Ultrafast Single-Molecule Fluorescence Measured by Femtosecond Double-Pulse Excitation Photon Antibunching.

Most measurements of fluorescence lifetimes on the single-molecule level are carried out using avalanche photon diodes (APDs). These single-photon counters are inherently slow, and their response shows a strong dependence on photon energy, which can make reconvolution of the instrument response function (IRF) challenging. An ultrafast time resolution in single-molecule fluorescence is crucial, e.g., in determining donor lifetimes in donor-acceptor couples which undergo energy transfer, or in plasmonic antenna structures, where the radiative rate and non-radiative rates are enhanced. We introduce a femtosecond double-excitation (FeDEx) photon correlation technique, which measures the degree of photon antibunching as a function of time delay between two excitation pulses. In this boxcar integration, the time resolution of fluorescence transients is limited solely by the laser pulse length and is independent of the detector IRF. The versatility of the technique is demonstrated with a custom-made donor-acceptor complex with one donor and two acceptors and with single dye molecules positioned accurately between two gold nanoparticles using DNA origami. The latter structures show ∼75-fold radiative-rate enhancement and fluorescence lifetimes down to 19 ps, which is measured without the need for any reconvolution. With the potential of measuring subpicosecond fluorescence lifetimes, plasmonic antenna structures can now be optimized further.

Anomalous Linear Dichroism in Bent Chromophores of π-conjugated Polymers: Departure from the Franck-Condon Principle.

We examine the influence of bending of π-conjugated chromophores on photoluminescence (PL) by spectrally resolving the depolarization of fluorescence on the single-molecule level. The effect of excited-state mixing mediated by molecular vibrations is manifested in the departure from the usual achromatic linear dichroism of fluorescence, with the polarization anisotropy decreasing in the vibronic progression. Bent chromophores reveal an overall increase in vibronic PL intensity with polarization orthogonal to the molecular long axis. This manifestation of the Renner-Herzberg-Teller (RHT) effect illustrates the breakdown of the Franck-Condon principle in macromolecules used in organic electronics, providing information on the orientation of transition-dipole moments and the origin of spectral broadening. While some of the spectral signatures of the RHT effect appear similar to those of H aggregation in molecular dimers, discrimination between the two phenomena is straightforward since H aggregation does not induce anomalous linear dichroism.

Interactions between π-conjugated chromophores in a giant molecular spoked wheel.

We discuss the intriguing photophysics of a giant molecular spoked wheel of π-conjugated arylene-alkynylene chromophores on the single-molecule level. This "molecular mesoscopic" structure, C1878H2682, shows fast switching between the 12 identical chromophores since the fluorescence is unpolarised but only one chromophore emits at a time.

Role of atrial natriuretic factor in renin release.

Atrial natriuretic factor (ANF) was studied for its effect on renin release by rat renal cortical slices. ANF (rat) alone (10(-9)-10(-6) M) had no effect on basal renin release, but significantly (P less than 0.001) potentiated angiotensin II (AII) inhibition of renin secretion in doses as low as 10(-9) M. ANF also potentiated the inhibitory effect of AII on 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride (which alters intracellular calcium) and calmidazolium (a calmodulin blocker) effects on renin release. ANF did not inhibit the action of isoproterenol, which probably acts through cAMP, at doses below micromolar concentrations. Large, probably pharmacological amounts (greater than 10(-6) M) produce some inhibition. Since AII action on renin is associated with increases in intracellular calcium, our studies suggest that ANF acts by altering the intracellular calcium-calmodulin-mediated steps of AII action on this tissue and not via cAMP.

Fatal hemoptysis in Ehlers-Danlos syndrome. Old malady with a new curse.

We describe the case of a 27-year-old man with Ehlers-Danlos syndrome, type IV. The patient had recurrent and eventually fatal pulmonary hemorrhage. Type IV Ehlers-Danlos syndrome is a rare disorder of type III collagen synthesis. It is characterized by an unusual facies, thin, translucent skin with venous vascular pattern, and hypermobility of the small joints. The cause of death is usually due to rupture of a viscus or a major arterial hemorrhage and, in women, rupture of the gravid uterus. Fatal lung hemorrhage in Ehlers-Danlos syndrome, to our knowledge, has not been previously described.

Postoperative intracranial abscess--clinical aspects in the differential diagnosis to early recurrence of malignant glioma.

Out of 2941 patients who received a clean, major craniotomy, 39 patients (1.3%) developed the complication of an intracranial deep infection, i.e. abscess or empyema. A total of 14 patients with a postoperative abscess were initially operated upon intracerebral malignant glioma (WHO III or IV) and could be compared to a matched group of patients with recurrent malignancy concerning clinical and radiological aspects. A statistically significant elevation of median values was seen for erythrocyte sedimentation rate (ESR), fibrinogen and body temperature in the study group. C-reactive protein (CRP) was not investigated in the control group and could not be compared, but it was elevated in all abscess patients when measured. CT-scan did not allow a safe differentiation between infection and recurrent glioma. Local signs like suppuration of the wound could be observed in 71% of patients with intracranial infection. Postoperative abscesses had been diagnosed in all cases within 3 months, whereas none of the early recurrences of intracerebral malignoma became symptomatic before 12 weeks after initial operation. Therefore, the course of time seems to be another important factor in this differential diagnosis.

Clinical results and surgical technique for the treatment of extreme lateral lumbar disc herniations: the minimally invasive microscopically assisted percutaneous approach.

OBJECTIVE: Operative techniques for the treatment of extreme lateral lumbar disc herniations (ELLDH) have ranged from an interlaminar approach with subtotal or total facetectomy to an enlarged midline approach and various paraspinal lateral, as well as endoscopic approaches. In contrast to purely endoscopic techniques, use of a working tube together with an operative microscope ("minimally invasive microscopically assisted percutaneous approach") combines the advantages of three-dimensional visual control with the minimal surgical trauma of an endoscopic approach. We present this technique and the clinical results in patients with extreme lateral lumbar disc herniation (ELLDH). METHODS: In a retrospective case series we analyzed the data of 73 consecutive patients with a disc herniation within or lateral to the intervertebral foramen. All of them were operated on using the surgical microscope after blunt dilatation of the paraspinal muscles and insertion of a tubular retractor system (METRx, Medtronic Sofamor Danek). Fifty-nine patients were included in the follow-up study. Follow-up ranged from 10 to 47 months (mean 30.4) and was evaluated after telephone inquiry by the co-author using the modified MacNab criteria . RESULTS: The results with respect to improvement of preoperative symptoms were excellent in 23 patients (39%), good in 25 patients (42.4%), fair in 8 patients (13.5%) and poor in 3 patients (5.1%). Twenty-four patients had still been working prior to surgery, and 20 returned to work after 4-8 weeks. CONCLUSION: The paraspinal approach for extreme lateral lumbar disc herniations using the minimally invasive microscopically assisted percutaneous technique is reasonable and safe and thus a good alternative to open surgical procedures.

The translaminar approach in combination with a tubular retractor system for the treatment of far cranio-laterally and foraminally extruded lumbar disc herniations.

OBJECTIVE: Standard surgical procedures for the treatment of far cranio-lateral or foraminally extruded lumbar disc herniations include interlaminar exposure with partial or complete resection of the upper hemilamina and sometimes partial removal of the facet joint and weakening of the pars interarticularis. We present our experiences with the translaminar approach to this entity of lumbar disc herniation using a tubular retractor system. METHODS: Fifteen patients with far cranio-laterally extruded disc herniations underwent neurosurgical intervention using a translaminar approach. The paraspinal muscles were spread with a dilatator after performing a 1.5 cm skin incision. A 16 mm METRx tubular retractor system (Medtronic Sofamor Danek, Memphis, TN) was directly placed on the upper lamina. The next steps were performed through this channel using the surgical microscope. A small ovoid fenestration (10x5 mm) was performed using a high speed drill and the disc prolapse was removed in a standard manner. Follow-ups were routinely carried out 3 weeks postoperatively and reassessment was subsequently carried out by telephone inquiry 10 to 44 months (median 23 months) after treatment. These results were rated according to the modified MacNab criteria. RESULTS: Five of the fifteen affected discs were at the level L3/4, eight at L4/5 and two at L5/S1. The average surgical time was 55 minutes. No complications occurred. In all patients sciatic pain disappeared immediately after the operation. One patient underwent fusion of the affected level one year later because of progression of a pre-existent pseudospondylolisthesis. Long-term follow-up demonstrated excellent results in six, good results in seven, a fair result in one and a poor result in one patient according to the modified MacNab criteria. CONCLUSION: The translaminar approach in conjunction with a tubular retractor system seems to be an effective and safe alternative technique for treating the small entity of far cranio- laterally or foraminally extruded lumbar disc herniations. It combines the advantages of a blunt muscle-spreading approach that produces little damage to the soft tissues, and the avoidance of large bone removal that may jeopardize vertebral stability. Since this approach does not permit sufficient exploration of the intervertebral disc space of origin, it should be limited to patients without significant bulging of the disc itself.

Plagiarism--an act of stealing.

Plagiarism is one of those ethical issues no one wants to talk about. This article sets the stage for educating readers, authors, and researchers in the fundamentals of scholarship. Legal ramifications for professional theft, deception, and misconduct provide information regarding the perpetration, constituents, and aftermath of the act of plagiarism. The article then communicates a shift in thinking about the deviation from ethical standards and strategies for the prevention of the ethical issue. Plagiarism can be prevented.

Continued contact with a familiar nurse affects women's perceptions of the ambulatory surgical experience: a qualitative-quantitative design.

Ambulatory surgery patients tend to have different nurses providing care during each phase of the surgical stay. The purpose of this study was to investigate the impact continued contact with a familiar nurse, from preadmission procedures through postoperative awakening to consciousness in the PACU, had on women's postdischarge evaluations of their ambulatory surgical experience. The study consisted of a convenience sample of 40 women between the ages of 19 and 68 years scheduled to receive general anesthesia. Women in the continued contact group (n = 20) reestablished contact with the familiar nurse when arriving at the ambulatory surgery unit (ASU) 1 hour before surgery and they maintained continued contact with that nurse while awakening to consciousness in the PACU. A postdischarge telephone interview was conducted with women in both groups 3 to 5 days following surgery. chi 2 Analysis found that women who had continued contact with a familiar nurse reported being ready to go home when discharged from the ASU significantly more often than women in the control group (P less than .05). By t test analysis, women in the continued contact group reported greater satisfaction with the nursing care received (P less than .01). Women in both groups also talked about their ambulatory surgical experience. The data are presented descriptively. Findings indicated that receiving continued contact with a familiar nurse significantly affected women's postdischarge evaluations of their ambulatory surgical experience compared with receiving standard nursing care in the study hospital.

Patients talk about their postanesthesia shaking experiences.

Postanesthesia shaking is a frequent complication developing for unknown reasons during emergence from general anesthesia. The sources of primary knowledge concerning how patients describe their postanesthesia shaking experiences are sparse. This study presents data to expand the body of PACU nursing knowledge through patients offering information about the shaking phenomenon. In an attempt to categorize ways patients talk about their shaking experience, the research question guiding this study was this: How do patients talk about the postanesthesia shaking phenomenon? This descriptive research used an interview design. Telephone interviews were conducted with 103 subjects. Tape recorded interviews with the 43 subjects who remembered their shaking experience are included in the presentation of data. These data show that when patients were asked to talk about their shaking experience, they not only had memory of the postanesthesia shaking phenomenon, but they talked about their shaking experience in various ways. Further research is needed to promote a greater understanding of patient responses to this postanesthesia complication.

Patients who develop postanesthesia shaking show no difference in postoperative temperature from those who do not develop shaking.

While the cause of postanesthesia shaking (PS) remains unknown, nurses traditionally believe that the etiology of PS is hypothermia. Two theoretical constructs have been proposed to describe the development of PS. The first is based on classic thermoregulation theory. The second is based on spinal reflex hyperactivity. The purpose of this comparison study was to determine if significant differences in postoperative temperature, as well as change in preoperative to postoperative temperature, exists between patients who develop and who do not develop PS. The study also examined the difference in postoperative temperature between women and men. Postoperative axillary temperature was measured on admission to the PACU. The nonprobability convenience sample consisted of patients between the ages of 18 and 89 years who were extubated and breathing spontaneously following general anesthesia. PS developed in 120 of 533 patients. By t-test analysis, there was no statistical significant difference between groups in postoperative mean temperature (P greater than .10) or in preoperative to postoperative mean temperature change (P greater than .40). The group that developed PS had a narrower and higher range of postoperative temperature and a smaller preoperative to postoperative temperature change than those who did not develop PS. In both groups, 52% of the patients were hypothermic (less than 35 degrees C[less than 95 degrees F]) on PACU admission. Women had lower postoperative mean temperature than men (P less than .05). Findings indicate that temperature on PACU admission is not a variable of difference between groups of patients who develop or who do not develop PS. As postoperative temperature decreases, the incidence of PS does not increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative research versus quality assurance, quality improvement, total quality management, and continuous quality improvement.

The purpose of this report is to provide a review of the scientific method used in the quantitative research studies for consumers, evaluators, and applied nurse researchers. The fundamental characteristics of the problem-solving/ performance-improvement processes of quality assurance, quality improvement, total quality management, and continuous quality improvement are described. Research is compared with these processes, and is followed by a discussion about the publication of quantitative research findings.

The qualitative-quantitative dichotomy.

The article presents information about the qualitative and quantitative differences in research approaches. A comparison of these research approaches is offered as an educational tool to increase understanding of why both approaches are needed to build a body of knowledge specific to perianesthesia nursing.

Patients who develop postanesthesia shaking increase body temperature at the same rate as those who do not develop shaking.

Postanesthesia shaking is a common complication occurring after general anesthesia. Although the cause is unknown, some nurses believe that shaking is useful and beneficial for patients because it increases body temperature and that shaking stops when patients are no longer hypothermic. The primary purpose of this study was to examine changes in body temperature among patients who developed and who did not develop shaking. Secondary purposes were to examine changes in body temperature among patients who received or who did not receive intravenous narcotic-analgesic medication treatment to stop shaking and among those who either stopped shaking or who continued to shake until spontaneous cessation occurred minutes to hours later. The convenience sample consisted of 36 shaking patients and 56 nonshaking patients who were extubated, were over 18 years of age, had an intact intravenous line, and received isoflurane anesthesia. Shaking was established when patients reached and sustained grade 2 or 3 shaking on a 0-to-3 visual scale for 3 minutes (no shaking to forceful shaking). Shaking was determined as having stopped when patients achieved grade 2 on a 0-to-2 visual scale (continues shaking to stopped shaking). Axillary temperature was measured on PACU admission and again after 60 minutes. The six hypotheses were supported. Patients who developed shaking (mean = .67 degrees C [1.2 degrees F]) changed body temperature at the same rate as those who did not develop shaking (mean = .72 degrees C [1.3 degrees F]). Administration of intravenous narcotic-analgesic medication to stop shaking did not alter the rate of body temperature change in patients who received or who did not receive treatment for shaking and those who did or who did not stop shaking. Findings suggest that postanesthesia shaking does not increase body temperature. This finding does not support the long-held belief that shaking is useful and beneficial for patients because it increases body temperature. Findings also indicated that the administration of intravenous narcotic-analgesic medications to stop shaking does not alter the rate of body temperature change. Suggestions for further research focus on systematically examining nursing interventions currently implemented to stop shaking. Research findings will provide evidence that either supports or fails to support the implementation of therapeutic interventions that effectively stop shaking within 5 minutes.