Ultratunable Quantum Frequency Conversion in Photonic Crystal Fiber

Quantum frequency conversion of single photons between wavelength bands is a key enabler to realizing widespread quantum networks. We demonstrate the quantum frequency conversion of a heralded 1551 nm photon to any wavelength within an ultrabroad (1226-1408 nm) range in a group-velocity-symmetric photonic crystal fiber, covering over 150 independent frequency bins. The target wavelength is controlled by tuning only a single pump laser wavelength. We find internal, and total, conversion efficiencies of 12(1)% and 1.4(2)%, respectively. For the case of converting 1551 to 1300 nm we measure a heralded g^{(2)}(0)=0.25(6) for converted light from an input with g^{(2)}(0)=0.034(8). We expect that this photonic crystal fiber can be used for myriad quantum networking tasks.

Resource-efficient frequency conversion for quantum networks via sequential four-wave mixing

We report a resource-efficient scheme in which a single pump laser was used to achieve frequency conversion by Bragg-scattering four-wave mixing in a photonic crystal fiber. We demonstrate bidirectional conversion of coherent light between Sr⁺²P_1/2→²D_3/2 emission wavelength at 1092 nm and the telecommunication C band with conversion efficiencies of 4.2% and 37% for up- and down-conversion, respectively. We discuss how the scheme may be viably scaled to meet the temporal, spectral, and polarization stability requirements of a hybrid light-matter quantum network.

Obese asthmatics are characterized by altered adipose tissue macrophage activation

BACKGROUND

Adipose tissue-derived inflammation is linked to obesity-related comorbidities. This study aimed to quantify and immuno-phenotype adipose tissue macrophages (ATMs) from obese asthmatics and obese non-asthmatics and to examine associations between adipose tissue, systemic and airway inflammation.

METHODS

Visceral (VAT) adipose tissue and subcutaneous (SAT) adipose tissue were collected from obese adults undergoing bariatric surgery and processed to obtain the stromovascular fraction. Pro-inflammatory (M1) and anti-inflammatory (M2) macrophages were quantified by flow cytometry. Cytospins of induced sputum were stained for differential cell counts. Plasma C-reactive protein (CRP) and CD163 were measured by ELISA.

RESULTS

VAT contained a higher number of ATMs compared to SAT. A higher percentage of M1 ATMs was observed in VAT of obese asthmatics compared to obese non-asthmatics. The M1:M2 ratio in VAT was negatively associated with FEV₁ %. Sputum macrophage count was correlated positively with M1 ATMs and negatively with M2 ATMs in VAT. In obese asthmatics, CRP was positively associated with M1:M2 ratio in VAT. There were no associations with CD163. An elevated ratio of M1:M2 ATMs was observed in VAT of obese asthmatics with increased disease severity.

CONCLUSIONS AND CLINICAL RELEVANCE

Visceral inflammation with increased pro-inflammatory macrophages (M1) occurs in obese asthma and may be a determinant of systemic inflammation and asthma severity.

Structural analysis of a set of proteins resulting from a bacterial genomics project

The targets of the Structural GenomiX (SGX) bacterial genomics project were proteins conserved in multiple prokaryotic organisms with no obvious sequence homolog in the Protein Data Bank of known structures. The outcome of this work was 80 structures, covering 60 unique sequences and 49 different genes. Experimental phase determination from proteins incorporating Se-Met was carried out for 45 structures with most of the remainder solved by molecular replacement using members of the experimentally phased set as search models. An automated tool was developed to deposit these structures in the Protein Data Bank, along with the associated X-ray diffraction data (including refined experimental phases) and experimentally confirmed sequences. BLAST comparisons of the SGX structures with structures that had appeared in the Protein Data Bank over the intervening 3.5 years since the SGX target list had been compiled identified homologs for 49 of the 60 unique sequences represented by the SGX structures. This result indicates that, for bacterial structures that are relatively easy to express, purify, and crystallize, the structural coverage of gene space is proceeding rapidly. More distant sequence-structure relationships between the SGX and PDB structures were investigated using PDB-BLAST and Combinatorial Extension (CE). Only one structure, SufD, has a truly unique topology compared to all folds in the PDB.

Brief examination of the career advancement ambition, organizational commitment, and professional commitment scales

Using scale items taken from Wright and Larwood's 1997 original research on the cosmopolitan-local latent role construct, Desrochers and Dahir recently proposed the Career Advancement Ambition, Organizational Commitment, and Professional Commitment Scales. Desrochers and Dahir's new scales raise serious issues regarding scale validity and item integrity for their measures.

Early results of laparoscopic swedish adjustable gastric banding for morbid obesity

AIMS: Gastric bypass and vertical banded gastroplasty (VBG) are currently the most commonly performed bariatric procedures but neither are ideal. The results of the first 56 patients who had laparoscopic Swedish adjustable gastric banding (SAGB) are presented. METHODS: All patients referred for bariatric surgery were considered for SAGB. Each was given the alternative of gastric bypass. Patients with a body mass index of less than 35, large hiatus hernia, under 18 years of age, gastric pathology and significant psychiatric illness were excluded. Preoperative gastroscopy, ultrasonographic examination of the gallbladder and specialist anaesthetic assessment were arranged. All but five patients had attempted laparoscopic procedures. Patients were discharged when they were mobile and could tolerate 1500 ml fluid per day. Patients were given a liquidized diet for 6 weeks. Assessments were made at 6 weeks and 3, 6, 9 and 12 months. RESULTS: Some 56 consecutive patients were followed for up to 12 months. The conversion rate fell from 52 per cent for the first 25 patients to 20 per cent for the last 20. Conversion rates were higher in men and in superobese patients. The duration of a laparoscopic operation fell significantly with experience but was still significantly longer than that of an open procedure (P < 0.004). The length of hospital stay was significantly shorter for laparoscopic procedures (P < 0.001). There was no death and little morbidity. Two bands had to be removed (easily) by open surgery, one for infection and one for a recurrence of gastric herniation. The mean excess weight loss was 60 per cent at 12 months. Greater than 50 per cent of excess body-weight was lost by 48 per cent of patients at 6 months and 69 per cent at 12 months. Band adjustments in most patients achieved further weight loss to compensate for late pouch dilatation. Most failures were in patients who failed to attend. CONCLUSION: SAGB appears to have many advantages over gastric bypass and VBG; it avoids stapling the stomach, should not cause any malabsorption, can be performed laparoscopically, is adjustable, is more readily reversed (if necessary) and, therefore, has the potential for lower associated morbidity and mortality rates. In terms of excess weight loss, the early results are certainly as good, if not better, than those of gastric bypass and VBG.

Psychological well-being and job satisfaction as predictors of job performance

The happy-productive worker hypothesis has most often been examined in organizational research by correlating job satisfaction to performance. Recent research has expanded this to include measures of psychological well-being. However, to date, no field research has provided a comparative test of the relative contribution of job satisfaction and psychological well-being as predictors of employee performance. The authors report 2 field studies that, taken together, provide an opportunity to simultaneously examine the relative contribution of psychological well-being and job satisfaction to job performance. In Study 1, psychological well-being, but not job satisfaction, was predictive of job performance for 47 human services workers. These findings were replicated in Study 2 for 37 juvenile probation officers. These findings are discussed in terms of research on the happy-productive worker hypothesis.

Psychological well-being and job satisfaction as predictors of job performance

The happy-productive worker hypothesis has most often been examined in organizational research by correlating job satisfaction to performance. Recent research has expanded this to include measures of psychological well-being. However, to date, no field research has provided a comparative test of the relative contribution of job satisfaction and psychological well-being as predictors of employee performance. The authors report 2 field studies that, taken together, provide an opportunity to simultaneously examine the relative contribution of psychological well-being and job satisfaction to job performance. In Study 1, psychological well-being, but not job satisfaction, was predictive of job performance for 47 human services workers. These findings were replicated in Study 2 for 37 juvenile probation officers. These findings are discussed in terms of research on the happy-productive worker hypothesis.

A prospective randomized study of calcium alginate (Sorbsan) versus standard gauze packing following haemorrhoidectomy

Post-haemorrhoidectomy pain is problematical but may be reduced by using less bulky haemostatic dressings in the anal canal. Fifty consecutive patients undergoing haemorrhoidectomy were prospectively randomized to receive either paraffin gauze/cotton gauze roll on calcium alginate (Sorbsan) roll as a post-operative pack. Post-operative pain was assessed at 6 h, on removal of rectal packing and at first bowel action. Haemorrhage was monitored at 6 h and removal of pack. There was no difference in the hospital stay between the two groups. Pain was significantly reduced at the time of removal/spontaneous discharge of rectal packing (P < 0.0001) and first post-operative bowel action (P = 0.0008) in the calcium alginate group. There was no significant difference in post-operative haemorrhage between the two groups. Calcium alginate dressings following haemorrhoidectomy effectively reduce post-operative pain compared to more bulky anal packs.

Gallstones

Lifetime risk of gallstones in Australia is 14%-20%. The most common symptom of gallstones in either the gallbladder or bile duct is epigastric to right upper quadrant pain. Cholecystectomy is indicated for symptomatic gallbladder stones and is usually performed laparoscopically; surgery is rarely indicated for asymptomatic stones. Endoscopic retrograde cholangiopancreatography is indicated for complications of bile duct stones, such as jaundice, cholangitis or severe pancreatitis, and for postcholecystectomy symptoms of stones; bile duct stones may be removed in the same procedure via endoscopic sphincterotomy. Bile duct stones are mostly diagnosed by operative cholangiography at cholecystectomy. Open surgery is used when minimal-access techniques are dangerous, unsuitable or impossible.

Emotional exhaustion as a predictor of job performance and voluntary turnover

Recent research suggests that a better understanding of emotional exhaustion requires the development of new theoretical perspectives. To that end, with the conservation of resources model (COR) as the theoretical framework, the present 1-year longitudinal study was undertaken. Composed of 52 social welfare workers, this research examined the relationship of emotional exhaustion to job satisfaction, voluntary turnover, and job performance. Positive affectivity (PA) and negative affectivity (NA) were used as control variables. Whereas emotional exhaustion was unrelated to job satisfaction, it was associated with both performance and subsequent turnover. In addition, the relationship between emotional exhaustion and performance and also between emotional exhaustion and turnover remained significant above and beyond the effects of PA and NA. Future research directions and implications of the findings are introduced.

The role of pleasantness and activation-based well-being in performance prediction

This study examined the relationships between 2 measures of psychological well-being and work performance using the circumplex model of emotion as the theoretical framework. Although the pleasantness-based measure of well-being predicted subsequent work performance, the results failed to establish a relationship between the activation-based measure of well-being and work performance. Future directions and implications of the findings regarding the further refinement of the role of psychological well-being in performance prediction are introduced.

Assessment of a new ultrafiltration blood processing system

PURPOSE

To report our clinical experience with a new blood processing device which uses ultrafiltration. We assessed safety and efficacy by evaluating: 1 ) the quality and the quantity of intraoperative shed blood processed and reinfused to the patient 2) homologous blood requirements 3) clinical status of the patient post-transfusion.

METHODS

With Ethics Committee approval, the ultrafiltration device was used in six consenting patients undergoing major elective spinal surgery. Blood samples for haematology and biochemistry tests were collected from patients post-induction of anaesthesia (baseline), 1 hr and 24 hr post-autotransfusion. Volumes of blood collected and processed, and all autologous and homologous transfusions were recorded. Patients were assessed post-operatively for any adverse effects.

RESULTS

Five patients had donated blood preoperatively. One patient required homologous blood products in addition to autologous blood. In two patients, the filtration cartridge became blocked and required changing midprocessing. No patient sustained device-related complications. One patient had postoperative haematuria which resolved spontaneously within two hours.

CONCLUSION

The ultrafiltration device was safe and effective in reducing homologous blood requirements in six patients undergoing elective spinal surgery. Further evaluation of the ultrafiltration device will be necessary, especially in view of the blockage of the filtration cartridge.

The role of pleasantness and activation-based well-being in performance prediction

This study examined the relationships between 2 measures of psychological well-being and work performance using the circumplex model of emotion as the theoretical framework. Although the pleasantness-based measure of well-being predicted subsequent work performance, the results failed to establish a relationship between the activation-based measure of well-being and work performance. Future directions and implications of the findings regarding the further refinement of the role of psychological well-being in performance prediction are introduced.

Helicobacter pylori colonization of Barrett's esophagus and its progression to cancer

Helicobacter pylori (HP) plays a crucial role in gastric carcinogenesis. Few studies have looked at the relationship between HP and Barrett's esophagus/cancer. To further investigate this, a study comparing the prevalence of HP and increasing grades of dysplasia was undertaken. Biopsies from 19 malignant and 94 benign cases of Barrett's esophagus were analysed histologically for the presence of HP. 34% of non-dysplastic Barrett's epithelium was colonized with HP compared with only 17% of dysplastic/malignant cases (P = 0.04). No relationship was found between HP status and: (i) length of Barrett's esophagus; (ii) the presence of ulcers or strictures; and (iii) previous anti-reflux surgery. HP colonization of Barrett's esophagus is not uncommon. We found that HP has a negative correlation with increasing dysplasia which is analogous to gastric carcinogenesis. This finding should be investigated in prospective studies to elucidate its role in Barrett's adenocarcinoma.

High-grade dysplasia in Barrett's oesophagus

BACKGROUND

The management of high-grade dysplasia (HGD) in Barrett's oesophagus is a controversial and challenging problem.

METHODS

An up-to-date review of the literature has been made using Index Medicus, the Medline database, and cross-referencing of major articles on this subject.

RESULTS

Diagnosis should be confirmed by a second expert pathologist. Repeat multiple jumbo biopsies and brushings need to be taken to reduce sample error and exclude associated invasive cancer. In young fit patients the advantages of surgery outweight the disadvantage of missing an early adenocarcinoma. Continued endoscopic surveillance may be more appropriate in elderly patients. New technology has increased the number of options. Early results of laser and multipolar electrocoagulation ablation of Barrett's epithelium are encouraging. Photodynamic therapy appears to be ideally suited to HGD and early cancers.

CONCLUSION

A selective approach to the management of HGD on an individual patient basis should be adopted.

Cost effectiveness of detecting Barrett's cancer

BACKGROUND

Screening Barrett's oesophagus is controversial owing to a large variation in the reported incidence of neoplastic change and lack of evidence that screening improves tumour prognosis.

AIMS

To determine the incidence of Barrett's cancer, its cost of detection, and stage of disease at time of diagnosis.

PATIENTS AND METHODS

Data from our surveillance programme have been reviewed to assess the incidence of malignant change, tumour stage at diagnosis, and the cost per cancer detected.

RESULTS

166 patients had annual endoscopic surveillance. Six patients (five men) developed cancer-an incidence of one cancer per 59 male and 167 female patient-years of follow up. The screened group had a significantly earlier stage than a control group of unscreened cancers (p < 0.05). The cost of detecting one cancer was Pounds 14 868 for men and Pounds 42 084 for women.

CONCLUSIONS

The cost of screening for Barrett's cancer is high but may be justified on the basis of the high incidence of detecting early stage disease.

Frequent loss of heterozygosity on chromosome 17 at 17q11.2-q12 in Barrett's adenocarcinoma

Allelic loss on chromosome 17 in 18 Barrett's oesophageal tumours was analysed with 17 polymorphic microsatellite markers. Loss of heterozygosity (LOH) of one or more markers was seen in 72% (13 of 18) tumours on 17p and 56% (10 of 18) on 17q. The highest 17p losses were found at D17S799 (62%, five of eight) and D17S261 (55%, five of nine), while loss at the p53 locus was 31% (5 of 16). The highest loss on 17q was found at the TCF-2 (17q11.2-q12) locus with 66% (8 of 12) LOH. TCF-2 was the only marker lost in two of the tumour samples; furthermore, TCF-2 was lost in four other tumours which retained heterozygosity at the markers on either side of it, D17S261 and D17S740. Six markers were used to assess LOH at 17q11.2-q12, and five of eight of the tumour specimens which had LOH at TCF-2 had no other loss on 17q. No statistically significant correlations were found between loss on 17q or 17p and any clinicopathological parameters. We propose from these data that the 17q11.2-q12 region contains a novel predisposing gene in Barrett's adenocarcinomas and may represent the site of a tumour-suppressor gene.

Nitrones and Oxaziridines. LXVII. Intermolecular Cycloaddition of Fused Indolyl Nitrone Ring Systems

The two dihydro-β-carboline N-oxides (6) and (18) have been prepared by reductive cyclization of 2-acetyl-3-(β- nitroethyl ) indoles. These cyclic nitrones undergo 1,3-dipolar cycloaddition to alkynes to give the cycloadducts (21)-(25). Thermal rearrangement of the adduct (22) gives the indolizino [8,7-b] indole (27) in high yield. The X-ray crystal structure determination of the adduct (24) is reported.

Coping and job performance

An organizational field study comprising 42 subjects examined the relationship between growth-oriented coping and subsequent job performance. Growth orientation was measured using the 7-item growth scale obtained from the Lazarus Ways of Coping Checklist. The hypothesized relationship between growth orientation and job performance was confirmed. Individuals obtaining high evaluations of managerial performance emphasized growth-oriented strategies in their behaviors. Further research directions are introduced.

The Ways of Coping instrument: reliability and temporal stability for a sample of employees

Convergent support is demonstrated for the use of seven empirically derived scales of the Ways of Coping instrument developed by Lazarus and his colleagues. While the instrument is widely used, until now the internal consistency of the coping measures and stability of the factor structure have yet to be shown for a sample of employed adults. While type of job and type of coping incident reported are not dependent, analysis indicates that work and nonwork groups differ across several coping dimensions. Research implications and directions are addressed.

Coping strategies and diastolic blood pressure

An organizational field study involving 95 civil service employees examined the ways these individuals coped with the stressful events of their daily living. Lazarus' cognitive-phenomenological analysis of psychological stress provided the theoretical framework. Subjects indicated on Lazarus' Ways of Coping Checklist those coping thoughts and actions used in the specific encounter described as stressful. As hypothesized, individuals experiencing higher diastolic blood pressure were more likely to cope using strategies characterized by wishful thinking, avoidance, and minimization of threat than were individuals exhibiting lower blood pressure. Implications from both an individual and organizational perspective are discussed.

A review of intra-articular knee injuries in racquet sports diagnosed by arthroscopy

Because of the recent rapid increase in the number of knee injuries related to racquet sports, the authors undertook a retrospective study of such injuries seen over a 5-year period at the Toronto Western Hospital Sports Medicine Institute. The 121 patients who presented over the study period with a racquet-sports-related knee injury requiring arthroscopy represented 30% of all racquet-sports related injuries seen during that period. The mean age at presentation was 32.8 years and two-thirds of the patients were men. All the major racquet sports were represented. In all, 213 lesions (7 bilateral) were seen at 128 arthroscopies, and 165 arthroscopic procedures were performed. The most common lesion was meniscal followed by chondromalacia patellae, anterior cruciate ligament tears, chondral lesions and pathologic plicae. Over 90% of the patients returned to their chosen racquet sport within 3 months of the arthroscopy and most were playing at a similar performance level to that before the initial injury.

Intra-articular knee injuries in racquet sports. A review of 128 arthroscopies

Within the last decade, there has been a significant increase in racquet sport participation. The authors report that in a 5-year period, 17% of the injuries seen in a busy sports injuries clinic were associated with racquet sports, and over half of these were injuries to the knee. The findings are reported of those patients requiring knee arthroscopy, and the patterns of injury sustained are identified. Injuries to the knee in racquet sports are largely unavoidable and are inherent to the nature of the game.

Ventilatory patterns during hypoxia, hypercapnia, and exercise in adolescents with mild scoliosis

Adolescents with mild, asymptomatic scoliosis (thoracic curvature less than 35 degrees) may have little or no impairment of resting lung volumes. Progression to more severe disease may, however, be accompanied by lung restriction, impaired exercise tolerance, and respiratory failure with CO2 retention. We wished to see whether adolescents with mild scoliosis and minimally abnormal resting pulmonary mechanics had impairment of their responses to hypercapnia, hypoxia, and progressive cycle exercise. Forty-four adolescents with idiopathic scoliosis were studied. The mean forced vital capacity (FVC), expressed as a percentage of the predicted value, was 94.3 +/- 2.2 (SE). The mean ventilatory response to hypercapnia (2.57 +/- 0.24 L/min/mm Hg) was within the normal range but was achieved with a tidal volume response (1.87 +/- .17% vital capacity [VC]/mm Hg) that was significantly lower than that previously reported in healthy young adults. Ventilatory responses to exercise were also within the normal range, the mean dyspnea index (VE-max/maximal voluntary ventilation) = 0.92 +/- 0.04. However, at a ventilation of 30 L/min, the tidal volume was 0.38 +/- 0.01% FVC, which was considerably lower than predicted. The tidal volume response to hypoxia was also abnormally low, the mean response being 0.52 +/- 0.059% VC/% decrease in arterial O2 saturation. These findings indicated that, even when scoliosis is asymptomatic and associated with minimal impairment of resting pulmonary function, abnormal patterns of ventilation occur during exercise or in response to chemical stimuli.

Kinetics and Stereochemistry of Elimination of Nitrous-Acid From 1-Para-Nitrophenyl-2-Nitroethyl Derivatives

The eliminations of nitrous acid from the compounds (1) and (6) are E2 processes, which proceed with a large primary kinetic isotope effect and with antiperiplanar stereochemistry. The rate of elimination of HNO2 from (1) is intermediate between the rate of elimination of HCl from (4) and HBr from (5). This order of nucleofugality , namely Br- > NO2- > Cl -, results from a more positive entropy of activation for the elimination of nitrous acid. The presence of an α-chlorine, as in compounds (8), (28) and (29), leads to elimination processes which are E1cB-like, with low primary kinetic isotope effects and with lack of stereospecificity.

Some Studies on the Reversibility of the Association Step in SRN 1 Reactions

The association step in SRN1 reactions, in which p- nitrobenzylic radicals are trapped by acinitronate ions or the anions from β- keto esters, is demonstrated to be effectively irreversible under the normal conditions of the SRN1 reaction. The dissociation [i.e. fragmentation of the C(α)-C(β) bond] of C- alkylates [e.g. (2) or (3)] formed from aci - nitronates and p- nitrobenzylic substrates appears to take place in a process involving transfer of two electrons and not through dissociation of radical anions.

Pulmonary function in adolescents with mild idiopathic scoliosis

Spirometric indices, lung volumes, maximum voluntary ventilation, and maximum inspiratory and expiratory pressures were measured in 44 adolescents with mild idiopathic scoliosis (spinal curvature less than 30 degrees). All were symptom free, but six (13.6%) showed a restrictive defect with forced vital capacity less than 80% of predicted. In 12 subjects (27.3%) maximum voluntary ventilation was reduced to less than 80% of predicted normal. Forced vital capacity was significantly correlated with maximum inspiratory pressure and with maximum expiratory pressure, measures of respiratory muscle strength, but was not related to the degree of thoracic curvature. When maximum inspiratory pressure and forced vital capacity were corrected for differences in body size these variables remained positively correlated, most significantly in the girls. These data indicate that ventilatory function may be impaired in mild, idiopathic scoliosis and that the force developed by the respiratory muscles is a more important determinant of this impairment than the radiologically determined degree of spinal curvature.

Evaluation of a Membrane Filter Test Kit for Monitoring Bacterial Counts in Cannery Cooling Waters

Performance of the Millipore SPC Sampler was compared with the Standard Plate count method for routine checks of bacterial counts in cannery cooling waters. Methods were tested with cooling waters from a hydrostatic retort. Recovery of viable bacteria was very low when the Millipore samples were incubated for 24 h, but incubation for 48 or 72 h consistently yielded higher counts with the Millipore than with the standard method. Duplication of counts between analysts was approximately equal with both methods. Replication of bacterial counts within samples was more erratic and skips were more frequent with the Millipore than with the standard method. Procedures to control replications and skips are discussed. The Millipore procedure is a convenient alternative to the Standard Plate Count for routine quality audit of cannery cooling waters.

The anomalous reaction of p-Methoxy-β,β-dimethylstyrene with mercury(II) acetate in methanol

The methoxymercurations of β, β-dimethylstyrene (7) and its p-nitro (12) and p-methoxy (13) derivatives with mercury(II) acetate in methanol are regiospecific and give methoxymercuration products in which the methoxy group is on the β-carbon. Demercuration of the adducts from (12) and (13) with alkaline borohydride proceeds normally, but the demercuration of the adduct from (7) gives considerable formation of the diastereoisomeric dimeric products (9a,b). The methoxymercuration product from (13) is surprisingly reactive and gives mercury or mercury(1) acetate and the vicinal diether 1,2-dimethoxy-1-(p-methoxyphenyl)-2-methylpropane (17).

Pathological plicae of the knee mistaken for arthritis

Synovial plicae are persistent embryological folds present in normal knee joints. Plicae may become pathological and give rise to symptoms. Two brothers with pathological medial plicae are described in whom the condition was mistaken for arthritis. The role of arthroscopy in diagnosis and treatment is discussed.

Gonococcal arthritis in pregnancy

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8. Self-compressing implants in the management of fractures

Internal fixation of fractures has become increasingly important since the introduction of self-compressing implants. Rigidity of fixation thus ensured permits primary bone healing. Two types of self-compressing implants are available--screws and plates. The former produces compression between fracture fragments, the latter, along the long axis of the bone. Two common types of plates are the dynamic compression plate and the Osteo self-compressing plate. Use of self-compressing implants requires familiarity with the technique, a definite plan of operation, and strict asepsis and lack of infection in the patient. Indications for the technique include failure or unsuitability of closed reduction of fractures, care of associated serious soft-tissue injuries, and displaced intra-articular fractures. Use of self-compressing plates hastens rehabilitation, lessens joint stiffness and reduces the duration of hospitalization. The incidence of nonunion with self-compression techniques is lower than with traditional methods of fracture management.

Accessory spinal nerve injury

In 7 cases of peripheral lesion of the spinal accessory nerve 4 were produced by malignancy, two by iatrogenical resection of lymph nodes, one by an en bloc dissection of the neck for arteriovenous malformation. Incapacity following the injury is quite marked and includes weakness of the sternomastoid and trapezius muscles, as well as pain presumably from traction on the brachial plexus. The importance of avoiding the nerve in surgical intervention in the neck must be strongly emphasized. A review of the literature suggests that in fresh injuries the spinal accessory nerve should be explored and resutured. Our own experience, however, with nerve repair has been disappointing.