Preprocessor Adapts Cardiovascular Signals to a Minicomputer

A laboratory-developed analog signal processor, driven by a conventional polygraph recorder and associated signal conditioning devices, provides automatic heart beat-by-heart beat preprocessing of various cardiovascular functions for input to a laboratory-type minicomputer. The technique of preprocessing individual functions, integrated with the minicomputer system which includes an A/D converter and teletype as input-output peripherals, provides a low-cost data acquisition and reduction system for the on-line computation and analysis of cardiovascular functions in experimental research applications. Such preprocessing more efficiently uses the minicomputer's memory to handle large amounts of information since the digitized data is in the form of one data sample, per function, per heart beat. Preprocessing analog data provides a low density data format and simplified software programs that are ideally suited for the utilization of a minicomputer in this on-line application.     

NKG2D blockade prevents autoimmune diabetes in NOD mice

NKG2D is an activating receptor on CD8(+) T cells and NK cells that has been implicated in immunity against tumors and microbial pathogens. Here we show that RAE-1 is present in prediabetic pancreas islets of NOD mice and that autoreactive CD8(+) T cells infiltrating the pancreas express NKG2D. Treatment with a nondepleting anti-NKG2D monoclonal antibody (mAb) during the prediabetic stage completely prevented disease by impairing the expansion and function of autoreactive CD8(+) T cells. These findings demonstrate that NKG2D is essential for disease progression and suggest a new therapeutic target for autoimmune type I diabetes.     

Neural measurement of sound duration: control by excitatory-inhibitory interactions in the inferior colliculus

In the inferior colliculus (IC) of the big brown bat, a subpopulation of cells ( approximately 35%) are tuned to a narrow range of sound durations. Band-pass tuning for sound duration has not been seen at lower levels of the auditory pathway. Previous work suggests that it arises at the IC through the interaction of sound-evoked, temporally offset, excitatory and inhibitory inputs. To test this hypothesis, we recorded from duration-tuned neurons in the IC and examined duration tuning before and after iontophoretic infusion of antagonists to gamma-aminobutyric acid-A (GABA(A)) (bicuculline) or glycine (strychnine). The criterion for duration tuning was that the neuron's spike count as a function of duration had a peak value at one duration or a range of durations that was >/=2 times the lowest nonzero value at longer durations. Out of 21 units tested with bicuculline, duration tuning was eliminated in 15, broadened in two, and unaltered in four. Out of 10 units tested with strychnine, duration tuning was eliminated in four, broadened in one, and unaltered in five. For units tested with both bicuculline and strychnine, bicuculline had a greater effect on reducing or abolishing duration tuning than did strychnine. Bicuculline and strychnine both produced changes in discharge pattern. There was nearly always a shift from an offset response to an onset response, indicating that in the predrug condition, inhibition arrived simultaneously with excitation or preceded it. There was often an increase in the length of the spike train, indicating that in the predrug condition, inhibition also coincided with later parts of excitation. These findings support two hypotheses. First, duration tuning is created in the IC. Second, although the construction of duration tuning varies in some details among IC neurons, it follows three rules: 1) an excitatory and an inhibitory event are temporally linked to the onset of sound but temporally offset from one another; 2) the duration of some inhibitory event must be linked to the duration of the sound; 3) an excitatory event must be linked to the offset of sound.     

A COMPARATIVE STUDY IN THE USE OF CLOSED-CIRCUIT TELEVISION READING MACHINES AND OPTICAL AIDS BY PATIENTS WITH RETINITIS PIGMENTOSA AND MACULOPATHY

Patients with retinitis pigmentosa (RP) who have insufficient vision to benefit from optical low vision aids are frequently helped by the closed-circuit television (CCTV) reading machines. RP patients' use of the CCTV is compared with that of patients with maculopathy (i.e. a group with a central scotoma only, is compared to a group which also has additional peripheral field loss), and with that of a "normal" control group. The performance of people with RP is improved by using white print on a black background, while macular degeneration subjects have no significant preference. Speed limits appear to be a function of restrictions imposed by the machine. Both groups frequently read faster with "optical aids".     

Chloride Ion-Containing Polymeric Ionic Liquids for Application as Electrolytes in Solid-State Batteries

Organic, solid-state batteries require efficient solid electrolytes able to provide stable ion conduction. Here, solid electrolytes based on ionic liquid (IL) polymers with chloride counterions as electrolyte materials for batteries are presented. Acrylic monomers with imidazolium substituents with alkyl side groups that are linked by alkyl spacers to the acrylic group are employed. The IL monomers with chloride counterions are either converted by thermally initiated radical polymerization into linear homopolymers or incorporated into polymer networks by UV-initiated copolymerization utilizing a bifunctional, non-ionic cross-linker. Both procedures successfully yielded the desired materials, which is confirmed by NMR spectroscopy (linear homopolymers) or Raman spectroscopy (IL networks). The ionic conductivities at room temperature are measured by Electrochemical Impedance Spectroscopy. The ionic conductivities of the linear homopolymers are in the range of 10⁻⁴ to 10⁻⁶ S cm⁻¹, while those of the IL networks are about two orders of magnitude lower. They increase to 10⁻⁴ S cm⁻¹ at 70 °C. The electrochemical stability is examined by Linear Sweep Voltammetry and is proven in the voltage range of −2 to +2 V. The results reveal that the materials represent promising electrolytes for potential solid-state battery applications.     

Impact of retrograde cerebral perfusion on aortic arch aneurysm repair

OBJECTIVE: Protection of the brain is a primary concern in aortic arch surgery. Retrograde cerebral perfusion is a relatively new technique used for cerebral protection during profound hypothermic circulatory arrest. This study was designed to compare, retrospectively, the outcome of 109 patients undergoing aortic arch operation with and without the use of retrograde cerebral perfusion. METHODS: Fifty-five patients had profound hypothermic circulatory arrest alone, and 54 patients had supplemental cerebral protection with retrograde cerebral perfusion. Mean age was 61 +/- 13 years and 58 +/- 14 years, respectively (mean +/- standard deviation). Twenty-two preoperative and intraoperative characteristics, including age, sex, acuity, presence of aortic dissection, and aneurysm rupture, were similar in the 2 groups (P >.05). RESULTS: Mean circulatory arrest times (in minutes) were 30 +/- 19 in the group without retrograde cerebral perfusion and 33 +/- 19 in the group with retrograde cerebral perfusion, respectively. chi(2) Analysis revealed that patients operated on with the use of retrograde cerebral perfusion had significantly lower hospital mortality (15% vs 31%; P =.04) and in-hospital permanent neurologic complications (9% vs 27%; P =.01). Retrograde cerebral perfusion failed to reduce the prevalence of temporary neurologic dysfunction (17% vs 18%; P =.9). Stepwise multiple logistic regression revealed that extracorporeal circulation time, age, and lack of retrograde cerebral perfusion were statistically significant independent risk factors for hospital mortality. The same analysis revealed that lack of retrograde cerebral perfusion was the only significant independent risk factor for permanent neurologic dysfunction. CONCLUSION: Retrograde cerebral perfusion decreased the prevalence of permanent neurologic complications and the hospital mortality in patients undergoing aortic arch operations.     

Effect of processed and non-processed coffee samples on gastric potential difference. Study with healthy male Helicobacter pylori-positive and Helicobacter pylori-negative volunteers.

In an open trial with 18 healthy male volunteers (21-45 years old) the effect of processed (test) and non-processed (reference) coffee samples of same origin on the gastric potential difference (GPD) was studied. Test coffee samples were processed with the patented "Darboven improvement procedure" before roasting. All treatment groups were subdivided according to the Helicobacter pylori status of the volunteers. The evaluation of the target parameters Reizindex (RI), area under the baseline (AUB), maximum potential difference (Pdmax) and total time (ttot) revealed a significant lower RI (p = 0.0282) and AUB (p = 0.0136), and a significant shorter ttot (p = 0.0286) for the processed coffee. Total cholesterol, high-density lipoprotein (HDL) cholesterol, and pancreatic peptides showed a comparable marked increase of the arithmetic mean with both coffee samples, however, being more intense in the Helicobacter pylori-positive subgroup than in the Helicobacter pylori-negative subgroup. No negative findings concerning tolerability and safety could be seen. In conclusion, the test coffee samples processed with a new method to improve the stomach mucosal irritation-potential of coffee charges revealed a remarkably lower stomach mucosal irritation.     

Double keystone bird in a keystone species complex

Species in a Colorado subalpine ecosystem show subtle interdependences. Red-naped sapsuckers play two distinct keystone roles. They excavate nest cavities in fungus-infected aspens that are required as nest sites by two species of swallows, and they drill sap wells into willows that provide abundant nourishment for themselves, hummingbirds, orange-crowned warblers, chipmunks, and an array of other sap robbers. The swallows thus depend on, and the sap robbers benefit from, a keystone species complex comprised of sapsuckers, willows, aspens, and a heartwood fungus. Disappearance of any element of the complex could cause an unanticipated unraveling of the community.