A quality improvement intervention on surgical prophylaxis impact in antibiotic consumption and cost in selected surgical procedures.

BACKGROUND: Improper compliance with antibiotic prophylaxis (AP) in surgery is associated with an increased risk of surgical site infection (SSI), and impacts the efficiency of healthcare. OBJECTIVE: Evaluate the impact of an intervention in compliance with AP in selected surgical procedures and its effect on antibiotic consumption and cost. METHODS: A prospective interventional study was performed in a community hospital from January to December 2022. The baseline period was considered January-April 2022 and the intervention period May-December 2022. All patients who underwent cesarean section, appendectomies, hernia surgery, open reduction and internal fixation (ORIF), abdominoplasty, and cholecystectomy during the study period were selected. The intervention includes staff education, pharmacy interventions, monitoring the quality of prescriptions and feedback, and improved role of anesthesia staff, and department champions. RESULTS: The study involved 192 and 617 surgical procedures in the baseline and intervention periods respectively. The compliance with timing, selection, dose, and discontinuation achieved 100%, 99.2%, and 97.6% from baseline figures of 92.7%, 95.8%, and 81.3%, respectively. The antibiotic consumption was reduced by 55.1% during the intervention with a higher contribution of other antibiotics (94.1% reduction) in comparison with antibiotics as per policy (31.2% reduction). The cost was reduced by 47.2% (antibiotic as per policy 31.9%, other antibiotics 94.2%). CONCLUSION: The implemented strategy was effective in improving the quality of antibiotic prophylaxis with a significant impact in reducing antibiotic consumption and cost.

Experimental and numerical observation of dark and bright breathers in the band gap of a diatomic electrical lattice.

We observe dark and bright intrinsic localized modes (ILMs), also known as discrete breathers, experimentally and numerically in a diatomic-like electrical lattice. The experimental generation of dark ILMs by driving a dissipative lattice with spatially homogenous amplitude is, to our knowledge, unprecedented. In addition, the experimental manifestation of bright breathers within the band gap is also novel in this system. In experimental measurements the dark modes appear just below the bottom of the top branch in frequency. As the frequency is then lowered further into the band gap, the dark ILMs persist, until the nonlinear localization pattern reverses and bright ILMs appear on top of the finite background. Deep into the band gap, only a single bright structure survives in a lattice of 32 nodes. The vicinity of the bottom band also features bright and dark self-localized excitations. These results pave the way for a more systematic study of dark breathers and their bifurcations in diatomic-like chains.

Impulse-induced generation of stationary and moving discrete breathers in nonlinear oscillator networks.

We study discrete breathers in prototypical nonlinear oscillator networks subjected to nonharmonic zero-mean periodic excitations. We show how the generation of stationary and moving discrete breathers are optimally controlled by solely varying the impulse transmitted by the periodic excitations, while keeping constant the excitation's amplitude and period. Our theoretical and numerical results show that the enhancer effect of increasing values of the excitation's impulse, in the sense of facilitating the generation of stationary and moving breathers, is due to a correlative increase of the breather's action and energy.

From nodeless clouds and vortices to gray ring solitons and symmetry-broken states in two-dimensional polariton condensates.

We consider the existence, stability and dynamics of the nodeless state and fundamental nonlinear excitations, such as vortices, for a quasi-two-dimensional polariton condensate in the presence of pumping and nonlinear damping. We find a series of interesting features that can be directly contrasted to the case of the typically energy-conserving ultracold alkali-atom Bose-Einstein condensates (BECs). For sizeable parameter ranges, in line with earlier findings, the nodeless state becomes unstable towards the formation of stable nonlinear single or multi-vortex excitations. The potential instability of the single vortex is also examined and is found to possess similar characteristics to those of the nodeless cloud. We also report that, contrary to what is known, e.g., for the atomic BEC case, stable stationary gray ring solitons (that can be thought of as radial forms of Nozaki-Bekki holes) can be found for polariton condensates in suitable parametric regimes. In other regimes, however, these may also suffer symmetry-breaking instabilities. The dynamical, pattern-forming implications of the above instabilities are explored through direct numerical simulations and, in turn, give rise to waveforms with triangular or quadrupolar symmetry.

Nonlinear localized modes in two-dimensional electrical lattices.

We report the observation of spontaneous localization of energy in two spatial dimensions in the context of nonlinear electrical lattices. Both stationary and moving self-localized modes were generated experimentally and theoretically in a family of two-dimensional square as well as honeycomb lattices composed of 6 × 6 elements. Specifically, we find regions in driver voltage and frequency where stationary discrete breathers, also known as intrinsic localized modes (ILMs), exist and are stable due to the interplay of damping and spatially homogeneous driving. By introducing additional capacitors into the unit cell, these lattices can controllably induce mobile discrete breathers. When more than one such ILMs are experimentally generated in the lattice, the interplay of nonlinearity, discreteness, and wave interactions generates a complex dynamics wherein the ILMs attempt to maintain a minimum distance between one another. Numerical simulations show good agreement with experimental results and confirm that these phenomena qualitatively carry over to larger lattice sizes.

Generation of localized modes in an electrical lattice using subharmonic driving.

We show experimentally and numerically that an intrinsic localized mode (ILM) can be stably produced (and experimentally observed) via subharmonic, spatially homogeneous driving in the context of a nonlinear electrical lattice. The precise nonlinear spatial response of the system has been seen to depend on the relative location in frequency between the driver frequency, ω(d), and the bottom of the linear dispersion curve, ω(0). If ω(d)/2 lies just below ω(0), then a single ILM can be generated in a 32-node lattice, whereas, when ω(d)/2 lies within the dispersion band, a spatially extended waveform resembling a train of ILMs results. To our knowledge, and despite its apparently broad relevance, such an experimental observation of subharmonically driven ILMs has not been previously reported.

Discrete breathers in a nonlinear electric line: modeling, computation, and experiment.

We study experimentally and numerically the existence and stability properties of discrete breathers in a periodic nonlinear electric line. The electric line is composed of single cell nodes, containing a varactor diode and an inductor, coupled together in a periodic ring configuration through inductors and driven uniformly by a harmonic external voltage source. A simple model for each cell is proposed by using a nonlinear form for the varactor characteristics through the current and capacitance dependence on the voltage. For an electrical line composed of 32 elements, we find the regions, in driver voltage and frequency, where n-peaked breather solutions exist and characterize their stability. The results are compared to experimental measurements with good quantitative agreement. We also examine the spontaneous formation of n-peaked breathers through modulational instability of the homogeneous steady state. The competition between different discrete breathers seeded by the modulational instability eventually leads to stationary n-peaked solutions whose precise locations is seen to sensitively depend on the initial conditions.

Traveling and stationary intrinsic localized modes and their spatial control in electrical lattices.

This work focuses on the production of both stationary and traveling intrinsic localized modes (ILMs), also known as discrete breathers, in two closely related electrical lattices; we demonstrate experimentally that the interplay between these two ILM types can be utilized for the purpose of spatial control. We describe a novel mechanism that is responsible for the motion of driven ILMs in this system, and quantify this effect by modeling in some detail the electrical components comprising the lattice.

Solitons in one-dimensional nonlinear Schrödinger lattices with a local inhomogeneity.

In this paper we analyze the existence, stability, dynamical formation, and mobility properties of localized solutions in a one-dimensional system described by the discrete nonlinear Schrödinger equation with a linear point defect. We consider both attractive and repulsive defects in a focusing lattice. Among our main findings are (a) the destabilization of the on-site mode centered at the defect in the repulsive case, (b) the disappearance of localized modes in the vicinity of the defect due to saddle-node bifurcations for sufficiently strong defects of either type, (c) the decrease of the amplitude formation threshold for attractive and its increase for repulsive defects, and (d) the detailed elucidation as a function of initial speed and defect strength of the different regimes (trapping, trapping and reflection, pure reflection, and pure transmission) of interaction of a moving localized mode with the defect.

Charge Transport in Poly(dG)-Poly(dC) and Poly(dA)-Poly(dT) DNA Polymers.

We investigate the charge transport in synthetic DNA polymers built up from single type of base pairs. In the context of a polaronlike model, for which an electronic tight-binding system and bond vibrations of the double helix are coupled, we present estimates for the electron-vibration coupling strengths utilizing a quantum-chemical procedure. Subsequent studies concerning the mobility of polaron solutions, representing the state of a localized charge in unison with its associated helix deformation, show that the system for poly(dG)-poly(dC) and poly(dA)-poly(dT) DNA polymers, respectively possess quantitatively distinct transport properties. While the former supports unidirectionally moving electron breathers attributed to highly efficient long-range conductivity, the breather mobility in the latter case is comparatively restrained, inhibiting charge transport. Our results are in agreement with recent experimental results demonstrating that poly(dG)-poly(dC) DNA molecules acts as a semiconducting nanowire and exhibit better conductance than poly(dA)-poly(dT) ones.

Breathers in a system with helicity and dipole interaction.

Recent papers that have studied variants of the Peyrard-Bishop model for DNA, have taken into account the long range interaction due to the dipole moments of the hydrogen bonds between base pairs. In these models the helicity of the double strand is not considered. In this paper we have performed an analysis of the influence of the helicity on the properties of static and moving breathers in a Klein-Gordon chain with dipole-dipole interaction. It has been found that the helicity enlarges the range of existence and stability of static breathers, although this effect is small for a typical helical structure of DNA. However, the effect of the orientation of the dipole moments is considerably higher with transcendental consequences for the existence of mobile breathers.

Type A behavior pattern today: relevance of the JAS-S factor to predict heart rate reactivity.

The authors used 89 undergraduate students' scores in the S-factor of the Jenkins Activity Survey, a measure of speed and impatience, to classify 45 participants as high scorers and 44 as low scorers. They then measured the students' tonic and phasic heart rates during an examination, a genuinely stressful situation. The experiment consisted of three phases: adaptation, task, and recovery. The findings confirmed the authors' hypothesis that the high-S scorers would show higher cardiac reactivity values than the low-S scorers. The authors also observed that the high-S scorers took more time than the low-S scorers to recover their initial heart rate values after being exposed to the stress situation. This finding led the authors to suggest that each group may have different response patterns. They call for further research on individuals with "fast activation-fast recovery" and "fast activation-slow recovery" profiles.

Psychophysiological activation, reactivity, and recovery in Type A and Type B scorers when in a stressful laboratory situation.

21 university students participated in a study to assess intergroup differences in psychophysiological activation, reactivity, and recovery. Findings support the hypothesis that 12 Type A scorers showed a greater activation and reactivity than the 9 Type B scorers. Type A scorers needed more time to recover normal psychophysiological levels than Type B scorers. We propose that the "fast activation-slow recovery" profile is characteristic of Type A scorers. The "fast activation-fast recovery" profile is characteristic of Type B-scoring college students.

Resting heart rate (HR) in women with and without premenstrual symptoms (PMS).

A sample of 64 undergraduate female students participated in the present experiment. During 3 consecutive months women answered a chart of daily report of symptoms, and finally, two groups were formed: women with premenstrual symptoms (PMS group) and women without premenstrual symptoms (NPMS group). Heart rates (HR) at rest were recorded throughout premenstrual, menstrual, postmenstrual, and ovulatory phases. In the premenstrual phase, PMS group showed significantly higher resting HR levels than NPMS group. With regard to resting HR levels across the four phases studied, significant differences within PMS group were observed. Our results are discussed from a psychophysiological point of view.