Arginine, ornithine and citrulline supplementation in rainbow trout: Free amino acid dynamics and gene expression responses to bacterial infection.

Supplementing the diet with functional ingredients is a key strategy to improve fish performance and health in aquaculture. The amino acids of the urea and nitric oxide (NO) cycles - arginine, ornithine and citrulline - perform crucial roles in the immune response through the generation of NO and the synthesis of polyamine used for tissue repair. We previously found that citrulline supplementation improves and maintains circulating free arginine levels in rainbow trout more effectively than arginine supplementation. Here, to test whether supplementation of urea cycle amino acids modulates the immune response in rainbow trout (Oncorhynchus mykiss), we supplemented a commercial diet with high levels (2% of total diet) of either arginine, ornithine or citrulline during a 7-week feeding trial, before challenging fish with the bacterium Aeromonas salmonicida. We carried out two separate experiments to investigate fish survival and 24 h post-infection to investigate the immediate response of free amino acid levels, and transcriptional changes in genes encoding urea cycle, NO cycle and polyamine synthesis enzymes. There were no differences in percentage fish mortality between diets, however there were numerous highly significant changes in free amino acid levels and gene expression to both dietary supplementation and infection. Out of 26 amino acids detected in blood plasma, 8 were significantly changed by infection and 9 by dietary supplementation of either arginine, ornithine or citrulline. Taurine, glycine and aspartic acid displayed the largest decreases in circulating levels in infected fish, while ornithine and isoleucine were the only amino acids that increased in concentration. We investigated transcriptional responses of the enzymes involved in arginine metabolism in liver and head kidney; transcripts for polyamine synthesis enzymes showed highly significant increases in both tissues across all diets following infection. The paralogous arginase-encoding genes, Arg1a, Arg1b, Arg2a and Arg2b, displayed complex responses across tissues and also due to diet and infection. Overall, these findings improve our understanding of amino acid metabolism following infection and suggests new potential amino acid targets for improving the immune response in salmonids.

Low-Power MEMS-Based Pierce Oscillator Using a 61-MHz Capacitive-Gap Disk Resonator.

A 61-MHz Pierce oscillator constructed in 0.35- [Formula: see text] CMOS technology and referenced to a polysilicon surface-micromachined capacitive-gap-transduced wine-glass disk resonator has achieved phase noise marks of -119 dBc/Hz at 1-kHz offset and -139 dBc/Hz at far-from-carrier offsets. When divided down to 13 MHz, this corresponds to -132 dBc/Hz at 1-kHz offset from the carrier and -152 dBc/Hz far-from-carrier, sufficient for mobile phone reference oscillator applications, using a single MEMS resonator, i.e., without the need to array multiple resonators. Key to achieving these marks is a Pierce-based circuit design that harnesses a MEMS-enabled input-to-output shunt capacitance more than 100× smaller than exhibited by macroscopic quartz crystals to enable enough negative resistance to instigate and sustain oscillation while consuming only [Formula: see text] of power-a reduction of  âˆ¼ 4.5× over previous work. Increasing the bias voltage of the resonator by 1.25 V further reduces power consumption to [Formula: see text] at the cost of only a few decibels in far-from-carrier phase noise. This oscillator achieves a 1-kHz-offset figure of merit (FOM) of -231 dB, which is now the best among published chip-scale oscillators to date. A complete linear circuit analysis quantifies the influence of resonator input-to-output shunt capacitance on power consumption and predicts further reductions in power consumption via reduction of electrode-to-resonator transducer gaps and bond pad sizes. The demonstrated phase noise and power consumption posted by this tiny MEMS-based oscillator are attractive as potential enablers for low-power "set-and-forget" autonomous sensor networks and embedded radios.

Supplementation of arginine, ornithine and citrulline in rainbow trout (Oncorhynchus mykiss): Effects on growth, amino acid levels in plasma and gene expression responses in liver tissue.

Functional amino acids (FAA) regulate metabolic pathways directly linked to health, survival, growth and development. Arginine is a FAA with crucial roles in protein deposition and the immune response. In mammals, supplementation of arginine's precursor amino acid, citrulline, is known to increase circulating arginine to levels beyond direct arginine supplementation, however, citrulline supplementation is poorly studied in fish. To address this knowledge gap, we supplemented the diet of rainbow trout with arginine and its precursor amino acids, ornithine and citrulline, at 3 levels (0.5%, 1% and 2% of the total diet) during a 14-week experiment. We sampled fish at 3 h and 24 h post-feeding to investigate immediate and steady-state effects, respectively. There were no differences in fish growth for any of the diets across a range of indicators. In blood plasma, out of 26 amino acids detected, 11 and 6 displayed significant changes 24 h and 3 h post-prandial, respectively. Arginine, ornithine and citrulline levels were all significantly increased by the citrulline supplemented diets. In muscle, 8 amino acids were significantly altered by supplemented diets, while there were no significant changes in liver. Arginine was increased by 2% citrulline supplementation in muscle tissue. We also investigated the transcriptional responses of urea cycle, nitric oxide cycle and rate-limiting polyamine synthesis enzymes, related to arginine's metabolism, in liver. At both time points, only 2 enzymes were significantly altered by the supplemented diets, however several significant changes were observed comparing 3 h and 24 h post-prandial expression levels. Of these, the paralogous polyamine synthesis enzyme encoding genes ODC1 and ODC2 displayed the largest increases in 3 h post-prandial fish. These findings demonstrate that endogenous synthesis of arginine is possible from a citrulline supplemented diet and improve our understanding of arginine metabolism in fish.

Rainbow trout (Oncorhynchus mykiss) urea cycle and polyamine synthesis gene families show dynamic expression responses to inflammation.

The urea cycle is an endogenous source of arginine that also supports removal of nitrogenous waste following protein metabolism. This cycle is considered inefficient in salmonids, where only 10-15% of nitrogenous waste is excreted as urea. In rainbow trout, arginine is an essential amino acid that has attracted attention due to its many functional roles. These roles include the regulation of protein deposition, immune responses and polyamine synthesis; the latter is directly linked to the urea cycle and involved in tissue repair. The key enzymes used in the urea cycle, namely arginase, ornithine transcarbamylase, argininosuccinate synthase and argininosuccinate lyase, in addition to two rate limiting enzymes required for polyamine synthesis (ornithine decarboxylase and s-adenosylmethionine decarboxylase) are poorly studied in fishes, and their responses to inflammation remain unknown. To address this knowledge gap, we characterised these gene families using phylogenetics and comparative genomics, investigated their mRNA distribution among a panel of tissues and established their transcriptional responses to an acute inflammatory response caused by bacterial infection in liver and muscle. Gene duplicates (paralogues) were identified for arginase (ARG1a, 1b, 2a and 2b), ornithine decarboxylase (ODC1 and 2) and s-adenosylmethionine decarboxylase (SAMdc1 and 2), including paralogues retained from an ancestral salmonid-specific whole genome duplication. ARG2a and 2b were highly upregulated following bacterial infection in liver, whereas ARG1b was downregulated, while both paralogues of SAMdc and ODC were upregulated in liver and unchanged in muscle. Overall, these findings improve our understanding of the molecules supporting the urea cycle and polyamine synthesis in fish, highlighting major changes in the regulation of these systems during inflammation.

RF Channel-Select Micromechanical Disk Filters-Part II: Demonstration.

This Part II of a two-paper sequence presents fabrication and measurement results for a micromechanical disk-based RF channel-select filter designed using the theory and procedure of Part I. Successful demonstration of an actual filter required several practical additions to an ideal design, including the introduction of a 39-nm-gap capacitive transducer, voltage-controlled frequency tuning electrodes, and a stress relieving coupled array design, all of which combine to enable a 0.1% bandwidth 223.4-MHz channel-select filter with only 2.7 dB of in-band insertion loss and 50-dB rejection of out-of-band interferers. This amount of rejection is more than 23 dB better than a previous capacitive-gap transduced filter design that did not benefit from sub-50-nm gaps. It also comes in tandem with a 20-dB shape factor of 2.7 realized by a hierarchical mechanical circuit design utilizing 206 micromechanical circuit elements, all contained in an area footprint of only [Formula: see text]. The key to such low insertion loss for this tiny percent bandwidth is Q 's >8800 supplied by polysilicon disk resonators employing for the first time capacitive transducer gaps small enough to generate coupling strengths of Cx/Co  âˆ¼  0.1 %, which is a 6.1× improvement over previous efforts. The filter structure utilizes electrical tuning to correct frequency mismatches due to process variations, where a dc tuning voltage of 12.1 V improves the filter insertion loss by 1.8 dB and yields the desired equiripple passband shape. Measured filter performance, both in- and out-of-channel, compares well with predictions of an electrical equivalent circuit that captures not only the ideal filter response, but also parasitic nonidealities that distort somewhat the filter response.

RF Channel-Select Micromechanical Disk Filters-Part I: Design.

This Part I of two papers introduces a design flow for micromechanical RF channel-select filters with tiny fractional bandwidths capable of eliminating strong adjacent channel blockers directly after the antenna, hence reducing the dynamic range requirement of subsequent stages in an RF front-end. Much like VLSI transistor circuit design, the mechanical circuit design flow described herein is hierarchical with a design stack built upon vibrating micromechanical disk building blocks capable of Q 's exceeding 10 000 that enable low-filter passband loss for tiny fractional bandwidths. Array composites of half-wavelength coupled identical vibrating disks constitute a second level of hierarchy that reduces the filter termination impedance. A next level of hierarchy couples array composites with full-wavelength beams to affect fully balanced differential operation. Finally, identical differential blocks coupled with quarter-wavelength beams generate the desired passband. Part II of this study corroborates the efficacy of this design hierarchy via experimental results that introduce a 39-nm-gap capacitive transducer, voltage-controlled frequency tuning, and differential operation toward demonstration of a 0.1% bandwidth, 223.4-MHz channel-select filter with only 2.7 dB of in-band insertion loss and 50 dB of stopband rejection.

A negative-capacitance equivalent circuit model for parallel-plate capacitive-gap-transduced micromechanical resonators.

A small-signal equivalent circuit for parallel-plate capacitive-gap-transduced micromechanical resonators is introduced that employs negative capacitance to model the dependence of resonance frequency on electrical stiffness in a way that facilitates circuit analysis, that better elucidates the mechanisms behind certain potentially puzzling measured phenomena, and that inspires circuit topologies that maximize performance in specific applications. For this work, a micromechanical disk resonator serves as the vehicle with which to derive the equivalent circuits for both radial-contour and wine-glass modes, which are then used in circuit simulations (via simulation) to match measurements on actual fabricated devices. The new circuit model not only correctly predicts the dependence of electrical stiffness on the impedances loading the input and output electrodes of parallel-plate capacitive- gap-transduced micromechanical device, but does so in a visually intuitive way that identifies current drive as most appropriate for applications that must be stable against environmental perturbations, such as acceleration or power supply variations. Measurements on fabricated devices confirm predictions by the new model of up to 4× improvement in frequency stability against dc-bias voltage variations for contour- mode disk resonators as the resistance loading their ports increases. By enhancing circuit visualization, this circuit model makes more obvious the circuit design procedures and topologies most beneficial for certain mechanical circuits, e.g., filters and oscillators.

Self-reported oral health, dental self-care and dental service use among New Zealand secondary school students: findings from the Youth 07 study.

AIM: The primary aim was to describe New Zealand secondary school students' use of dental services and determine the nature and extent of any inequities by deprivation status and ethnicity. A secondary aim was to to describe their toothbrushing practices and self-reported dental pain experience, past restorative treatment and tooth loss. METHOD: Secondary analysis of data from the cross-sectional Youth 07: National Survey of the Health and Wellbeing of New Zealand Secondary School Students. A representative sample of 9,098 secondary school students aged 13-17 years from 96 secondary schools across New Zealand took part, with a response rate of 73%. Self-report information about oral health care behaviour, past dental experiences and dental visiting pattern was collected. Data analysis took the complex survey design into account, and multivariate analysis was undertaken to examine the associations of dental service-use. RESULTS: A dental visit in the previous 12 months was reported by 72% of participants. The odds of having done so were higher among females, those who brushed at least twice daily, and those who had been kept awake at night by dental pain. Lower odds were seen among students identifying with Maori, Pacific or Asian people (and those in the 'Other' ethnic category) than among European students, and among those residing in medium- or high-deprivation areas than those in lo-deprivation areas. One in seven participants reported having lost a tooth due to oral disease. Having had a tooth filled was reported by almost three-quarters of the sample, and having been kept awake by dental pain at night was reported by just over one in five. Almost two-thirds reported brushing their teeth twice or more in the previous 24 hours, and a small minority had not brushed at all. CONCLUSION: Ethnic and socio-economic inequities in the use of dental services are apparent among New Zealand adolescents.

1.52-GHz micromechanical extensional wine-glass mode ring resonators.

Vibrating polysilicon micromechanical ring resonators, using a unique extensional wine-glass-mode shape to achieve lower impedance than previous UHF resonators, have been demonstrated at frequencies as high as 1.2 GHz with a Q of 3,700, and 1.52 GHz with a Q of 2,800. The 1.2-GHz resonator exhibits a measured motional resistance of 1 MOmega with a dc-bias voltage of 20 V, which is 2.2 times lower than the resistance measured on radial contourmode disk counterparts at the same frequency. The use of larger rings offers a path toward even lower impedance, provided the spurious modes that become more troublesome as ring size increases can be properly suppressed using methods described herein. With spurious modes suppressed, the high-Q and low-impedance advantages, together with the multiple frequency on-chip integration advantages afforded by capacitively transduced micromechanical resonators, make this device an attractive candidate for use in the front-end RF filtering and frequency generation functions needed by wireless communication devices.

MEMS technology for timing and frequency control.

An overview on the use of microelectromechanical systems (MEMS) technologies for timing and frequency control is presented. In particular, micromechanical RF filters and reference oscillators based on recently demonstrated vibrating on-chip micromechanical resonators with Q's > 10,000 at 1.5 GHz are described as an attractive solution to the increasing count of RF components (e.g., filters) expected to be needed by future multiband, multimode wireless devices. With Q's this high in on-chip abundance, such devices might also enable a paradigm shift in the design of timing and frequency control functions, where the advantages of high-Q are emphasized, rather than suppressed (e.g., due to size and cost reasons), resulting in enhanced robustness and power savings. Indeed, as vibrating RF MEMS devices are perceived more as circuit building blocks than as stand-alone devices, and as the frequency processing circuits they enable become larger and more complex, the makings of an integrated micromechanical circuit technology begin to take shape, perhaps with a functional breadth not unlike that of integrated transistor circuits. With even more aggressive three-dimensional MEMS technologies, even higher on-chip Q's are possible, such as already achieved via chip-scale atomic physics packages, which so far have achieved Q's > 10(7) using atomic cells measuring only 10 mm3 in volume and consuming just 5 mW of power, all while still allowing atomic clock Allan deviations down to 10(-11) at one hour.

1.156-GHz self-aligned vibrating micromechanical disk resonator.

A new fabrication methodology that allows self-alignment of a micromechanical structure to its anchor(s) has been used to achieve vibrating radial-contour mode polysilicon micromechanical disk resonators with resonance frequencies up to 1.156 GHz and measured Q's at this frequency >2,650 in both vacuum and air. In addition, a 734.6-MHz version has been demonstrated with Q's of 7,890 and 5,160 in vacuum and air, respectively. For these resonators, self-alignment of the stem to exactly the center of the disk it supports allows balancing of the resonator far superior to that achieved by previous versions (in which separate masks were used to define the disk and stem), allowing the present devices to retain high Q while achieving frequencies in the gigahertz range for the first time. In addition to providing details on the fabrication process, testing techniques, and experimental results, this paper formulates an equivalent electrical circuit model that accurately predicts the performance of these disk resonators.

Comparison of health-risk behaviours among students in alternative high schools from New Zealand and the USA.

OBJECTIVES: To describe the prevalence of health-risk behaviours of New Zealand alternative education students, and to compare these behaviours to similar students in the USA. METHODS: Thirty-six alternative education schools in the northern region of New Zealand were surveyed. A total of 269 students completed a youth health questionnaire using laptop computers. These data were compared to data from an equivalent population of alternative education students in the USA. RESULTS: Alternative education students from New Zealand and the USA engage in similar high levels of health-risk behaviours. Female students in New Zealand are at particularly high risk of poor health and social outcomes due to high levels of alcohol and marijuana use, driving under the influence of alcohol and high prevalence of risky sexual behaviours. Such health-risk behaviours place alternative education students at greater risk of some of the leading causes of morbidity and mortality in both youth and adult populations. CONCLUSIONS: Findings from the present study support the need for specific health policies and programmes for alternative high school students. Providers of New Zealand alternative education should be aware that female students are at particularly high risk of many health-risk behaviours.

Adolescents' perceptions of a health survey using multimedia computer-assisted self-administered interview.

OBJECTIVE: To ascertain young people's perceptions of an adolescent health survey when administered by multimedia computer assisted self-administered Interview (M-CASI) through analysis of (1) questionnaire item responses and (2) focus group interviews. SETTING: Auckland, New Zealand, 1999. STUDY TYPE: Pilot testing of a 488-item branching questionnaire delivered using a youth-oriented and user-friendly M-CASI interface in a variety of settings using both desktop and laptop computers. Post pilot focus groups of participants identifying their perceptions and experiences of the survey. SAMPLE: 110 school students aged 12 to 18 years. RESULTS: The mean number of questions answered by participants was 316 with the median time to completion being 48 minutes. On average 65% of the total number of questions were seen and of these 1.5% were deliberately not answered. A high level of acceptability and enjoyment of M-CASI was found in the analysis of focus group responses and agreed with the item responses relating to M-CASI within the questionnaire itself. Participants identified privacy and confidentiality as being particularly important for the honesty of their responses. The passive matrix screens of the computers were popular as they could only be viewed from in front. CONCLUSIONS: M-CASI is an acceptable instrument for the administration of a youth health survey. Laptop computers with passive matrix screens are able to enhance perceptions of privacy and confidentiality, which may improve honesty of responses. IMPLICATIONS: M-CASI is now feasible and offers advantages in health surveying.

Does pneumoperitoneum during laparoscopy increase bacterial translocation?

BACKGROUND: To evaluate the impact of laparoscopy in the presence of peritonitis, this study was designed to assess bacteremia caused by E. coli-induced peritonitis with a carbon dioxide pneumoperitoneum in a rat model. METHODS: Sixty Sprague-Dawley rats were divided into inoculum groups (no E. coli, 10(6) colony-forming units [CFU] E. coli, and 10(8) CFU E. coli), followed by induction of a carbon dioxide pneumoperitoneum or no pneumoperitoneum. Fifteen-minute-interval blood cultures were obtained to determine time of bacteremia development. Statistical assessment to determine significant differences among groups was done using ANOVA and t-test analysis. RESULTS: A total of 20 animals with E. coli introduced into the peritoneum and a carbon-dioxide-induced pneumoperitoneum had more frequent positive blood cultures at all time intervals compared to identical inoculum subgroups without a pneumoperitoneum. ANOVA revealed a significant difference in bacteremia within the same concentration inoculum groups in animals receiving a pneumoperitoneum vs none (p < 0.01). Bacteremia increased significantly as inoculum concentrations increased (25% with 10(6) E. coli inoculum vs 80% with 10(8) E. coli), especially among the insufflated subgroups (45% with 10(6) E. coli vs 100% with 10(8) E. coli) over 180 min (p < 0.01). CONCLUSION: Carbon dioxide pneumoperitoneum increases the incidence of E. coli bacterial translocation from the peritoneum into the bloodstream in this rat model.

Health care for the uninsured in Duluth.

Providing health care for Minnesota's uninsured population continues to be both a clinical and political challenge. Between October 1, 1991, and September 30, 1993, 1,260 previously uninsured people received charity health care in Duluth. No one was excluded because of pre-existing conditions. Their utilization of services and associated costs can help project the health care needs and costs of care for uninsured Minnesotans. This group of uninsured people used a different mix of health care services compared with insured Minnesotans, and their total costs (including prescriptions) were about 15% greater. A large proportion of these uninsured Minnesotans had chronic health conditions and a "pent-up need" for services and medications. This experience demonstrated that it is possible to administer a limited benefits plan in coordination with existing public and private resources.

The relationship of hearing-loss severity to demographic, age, treatment, and intervention-effectiveness variables.

The purpose of this study was to demonstrate how hearing-loss severity and the variables of demographics, age, treatment, and intervention effectiveness were related for 2519 children served by SKI*HI home-based programs between July 1979 and June 1991. Relationships between hearing-loss severity and demographic variables were negligible to small. Severity was inversely associated with identification, amplification, and program-start ages. The relationship between severity and early versus late program start was small; this was also true for the relationship between severity and communication methodology. Severity was positively associated with treatment duration; however, severity was not associated with treatment density. Intervention effectiveness for the severity levels, based on expressive and receptive language scores, was examined using three predictive models. These included the residuals between actual and predicted posttest scores, proportional change indices, and value-added gains per month. The usefulness of the three procedures for clinical and program-evaluation purposes is discussed.

Screening procedures used to identify children with hearing loss.

This study focused on the hearing-screening procedures used to identify children who have hearing losses who were later enrolled in SKI*HI parent/infant programs throughout the country. Responses to a questionnaire for 1,404 children indicated that although auditory brainstem response (ABR) technology provided the lowest mean identification age, informal hearing-screening procedures (parental suspicion and referral) were the procedure of identification for 80% of the children. The data suggest that formal screening programs are not presently locating the vast majority of infants who have hearing losses. Recommendations for professional and parental education in the area of hearing-loss screening are provided.

A coactive sign system for children who are dual-sensory impaired.

The SKI*HI Institute developed a system of coactive signing to help alleviate communication and instructional barriers for children who are dual-sensory impaired (deaf and blind). The system also can be used to help children who are severely multihandicapped learn how to communicate. The system includes optimized coactive signs that are functional, easy to feel, easy to relate to the referent, and easy to make, and it also includes techniques related to effective coactive sign use. The coactive sign system is illustrated on a series of video tapes that has been field tested and produced and is being disseminated throughout the United States and Canada.