Objective:
Alvimopan use has reduced the length of hospital stay in patients undergoing major abdominal surgeries and radical cystectomy. Retroperitoneal lymph node dissection for testicular cancer ...may be associated with delayed gastrointestinal recovery prolonging hospital length of stay. We evaluate whether alvimopan is associated with enhanced gastrointestinal recovery and shorter hospital length of stay in men undergoing retroperitoneal lymph node dissection for testicular cancer.
Materials and methods:
From 2010 to 2016, 29 patients underwent open, transperitoneal bilateral template retroperitoneal lymph node dissection. Data for patients who received alvimopan were prospectively collected and compared to a historical cohort of patients who did not receive alvimopan. Primary outcome measures were length of stay and recovery of gastrointestinal function. Descriptive statistics were reported. Time-to-event outcomes were evaluated using cumulative incidence curves and log rank test. Factors associated with length of stay were analyzed for correlation using multiple linear regression.
Results:
Of 29 men undergoing retroperitoneal lymph node dissection, eight received alvimopan and 21 did not. The two cohorts were well matched, with no significant differences. In the alvimopan cohort compared with those who did not receive alvimopan median time to return of flatus was 2 versus 4 days (p=0.0002), and median time to first bowel movement was 2.5 versus 5 days (p=0.046), respectively. Median length of stay in the alvimopan cohort was 4 days versus 6 days in those who did not receive alvimopan (p=0.074). In adjusted analyses, receipt of alvimopan did not influence length of stay.
Conclusion:
Alvimopan may facilitate gastrointestinal recovery after retroperitoneal lymph node dissection for testicular cancer. Whether this translates into reduced length of stay needs to be determined by randomized controlled trials using larger cohorts.
Level of evidence:
3b.
Single-component monolayers of dendrimers and two-component monolayers consisting of dendrimers and n-alkanethiols immobilized on Au substrates are described. Single-component monolayers are prepared ...by exposing an Au substrate to ethanolic solutions of amine- or hydroxy-terminated polyamidoamine (PAMAM) dendrimers. The resulting monolayers are highly stable and nearly close-packed for dendrimer generations ranging from 4 to 8 (G4−G8). Electrochemical ac-impedance measurements indicate that the dendrimer surface is very porous toward the electroactive redox couple Fe(CN)6 3-/4-. Ferrocene-terminated dendrimer monolayers have also been investigated. Exposure of higher-generation dendrimer monolayers to ethanolic solutions of hexadecanethiol (C16SH) results in a dramatic compression of the dendrimers, and causes them to reorient on the surface from an oblate to prolate configuration. The dendrimers originally present on the surface do not desorb as a consequence of this configurational change. Comparison of the extent of adsorption of C16SH in different media (vapor-phase N2, hexane, and ethanol) shows that solvation of the dendrimers is the primary driving force for the structural change. Finally, the reactivity and stability of the dendrimer monolayers is investigated by on-surface functionalization of the dendrimer monolayer with 4-(trifluoromethyl)benzoyl chloride. The physical and chemical properties of the single- and two-component monolayers are evaluated by using reflection infrared spectroscopy, ellipsometry, contact-angle measurements, ac-impedance spectroscopy, cyclic voltammetry, and surface acoustic wave (SAW)-based analyte-dosing experiments.
We investigate evolving surface morphology during focused ion beam bombardment of C and determine its effects on sputter yield over a large range of ion dose (10
17–10
19
ions/cm
2) and incidence ...angles (
Θ
=
0–80°). Carbon bombarded by 20
keV Ga
+ either retains a smooth sputtered surface or develops one of two rough surface morphologies (sinusoidal ripples or steps/terraces) depending on the angle of ion incidence. For conditions that lead to smooth sputter-eroded surfaces there is no change in yield with ion dose after erosion of the solid commences. However, for all conditions that lead to surface roughening we observe coarsening of morphology with increased ion dose and a concomitant decrease in yield. A decrease in yield occurs as surface ripples increase wavelength and, for large
Θ, as step/terrace morphologies evolve. The yield also decreases with dose as rippled surfaces transition to have steps and terraces at
Θ
=
75°. Similar trends of decreasing yield are found for H
2O-assisted focused ion beam milling. The effects of changing surface morphology on yield are explained by the varying incidence angles exposed to the high-energy beam.
We have investigated the thermochromic transition of an ultrathin poly(diacetylene) film. The Langmuir film is composed of three layers of polymerized 10,12-pentacosadiynoic acid ...CH3(CH2)11C⋮CC⋮C(CH2)8COOH (poly-PCDA) organized into crystalline domains on a silicon substrate. Spectroscopic ellipsometry and fluorescence intensity measurements are obtained with in situ temperature control. Poly-PCDA films exhibit a reversible thermal transition between the initial blue form and an intermediate “purple” form that exists only at elevated temperature (between 303 and 333 K), followed by an irreversible transition to the red form after annealing above 320 K. We propose that the purple form is thermally distorted blue poly-PCDA and may represent a transitional configuration in the irreversible conversion to red. This hypothesis is supported by the appearance of unique features in the absorption spectra for each form as derived from the ellipsometry measurements. Significant fluorescence emission occurs only with the red form and is reduced at elevated temperatures while the absorption remains unchanged. Reduced emission is likely related to thermal fluctuations of the hydrocarbon side chains. Time-resolved fluorescence measurements of the irreversible transition have been performed. Using a first-order kinetic analysis of these measurements, we deduce an energy barrier of 17.6 ± 1.1 kcal mol-1 between the blue and red forms.
We have investigated the temperature-dependent roughening kinetics of Ge surfaces during low energy ion sputtering using energy dispersive x-ray reflectivity. At 150 degreeC and below, the surface is ...amorphized by ion impact and roughens to a steady state small value. At 250 degreeC the surface remains crystalline, roughens exponentially with time, and develops a pronounced ripple topography. At higher temperature this exponential roughening is slower, with an initial sublinear time dependence. A model that contains a balance between smoothing by surface diffusion and viscous flow and roughening by atom removal explains the kinetics. Ripple formation is a result of a curvature-dependent sputter yield.
We review the use of specular X-ray reflectivity (XRR) for the characterization of thin-film and surface structures. Specular X-ray scattering at small scattering vectors allows characterization of ...electron density profiles perpendicular to the surface on the length scale of 0.1 to 100 nm. This allows measurement of surface morphology, thin films, multilayer structures, and buried interfaces. The technique is nondestructive and can be applied in situ in a variety of processing environments. In the first half of the article, we review the theory and methods of XRR, including analysis of XRR spectra by a multilayer optical approach and a discussion of surface roughness measurements by XRR and other techniques. In the second half, we present a wide range of examples of XRR applications in thin-film structures, dynamic processes, liquid surfaces, and macromolecular structures.
Background: The use of dental implants for single‐tooth replacement cases introduces a challenge to the performance of these restorations. Clinical data suggest that single‐tooth implant restorations ...do not benefit from lateral support from the surrounding dentition as do bridged implants, and that these restorations are subjected to greater masticatory forces. Therefore, single‐tooth implants are exposed to an increased risk of failure. This prospective clinical trial was designed to evaluate the cumulative success rate of dual acid‐etched single‐tooth replacement implants in two clinical centers.
Methods: The study protocol included 59 patients between 19 and 73 years. Implants were evaluated for mobility, infection, and crestal bone loss from 30.9 to 60 months.
Results: Seventy‐one (71) implants were placed in 59 patients, 20 male and 39 female. Forty‐seven (47) were placed in the maxilla and 24 in the mandible. The percentages of anterior and posterior implants were 45.1 % and 54.9%, respectively. A total of 13 (18.4%) implants were placed in soft, poor quality (Type IV) bone. Beginning 1 month post‐implant placement, cases were followed for 30.9 to 60 months with a mean followup of 45.9 months. One implant failed (peri‐implant infection) yielding an overall success rate of 98.6%.
Conclusions: This success rate for single‐tooth replacement dual acid‐etched implants compares favorably with bridged implants and with success rates of other single‐tooth implant studies. Dual acid‐etched implants performed well even under conditions of poor quality bone, where concomitant bone augmentation was performed, and when used for immediate replacement of extracted teeth. J Periodontal 2002;73:687‐693.
We have investigated the liquid-phase self-assembly of 1-alkanethiols (HS(CH2) n - 1CH3, n = 8, 16, and 18) on hydrogenated Ge(111), using attenuated total reflection Fourier transform infrared ...spectroscopy as well as water contact angle measurements. The infrared absorbance of C−H stretching modes of alkanethiolates on Ge, in conjunction with water contact angle measurements, demonstrates that the final packing density is a function of alkanethiol concentration in 2-propanol and its chain length. High concentration and long alkyl chain increase the steady-state surface coverage of alkanethiolates. A critical chain length exists between n = 8 and 16, above which the adsorption kinetics is comparable for all long alkyl chain 1-alkanethiols. The steady-state coverage of hexadecanethiolates, representing long-chain alkanethiolates, reaches a maximum at approximately 5.9 × 1014 hexadecanethiolates/cm2 in 1 M solution. The characteristic time constant to reach a steady state also decreases with increasing chain length. This chain length dependence is attributed to the attractive chain-to-chain interaction in long-alkyl-chain self-assembled monolayers, which reduces the desorption-to-adsorption rate ratio (k d/k a). We also report the adsorption and desorption rate constants (k a and k d) of 1-hexadecanethiol on hydrogenated Ge(111) at room temperature. The alkanethiol adsorption is a two-step process following a first-order Langmuir isotherm: (1) fast adsorption with k a = 2.4 ± 0.2 cm3/(mol s) and k d = (8.2 ± 0.5) × 10-6 s-1; (2) slow adsorption with k a = 0.8 ± 0.5 cm3/(mol s) and k d = (3 ± 2) × 10-6 s-1.
We have investigated in situ and in real time vapor-phase self-assembly of 1-decene on Si, using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIRS). The adsorption of ...1-decene on hydrogenated Si(100) results in a decane-terminated hydrophobic surface, indicated by the sessile-drop water contact angle at 107 ± 2°. This maximum contact angle is achieved at 160 °C under 30 mTorr of vapor-phase 1-decene. The fractional surface coverage of decane, calculated from the IR absorbance of C−H stretching vibrational modes near 2900 cm-1, follows a Langmuir isotherm. The absolute surface coverage calculated from the IR absorbance saturates at 3.2 × 1014 cm-2. On the basis of this isotherm, the empirical rate constant ( ) that governs the rate-limiting step in 1-decene adsorption on HF-treated Si(100) is (3.3 ± 0.7) × 10-2 min-1. The thickness and cant angle of the decane monolayer at the saturation coverage are calculated from angle resolved X-ray photoelectron spectroscopy (AR-XPS). The calculated thickness ranges from 8.4 to 18 Å due to the uncertainty in the attenuation lengths of C(1s) and Si(2p) photoelectrons through the decane layer. For the same uncertainty, the calculated cant angle ranges from 0 to 55°. Spectroscopic ellipsometry is independently used to approximate the film thickness at 16 Å. Monitoring the decane monolayer over a period of 50 days using AR-XPS indicates that the Si surface underneath the decane monolayer gets oxidized with time, leading to the degradation of the decane layer.
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