Background: Delayed gastric emptying (DGE) is one of the most common postoperative complications in patients following pancreaticoduodenectomy (PD). This complication has been shown to effect 14-30% of patients postoperatively. Many randomized studies have shown no statistical difference between pylorus-sparing PD vs. classic PD. Additionally, the position of the anastomosis in classic PD, antecolic versus retrocolic, has also undergone randomized trials which have shown no difference in rates of DGE. The aim of this study was to report our incidence of DGE after a departmental change to a stapled retrocolic loop gastrojejunostomy as a result of high DGE with antecolic approach. The secondary aim was to identify risk factors for developing DGE on multivariate analysis.

Presenter: Veronika Lobova BS | Washington State University Background: As the population of the United States continues to age, incidence of pancreatic adenocarcinoma (PDAC) is also expected to increase, making more elderly patients candidates for surgical resection. In patients over 75 years old, however, the risk of pancreatic resection may outweigh the survival benefits. Thus, the primary aim of this study was to evaluate both progression-free and overall survival among PDAC patients over 75 years old and to determine factors associated with survival duration. Methods: A retrospective chart review was conducted for patients older than 75 years old who underwent surgical resection (Whipple surgery and distal pancreatectomy) of PDAC from February 2014 to May 2020 at a single community-based hospital. Clinical parameters, additional treatments, complications, and survival curves were analyzed. Results: A total of 44 patients over the age of 75 years underwent surgical resection of PDAC (median age 79, 48% female). More patients underwent a Whipple procedure compared to distal pancreatectomy (73% vs. 27%, respectively). Fifty-five percent received adjuvant chemotherapy, 18% received neoadjuvant chemotherapy, and 20% had radiation. The median survival for all patients was 9.0 months (quartiles 3.5 - 15.5). Among patients who survived > 3 months (i.e. cancer specific survival) the median survival duration was 12 months (quartiles 8-18 months). Among patients who underwent Whipple surgery and survived there was only one case of progression, and median progression-free survival was 9.0 months (quartiles 4.0-14.0 months). There was no significant difference in survival between Whipple procedures and distal pancreatectomies. Perioperative complications occurred in 32% of patients within 30 days, respectively. Death occurred in 11% of patients within 30 days and 40% of deaths occurred due to cardiac arrest. Survival was significantly longer among patients who had adjuvant chemotherapy or radiation compared to those who did not (median 13.0 vs. 5.0 months, P=0.01, and 18.0 vs. 7.0 months, P=0.002, respectively, see Graph). Survival duration was not different between individuals who received neoadjuvant chemotherapy (median 6.5 months) and those who did not (9.5 months, P=0.45), and did not differ by number of regional nodes involved. Conclusion: The complication rate of surgical resection of PDAC in this elderly population is comparable to the generalized population. However, the mortality rate is higher. More comprehensive preoperative cardiovascular screening may be necessary in the elderly population to prevent cardiovascular related deaths.

A radical approach to an 18 yo woman with extensive bilobar HCC, initially downsized with Y-90/ TACE, resection, VATs metastectomy, development of intrahepatic biliary strictures secondary to Y-90, who developed liver recurrence, and ultimately underwent successful liver transplantation. Patient intitally presented with 2 yrs RUQ pain and had a CT scan 6/2011 revealing infiltrative 15 cm bilobar HCC and AFP 22,000. The patient was not considered a resection candidate and underwent 5 Y-90/4 DEB-TACE treatments between 8/2011-4/2012. Post Y-90/TACE, CT scan improvement in tumor burden (AFP 3,350). The patient underwent a right trisectionectomy, combination RFA/ non-anatomical resections of 4 lesions in the left lateral section (5/7/2012). The patient developed a left lower lung nodule and underwent VATS metastectomy (11/2012). The patient's course was complicated by bronchobiliary fistula requiring subdiaphragmatic and PTC drains for progressive intrahepatic biliary strictures (radiation effect). She was 4 years recurrence free, however, in 10/2016 developed 3.5 cm liver recurrence (AFP 3,600) and underwent TACE (AFP 40) and evaluation and listing for transplant. She received HCC MELD exception points of 28, laboratory MELD 21. She underwent transplantation on 4/4/2017. The operation was extremely difficult secondary to multiple previous procedures. Her current AFP <1.3. Lessons learned: It was worth it! Nearly one year out, and she is highly functional. Length of time for HCC recurrence, AFP response, and patient factors should be considered when looking at contraindications to transplant. Multiple Y-90 treatments can cause extensive biliary stricturing, due to repeated radiation, and can present years later.

Background: Liver resection for malignancy in the elderly is common given most malignancies occur in the 6th and 7th decades. Previous studies show increasing age in surgical patients is the most important predictor of morbidity and mortality. The aim was to evaluate patients > 65yrs undergoing liver resection for malignancy and determine risk factors for morbidity and mortality. Methods: The National Surgical Quality Improvement Program (NSQIP) database (2014-2016) was queried for patients age>65 who underwent liver resection for malignancy. Odds ratios for factors associated with increased risk of post-hepatectomy complications and death were evaluated with Cox logistical regression. Results: 3,460 patients underwent liver resection with a 3% mortality and 32% complication rate. Post-operative bile leak occurred in 9.4% of patients, liver failure occurred in 5.7%, and transfusions occurred in 20% of patients. On univariate analysis, there was no association between complications and age (p=.75), neoadjuvant therapy (p= 0.13), diabetes (p=.44), and smoking (p=0.73). Factors associated with complications: decreased BMI (p< 0.01), higher ASA (p< .01), pringle maneuver (p< .01), hilar cholangiocarcinoma (p< .01), and open surgery (p< .01). On multivariate analysis, factors associated with increased risks can be seen in Figure 1.Tabled 1FP28-05 Table [Table 1]Multivariable Adjusted Odds Ratios ond 95% Confidence intervals for Post Hepotectomy Compactions and Mortality for Elderly Patients Age ≥ 65TermMultivariate model: at least one complicationMultivariate model: modalityOdds95% CIOdds95% CIRatioLowerUpperp-valueRatiolowerUpperp-valueBMI (per ↑ 1)0.980.971.000.01490.990.961.020.5036Pre-operative platelet count (per ↑ 25)1.000.981.030.95680.930.870.990.0191Preoperative serum albumin (per ↑ 1)0.600.500.72

Objective: With the evolution of GSR training, we have seen an increase in graduates pursuing fellowships. While training of the GSR is valuable, there has been an emerging focus on educating fellows and sharing GSR cases. Our aim was to evaluate the role of the HPB fellow with respect to GSR training and to determine each group's perception of the role of the fellow on resident education Methods: Two surveys were created to evaluate both fellows' and GSRs' perception of the fellows impact on GSR education. HPB fellows and PGY 3–5s at the 18 AHPBA accredited fellowships were invited to participate. Survey was conducted on Survey Monkey. Statistics were computed with a Fischer's test. Results: 15/35 (42.9%) fellows and 11/18 (61%) institutions (59 residents) responded to the survey. Fellows and GSR average cases were 58.5 liver, 26.7 complex biliary and 52 pancreas vs. 5 liver, 5 complex biliary, and 6 pancreas, respectively. 78.9% of fellows compared to 32.2% GSRs (p

Growth of Hg 1−x Cd x Te by molecular beam epitaxy (MBE) has been under development since the early 1980s at Rockwell Scientific Company (RSC), formerly the Rockwell Science Center; and we have shown that high-performance and highly reproducible MBE HgCdTe double heterostructure planar p-on-n devices can be produced with high throughput for various single- and multiplecolor infrared applications. In this paper, we present data on Hg 1−x Cd x Te epitaxial layers grown in a ten-inch production MBE system. For growth of HgCdTe, standard effusion cells containing CdTe and Te were used, in addition to a Hg source. The system is equipped with reflection high energy electron diffraction (RHEED) and spectral ellipsometry in addition to other fully automated electrical and optical monitoring systems. The HgCdTe heterostructures grown in our large ten-inch Riber 49 MBE system have outstanding structural characteristics with etch-pit densities (EPDs) in the low 10 4 cm −2 range, Hall carrier concentration in low 10 14 cm −3 , and void density <1000 cm 2 . The epilayers were grown on near lattice-matched (211)B Cd 0.96 Zn 0.04 Te substrates. High-performance mid wavelength infrared (MWIR) devices were fabricated with R 0 A values of 7.2×10 6 Ω-cm 2 at 110 K, and the quantum efficiency without an antireflection coating was 71.5% for cutoff wavelength of 5.21 µm at 37 K. For short wavelength infrared (SWIR) devices, an R 0 A value of 9.4×10 5 Ω-cm 2 at 200 K was obtained and quantum efficiency without an antireflection coating was 64% for cutoff wavelength of 2.61 µm at 37 K. These R 0 A values are comparable to our trend line values in this temperature range.

Rockwell Science Center has developed a double layer planar heterostructure (DLPH) detector array fabrication process with significant advantages over the PACE-1 process now being used to produce 256 X 256 and 1024 X 1024 FPAs for low background IR astronomy. The DLPH detectors are p- on-n photodiodes fabricated in a double layer of wide and narrow bandgap HgCdTe grown by molecular beam epitaxy on CdZnTe substrates. The double layer structure provides superior surface passivation while the lattice matched CdZnTe substrate reduces the defect density. DLPH FPAs have been fabricated in array sizes up to 640 X 480 and with cutoff wavelengths as long as 15 micrometers . Quantum efficiencies are typically in the 0.5 to 0.8 range. For a 256 X 256 array DLPH detectors with 5.3 micrometers cutoff wavelength at 50K, the median dark current was 0.39 e-/sec at 0.5V reverse bias. For 7 of 17 individual DLPH detector with 10.6 micrometers cutoff at 30K, the dark current was less than 104 e-/sec at 20 mV bias. For long cutoff wavelengths, the detector breakdown voltage is too low to permit signal integration directly on the reverse biased detector capacitance. Such detectors require a readout circuit that maintains the detector near zero bias and provides a separate capacitor to store the integrated signal.

This work presents characterization of implanted and annealed double layer planar heterostructure HgCdTe for p-on-n photovoltaic devices. Our observation is that compositional redistribution in the structure during implantation/ annealing process differs from that expected from classical composition gradient driven interdiffusion and impacts the placement of the electrical junction with respect to the metallurgical heterointerface, which in turn affects quantum efficiency and RoA. The observed anomalous interdiffusion results in much wider cap layers with reduced composition difference between base and cap layer composition. The compositional redistribution can, however, be controlled by varying the material structure parameters and the implant/anneal conditions. Examples are presented for dose and implanted species variation. A model is proposed based on the fast diffusion in the irradiation induced damage region of the ion implantation. In addition, we demonstrate spatial uniformity obtained on molecular beam epitaxy (MBE) material of the compositional and implanted species profile. This reflects spatial uniformity of the ion implantation/annealing Processes and of the MBE material characteristics.

Deep levels in p+n Hg0.73Cd0.27Te/Hg0.68Cd0.32Te planar heterostructure diodes, grown by molecular beam epitaxy on CdZnTe wafers, were studied using deep level transient spectroscopy (DLTS). The DLTS spectra showed the presence of at least two hole traps with activation energies close to midgap. The activation energy obtained from the Arrhenius plots showed a strong dependence on the aplied bias, making it difficult to obtain a precise value.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Bajaj, Jose Arias, Majid Zandian, and John PaskoScience Center Rockwell International Corporation1049 Camino Dos Rios, Thousand Oaks, California 91358ABSTRACTDeep-level transient spectroscopy (DLTS) measurements were performed on midwavelength HgCdTemesa diodes grown by LPE and pn HgCdTe planar heterostructures grown on CdZnTe wafers by MBE.The DLTS spectra of the MBE samples showed the presence of at least two hole traps, while at least twoshallower electron traps were observed from the LPE samples. In addition to DLTS measurements, thediodes were also studied using double correlation DLTS (DDLTS) and current transient spectroscopy(CTS). The DDLTS spectra showed sharper peaks than the corresponding DLTS spectra. CTS measure-ments complement the DLTS data in the temperature range where the diode's leakage current is too highfor capacitance measurements. These measurements revealed the presence of additional trapping centersin the LPE samples studied. This paper discusses the interpretation of these results and the suitability ofthe DLTS technique for the study ofpoint defects in HgCdTe.1. INTRODUCTIONImprovements in the mercury cadmium telluride (MCT) material and in device processing have elimi-nated many problems affecting the performance of JR detectors. However, there remain many problemsthat must be solved to improve the performance of long wavelength devices1 .

Device‐quality Hg1−xCdxTe (0.26<x<0.33) epilayers with thicknesses in the range 10–20 μm were grown on (111)B CdTe substrates by molecular beam epitaxy (MBE). The as‐grown layers were p type, and typically had carrier concentrations in the low 1016 cm−3 range and hole mobilities greater than 220 cm2/V s at 77 K. The n+‐p junction was formed by Be ion implantation; unpassivated mesa photodiodes were fabricated by standard photolithographic techniques. Resistance‐area products (R0A) at zero bias were 5.2×106 and 1.4×104 Ω cm2 at 77 K for Hg1−xCdxTe with cutoff wavelengths of 4.0 and 5.7 μm, respectively. These R0A values approach typical ones obtained by liquid phase epitaxy and represent a very promising initial effort for MBE‐grown Hg1−xCdxTe.

The large optical anisotropy of liquid crystal molecules is employed to realize an efficient, voltage tunable Fabry-Perot filter. Tuning has been demonstrated in both the visible and middle infrared. The small voltages required to tune over one free spectral range (FSR) result in a device having greater potential for designing filters having a larger range of FSRs, and therefore bandpass widths, than is possible for the solid electro-optic Fabry-Perot described in previous work.1 We show that for many commercially available liquid crystal materials, infrared operation is possible over wide regions where molecular absorptions do not occur.