Machine Learning Prediction of TiO2-Coating Wettability Tuned via UV Exposure.

Surfaces with extreme wettability (too low, superhydrophobic; too high, superhydrophilic) have attracted considerable attention over the past two decades. Titanium dioxide (TiO2) has been one of the most popular components for generating superhydrophobic/hydrophilic coatings. Combining TiO2 with ethanol and a commercial fluoroacrylic copolymer dispersion, known as PMC, can produce coatings with water contact angles approaching 170°. Another property of interest for this specific TiO2 formulation is its photocatalytic behavior, which causes the contact angle of water to be gradually reduced with rising timed exposure to UV light. While this formulation has been employed in many studies, there exists no quantitative guidance to determine or tune the contact angle (and thus wettability) with the composition of the coating and UV exposure time. In this article, machine learning models are employed to predict the required UV exposure time for any specified TiO2/PMC coating composition to attain a certain wettability (UV-reduced contact angle). For that purpose, eight different coating compositions were applied to glass slides and exposed to UV light for different time intervals. The collected contact-angle data was supplied to different regression models to designate the best method to predict the required UV exposure time for a prespecified wettability. Two types of machine learning models were used: (1) parametric and (2) nonparametric. The results showed a nonlinear behavior between the coating formulation and its contact angle attained after timed UV exposure. Nonparametric methods showed high accuracy and stability with general regression neural network (GRNN) performing best with an accuracy of 0.971, 0.977, and 0.933 on the test, train, and unseen data set, respectively. The present study not only provides quantitative guidance for producing coatings of specified wettability, but also presents a generalized methodology that could be employed for other functional coatings in technological applications requiring precise fluid/surface interactions.

Neoadjuvant chemoradiation is associated with decreased lymph node ratio in borderline resectable pancreatic cancer: A propensity score matched analysis.

BACKGROUND: Lymph node ratio (LNR) and margin status have prognostic significance in pancreatic cancer. Herein we examined the pathologic and clinical outcomes in patients with borderline resectable pancreatic cancer (BRPC) following neoadjuvant therapy (NAT) and pancreaticoduodenectomy. METHODS: Patients who underwent treatment between January 1, 2012 and June 30, 2017 were included. Sequential patients in the BRPC group were compared to a propensity score matched cohort of patients with radiographically resectable pancreatic cancer who underwent upfront surgical resection. The BRPC group was also compared to sequential patients with radiographically resectable pancreatic cancer who required vein resection (VR) during upfront surgery. RESULTS: There were 50 patients in the BRPC group, 50 patients in the matched control group, and 38 patients in the VR group. Negative margins (R0) were seen in 72%, 64%, and 34% of the BRPC, control, and VR groups, respectively (P = 0.521 for BRPC vs. control; P = 0.002 for BRPC vs. VR), with 24% of the BRPC group requiring a vascular resection. Nodal stage was N0 in 64%, 20%, and 18% of the BRPC, control, and VR groups, respectively (P < 0.001 for BRPC vs. control or VR). When nodal status was stratified into four groups (N0, or LNR ≤ 0.2, 0.2-0.4, ≥ 0.4), the BRPC group had a more favorable distribution (P < 0.001). The median overall survival were 28.8, 38.6, and 19.0 months for the BRPC, control, and VR groups, respectively (log-rank P = 0.096). CONCLUSIONS: NAT in BRPC was associated with more R0 and N0 resections and lower LNR compared to patients undergoing upfront resection for resectable disease.

Diagnostic Laparoscopy Prior to Neoadjuvant Therapy in Pancreatic Cancer Is High Yield: an Analysis of Outcomes and Costs.

BACKGROUND: There is currently no standardized regimen for management of borderline resectable pancreatic cancer (BRPC), and treatment includes varying sequences of surgery, chemotherapy, and/or radiation. This study examines the diagnostic yield and cost of performing staging diagnostic laparoscopy (SDL) prior to neoadjuvant therapy (NAT) in BRPC. METHODS: Sequential patients treated for BRPC between January 2010 and October 2013 were included. SDL was adopted in a staged fashion due to surgeon preference, and included biopsy of visible lesions and washings for cytology. Cost ratios (CRs) were calculated to compare the direct cost of the SDL versus no-SDL groups and to compare patients with positive versus negative SDL. RESULTS: Of 116 patients evaluated for BRPC, 75 patients underwent SDL and 19 (25%) revealed occult metastatic disease. Sixteen patients had a positive biopsy and three had positive cytology alone. There was no difference in overall treatment cost (CR 0.95, 95% CI 0.62-1.37), oncologic treatment (CR 0.66, 95% CI 0.32-1.23), or remaining surgical treatment (CR 1.14, 95% CI 0.77-1.71) for patients who underwent SDL compared to those who did not. Patients with a positive SDL incurred lower overall cost compared to those with a negative SDL (CR 0.23, 95% CI 0.16-0.32) due to lack of further surgery or radiation, and less intensive chemotherapy regimens. CONCLUSIONS: SDL prior to NAT is a useful adjunct to CT to diagnose occult metastatic disease in BRPC.

Laparoscopic microwave thermosphere ablation of malignant liver tumors: An analysis of 53 cases.

BACKGROUND AND OBJECTIVES: Microwave thermosphere ablation (MTA) is a new technology that is designed to create spherical zones of ablation using a single antenna. The aim of this study is to assess the results of MTA in a large series of patients. METHODS: This was a prospective study assessing the use of MTA in patients with malignant liver tumors. The procedures were done mostly laparoscopically and ablation zones created were assessed for completeness of tumor response, spherical geometry and recurrence on tri-phasic CT scans done on follow-up. RESULTS: There were a total of 53 patients with an average of 3 tumors measuring 1.5 cm. Ablations were performed laparoscopically in all but eight patients. Morbidity was 11.3% (n = 6), and mortality zero. On postoperative scans, there was 99.3% tumor destruction. Roundness indices A, B, and transverse were 1.1, 1.0, and 0.9, respectively. At a median follow-up of 4.5 months, incomplete ablation was seen in 1 of 149 lesions treated (0.7%) and local tumor recurrence in 1 lesion (0.7%). CONCLUSIONS: The results of this series confirm the safety and feasibility of MTA technology. The 99.3% rate of complete tumor ablation and low rate of local recurrence at short-term follow up are promising.

Training and practice of the next generation HPB surgeon: analysis of the 2014 AHPBA residents' and fellows' symposium survey.

BACKGROUND: Hepato-pancreato-biliary (HPB) surgery is a complex subspecialty drawing from varied training pools, and the need for competency is rapidly growing. However, no board certification process or standardized training metrics in HPB surgery exist in the Americas. This study aims to assess the attitudes of current trainees and HPB surgeons regarding the state of training, surgical practice and the HPB surgical job market in the Americas. STUDY DESIGN: A 20-question survey was distributed to members of Americas Hepato-Pancreato-Biliary Association (AHPBA) with a valid e-mail address who attended the 2014 AHPBA. Descriptive statistics were generated for both the aggregate survey responses and by training category. RESULTS: There were 176 responses with evenly distributed training tracks; surgical oncology (44, 28%), transplant (39, 24.8%) and HPB (38, 24.2%). The remaining tracks were HPB/Complex gastrointestinal (GI) and HPB/minimally invasive surgery (MIS) (29, 16% and 7, 4%). 51.2% of respondents thought a dedicated HPB surgery fellowship would be the best way to train HPB surgeons, and 68.1% felt the optimal training period would be a 2-year clinical fellowship with research opportunities. This corresponded to the 67.5% of the practicing HPB surgeons who said they would prefer to attend an HPB fellowship for 2 years as well. Overall, most respondents indicated their ideal job description was clinical practice with the ability to engage in clinical and/or outcomes research (52.3%). CONCLUSIONS: This survey has demonstrated that HPB surgery has many training routes and practice patterns in the Americas. It highlights the need for specialized HPB surgical training and career education. This survey shows that there are many ways to train in HPB. A 2-year HPB fellowship was felt to be the best way to train to prepare for a clinically active HPB practice with clinical and outcomes research focus.

Estimating the need for hepato-pancreatico-biliary surgeons in the USA.

BACKGROUND: Hepato-pancreatico-biliary (HPB) fellowship training has risen in popularity in recent years and hence large numbers of graduating fellows enter the workforce each year. Studies have proposed that the increase in HPB-trained surgeons will outgrow demand in the USA. This study shows that the need for HPB-trained surgeons refers not to the meeting of demand in terms of case volume, but to improving patient access to care. METHODS: The National Inpatient Sample (NIS) database for the years 2005-2011 was queried for CPT codes relating to pancreatic, liver and biliary surgical cases. These numbered 6627 in 2005 and increased to 8515 in 2011. Cases were then mapped to corresponding states. The number of procedures in an individual state was divided by the total number of procedures to give a ratio for each state. A similar ratio was calculated for the population of each state to the national population. These ratios were combined to give a ratio by state of observed to expected HPB surgical cases. RESULTS: Of the 46 states that participate in the NIS, only 18 achieved ratios of observed to expected cases of >1. In the remaining 28 states, the number of procedures was lower than that expected according to each state's population. CONCLUSIONS: The majority of the USA is underserved in terms of HPB surgery. Given the growing number of HPB-trained physicians entering the job market, this sector should focus on bringing understanding and management of complex disease to areas of the country that are currently in need.

Total pancreatectomy with islet cell auto-transplantation: update and outcomes from major centers.

OPINION STATEMENT: Chronic pancreatitis is the result of irreversible damage to pancreatic acinar cells, and can result in debilitating chronic pain for patients. Treatment centers on pain relief, often with chronic narcotic use. Surgical therapy consists of both resection procedures to remove affected pancreatic parenchyma and drainage procedures to facilitate drainage of the main pancreatic duct. Total pancreatectomy historically was utilized in extreme cases due to the brittle glucose control that followed from the total loss of islet cells. Total pancreatectomy with islet cell auto-transplantation (TP-AIT) is gaining in popularity due to the maintenance of beta cell mass and the ability of patients to potentially be insulin independent post-operatively. TP-AIT is very helpful in the treatment of pain for patients with chronic pancreatitis. The overall majority of patients have an improvement in pain and quality-of-life scores. AIT also allows the majority of patients to have minimal insulin requirements post-operatively. With proper patient selection, these outcomes can be achieved.