Thermochemistry and Kinetics of Intermolecular Addition of Radicals to Toluene and Alkylaromatics.

To better understand intermolecular radical additions to aromatic rings that take place in the pyrolysis of alkylaromatics at low to moderate temperatures (∼450 °C), the thermochemistry and kinetics of several reactions of this type are investigated using the CBS-QB3 level of theory. The calculated thermochemistry of the adduct radicals is significantly different from previous estimates; the average discrepancy in Gibbs free energy at 298 K is 5.3 kcal/mol. A group additivity value for aromatic π radicals was developed to facilitate rapid accurate estimates for other molecules containing this functional group; the average discrepancy in Gibbs free energy using the updated group additivity value is improved to 0.5 kcal/mol. Previous estimations of the rate coefficients of these reactions were found to be inaccurate due to the lack of important features such as loss of aromaticity in the compounds used as the training set for the estimation. Rate coefficients for addition of several different radicals to aromatic rings are reported. The reaction rates are comparable for ortho, meta, and para additions, slowest for addition to the substituted position, and insensitive to the length of alkyl chains attached to the aromatic reactant.

Thermochemistry and Group Additivity Values for Fused Two-Ring Species and Radicals.

Motivated by a lack of understanding in the chemical mechanisms of alkylaromatic pyrolysis, the thermochemistry of fused two-ring aromatic molecules and radicals was calculated in this work using the CBS-QB3 level of theory. The enthalpies of formation of some fused ring species differ by as much as 13 kcal/mol from previous estimates. New group values were defined to facilitate better thermochemistry estimates in the future and were found to match the CBS-QB3 calculated values with an average deviation of 0.4 kcal/mol and a standard deviation of 0.9 kcal/mol, a substantial improvement from previous estimation methods. We discuss the thermochemical characteristics of the various polycyclic and radical groups developed in this work.

Territory-wide population-based study of chronic hepatitis C infection and implications for hepatitis elimination in Hong Kong.

BACKGROUND: To study the epidemiology of chronic hepatitis C virus infection in Hong Kong and to estimate the service gap for achieving the WHO hepatitis elimination targets of attaining a diagnosis rate of 90%, treatment rate of 80% and 65% reduction in mortality rate by 2030. METHODS: From January 2005 to March 2017, patients who were tested positive for anti-HCV were retrospectively retrieved from all public hospitals in Hong Kong. The epidemiological data of 15 participating hospitals were analysed. RESULTS: A total of 11 309 anti-HCV+ patients were identified and the estimated diagnosis rate was 50.9%. Our HCV-infected patients were ageing (median age 59). The all-cause mortality rate increased from 26.2 to 54.8 per 1000 person-years over the last decade. Our estimated treatment rate was 12.4%. Among the treated patients, 93.6% had received pegylated interferon/ribavirin (Peg-IFN/RBV) but only 10.8% had received interferon-free direct-acting antivirals (DAAs). In a cohort of 1533 patients, 39% already had advanced liver fibrosis or cirrhosis. The sustained virological response rate for Peg-IFN/RBV and DAAs were 74.8% and 97.2% respectively. However, more than 70% of patients were not subjected to interferon treatment for various reasons. Patients who achieved SVR were associated with a significantly lower risk of HCC (4.7% vs 9.6%, P = 0.005) and death (1.7% vs 23.8%, P < 0.001). CONCLUSION: Our diagnosis rate, treatment rate and mortality rate reduction were still low, particularly the Peg-IFN outcomes, making it difficult to meet the WHO hepatitis elimination targets. A more generalized use of DAAs is urgently needed to improve the situation.

Kinetics of Intramolecular Phenyl Migration and Fused Ring Formation in Hexylbenzene Radicals.

A combined ab initio/TST study was conducted to study the phenyl migration and fused ring formation of a series of 1-phenyl-hex- x-yl radicals. Phenyl shift proceeds through a two-step mechanism with a ring closure by ipso-cycloaddition, followed by a ring-opening by ß-scission leading to x-phenyl-hex-1-yl radical isomers. Both steps involve a spirocyclic transition state connected by a spirocyclic intermediate. Barrier heights at the CBS-QB3 level range from 9.9 to 17.7 kcal mol-1 depending on the size of the newly formed ring. Formation of fused rings by peri-cycloaddition reactions occur through barrier heights that range from 8.8 to 28.8 kcal mol-1. The addition sites are the substituted and ortho carbons of the phenyl ring for the ipso- and peri-cycloadditions, respectively. For both types of reaction, the Arrhenius A factor decreases as the ring size increases. This is related to the number of internal rotors lost across the reaction. In addition, length of the side chain also impacts on the kinetics as longer side chains decrease the barrier height required to form a second cycle. Electrons in the cyclohexadienyl group of the spiro and fused rings are much more localized than expected, with the presence of two distinct π bonds. Rate coefficients for each reaction are provided. The unimolecular reactions are fast at most conditions, implying that ring formation and/or ring-opening processes will equilibrate 1-phenyl-hex- x-yl and x-phenyl-hex-1-yl radicals and the spiro and fused isomers.

Journey of a Hong Kong public teaching hospital in preparation of hospital accreditation.

Hospital accreditation is a new concept for Hong Kong Hospital Authority hospitals. Queen Mary Hospital has been engaged as one of the hospitals in a territory-wide Pilot Scheme of Hospital Accreditation. In preparation for accreditation, Queen Mary Hospital has undergone the process of self-assessment, staff engagement, and service improvements which all require well-planned strategies to achieve successful outcomes. In this article, we highlight the journey of preparation and the staff engagement exercise we conducted to attain full accreditation. We also highlight the obstacles, conundrums, and pitfalls we encountered, along with successful overcoming strategies and countermeasures we adopted, and quandaries to be avoided. Throughout the preparation, the hospital's senior executives insisted that achieving hospital accreditation was not the main focus, but rather an emphasis on how the Pilot Scheme would bring about organisational transformations in our culture, and thus foster quality, safety, effectiveness, and reliability of services. We hope our experience can provide a reference and be of value to other hospitals that will go through the journey in the future.

Open space office: A review of the literature and Hong Kong case studies.

BACKGROUND: Open plan or open space office has become increasingly popular but those who promote the concept seldom refer to health studies or workers' perceptions of a change in office layout towards an open space arrangement. OBJECTIVE: To review the literature on open plan or open space office layouts in terms of facilities management (FM) with users' perceptions in mind and to obtain opinions of users of open space offices for a better appreciation of the FM issues. METHODS: A literature search of research papers from 2007 in journals using the keywords "open plan office" and "open space office" plus "health", first in the titles then in the text, was carried out. Thirty-two of those papers, accessible by the authors' institutions, were consulted together with 5 other works in the Harvard Business Review. The review consulted but excluded papers and reports published or sponsored by commercial firms that were in favour of open space layouts. Case studies were conducted by face to face meetings in confidence with workers in the middle managements of twelve Hong Kong organisations known as friends to two of the authors. Problems as seen by staff are reported and discussed. RESULTS: The literature review reveals that apart from writing that promotes the use of an open plan office layout, a host of scientific works point to the problems of perceived dissatisfaction with such a layout, the nature of the dissatisfaction tending to depend on the actual design. Most workers interviewed disliked the new style open plan layouts, which points to the necessity of consulting workers when such changes are contemplated, as well as monitoring the results of the change once it is in place whether against workers' wishes or with their support. There is a need for a number of facility arrangements in making a change to open plan that ensures that worker needs for proper lighting, privacy, and indoor health will be met. CONCLUSIONS: If the aim of a change to an open plan arrangement is to promote collegial communications in office, the study sheds light on the extent to which such arrangements may not in practice be suitable for achieving the aim. It follows that further, more specifically sociological studies of workers' job satisfaction and emotional health in open plan office settings would be worth doing.

Ten-year review of epidemiology, clinical features, and treatment outcome of achalasia in a regional hospital in Hong Kong.

OBJECTIVE: To describe the epidemiology, clinical features, and treatment outcome of achalasia in Chinese patients. DESIGN: Retrospective study. SETTING: Major regional hospital, Hong Kong. PATIENTS: Clinical records of patients with the diagnosis of achalasia from July 1997 to June 2007 were reviewed. RESULTS: Thirty-two patients were diagnosed with achalasia during the study period. The mean age at diagnosis was 50 years (standard deviation, 20 years). The female-to-male ratio was 1.3:1. The main presenting symptoms were dysphagia (78%) and vomiting (50%). Nine laparoscopic and two open Heller's operations had been performed and 16 patients had undergone endoscopic dilatations. Four patients had botulinum toxin injection and four were taking calcium channel blocker (nifedipine) medications. Botulinum toxin injection and medical therapy had poor short- and long-term responses. Laparoscopic myotomy and pneumatic dilatation had comparable good short- and long-term responses. CONCLUSION: Achalasia affected all age-groups but there was a peak at middle age. Pneumatic dilatation and Heller's myotomy (open or laparoscopic approach) appeared able to maintain longer symptom responses than medical therapy and botulinum toxin injection.

Non-alcoholic fatty liver disease: an expanding problem with low levels of awareness in Hong Kong.

BACKGROUND AND AIM: With the Westernization of the lifestyle and the rising prevalence of obesity and diabetes mellitus, non-alcoholic fatty liver disease (NAFLD) is an emerging health problem in the Asia-Pacific region. The purpose of this study was to determine the awareness of NAFLD among the general population in Hong Kong. METHODS: A random telephone survey was conducted from September 2007 to January 2008 using a structured multiple-choice questionnaire. Subjects were Hong Kong residents aged 18 or above who spoke Cantonese. RESULTS: In the first phase of the telephone survey, 521 subjects were interviewed and the results showed that as high as 83% of respondents had never come across the term 'NAFLD'. Upon completion of the second phase telephone survey, a total of 508 respondents who had heard of NAFLD were successfully interviewed. Of the 508 respondents, nearly half of them (42%) expressed no idea about the prevalence of NAFLD in Hong Kong. About half of respondents (47%) knew nothing about the clinical presentation of NAFLD. The majority of them (78%) had a misconception that blood tests could provide a definite diagnosis of NAFLD. Smoking, hepatitis B carriage and a past history of hepatitis A infection were cited as risk factors of NAFLD by 52%, 57% and 42% of respondents, respectively. Of the 508 respondents who had heard of NAFLD, most of them perceived that their knowledge of NAFLD was either inadequate (46%) or highly inadequate (35%). CONCLUSION: This survey revealed an inadequate knowledge of NAFLD among the general population in Hong Kong.

Concomitant correction of spinal deformity and spasticity management with posterior instrumentation and baclofen pump implantation.

Patients with spastic quadriplegia secondary to cerebral palsy manifest with severe spasticity and often with neuromuscular scoliosis. In order to optimize treatment and minimize morbidity in selected cases, the authors present a surgical option concurrently addressing these problems. This study reviews one case and describes the surgical technique in detail where intrathecal baclofen pump implantation and posterior spinal fusion are concomitantly performed to manage spasticity and scoliosis, respectively.

Seasonal birth patterns of cerebral palsy in North Carolina.

This study examined the seasonal birth patterns of patients with cerebral palsy (CP) in North Carolina. Data regarding live births in North Carolina were obtained for years 1980 to 2002 from the National Center for Health Statistics. Data from a pediatric orthopaedic multidisciplinary cerebral palsy clinical database at a regional medical center were weighted against the live births data. The results showed that despite slight fluctuations throughout the year, there was no significant difference between the actual monthly distribution of CP births and the expected monthly distribution (p = .68). There was no significant difference between the actual and expected seasonal distributions for overall CP births (p = .40). In conclusion, the monthly and seasonal distributions of cerebral palsy births are similar to those of live births in North Carolina. This study failed to identify any seasonal birth patterns specific for cerebral palsy.

Sick building syndrome and perceived indoor environmental quality: A survey of apartment buildings in Hong Kong.

The outbreak of a highly communicable disease, SARS, in Asia in 2003 has revealed the health risk of living in a high-density environment. To show the important connection between human health and environmental quality, this study surveys the prevalence of sick building syndrome (SBS) among apartment residents and their evaluation of indoor environmental quality (IEQ). Based on a sample of 748 households living in Hong Kong, two interesting findings are revealed: (1) nasal discomfort was the commonest home-related SBS symptom despite the absence of any central ventilation system in apartment buildings; (2) noise, rather than ventilation, was the major IEQ problem perceived by residents. Our statistical analysis further showed that residents with SBS symptoms were less satisfied with their IEQ than those without. That is, despite a positive evaluation of specific IEQ criteria with respect to the building residents lived in, if they reported feeling SBS related symptoms, the overall IEQ evaluation of their building could still be negative. This perception bias gives rise to a sample selection problem in measuring perceived IEQ, which has implications on housing management practices and the formulation of a healthy housing policy.

The impact of intrathecal baclofen on the natural history of scoliosis in cerebral palsy.

BACKGROUND: Intrathecal baclofen (ITB) is an effective treatment of spasticity in patients with cerebral palsy. However, several recent reports have raised concerns that the treatment may be associated with a rapid progression of scoliosis. The objective of this study was to further examine the effect of ITB treatment on the progression of scoliosis in patients with cerebral palsy. METHODS: Spastic cerebral palsy patients who were ITB candidates were followed radiographically. Baseline Cobb angles of the primary curve were measured during the period of ITB pump insertion and at the most recent follow-up visit. Each patient was matched with a control patient by the diagnosis of cerebral palsy, age, sex, topographic involvement, and initial Cobb angle. The mean rate of change in Cobb angle was compared between ITB and control patients using paired t test. A multiple linear regression model was used to examine the difference, controlling for age, sex, topographic involvement, and initial Cobb angle. RESULTS: Fifty ITB patients and 50 controls were included in the analysis. There was no statistically significant difference between the mean change in Cobb angle in ITB patients (6.6 degrees per year) compared with the matched control patients (5.0 degrees per year, P = 0.39). The results from the multiple regression analysis also failed to show a statistically significant difference (0.92 degrees per year difference between ITB patients and controls, P = 0.56). CONCLUSIONS: The progression of scoliosis in cerebral palsy patients with ITB treatment is not significantly different from those without ITB treatment. The findings suggest that patients receiving ITB experience a natural progression of scoliosis similar to the natural history reported in the literature. LEVEL OF EVIDENCE: Level III.

Instability after total hip arthroplasty: treatment with large femoral heads vs constrained liners.

One of the most common complications after total hip arthroplasty is instability. This study reviewed the recent literature concerning the indications, contraindications, and results of recent studies using both constrained liners and large femoral heads to treat instability after total hip arthroplasty. We also report on the results of a series of 41 patients (52 hips) considered being at high risk for dislocation who were treated with large-diameter metal-on-metal bearings and who were compared with a matched group of hips treated with standard-size metal-on-polyethylene bearings. The large-diameter femoral head group had no dislocations at a minimum follow-up of 24 months, whereas the standard-size group had 2 dislocations. We support the use of large femoral heads to treat instability in a wide variety of patients because of the increased stability, decreased wear of modern metal-on-metal designs, increased range of motion, and variety of revision options.

Instability of clonality in gastric lymphoid infiltrates: a study with emphasis on serial biopsies.

The evolution of low-grade B-cell mucosa-associated lymphoid-tissue (MALT) lymphoma of the stomach is a multistage process, reflected in the histologic continuum from Helicobacter pylori-chronic gastritis, to low-grade and high-grade lymphoma. Interestingly, in daily gastric biopsy sign-out, the authors observed that some biopsies showed monoclonality on polymerase chain reaction (PCR) even though there were no definite histologic features of malignancy and vice versa. To address the question, the authors studied the endoscopic gastric biopsies at first presentation of 46 patients to examine any clonality differences among various histologic patterns within the spectrum of MALT lymphoma evolution. The gastric biopsies were reviewed histologically and graded according to the Wotherspoon-Isaacson histologic scoring system from grade 0 (normal) to grade 5 (MALT lymphoma). The clonality of cases in each grade was determined by performing nested PCR for immunoglobulin heavy chain (IgH) gene rearrangement using FR2/JH and FR3/JH primer sets. The monoclonality rates among different grades were as follows: grade 2, 6.3% (1 of 16); grade 3, 27.3% (3 of 11); grade 4, 83.3% (5 of 6); grade 5, 69.2% (9 of 13). Statistically significant difference of monoclonality rate is demonstrated in histologic grade 4 versus grades 2 and 3, and grade 5 versus grade 2 (P < 0.05, Fisher exact test). The authors went on to examine the progress of disease by following up the clinical status, histologic changes, and clonality fluctuation of these cases. Four of the 8 patients with monoclonality on PCR, but no definite lymphoma at first presentation later progressed to frank MALT lymphoma. Our study shows that, during the progression to MALT lymphoma, there is an instability of clonality. Clonality can fluctuate between polyclonality, oligoclonality, and monoclonality, none of which defines an irreversible stage for progression to MALT lymphoma. Monoclonality is a risk factor for development of MALT lymphoma. Those cases with dense gastric mucosal lymphoid infiltrate (without definite MALT lymphoma) and monoclonality on PCR need to be closely monitored and Helicobacter infection promptly treated if present. In combination with clinicohistologic examination, PCR can serve as a complementary tool in arriving at a definite diagnosis of MALT lymphoma in cases with borderline histologic features.

Use of Platelet-Rich Plasma in Intra-Articular Knee Injections for Osteoarthritis: A Systematic Review.

OBJECTIVE: To systematically analyze the literature on the use of platelet-rich plasma (PRP) for intra-articular injections of the knee and its efficacy in the treatment of knee osteoarthritis (OA). DESIGN: Systematic literature reviews were conducted in PubMed, Embase, and CINAHL (ie, Cumulative Index to Nursing and Allied Health Literature) on October 30, 2013, using the keywords "platelet-rich plasma" and "knee" and "osteoarthritis." Inclusion criteria included (1) studies with human subjects, (2) prospective clinical studies (including either clinical trials or observational studies), and (3) full-text articles published in English. Exclusion criteria were: (1) animal studies; (2) retrospective studies; (3) patients with previous surgical intervention with total knee arthroplasty or reconstruction of the anterior cruciate ligaments; and (4) articles not published in English RESULTS: A total of 319 abstracts and titles were reviewed (60 from PubMed, 250 from Embase, and 9 from CINAHL). A total of 8 relevant journal articles were identified, all of which were published between 2010 and 2013. One-half of the studies were prospective observational studies that included only PRP treatment; the rest were prospective comparative studies including both PRP and controls-2 were randomized controlled trials. Of the 4 comparative studies, 3 compared PRP with hyaluronic acid, which was considered as a commonly used effective treatment for knee OA; the other one used saline injection (ie, placebo) as the control. Although most of the analyses suffered from small sample size and was thus inconclusive, the findings consistently indicated that PRP might have better outcomes in patients with a lesser degree of degeneration and in younger patients. CONCLUSION: PRP intra-articular injections of the knee may be an effective alternative treatment for knee OA. However, current studies are at best inconclusive regarding the efficacy of the PRP treatment. A large, multicenter randomized trial study is needed to further assess the efficacy of PRP treatment for patients with knee OA.

Ventricular peritoneal shunt malfunction after operative correction of scoliosis: report of three cases.

BACKGROUND CONTEXT: Two of the most common disease processes associated with hydrocephalus in children are spina bifida and intraventricular hemorrhage of prematurity, both of which are known to be also associated with spinal deformity in later childhood. The occurrence of shunt malfunction after mechanical injury or stress to the hardware has been well documented. Newer techniques in the treatment of neuromuscular scoliosis, including anterior release with segmental fixation, have resulted in more powerful corrections of these large spinal deformities. A new potential cause of shunt malfunction is the aggressive correction of scoliosis. PURPOSE: To report patients with neuromuscular curves averaging 100° who were subsequently recognized to have perioperative shunt malfunction. STUDY DESIGN: Three case studies from a university hospital setting were included. PATIENT SAMPLE: All three children were young adolescents and had-long term shunts. Two of the children had spina bifida and a third had cerebral palsy. All children underwent anterior release of their scoliosis with posterior segmental instrumentation, with unit rods and sublaminar wires. All had significant correction of their scoliosis. OUTCOME MEASURES: Malfunctioning of the ventriculoperitoneal shunts were recorded. METHODS: Chart reviews of three cases were analyzed. RESULTS: Two children had shunt malfunctions within a month of their surgery, and one child had intraoperative recognition and externalization of the shunt. CONCLUSIONS: Older children undergoing repair of neuromuscular scoliosis are often preadolescents or adolescents who have the same indwelling shunt systems originally implanted in early infancy. The shunt may be brittle and calcified, and the peritoneal catheter may be short. The correction of scoliosis often results in an almost instantaneous growth of a few inches. Because of the potential difficulty in recognizing shunt malfunction in the perioperative period, consideration should be given for elective revision of the peritoneal catheter in children at risk.

Ganglion cyst at the fibular head causing common peroneal neuropathy diagnosed with ultrasound and electrodiagnostic examination: a case report.

The common peroneal nerve is a major source of innervation to the lower limb, but it is sometimes compressed or entrapped at the fibular head. The authors present what they believe is the first reported case where peroneal nerve impingement caused by ganglion cyst compression of the nerve at the fibular head was diagnosed using a combination of ultrasound imaging and electrodiagnostic studies. The authors described the history, physical examination, electrodiagnostic findings, and musculoskeletal ultrasound findings of a patient with a left foot drop caused by a ganglion cyst compressing the common peroneal nerve at the fibular head. The increasing role of ultrasound imaging to evaluate musculoskeletal pathology is discussed.

Perioperative pain management in the neurosurgical patient.

Perioperative pain management in neurosurgical patients has been inadequately recognized and treated. An increased awareness of pain management and advances in understanding of pain modulation and pathophysiology have led to improved perioperative care of patients. There is a need to assess neurologic function while providing superior analgesia with minimal side effects. Several classes of drugs are currently available or under investigation for use as adjuvants or alternative therapies. There remains a need to determine the best treatment of perioperative pain in this patient population. Improved awareness, assessment, and treatment of pain result in better care and overall patient outcome.

Deficiency of complement factor MBL in a patient required cardiac surgery after an acute myocardial infarction with underlining chronic lymphocytic leukemia.

Increasing evidence suggests that Mannan-binding lectin (MBL), the initial factor of the lectin pathway of complement, plays a role in cardiovascular diseases, i.e. inversely associated with risk of myocardial infarction (MI). In the present case, a patient with MBL deficiency underwent coronary artery bypass grafting (CABG) after an acute MI with underlining chronic lymphocytic leukemia (CLL). Post-operatively, the patient had a cerebral vascular accident and eventually expired. Analysis of his blood samples from pre-, intra-, and post-operative periods showed that MBL levels abruptly increased post-operatively. We hypothesize that the post-operative increase of MBL in the patient with pre-existing MBL deficiency may contribute to systemic inflammation, causing a detrimental effect after cardiac surgery.