Observation of void formation patterns in SnAg films undergoing electromigration and simulation using random walk methods.

With the ever-reducing sizes of electronic devices, the problem of electromigration (EM) has become relevant and requires attention. However, only the EM behavior of Sn-Ag solders within the solder joint structure has been focused on thus far. Therefore, in this study, a thin metallic film composed of Sn-3.5Ag (wt.%) was subjected to a current density of 7.77 × 104 A/cm2 at a temperature of 15 °C to test the ability of existing EM models to predict the nucleation and evolution of voids generated by the resulting atomic migration. A computer simulation was then used to compute the coupled current distribution, thermal distribution, and atomic migration problems. It relied on an original random walk (RW) method, not previously applied to this problem, that is particularly well suited for modelling domains that undergo changes owing to the formation of voids. A comparison of the experimental results and computer simulations proves that the RW method can be applied successfully to this class of problems, but it also shows that imperfections in the film can lead to deviations from predicted patterns.

Lo, the ever confounding nipple shadow!

The discovery of a solitary pulmonary nodule (SPN) on chest imaging can be alarming for both the clinician and the patient. In the absence of a uniform guideline, managing SPN is nothing short of challenging for primary care physicians (PCPs). We present a case here of a patient presenting with prolonged cough who also displayed unilateral SPN on her chest radiograph. Through further examination, this presence was later shown to be a nipple shadow simulating SPN, and the patient was spared unnecessary testing and psychological distress.

Methods and clinical outcomes of in situ fenestration for aortic arch revascularization during thoracic endovascular aortic repair.

OBJECTIVE: Despite endovascular advances in fenestrated and branched devices, thoracic endovascular aortic repair (TEVAR) for arch pathologies remains challenging. The aim of this study was to provide a contemporary review on the current evidence for in situ fenestration during TEVAR and to evaluate its short- and mid-term clinical outcome in the management of arch pathology. METHODS: A systematic literature review on in situ fenestration of thoracic aortic stent-graft from January 2003 to September 2018 was performed under the instruction of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. RESULTS: Our initial search yielded 169 studies, of which 21 articles were relevant to the topic and were finally included. One hundred and forty-five in situ fenestration procedures in 99 patients were reviewed, involving 25 innominate arteries (17%), 33 left common carotid arteries (23%) and 87 left subclavian arteries (60%). Twelve patients (12/99, 12%) had two-vessel fenestration and three-vessel fenestration was performed in 17 patients (17/99, 17%). Technical success was achieved in 136 arteries (136/145, 93%). Talent/Valiant with monofilament twill woven polyester fabric was the most common (50/99, 51%) stent-graft used for fenestration. Three methods reported for in situ fenestration were needle, laser and radiofrequency. Needle was the most frequently used device for fenestration, which was performed in 60 patients (60/99, 61%). Three patients (3/99, 3%) died with 30 days, none were in situ fenestration TEVAR procedure-related. Perioperative complications including one (1%) retrograde type A aortic dissection, two (2%) type II endoleaks, and three (3%) strokes were reported. The pooled estimate for overall technical success, perioperative mortality and stroke was 88.3% (95% CI, 78.6%-93.9%), 5.9% (95% CI, 2.5%-13.4%) and 9.5% (95% CI, 4.1%-20.6%), respectively. Four patients (4/96, 4%) died during follow-up, none were aortic-related. All the fenestration bridging stents were reportedly patent, with only 1 (1/96, 1%) asymptomatic left subclavian stent stenosis. Two patients (2/96, 2%) with type II endoleak from left subclavian artery required secondary intervention. CONCLUSION: In situ fenestration appeared to be a feasible and effective method to extend proximal landing zone during TEVAR. It had an acceptable short-term result with high technical success and low fenestration related morbidity. Long-term durability data were lacking, and there was no high level evidence to recommend the routine use of in situ fenestration TEVAR for the management of arch pathology.

Clinical Toxicology and Overdose of Psychiatric Medications.

This article reviews the poisoning epidemiology in Hong Kong, assessment and treatment of acute poisoning, and management of acute psychiatric medication overdose. In 2016, nearly 4000 poisoning cases involving approximately 6000 poisons were reported to Hong Kong Poison Information Centre. About 25% of the poisons involved were psychiatric-related medications. The initial medical assessment on poisoning includes history taking, vital signs monitoring, and focused physical examination. Approaches in managing acute poisoning include supportive measures, decontamination, antidote use, and enhanced elimination. Management on overdose of psychiatric medications (zopiclone, tricyclic antidepressants, selective serotonin reuptake inhibitor, antipsychotics, valproic acid, lithium, and methylphenidate) are discussed with practical tips highlighted.

Percutaneous mechanical thrombectomy in the treatment of acute iliofemoral deep vein thrombosis: a systematic review.

BACKGROUND: Conventional treatment of deep vein thrombosis (DVT) of the lower extremities by anticoagulation alone has been proven to be insufficient to prevent recurrence and post-thrombotic syndrome (PTS). Early restoration of venous patency and preservation of valvular function by endovascular surgery has been advocated. The aim of this study was to review the efficacy and safety of percutaneous mechanical thrombectomy (PMT) against catheter-directed thrombolysis (CDT) in the treatment of acute iliofemoral DVT. METHODS: Three hundred sixty-nine articles were identified through screening of the PubMed, EMBASE, and Cochrane databases from January 2006 to December 2016. RESULTS: Fifteen retrospective studies and one prospective registry, totalling 1170 patients, were recruited for qualitative synthesis. The venous patency rate ranged from 75% to 100% with mean follow-up of 12.3 months. The rates of PTS and recurrent DVT were less than 17% and 15%, respectively. The overall mortality rate was 0.26%. Compared with CDT, PMT was shown to reduce PTS at 1 year (Villalta score: 2.1 ± 3.0 in the PMT group and 5.1 ± 4.1 in the CDT group, P=0.03) and bleeding complications (packed cells transfused: 0.2 ± 0.3 units in the pharmacomechanical thrombectomy group and 1.2 ± 0.7 units in the CDT group, P<0.05). CONCLUSION: Percutaneous mechanical thrombectomy is a safe and effective treatment for acute iliofemoral DVT in terms of restoration of venous patency, prevention of DVT recurrence, and PTS. Compared with CDT alone, PMT offers a lower risk of PTS and bleeding complications.

Arch branch endografts for arch aneurysms associated with bovine anomaly.

Bovine aortic arch is known to be associated with an increased rate of aortic arch expansion. The most frequently observed human variant of bovine aortic arch is a common origin of the innominate trunk and left common carotid artery. This is a report of two patients who had successful custom-made arch branch endograft treatment for an arch aneurysm associated with bovine arch anomaly. Modular endovascular repair of aortic arch aneurysms using an inner-branched device adds to the armamentarium of treatment options, and is a minimally invasive management modality without the need for sternotomy or intraoperative extracorporeal bypass.

Delayed open conversion after endovascular aortic repair.

AIM: We present the clinical outcomes of patients who underwent delayed (>30 days) open surgical repair after endovascular aortic aneurysm repair. METHODS: All patients receiving delayed open repair of infrarenal and juxtarenal aortic aneurysms after endovascular repair from July 2001 to December 2017 were retrospectively reviewed. Patients' baseline characteristics, indications for delayed open conversion, and time between endovascular repair and open conversion are described. Early outcomes included operative approach, morbidity, and mortality. Midterm outcomes included survival. RESULTS: Twenty-two (3.3%) of 667 patients with prior infrarenal endovascular aortic aneurysm repair had delayed open conversion (20 elective and 2 emergency). The time from endovascular repair to open conversion was 60 ± 36 months. The indications were 6 (27%) type Ia endoleaks, 6 (27%) type II endoleaks with enlarging sac size, 2 (9%) endotensions, 7 (32%) unknown types of endoleak, and 1 (5%) graft infection. The 7 minutes unknown endoleaks were confirmed as lumbar leaks in 4 cases and fabric leaks in 3. Operative time was 222 ± 48 min with blood loss of 2211 ± 2057 mL. Hospital stay after conversion was 12 ± 8 days. There was no 30-day mortality. Estimated survival rates were 96%, 91%, 86%, 79% and 57% at 1, 2, 3, 4, and 5 years postoperatively. CONCLUSION: Delayed conversion to open surgery after endovascular aortic aneurysm repair by endograft explantation appears to be safe with good short- and mid-term outcomes. With careful preoperative assessment, open conversion remained a realistic and viable option in patients with failed endovascular treatment.

Donor-Transmitted Bacterial Infection in Deceased Donor Liver Transplantation: Experience of Southern Taiwan Medical Center.

BACKGROUND: Bacterial Infection is the most important source of mortality and morbidity in liver transplantation recipients. Donor transmitted bacterial infection is rare but one of the most important infection sources. This kind of infection is difficult to identify, causing treatment dilemma. PATIENTS AND METHODS: In this article, we retrospectively reviewed our deceased donor liver transplants performed from January 2014 to December 2016. Forty-two recipients in Kaohsiung Chang Gung Memorial Hospital receiving liver grafts from 35 deceased liver donors were evaluated. The demography, donor transmitted infection, and outcomes were evaluated. RESULT: Two patients had probable donor transmitted bacterial infection and 1 patient died of suspected transmitted infection. CONCLUSION: Early identification of donor infection and adequate antibiotic treatment for the donor and recipient are the keys to preventing donor transmitted bacterial infection. Donor infection is not an absolute contraindication for organ donation in the area of organ shortage. Organ procurement organizations or similar authorities may establish the platform for sharing the data about donor and recipient infections.

Predictors of early operative mortality and long-term survival in octogenarians undergoing open and endovascular repair of abdominal aortic aneurysm.

BACKGROUND: The study aims to report outcomes of open repair (OR) and endovascular aneurysm repair (EVAR) in octogenarians. METHODS: Consecutive patients aged between 80 and 89 who underwent OR or EVAR were identified from a prospectively collected departmental database. Short-term outcomes included 30 days mortalities and perioperative complications; long-term outcomes included overall survival and re-intervention using the Kaplan-Meier method. Logistic regression was used to identify predictors for operative mortality and Cox regression analysis was used to identify predictors for long-term survival. RESULTS: From January 1999 to December 2013, 53 underwent open repairs (23 emergency and 30 elective) and 115 underwent endovascular repairs (11 emergency and 104 elective). For elective procedures, 30 days operative mortalities were 6.7% and 0% in OR and EVAR respectively (Chi square test, p = 0.049). For emergency procedures, 30 days mortalities were 39.1% and 27.2% respectively (Chi square test, p = 0.705). Overall 5 years survival rates were 40.4% and 36.7% after OR and EVAR respectively. Rupture of aneurysm (Odd ratio 18.8, 95% CI 3.4-104.5, p = 0.001) was the only predictor for 30 days mortality. Rupture of aneurysm (Hazard ratio 2.0, 95% CI 1.3-3.3, p = 0.003), history of lung disease (Hazard ratio 1.7, 95% CI 1.0-2.9, p = 0.039) and history of renal disease (Hazard ratio 2.1, 95% CI 1.4-3.1, p < 0.001) were independent predictors for long-term overall survival. CONCLUSION: Decision of AAA repair in octogenarians should not be based on age alone. Both elective OR and EVAR had acceptable perioperative risk, but emergency repair, lung disease and renal impairment predicted poor long-term survival.

Maximizing T c by tuning nematicity and magnetism in FeSe1-x S x superconductors.

A fundamental issue concerning iron-based superconductivity is the roles of electronic nematicity and magnetism in realising high transition temperature (T c). To address this issue, FeSe is a key material, as it exhibits a unique pressure phase diagram involving non-magnetic nematic and pressure-induced antiferromagnetic ordered phases. However, as these two phases in FeSe have considerable overlap, how each order affects superconductivity remains perplexing. Here we construct the three-dimensional electronic phase diagram, temperature (T) against pressure (P) and isovalent S-substitution (x), for FeSe1-x S x . By simultaneously tuning chemical and physical pressures, against which the chalcogen height shows a contrasting variation, we achieve a complete separation of nematic and antiferromagnetic phases. In between, an extended non-magnetic tetragonal phase emerges, where T c shows a striking enhancement. The completed phase diagram uncovers that high-T c superconductivity lies near both ends of the dome-shaped antiferromagnetic phase, whereas T c remains low near the nematic critical point.

Influence of meteorological factors on acute aortic events in a subtropical territory.

BACKGROUND/OBJECTIVE: This study aims to examine the relationship between weather changes and acute aortic events in a subtropical territory. METHODS: A linear regression analysis was performed in a pan-territory epidemiological survey for a period of 10 years on the impacts of meteorological factors (ambient temperature, atmospheric pressure, relative humidity, amount of cloud, rainfall, number of lightning strikes, presence of typhoon, and thunderstorm warning) on the daily incidences of acute aortic dissections and ruptured aortic aneurysms. Meteorological variables were retrieved on a daily basis from a well-established observatory, and the daily incidences of aortic dissections and rupture of aortic aneurysms were retrieved from the Clinical Data Analysis and Reporting System. RESULTS: During the study period (January 2005 to December 2014), 3878 patients were identified as having acute aortic dissections, and 1174 patients had ruptured aortic aneurysms. Corresponding averaged daily incidences were 1.06 and 0.32, respectively. The incidences of aortic dissection and ruptured aortic aneurysm in a day could be predicted by ambient temperature in degrees Celsius using the following linear regression models: (1) incidence of aortic dissection = 1.548 - 0.021 × temperature; (2) incidence of ruptured aortic aneurysm = 0.564 - 0.010 × temperature. In addition, both high atmospheric pressure and absence of thunderstorm warning are positively associated with more aortic dissections. For rupture of aortic aneurysms, high atmospheric pressure and low relative humidity were positive predictors. In multiple regression analysis, however, ambient temperature was the only significant predictor for both acute aortic dissections and ruptured aortic aneurysms. CONCLUSION: This is the first pan-territory study to show an attributable effect of ambient temperature on acute aortic events. This paper confirms that even in a subtropical country, meteorological variables were important factors influencing acute aortic events.

Surgical management of carotid body tumor - Is Shamblin classification sufficient to predict surgical outcome?

Background The study aims to conduct a review of the surgical management of carotid body tumor. Methods Consecutive patients with CBT who received surgical interventions from January 1994 to January 2014 at our institution were reviewed. Clinical, operative, pathological and follow up information were reported. Results Twenty patients (four males; median age was 36) with 21 CBT operations were recorded during the period. One patient undertook sequential operations for bilateral CBTs. Patients had 19 neck mass, 1 incidental finding and 1 facial nerve palsy. Six CBTs (28.6%) were Shamblin class I, ten (47.6%) were class II and five (23.8%) were class III. Nine CBTs had preoperative conjunctive embolization. Two operations required internal carotid artery resection and reconstruction. Four patients received subtotal resections, while 17 achieved complete resection. Complications included two major strokes, three hoarse voice and two Horner's syndrome. Shamblin class was significant predictor of operative time, blood loss, and whether complete resection accomplished, but could not predict postoperative complication. With median follow up period of 94 months, there was no tumor recurrence found in those had complete resection. Conclusions This small cohort showed that Shamblin class was significant in predicting technical difficulties but could not predict occurrence of complications.

Ontogeny of human IgE-expressing B cells and plasma cells.

BACKGROUND: IgE-expressing (IgE+ ) plasma cells (PCs) provide a continuous source of allergen-specific IgE that is central to allergic responses. The extreme sparsity of IgE+ cells in vivo has confined their study almost entirely to mouse models. OBJECTIVE: To characterize the development pathway of human IgE+ PCs and to determine the ontogeny of human IgE+ PCs. METHODS: To generate human IgE+ cells, we cultured tonsil B cells with IL-4 and anti-CD40. Using FACS and RT-PCR, we examined the phenotype of generated IgE+ cells, the capacity of tonsil B-cell subsets to generate IgE+ PCs and the class switching pathways involved. RESULTS: We have identified three phenotypic stages of IgE+ PC development pathway, namely (i) IgE+ germinal centre (GC)-like B cells, (ii) IgE+ PC-like 'plasmablasts' and (iii) IgE+ PCs. The same phenotypic stages were also observed for IgG1+ cells. Total tonsil B cells give rise to IgE+ PCs by direct and sequential switching, whereas the isolated GC B-cell fraction, the main source of IgE+ PCs, generates IgE+ PCs by sequential switching. PC differentiation of IgE+ cells is accompanied by the down-regulation of surface expression of the short form of membrane IgE (mIgES ), which is homologous to mouse mIgE, and the up-regulation of the long form of mIgE (mIgEL ), which is associated with an enhanced B-cell survival and expressed in humans, but not in mice. CONCLUSION: Generation of IgE+ PCs from tonsil GC B cells occurs mainly via sequential switching from IgG. The mIgEL /mIgES ratio may be implicated in survival of IgE+ B cells during PC differentiation and allergic disease.

Haemodynamic Variations of Flow to Renal Arteries in Custom-Made and Pivot Branch Fenestrated Endografting.

OBJECTIVE: This study aimed to investigate variation of blood flow to renal arteries in custom-made and pivot branch (p-branch) fenestrated endografting, using a computational fluid dynamics (CFD) technique. METHODS: Idealised models of custom-made and p-branch fenestrated grafting were constructed on a basis of a 26 mm stent graft. The custom-made fenestration was designed with a 6 mm diameter, while the 5 mm depth renal p-branch was created with a 6 mm inner and 15 mm outer fenestration. Two configurations (option A and option B) were constructed with different locations of p-branches. Option A had both renal p-branches at the same level, whereas option B contained two staggered p-branches at lower positions. The longitudinal stent orientation in both custom-made and p-branch models was represented by a takeoff angle (ToA) between the renal stent and distal stent graft centreline, varying from 55° to 125°. Computational simulations were performed with realistic boundary conditions governing the blood flow. RESULTS: In both custom-made and p-branch fenestrated models, the flow rate and wall shear stress (WSS) were generally higher and recirculation zones were smaller when the renal stent faced caudally. In custom-made models, the highest flow rate (0.390 L/min) was detected at 70° ToA and maximum WSS on vessel segment (16.8 Pa) was attained at 55° ToA. In p-branch models, option A and option B displayed no haemodynamic differences when having the same ToA. The highest flow rate (0.378 L/min) and maximum WSS on vessel segment (16.7 Pa) were both calculated at 55° ToA. The largest and smallest recirculation zones occurred at 90° and 55° ToA respectively in both custom-made and p-branch models. Custom-made fenestrated models exhibited consistently higher flow rate and shear stress and smaller recirculation zones in renal arteries than p-branch models at the same ToA. CONCLUSIONS: Navigating the renal stents towards caudal orientation can achieve better haemodynamic outcomes in both fenestrated devices. Custom-made fenestrated stent grafts are the preferred choice for elective patients. Further clinical evidence is required to validate the computational simulations.

Spontaneous Retroperitoneal Hematoma Simulating Ruptured Infrarenal Aortic Aneurysm in a Patient with End-Stage Renal Disease.

We reported a case of spontaneous retroperitoneal hematoma (SRH) simulating a ruptured infrarenal aortic aneurysm. A 72-year-old man with a history of infrarenal aortic aneurysm and end-stage renal disease on hemodialysis presented with malaise and nonspecific central abdominal pain and left loin discomfort. An emergency computed tomography scan showed a large retroperitoneal hematoma and clinical suspicion of ruptured infrarenal aortic aneurysm. However, the hematoma was discontinuous with the aneurysm sac and raised the clinical suspicion on dual pathology. The SRH was treated conservatively with transfusion of blood products, and the aneurysm was treated with nonemergency endovascular repair electively. This case demonstrates the importance of recognizing different clinical and radiological characteristics and be aware of dual pathology.

Effectiveness of proximal intra-operative salvage Palmaz stent placement for endoleak during endovascular aneurysm repair.

INTRODUCTION: The use of a proximal Palmaz stent is a well-recognised technique to treat proximal endoleak in endovascular aortic repair. This study aimed to report the effectiveness and safety of an intra-operative Palmaz stent for immediate type 1a endoleak in Hong Kong patients. METHODS: This case series was conducted at a tertiary hospital in Hong Kong. In a cohort of 494 patients who underwent infrarenal endovascular aortic repair from July 1999 to September 2015, 12 (2.4%) received an intra-operative proximal Palmaz stent for type 1a endoleak. Immediate and subsequent proximal endoleak on follow-up image was documented. RESULTS: Morphological review of the pre-repair aneurysm neck showed five conical, one funnel, five cylindrical and one undetermined short neck, with a median neck angle of 61 degrees (range, 19-109 degrees). Stent grafts used included seven Cook Zenith, one Cook Aorto-Uni-Iliac device, three Metronic Endurant, and one TriVascular Ovation. Eleven Palmaz stents were placed successfully as intended, but one of them was accidentally placed too low. Of the 12 type 1a endoleaks, postoperative imaging revealed immediate resolution of eight whilst four had improved. After a median follow-up of 16 (range, 1-59) months, none of the subsequent imaging showed a type 1a endoleak. The mean size of the aneurysm sac reduced from 7.4 cm preoperatively to 7.3 cm at 1 month, 6.9 cm at 6 months, 7.1 cm at 1 year, and 6.1 cm at 2 years postoperatively. None of these patients required aortic reintervention or had device-related early- or mid-term mortality. One patient required delayed iliac re-interventions for an occluded limb at 10 days post-surgery. CONCLUSION: In our cohort, Palmaz stenting was effective and safe in securing proximal sealing and fixation.

Modality specificity in the cerebro-cerebellar neurocircuitry during working memory.

Previous studies have suggested cerebro-cerebellar circuitry in working memory. The present fMRI study aims to distinguish differential cerebro-cerebellar activation patterns in verbal and visual working memory, and employs a quantitative analysis to deterimine lateralization of the activation patterns observed. Consistent with Chen and Desmond (2005a,b) predictions, verbal working memory activated a cerebro-cerebellar circuitry that comprised left-lateralized language-related brain regions including the inferior frontal and posterior parietal areas, and subcortically, right-lateralized superior (lobule VI) and inferior cerebellar (lobule VIIIA/VIIB) areas. In contrast, a distributed network of bilateral inferior frontal and inferior temporal areas, and bilateral superior (lobule VI) and inferior (lobule VIIB) cerebellar areas, was recruited during visual working memory. Results of the study verified that a distinct cross cerebro-cerebellar circuitry underlies verbal working memory. However, a neural circuitry involving specialized brain areas in bilateral neocortical and bilateral cerebellar hemispheres subserving visual working memory is observed. Findings are discussed in the light of current models of working memory and data from related neuroimaging studies.