Spatial metrology of dopants in silicon with exact lattice site precision

Scaling of Si-based nanoelectronics has reached the regime where device function is affected not only by the presence of individual dopants, but also by their positions in the crystal. Determination of the precise dopant location is an unsolved problem in applications from channel doping in ultrascaled transistors to quantum information processing. Here, we establish a metrology combining low-temperature scanning tunnelling microscopy (STM) imaging and a comprehensive quantum treatment of the dopant-STM system to pinpoint the exact coordinates of the dopant in the Si crystal. The technique is underpinned by the observation that STM images contain atomic-sized features in ordered patterns that are highly sensitive to the STM tip orbital and the absolute dopant lattice site. The demonstrated ability to determine the locations of P and As dopants to 5 nm depths will provide critical information for the design and optimization of nanoscale devices for classical and quantum computing applications.

Pre-endoscopic erythromycin administration in upper gastrointestinal bleeding: an updated meta-analysis and systematic review

Background

In patients suffering from upper gastrointestinal bleeding (UGIB), adequate visualization is essential during endoscopy. Prior to endoscopy, erythromycin administration has been shown to enhance visualization in these patients; however, guidelines have not fully adopted this practice. Thus, we performed a comprehensive, up-to-date meta-analysis on the issue of erythromycin administration in this patient population.

Methods

After searching multiple databases (November 2015), randomized controlled trials on adult subjects comparing administration of erythromycin before endoscopy in UGIB patients to no erythromycin or placebo were included. Pooled estimates of adequacy of gastric mucosa visualized, need for second endoscopy, duration of procedure, length of hospital stay, units of blood transfused, and need for emergent surgery using odds ratio (OR) or mean difference (MD) were calculated. Heterogeneity and publication bias were assessed.

Results

Eight studies (n=598) were found to meet the inclusion criteria. Erythromycin administration showed statistically significant improvement in adequate gastric mucosa visualization (OR 4.14; 95% CI: 2.01-8.53, P<0.01) while reduced the need for a second-look endoscopy (OR 0.51; 95% CI: 0.34-0.77, P<0.01) and length of hospital stay (MD -1.75; 95% CI: -2.43 to -1.06, P<0.01). Duration of procedure (P=0.2), units of blood transfused (P=0.08), and need for emergent surgery (P=0.88) showed no significant differences.

Conclusion

Pre-endoscopic erythromycin administration in UGIB patients significantly improves gastric mucosa visualization while reducing length of hospital stay and the need for second-look endoscopy.

Quantum simulation of the Hubbard model with dopant atoms in silicon

In quantum simulation, many-body phenomena are probed in controllable quantum systems. Recently, simulation of Bose-Hubbard Hamiltonians using cold atoms revealed previously hidden local correlations. However, fermionic many-body Hubbard phenomena such as unconventional superconductivity and spin liquids are more difficult to simulate using cold atoms. To date the required single-site measurements and cooling remain problematic, while only ensemble measurements have been achieved. Here we simulate a two-site Hubbard Hamiltonian at low effective temperatures with single-site resolution using subsurface dopants in silicon. We measure quasi-particle tunnelling maps of spin-resolved states with atomic resolution, finding interference processes from which the entanglement entropy and Hubbard interactions are quantified. Entanglement, determined by spin and orbital degrees of freedom, increases with increasing valence bond length. We find separation-tunable Hubbard interaction strengths that are suitable for simulating strongly correlated phenomena in larger arrays of dopants, establishing dopants as a platform for quantum simulation of the Hubbard model.

Depression and quality of life in hospitalised patients with congestive heart failure (CHF): A cross-sectional study from Karachi, Pakistan

Introduction

There is strong association between depression and mortality rates among patients with CHF. Despite the massive burden of cardiac disease as well as that of depression in Pakistan, there is limited data regarding the prevalence of depression in patients suffering from CHF. The aim of this study was to assess prevalence of depression in patients with CHF and to compare the health related quality of life of depressed and non-depressed patients with CHF.

Methods

A total of 1009 patients diagnosed with CHF were recruited from different public hospitals in Karachi, Pakistan. Depression was assessed at baseline using the Beck Depression Inventory (BDI) and health related quality of life was assessed using Euro Qol (EQ-5D).

Results

Of the 1009 participants recruited to the study, 66.4% (n = 670) met the threshold for depression using the BDI measure. Of the depressed patients, 66.7% (n = 447) were male. Preliminary results indicate that participants who were depressed at baseline had poorer health related quality of life on EQ-5D measures as compared to those who were non-depressed (mean EQ-5D descriptive score 10.45 in depressed patients vs 7.37 in non-depressed patients and mean EQ-5D visual scale score 35.09 in depressed patients vs 52.19 in non-depressed patients).

Conclusion

Considering the high prevalence of depression and its serious negative impact on quality of life of patients suffering from chronic physical illness, it is important to design and test culturally adapted psychosocial interventions to reduce depression and improve quality of life for these patients.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Increased risk for colorectal cancer under age 50 in racial and ethnic minorities living in the United States

Colorectal cancer (CRC) is the second most common cause of cancer death in USA. We analyzed CRC disparities in African Americans, Hispanics, Asians/Pacific Islanders, and American Indians/Alaska Natives compared to non‐Hispanic Whites. Current guidelines recommend screening for CRC beginning at age 50. Using SEER (Surveillance, Epidemiology, and End Results) database 1973–2009 and North American Association of Central Cancer Registries (NAACCR) 1995–2009 dataset, we performed frequency and rate analysis on colorectal cancer demographics and incidence based on race/ethnicity. We also used the SEER database to analyze stage, grade, and survival based on race/ethnicity. Utilizing SEER database, the median age of CRC diagnosis is significantly less in Hispanics (66 years), Asians/Pacific Islanders (68 years), American Indians/Alaska Natives (64 years), and African Americans (64 years) compared to non‐Hispanic whites (72 years). Twelve percent of Asians/Pacific Islanders, 15.4% Hispanics, 16.5% American Indians/Alaska Natives, and 11.9% African Americans with CRC are diagnosed at age <50 years compared to only 6.7% in non‐Hispanic Whites (P < 0.0001). Minority groups have more advanced stages at diagnosis compared to non‐Hispanic Whites. Trend analysis showed age‐adjusted incidence rates of CRC diagnosed under the age of 50 years have significantly increased in all racial and ethnic groups but are stable in African Americans. These results were confirmed through analysis of NAACCR 1995–2009 dataset covering nearly the entire USA. A significantly higher proportion of minority groups in USA with CRC are diagnosed before age 50 compared to non‐Hispanic Whites, documenting that these minority groups are at higher risk for early CRC. Further studies are needed to identify the causes and risk factors responsible for young onset CRC among minority groups and to develop intervention strategies including earlier CRC screening, among others.

Ambras Syndrome: First Reported Case in Bangladesh and its Oral Rehabilitation

People with rare hypertrichosis syndromes became crowd-drawing money-making phenomena in many 19th century sideshow acts. These individuals have been referred to as dog-men, hair-men, and werewolves. In 1993, Baumister et al. described congenital hypertrichosis lanuginose or Ambras syndrome: a distinct form of congenital hypertrichosis characterized by excessive hair growth over the body and face associated with facial and occasional dental anomalies. Much is not known about this syndrome since fewer than 50 cases have been documented worldwide. In this case report, a nine year old girl presented with excessive hair growth throughout her body that was denser along her midline. Furthermore, her face displayed the typical dysmorphic features characteristic of Ambras syndrome: a round tip nose, thickened nasal cartilage, antiverted nares, prominent philtrum with deep groove, and a trapezoid mouth. Oral examination revealed normal oral mucosa with completely missing and unerupted decidious and permanent teeth. Panoramic radiographs confirmed unerupted deciduous teeth. Previous case reports have mentioned the presence of occasional dental anomalies such as retarded first and second dentition and absence of some teeth. However, this is the first reported case of Ambras syndrome presenting with complete anodontia. Prior cytogenetic studies performed on persons with Ambras syndrome have implicated a balanced pericentric inversion of chromosome 8. However, it is likely that dental anomalies are likely a result of a different genetic rearrangement. Further studies are needed to explore the cause of this rare phenotype of Ambras syndrome with complete unerupted dentition.

Study on Association of Maternal Serum Triglyceride with Pre-eclampsia

Till now pre-eclampsia is a disease of multiple theories. This case control study was carried out in the department of Obstetrics and Gynaecology of Bangabandhu Sheikh Mujib Medical University Hospital and Dhaka Medical College Hospital, from January 2006 to December 2007 to determine the association of maternal serum triglyceride with pre-eclampsia. Ninety pregnant women were studied, among them 45 patients were pre-eclamptic and served as case and 45 normal healthy pregnant women served as control. Estimation of serum triglyceride levels of all study patients was done with the help of enzymatic method. The mean (± SD) systolic blood pressure was 152.4 ± 19.8 mmHg in study group and 112.0 ± 8.9 mmHg in control group (p<0.05). Similarly the mean (± SD) diastolic blood pressure was 103.1 ± 12.2 mmHg in case group and 75.5 ± 6.6 mmHg in control group (p<0.05). Serum triglyceride level was more than the normal reference value in pre-eclamptic group. The mean (± SD) serum triglyceride level was 242.9 ± 36.8 mg/dl in case group and 184.6 ± 12.5mg/dl in control group. Statistically the difference was significant (p<0.05). The level of serum triglyceride positively correlated with the rise of blood pressure and degree of albuminuria. Thus serum triglyceride level increase in pre-eclampsia and the level correlate with the severity of the disease.

Spatially resolved resonant tunneling on single atoms in silicon

The ability to control single dopants in solid-state devices has opened the way towards reliable quantum computation schemes. In this perspective it is essential to understand the impact of interfaces and electric fields, inherent to address coherent electronic manipulation, on the dopants atomic scale properties. This requires both fine energetic and spatial resolution of the energy spectrum and wave-function, respectively. Here we present an experiment fulfilling both conditions: we perform transport on single donors in silicon close to a vacuum interface using a scanning tunneling microscope (STM) in the single electron tunneling regime. The spatial degrees of freedom of the STM tip provide a versatility allowing a unique understanding of electrostatics. We obtain the absolute energy scale from the thermal broadening of the resonant peaks, allowing us to deduce the charging energies of the donors. Finally we use a rate equations model to derive the current in presence of an excited state, highlighting the benefits of the highly tunable vacuum tunnel rates which should be exploited in further experiments. This work provides a general framework to investigate dopant-based systems at the atomic scale.

Characteristics of gastric cancer in Asia

Gastric cancer (GC) is the fourth most common cancer in the world with more than 70% of cases occur in the developing world. More than 50% of cases occur in Eastern Asia. GC is the second leading cause of cancer death in both sexes worldwide. In Asia, GC is the third most common cancer after breast and lung and is the second most common cause of cancer death after lung cancer. Although the incidence and mortality rates are slowly declining in many countries of Asia, GC still remains a significant public health problem. The incidence and mortality varies according to the geographic area in Asia. These variations are closely related to the prevalence of GC risk factors; especially Helicobacter pylori (H. pylori) and its molecular virulent characteristics. The gradual and consistent improvements in socioeconomic conditions in Asia have lowered the H. pylori seroprevalence rates leading to a reduction in the GC incidence. However, GC remains a significant public health and an economic burden in Asia. There has been no recent systemic review of GC incidence, mortality, and H. pylori molecular epidemiology in Asia. The aim of this report is to review the GC incidence, mortality, and linkage to H. pylori in Asia.

Prophylactic tracheal intubation for upper GI bleeding: A meta-analysis

AIM: To evaluate usefulness of prophylactically intubating upper gastrointestinal bleeding (UGIB) patients.

METHODS: UGIB results in a significant number of hospital admissions annually with endoscopy being the key intervention. In these patients, risks are associated with the bleeding and the procedure, including pulmonary aspiration. However, very little literature is available assessing the use of prophylactic endotracheal intubation on aspiration in these patients. A comprehensive search was performed in May 2014 in Scopus, CINAHL, Cochrane databases, PubMed/Medline, Embase, and published abstracts from national gastroenterology meetings in the United States (2004-2014). Included studies examined UGIB patients and compared prophylactic intubation to no intubation before endoscopy. Meta-analysis was conducted using RevMan 5.2 by Mantel-Haenszel and DerSimonian and Laird models with results presented as odds ratio for aspiration, pneumonia (within 48 h), and mortality. Funnel plots were utilized for publication bias and I² measure of inconsistency for heterogeneity assessments.

RESULTS: Initial search identified 571 articles. Of these articles, 10 relevant peer-reviewed articles in English and two relevant abstracts were selected to review by two independent authors (Almashhrawi AA and Bechtold ML). Of these studies, eight were excluded: Five did not have a control arm, one was a letter the editor, one was a survey study, and one was focused on prevention of UGIB. Therefore, four studies (N = 367) were included. Of the UGIB patients prophylactically intubated before endoscopy, pneumonia (within 48 h) was identified in 20 of 134 (14.9%) patients as compared to 5 of 95 (5.3%) patients that were not intubated prophylactically (P = 0.02). Despite observed trends, no significant differences were found for mortality (P = 0.18) or aspiration (P = 0.11).

CONCLUSION: Pneumonia within 48 h is more likely in UGIB patients who received prophylactic endotracheal intubation prior to endoscopy.

Role of D-dimer in determining coagulability status in pre-eclamptic and normotensive pregnant women

A cross sectional study was carried out from January 2007 to December 2008 in the department of Obstetrics and Gynaecology, Dhaka Medical College Hospital, Dhaka in collaboration with Department of Haematology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. Pregnant women with pre-eclampsia attending at Out-patient Department (OPD) and admitted in In-patient Department of Obstetrics and Gynaecology Dhaka Medical College Hospital, Dhaka were selected as cases. Healthy and uncomplicated pregnant women admitted in the same hospital were taken as controls. The study showed that 26-30 years and 21-25 years age category was higher in the case and control groups and the mean age was significantly higher in case group compared to control group (p=0.025). The study showed that 44% of case group had a significantly high level of plasma D-dimer (>0.5μg/ml) as opposed to control group (8%) (p<0.001). Estimation of odds ratio demonstrates that pre-eclamptic women (case) had 9 times (95% of CI = 2.8 - 28.9) more risk of having plasma D-dimer >0.5μg/ml than that of normal pregnant women (control). The mean systolic and diastolic blood pressures in patients with plasma D-dimer >0.5μg/ml were considerably higher than those who had plasma D-dimer ≤0.5μg/ml (p<0.001). The study showed that majority (81.8%) of pre-eclamptic women with plasma D-dimer >0.5μg/ml had systolic blood pressure ≥ 160 mm Hg compared to 46.4% of those who had plasma D-dimer ≤0.5μg/ml (p=0.010). And ninety percent of pre-eclamptic women with plasma D-dimer >0.5μg/ml had exhibited severe proteinuria as opposed to 53.6% of those who had plasma D-dimer ≤0.5μg/ml (p=0.017). The study concludes that plasma D-dimer level can easily be used in screening for the hypercoagulable state in pre-eclamptic patients which have preventive and therapeutic implications.

Policy advocacy and leadership training for formerly incarcerated women: an empowerment evaluation of ReConnect, a program of the Women in Prison Project, Correctional Association of New York

There is limited knowledge on re-entry initiatives for formerly incarcerated women specifically on building women's advocacy and leadership skills. Our research highlights an empowerment evaluation on ReConnect, a 12-session; innovative advocacy and leadership development program rooted in an integrated framework of empowerment, and transformational leadership theories. Using thematic analysis, we coded three focus groups with 24 graduates, for themes that matched our framework's concepts. ReConnect graduates reported being empowered by the information they received on parental rights, housing, and employment. Participants agreed that ReConnect improved their communication skills, preparing them to advocate for themselves and community members.

Surgical delivery of drug releasing poly(lactic-co-glycolic acid)/poly(ethylene glycol) paste with in vivo effects against glioblastoma

INTRODUCTION

The median survival of patients with glioblastoma multiforme (astrocytoma grade 4) remains less than 18 months despite radical surgery, radiotherapy and systemic chemotherapy. Surgical implantation of chemotherapy eluting wafers into the resection cavity has been shown to improve length of survival but the current licensed therapy has several drawbacks. This paper investigates in vivo efficacy of a novel drug eluting paste in glioblastoma.

METHODS

Poly(lactic-co-glycolic acid)/poly(ethylene glycol) (PLGA/PEG) self-sintering paste was loaded with the chemotherapeutic agent etoposide and delivered surgically into partially resected tumours in a flank murine glioblastoma xenograft model.

RESULTS

Surgical delivery of the paste was successful and practical, with no toxicity or surgical morbidity to the animals. The paste was retained in the tumour cavity, and preliminary results suggest a useful antitumour and antiangiogenic effect, particularly at higher doses. Bioluminescent imaging was not affected significantly by the presence of the paste in the tumour.

CONCLUSIONS

Chemotherapy loaded PLGA/PEG paste seems to be a promising technology capable of delivering active drugs into partially resected tumours. The preliminary results of this study suggest efficacy with no toxicity and will lead to larger scale efficacy studies in orthotopic glioblastoma models.

Spatially resolving valley quantum interference of a donor in silicon

Electron and nuclear spins of donor ensembles in isotopically pure silicon experience a vacuum-like environment, giving them extraordinary coherence. However, in contrast to a real vacuum, electrons in silicon occupy quantum superpositions of valleys in momentum space. Addressable single-qubit and two-qubit operations in silicon require that qubits are placed near interfaces, modifying the valley degrees of freedom associated with these quantum superpositions and strongly influencing qubit relaxation and exchange processes. Yet to date, spectroscopic measurements have only probed wavefunctions indirectly, preventing direct experimental access to valley population, donor position and environment. Here we directly probe the probability density of single quantum states of individual subsurface donors, in real space and reciprocal space, using scanning tunnelling spectroscopy. We directly observe quantum mechanical valley interference patterns associated with linear superpositions of valleys in the donor ground state. The valley population is found to be within 5% of a bulk donor when 2.85 ± 0.45 nm from the interface, indicating that valley-perturbation-induced enhancement of spin relaxation will be negligible for depths greater than 3 nm. The observed valley interference will render two-qubit exchange gates sensitive to atomic-scale variations in positions of subsurface donors. Moreover, these results will also be of interest for emerging schemes proposing to encode information directly in valley polarization.

Characteristics of gastric cancer in Asia

Gastric cancer (GC) is the fourth most common cancer in the world with more than 70% of cases occur in the developing world. More than 50% of cases occur in Eastern Asia. GC is the second leading cause of cancer death in both sexes worldwide. In Asia, GC is the third most common cancer after breast and lung and is the second most common cause of cancer death after lung cancer. Although the incidence and mortality rates are slowly declining in many countries of Asia, GC still remains a significant public health problem. The incidence and mortality varies according to the geographic area in Asia. These variations are closely related to the prevalence of GC risk factors; especially Helicobacter pylori (H. pylori) and its molecular virulent characteristics. The gradual and consistent improvements in socioeconomic conditions in Asia have lowered the H. pylori seroprevalence rates leading to a reduction in the GC incidence. However, GC remains a significant public health and an economic burden in Asia. There has been no recent systemic review of GC incidence, mortality, and H. pylori molecular epidemiology in Asia. The aim of this report is to review the GC incidence, mortality, and linkage to H. pylori in Asia.

Gastric cancer in Africa: Current management and outcomes

Gastric cancer is the fourth most common cancer and second most common cause of cancer death worldwide. Globally, gastric cancer poses a significant public health burden - both economically and socially. In 2008, the economic burden from premature cancer deaths and disability was $895 billion and gastric cancer was the second highest cancer responsible for healthy life lost. With the expected increase in cancer deaths and non-communicable diseases, these costs are expected to rise and impact patient care. World Health Organization, estimates a 15% increase in non-communicable disease worldwide, with more than 20% increase occurring in Africa between 2010 and 2020. Mali, West Africa, is ranked 15^th highest incidence of gastric cancer worldwide at a rate of 20.3/100000, yet very scarce published data evaluating etiology, prevention or management exist. It is understood that risk factors of gastric cancer are multifactorial and include infectious agents (Helicobacter pylori, Epstein-Barr virus), genetic, dietary, and environmental factors (alcohol, smoking). Interestingly, African patients with gastric cancer are younger, in their 3^rd-4^th decade, and present at a late stage of the disease. There is sparse data regarding gastric cancer in Africa due to lack of data collection and under-reporting, which impacts incidence and mortality rates. Currently, GLOBOCAN, an International Agency for Research on Cancer resource, is the most comprehensive available resource allowing comparison between nations. In resource limited settings, with already restricted healthcare funding, data is needed to establish programs in Africa that increase gastric cancer awareness, curtail the economic burden, and improve patient management and survival outcomes.

Pregnancy with myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular transmission, caused by auto antibodies against the nicotinic acetylcholine receptor. These antibodies of the IgG isotype are detected in 80-90% of generalized MG and in 50-70% of ocular MG. Seronegative MG is caused by humoral factors. Prevalence of MG lies between 1 in 10.000 and 1 in 50.000, with 2/3 of affected individuals being female. In the case of maternal myasthenia gravis, both the mother and the child may develop myasthenia symptoms with varying degrees of weakness and progressive fatigability of the skeletal muscles. Data for the case report were generated by reviewing labour, delivery, and postpartal records. We present a 26 years old lady who suffered from a generalized form of myasthenia gravis since the age of 15. She got herself admitted to a neurologic clinic for a myasthenic crisis when she was two and half months pregnant. The patient was treated with anticholinesterase medication, corticosteroids and intravenous immunoglobulin. Clinically, the patient's condition improved significantly during pregnancy. Delivery and the post delivery period were also normal for the patient. Myasthenia gravis especially when associated with pregnancy is a high-risk disease. As this disease predominantly occurs in women of reproductive age, it is important to be aware of this condition in obstetrics and its interdisciplinary diagnostic and therapeutic management is required.

Early surgery for epiretinal membrane preserves more vision for patients

PURPOSE

To establish whether early vitrectomy for epiretinal membrane (ERM) is preferable to delayed surgery.

METHODS

We carried out a retrospective study of 120 eyes from 120 patients with pre-operative visual acuity (VA) of 6/60 or better. Pre-operative logMAR score was considered to act as an appropriate proxy measure for time of surgical procedure, with scores of 0.3 or less considered to represent early surgery, scores of 0.4 or 0.5 considered to represent medium surgery, and scores of 0.6 or more considered to represent late surgery for ERM. Patients were either pseudophakic at the time of vitrectomy or underwent combined phaco-vitrectomy for symptomatic ERM.

RESULTS

Evaluation of parameter coefficients indicated that controlling for other factors, a delay of the surgical procedure from a state of early to medium corresponded to an increase (ie, disbenefit) of 0.074 units in post-operative logMAR score (95% confidence interval -0.001-0.15). A delay of the surgical procedure from a state of early to late corresponded to an increase (ie, disbenefit) of 0.21 units in post-operative logMAR score (95% confidence interval 0.13-0.29). Mean post-operative VA for early surgery was 0.16, out of which 36.2% of patients had a LogMAR score of 0.1 or better. This is in comparison to 17.2% in late ERM (those with a pre-operative logMAR score of 0.6 or more).

CONCLUSION

We conclude that early surgery is associated with a lower (ie, better) post-operative logMAR score. Vitrectomy for early symptomatic ERM, in carefully selected patients, is beneficial in preserving excellent vision and allows quicker visual rehabilitation.