Analysis of an adaptive lead weighted ResNet for multiclass classification of 12-lead ECGs.

Background. Twelve lead ECGs are a core diagnostic tool for cardiovascular diseases. Here, we describe and analyse an ensemble deep neural network architecture to classify 24 cardiac abnormalities from 12 lead ECGs.Method. We proposed a squeeze and excite ResNet to automatically learn deep features from 12-lead ECGs, in order to identify 24 cardiac conditions. The deep features were augmented with age and gender features in the final fully connected layers. Output thresholds for each class were set using a constrained grid search. To determine why the model made incorrect predictions, two expert clinicians independently interpreted a random set of 100 misclassified ECGs concerning left axis deviation.Results. Using the bespoke weighted accuracy metric, we achieved a 5-fold cross-validation score of 0.684, and sensitivity and specificity of 0.758 and 0.969, respectively. We scored 0.520 on the full test data, and ranked 2nd out of 41 in the official challenge rankings. On a random set of misclassified ECGs, agreement between two clinicians and training labels was poor (clinician 1:κ= -0.057, clinician 2:κ= -0.159). In contrast, agreement between the clinicians was very high (κ= 0.92).Discussion. The proposed prediction model performed well on the validation and hidden test data in comparison to models trained on the same data. We also discovered considerable inconsistency in training labels, which is likely to hinder development of more accurate models.

Potential for Electric Vehicle Adoption to Mitigate Extreme Air Quality Events in China.

Electric vehicle (EV) adoption promises potential air pollutant and greenhouse gas (GHG) reduction co-benefits. As such, China has aggressively incentivized EV adoption, however much remains unknown with regard to EVs' mitigation potential, including optimal vehicle type prioritization, power generation contingencies, effects of Clean Air regulations, and the ability of EVs to reduce acute impacts of extreme air quality events. Here, we present a suite of scenarios with a chemistry transport model that assess the potential co-benefits of EVs during an extreme winter air quality event. We find that regardless of power generation source, heavy-duty vehicle (HDV) electrification consistently improves air quality in terms of NO2 and fine particulate matter (PM2.5), potentially avoiding 562 deaths due to acute pollutant exposure during the infamous January 2013 pollution episode (~1% of total premature mortality). However, HDV electrification does not reduce GHG emissions without enhanced emission-free electricity generation. In contrast, due to differing emission profiles, light-duty vehicle (LDV) electrification in China consistently reduces GHG emissions (~2 Mt CO2), but results in fewer air quality and human health improvements (145 avoided deaths). The calculated economic impacts for human health endpoints and CO2 reductions for LDV electrification are nearly double those of HDV electrification in present-day (155M vs. 87M US$), but are within ~25% when enhanced emission-free generation is used to power them. Overall, we find only a modest benefit for EVs to ameliorate severe wintertime pollution events, and that continued emission reductions in the power generation sector will have the greatest human health and economic benefits.

Mapping ozone source-receptor relationship and apportioning the health impact in the Pearl River Delta region using adjoint sensitivity analysis.

While fine particulate matters are decreasing in the Pearl River Delta (PRD) region, the regional ozone (O3) shows an increasing trend that affects human health, leading to an urgent need for scientific understanding of source-receptor relationship between O3 and its precursor emissions given the changing background composition. We advanced and applied an adjoint air quality model to map contributions of individual O3 precursor emission sources [nitrogen oxides (NOx) and volatile organic compound (VOC)] at each location to annual regional O3 concentrations and to identify the possible dominant influential pathways of emission sources to O3 at different spatiotemporal scales. Additionally, we introduced the novel adjoint sensitivity approach to assess the relationship between precursor emissions and O3-induced premature mortality. Adjoint results show that Shenzhen was a major source contributor to regional O3 throughout all seasons, of which 49.4% (3.8%) were from its NOx (VOC) emissions. Local emissions (within PRD) contributed to 83% of the regional O3 whereas only ~54% of the estimated ~4000 regional O3-induced premature mortalities. The discrepancy between these two contributions was because O3-induced mortalities are dependent on not only O3 concentration, but incident rate and population density. We also found that a city with low O3-induced mortalities could have significant emission contributions to health impact in the region since the transport pathways could be through transport of local O3 or through transport of O3 precursors that form regional O3 thereafter. It is therefore necessary to formulate emission control policies from both air quality and public health perspectives, and it is also critical to have better understanding of influential pathways of emission sources to O3.

Source contributions of surface ozone in China using an adjoint sensitivity analysis.

Air pollution has become an adverse environmental problem in China, resulting in serious public health impacts. This study advanced and applied the CMAQ adjoint model to quantitatively assess the source-receptor relationships between surface ozone (O3) changes over different receptor regions and precursor emissions across all locations in China. Five receptor regions were defined based on the administrative division, including northern China (NC), southern China (SC), Pearl River Delta region (PRD), Yangtz River Delta region (YRD), and Beijing-Tianjin-Hebei region (BTH). Our results identified the different influential pathways of atmospheric processes and emissions to O3 pollution. We found that the atmospheric processes such as horizontal and vertical advection could offset the O3 removal through chemical reactions in VOC-limited areas inside the receptor regions. In addition, O3 pollution can be induced by transport of O3 directly or its precursors. Our results of relative source contributions to O3 show that transboundary O3 pollution was significant in SC, NC and YRD, while the O3 pollution in PRD and BTH were more contributed by local sources. Anhui, Hubei and Jiangsu provinces were the three largest source areas of NOx and VOC emissions to O3 in SC (>52%) and YRD (>69%). NOx and VOC emissions from Tianjin and Beijing were the largest contributors to O3 in NC (>34%) and BTH (>51%). PRD was the dominant source areas of NOx (>89%) and VOC emissions (~98%) to its own regional O3.

Combined physiological, transcriptome, and cis-regulatory element analyses indicate that key aspects of ripening, metabolism, and transcriptional program in grapes (Vitis vinifera L.) are differentially modulated accordingly to fruit size.

BACKGROUND: In wine grape production, management practices have been adopted to optimize grape and wine quality attributes by producing, or screening for, berries of smaller size. Fruit size and composition are influenced by numerous factors that include both internal (e.g. berry hormone metabolism) and external (e.g. environment and cultural practices) factors. Combined physiological, biochemical, and transcriptome analyses were performed to improve our current understanding of metabolic and transcriptional pathways related to berry ripening and composition in berries of different sizes. RESULTS: The comparison of berry physiology between small and large berries throughout development (from 31 to 121 days after anthesis, DAA) revealed significant differences in firmness, the rate of softening, and sugar accumulation at specific developmental stages. Small berries had significantly higher skin to berry weight ratio, lower number of seeds per berry, and higher anthocyanin concentration compared to large berries. RNA-sequencing analyses of berry skins at 47, 74, 103, and 121 DAA revealed a total of 3482 differentially expressed genes between small and large berries. Abscisic acid, auxin, and ethylene hormone pathway genes were differentially modulated between berry sizes. Fatty acid degradation and stilbenoid pathway genes were upregulated at 47 DAA while cell wall degrading and modification genes were downregulated at 74 DAA in small compared to large berries. In the late ripening stage, concerted upregulation of the general phenylpropanoid and stilbenoid pathway genes and downregulation of flavonoid pathway genes were observed in skins of small compared to large berries. Cis-regulatory element analysis of differentially expressed hormone, fruit texture, flavor, and aroma genes revealed an enrichment of specific regulatory motifs related to bZIP, bHLH, AP2/ERF, NAC, MYB, and MADS-box transcription factors. CONCLUSIONS: The study demonstrates that physiological and compositional differences between berries of different sizes parallel transcriptome changes that involve fruit texture, flavor, and aroma pathways. These results suggest that, in addition to direct effects brought about by differences in size, key aspects involved in the regulation of ripening likely contribute to different quality profiles between small and large berries.

Comparison of magnetic resonance imaging-fluorodeoxy- glucose positron emission tomography fusion with pathological staging in rectal cancer.

BACKGROUND: : This study represents an initial experience with combined magnetic resonance imaging (MRI) and [(18)F]fluorodeoxyglucose positron emission tomography (FDG PET) (MRI-PET fusion) in the primary staging of rectal carcinoma. METHODS: : A retrospective analysis of data recorded on patients with rectal cancer was undertaken. Patients requiring long-course radiotherapy were excluded. Chest radiography, abdominal computed tomography and endorectal ultrasonography were performed. In addition, MRI of the pelvis, whole-body FDG PET and MRI-PET fusion were carried out. All patients subsequently underwent anterior resection. RESULTS: : Twenty-three patients with rectal carcinoma (15 men), of median age 60 (range 46-75) years, were enrolled. In tumour (T) assessment, MRI correctly staged 14 of 22 T2/T3 tumours. In lymph node assessment, MRI-PET fusion had a sensitivity of 44 per cent, with a specificity and positive predictive value of 100 per cent. No additional information was acquired from MRI-PET fusion over MRI plus abdominal computed tomography and chest radiography. CONCLUSION: : MRI-PET fusion adds little to conventional investigations for staging rectal carcinoma.

Ultrasonography of the hand and wrist.

Musculoskeletal ultrasonography (US) of the hands and wrist has recently been increasing in popularity. Recent rapid technical advances in the US, such as new ultra-high frequency probes and smaller probe sizes, have led to improved image quality. This, in turn, has accelerated the growth of musculoskeletal US. Known advantages of US are its lack of ionising radiation, noninvasiveness, portability and low cost. Dynamic and real-time assessment and Doppler imaging are additional benefits of this modality, especially in the imaging of the hands and wrist. Superficial structures of the hands and wrist, including the tendons, ligaments, nerves and vessels, are amenable to imaging with high frequency US. In this article, we demonstrate a spectrum of hand and wrist pathology using US, including entrapment neuropathy, inflammatory conditions, traumatic injury and masses. Ultrasound-guided procedures applicable to the hand and wrist are also briefly discussed.

Stapled technique for acute thrombosed hemorrhoids: a randomized, controlled trial with long-term results.

PURPOSE: This study was designed to compare stapled vs. conventional hemorrhoidectomy for patients with acute thrombosed hemorrhoids. METHODS: Forty-one patients with acute thrombosed hemorrhoids were randomized into: 1) stapled hemorrhoidectomy (PPH group; n = 21), and 2) open hemorrhoidectomy (open group; n = 20). Emergency surgery was performed with perioperative data and complications were recorded. Patients were followed up by independent assessors to evaluate pain, recurrence, continence function, and satisfaction at regular intervals. RESULTS: The median follow-up for the PPH group and open group were 59 and 56 weeks, respectively. There was no significant difference in terms of the hospital stay, complication rate, and continence function; however, the mean pain intensity in the first postoperative week was significantly less in the PPH group (4.1 vs. 5.7, P = 0.02). Patients in the PPH group recovered significantly faster in terms of the time to become analgesic-free (4 vs. 8.5 days, P < 0.01), time to become pain-free (9 vs. 20.5 days, P = 0.01), resumption of work (7 vs. 12.5 days, P = 0.01), and time for complete wound healing (2 vs. 4 weeks, P < 0.01). On long-term follow-up, significantly fewer patients in the PPH group complained of recurrent symptoms (0 vs. 5, P = 0.02). The overall symptom improvement and patients' satisfaction were significantly better in the PPH group (90 vs. 80 percent, P = 0.03 and +3 vs. +2, P < 0.01 respectively). CONCLUSIONS: Stapled hemorrhoidectomy is safe and effective for acute thrombosed hemorrhoids. Similar to elective stapled procedure, emergency stapled excision has greater short-term benefits compared with conventional excision: diminished pain, faster recovery, and earlier return to work. Long-term results and satisfaction were excellent.

Erdheim-Chester disease: a rare cause of acute renal failure.

Erdheim-Chester disease (ECD) is a rare systemic histiocytic infiltrative disease of unknown aetiology. In radiology it is characterized by symmetrical sclerotic bone lesions predominantly affecting the diaphyses and metaphyses of long bones. Perivascular fibrosis has been reported in the literature as being a feature of this disease and we report one such case that presented with an encased aorta and renal arteries leading to acute renal failure. The diagnosis of ECD was delayed until a biopsy of the retroperitoneal infiltrate was performed. Further imaging with fluorine 18 deoxyglucose positron emission tomography, bone scintigraphy, plain films of the long bones and CT of the chest, abdomen and pelvis were performed to assess the extent of the patient's systemic disease involvement. To our knowledge, this is the first reported case of ECD presenting with acute renal failure secondary to bilateral occlusion of the renal arteries.

Non-operative management of small cell carcinoma of esophagus.

Primary small cell carcinoma of the esophagus (SmCC) is an uncommon aggressive tumor characterized by early systemic dissemination and poor prognosis, regardless of the methods of treatment. The optimal treatment strategy remains uncertain. A retrospective study was conducted to review the results of non-operative treatment for patients with limited and metastatic esophageal SmCC. Between 1993 and 2003, 10 patients were diagnosed to have primary esophageal SmCC in our institution. Six of them had disseminated diseases, whereas the other four had limited disease upon diagnosis. All patients were managed non-operatively by either chemotherapy and/or radiotherapy. The overall median survival was 8 months (range, 2-62 months). The survival was 4-62 months for patients with limited disease, whereas it was 2-10 months for patients with disseminated disease at initial diagnosis. In summary, the current study demonstrated satisfactory palliation could be achieved with chemo-radiation for patients with limited disease; however, the ultimate role of primary chemo-radiation for esophageal SmCC must await results from randomized trials.

Laparoscopic distal pancreatectomy: a comparative study.

BACKGROUND/AIMS: This article aims to describe the different techniques of laparoscopic distal pancreatectomy and to compare the results of our series of 9 laparoscopic resections against the historical open control in the same institution. With the advent of laparoscopic surgery, there is an increasing number of patients with different pancreatic pathologies that can now be managed by minimal access surgery. The initial results of laparoscopic pancreatectomy are quite promising particularly for those small neuroendocrine and cystic neoplasms located at the body and tail of pancreas. METHODOLOGY: The different techniques of laparoscopic distal pancreatectomy are described in detail with special emphasis on the need of "hand assistance" and the different methods of splenic preservation. The perioperative data of 9 laparoscopic distal pancreatectomies are analyzed and compared against the 5 historical open controls in the same institution. RESULTS: There were 9 laparoscopic pancreatic resections performed in our institution since 1999. Indications for surgery included 5 cystic neoplasms (1 patient with concomitant splenic artery aneurysm), 1 chronic pancreatitis with pancreatic duct stricture and a small pseudocyst, 1 pseudopancreatic tumor secondary to seal off perforated posterior gastric ulcer, 1 pseudopapillary tumor and 1 neuroendocrine tumor. There were 6 females and 3 males with median age of 61 years (range 18-79). The majority of patients was of low anesthetic risk (ASA 1 or 2). Total laparoscopic resection was performed in 7 cases and 2 resections were performed using the hand-assisting technique. Out of the 4 cases with splenic preservation, only one patient had both splenic artery and vein successfully preserved, whereas the other 3 cases had to rely on the short gastric arcade. Median operating time was 180 minutes (range 120-250) and median blood loss was 100cc (range 50-500). Pancreatic leak occurred in two patients (22.2%) and 1 patient developed intraabdominal collection, all of which settled upon conservative treatment. In our series, clear resection margin was obtained for all the neoplastic cases. Median hospital stay was 7 days (4-53). Postoperatively, patients consumed an average of 15 tablets of dologesic. No other complications were observed upon a median follow-up of 15 months (1-50). When results were compared to the 5 historical open controls (excluding those malignant tumors), patients managed with this new approach had significantly less intraoperative blood loss (100 vs. 450 mL, P = 0.021). CONCLUSIONS: Our initial experience not only confirmed the feasibility oflaparoscopic pancreatectomy, but also demonstrated the promising results of this approach in selected patients.

Antegrade biliary stenting versus T-tube drainage after laparoscopic choledochotomy--a comparative cohort study.

BACKGROUND/AIMS: Laparoscopic exploration of the common bile duct (LECBD) has been proven to be an effective and preferred treatment approach for uncomplicated common bile duct stones. However there is still controversy regarding the choice of biliary decompression after laparoscopic choledochotomy. METHODOLOGY: This is a retrospective comparison between the use of antegrade biliary stenting and T-tube drainage following successful laparoscopic choledochotomy. During the period between January 1995 and July 2003, biliary decompression was achieved by either antegrade biliary stenting or T-tube drainage based on the discretion of the operating surgeon. For antegrade biliary stenting, a 10-Fr Cotton-Leung biliary stent was inserted through the choledochotomy and passed down across the papilla. The stent position was confirmed by on-table choledochoscopy before interrupted single-layered closure of the common bile duct. Endoscopic retrograde cholangiopancreatography (ERCP) was performed to remove the stent 4 weeks after operation and at the same time to check for any residual stones or other complications like stricture or leak. In the T-tube group, a 16-Fr latex T-tube was used and the long limb was brought out through the subcostal trocar port followed by the same method of bile duct closure. Cholangiogram through the T-tube was performed on day 7 and the tube would be taken off 1 week later (about 2 weeks after operation) if the cholangiogram did not reveal any abnormality. The two groups were compared according to the demographic data, operation time, length of hospital stay and complication rates. RESULTS: During the study period, 108 laparoscopic explorations of the common bile duct were performed in our centre of which 95 were attempted laparoscopic choledochotomies and 13 were transcystic duct explorations. Of the 95 patients with attempted laparoscopic choledochotomy, there were 9 open conversions, 17 laparoscopic bilioenteric bypasses and 6 primary closures of the common bile duct. All of these patients together with those receiving transcystic duct explorations were excluded and the remaining 63 patients having postoperative bile diversion by either antegrade biliary stenting or T-tube drainage were included in this study. Bile diversion was achieved by antegrade biliary stenting in 35 patients whereas 28 patients had T-tube drainage. There was no difference between the two groups in terms of age, clinical presentation, bilirubin level, length of hospital stay, follow-up duration, common bile duct size, size of common bile duct stones, incidence of residual/recurrent stone and complication rate. It was observed that more patients in the stenting group developed bile leak (14.2% vs. 3.5%) and required more intramuscular pethidine injections (182.86 +/- 139.30 vs. 92.81+/-81.15mg, P=0.000). On the other hand, the T-tube group had longer operation time (141.4+/-45.1 vs. 11 1.1+/-33.9 minutes, P=0.006) and had a longer postoperative hospital stay (10.0+/-7.4 vs. 8.8+/-9.3 days, P=0.020) reaching statistical significance. CONCLUSIONS: Postoperative bile diversion by antegrade biliary stenting after laparoscopic choledochotomy is shown to shorten operation duration and postoperative stay as compared to T-tube drainage, but the problem of bile leak needs further refinement of insertion technique.

Laparoscopic abdominoperineal resection revisited: are there any health-related benefits? A comparative study.

BACKGROUND: Laparoscopic colectomy is associated with less overall morbidity and improved survival for patients with colonic cancers. There are unfortunately limited clinical reports on laparoscopic abdominoperineal resection. We therefore designed this study to compare laparoscopic abdominoperineal resection with conventional open surgery, with emphasis on health-related issues from the patients' perspective in order to justify its role in the management of low rectal or anal canal tumours. METHODS: We carried out a non-randomized, prospective comparative study on a cohort of patients who underwent either laparoscopic or open abdominoperineal resection between March 1994 and December 2003. Patient demographics, tumour characteristics, operative morbidity and mortality, as well as overall survival were considered. The standard endpoints of last follow-up date and deaths were used. Data was analyzed according to intention-to-treat principle. RESULTS: A total of 102 patients were recruited: 31 patients underwent conventional open abdominoperineal resection (OAPR) and 71 patients were treated laparoscopically. Patient demographics, median follow-up period, as well as tumour characteristics were similar between groups. The median operating time was similar among groups (145 min in laparoscopic group vs. 156 min in open group; p=0.62). Patients in the laparoscopic group had significantly less blood loss (p=0.01) and fewer requirements for blood transfusion (p=0.01). Despite similar overall morbidity, the laparoscopic group had a reduced incidence of abdominal wound infections (p=0.01) and chest infections (p=0.01). Overall survival was significantly better in the laparoscopic group (p=0.01). CONCLUSIONS: Laparoscopic abdominoperineal resection confers definite health-related benefits the over open approach in terms of reduced septic complications and fewer requirements for blood transfusion. It should be considered the procedure of choice for patients with low rectal or anal canal tumour in whom sphincter excision proved inevitable.

An alternative gallbladder extraction technique in laparoscopic cholecystectomy.

In this era of minimally invasive surgery, the challenge remains in finding techniques to reduce access trauma in terms of fewer and smaller size trocar ports. Our new described technique will allow a smaller subxiphoid port to be used to achieve extraction of the gallbladder without the need to change to a 5 mm laparoscope. We believe this method is easy to learn, safe and with no observable complications from our experience.

Incidental finding of meningioma on bone scintigraphy.

An incidental finding of an intracranial posterior fossa meningioma detected by bone scintigraphy is presented. Most of the published literature on the diagnosis of meningioma is on the use of CT and MRI. There is limited published literature on the detection of meningioma with bone scintigraphy.

MTBE ambient water quality criteria development: a public/private partnership.

A public/private partnership was established in 1997, under the administrative oversight of the American Petroleum Institute (API), to develop aquatic toxicity data sufficient to calculate ambient water quality criteria for methyl tertiary-butyl ether (MTBE), a gasoline oxygenate. The MTBE Water Quality Criteria Work Group consisted of representatives from private companies, trade associations, and USEPA. Funding was provided by the private entities, while aquatic biological/toxicological expertise was provided by industry and USEPA scientists. This public/private partnership constituted a nonadversarial, cost-effective, and efficient process for generating the toxicity data necessary for deriving freshwater and marine ambient water quality criteria. Existing aquatic toxicity data were evaluated for acceptability, consistent with USEPA guidance, and nineteen freshwater and marine tests were conducted by commercial laboratories as part of this effort to satisfy the federal criteria database requirements. Definitive test data were developed and reported under the oversight of industry study monitors and Good Laboratory Practice standards auditors, and with USEPA scientists participating in advisory and critical review roles. Calculated, preliminary freshwater criteria for acute (Criterion Maximum Concentration) and chronic (Criterion Continuous Concentration) exposure effect protection are 151 and 51 mg MTBE/L, respectively. Calculated, preliminary marine criteria for acute and chronic exposure effect protection are 53 and 18 mg MTBE/L, respectively. These criteria values may be used for surface water quality management purposes, and they indicate that ambient MTBE concentrations documented in U. S. surface waters to date do not constitute a risk to aquatic organisms.

Management of a Class II deep bite malocclusion with combined straightwire appliance and bioprogressive therapy.

Development of straightwire appliances and improvement in archwire technology have simplified fixed appliance therapy in orthodontics. Although straightwire appliances are routinely used to treat most malocclusions, there are inherent limitations and it is necessary to look at the needs of each individual case rather than to simply proceed through a "cookbook" series of archwires to achieve a desired result. The Bioprogressive Therapy, although biomechanically complex, offers several advantages that can be integrated with the straightwire appliances to overcome the latter's shortcomings. This article illustrates the use of simplified Bioprogressive mechanics by means of utility arch in the treatment of a Class II deep bite malocclusion with high anchorage requirement.