serotonin stimulated Cl- and Na+ transport in pond-water-acclimated animals by increasing influx while having little influence on efflux. Acetazolamide increased the Cl- and Na+ efflux of salt-depleted animals. Both serotonin and acetazolamide elevated the net loss of titratable base.

Implantable hearing device performance measured by laser Doppler interferometry.

Recent application of the Doppler principle laser interferometry to audiology, acoustics and otology has facilitated the development of implantable hearing devices (IHDs). During the design and testing of two different electromagnetic middle ear implants for sensorineural hearing loss, we used single-point laser Doppler interferometry (LDI). A commercially available interferometer, internally calibrated and validated against a National Institute for Standards and Technology (NIST) standard, was used with both mechanical fixtures and fresh temporal bones to evaluate implant mass, shape and orientation, attachment, electromagnetic coupling and acoustic properties. At both Hough Ear Institute and Symphonix Devices, Inc., we have shown that high fidelity and amplitudes can be recorded in vitro over a frequency range of 500 Hz to 10 kHz. These data can provide greater assurance of safety and efficacy to regulatory agencies before entering clinical trials. We propose that LDI be considered as an international standard for accurate, consistent comparison of performances of all IHDs during development. Furthermore, the future availability of human IHD data will allow for the extrapolation of a mechanical bench model of the middle ear transfer function for use in quality control during manufacturing and diagnosis of failure in IHDs.

Ion transport and acid-base balance in freshwater bivalves

Blood acid­base and ionic balance in freshwater bivalves is affected by the relative activities of epithelial Na+ and Cl- transporters. In the unionid Carunculina texasensis, the Na+/H+ exchanger is the predominant epithelial transporter that affects acid­base state, while Cl-/HCO3- exchange is of lesser importance. In the corbiculid Corbicula fluminea, Cl- and Na+ transport are both significant components affecting acid­base state. Serotonin (5-hydroxytryptamine, 5-HT) stimulates Na+ and Cl- transport in both species. In C. texasensis, the effect of exogenous serotonin is four times greater on Na+/H+ exchange than on Cl-/HCO3- transport, resulting in an increase in acid secretion and a rise in blood pH. In a Na+-free environment, serotonin had no effect on blood acid­base state in C. texasensis. In C. fluminea, the acid­base consequences of serotonin stimulation of Na+/H+ exchange were offset by similar increases in Cl-/HCO3- exchange and by alterations in blood PCO(sum) in medium containing Na+. In Na+-free medium, stimulation of the Cl- transporter with 5-HT resulted in a decrease in blood pH. The differences between these two species are related to the reliance of C. fluminea on Cl- as the major anion in the blood, requiring high levels of epithelial Cl- transport. In C. texasensis, the anionic component of the blood consists of both Cl- and HCO3- and these ions are interchangeable over a wide concentration range. Extracellular acid­base balance in freshwater bivalves is governed, in part, by epithelial ion transporters.

Effects of population and affluence on CO2 emissions.

We developed a stochastic version of the Impact = Population x Affluence x Technology (IPAT) model to estimate the effects of population, affluence, and technology on national CO2 emissions. Our results suggest that, for population, there are diseconomies of scale for the largest nations that are not consistent with the assumption of direct proportionality (log-linear effects) common to most previous research. In contrast, the effects of affluence on CO2 emissions appear to reach a maximum at about $10,000 in per- capita gross domestic product and to decline at higher levels of affluence. These results confirm the general value of the IPAT model as a starting point for understanding the anthropogenic driving forces of global change and suggest that population and economic growth anticipated over the next decade will exacerbate greenhouse gas emissions.