Metal-Free Enantioselective 1,4-Addition of Diarylphosphine Oxides to α,β-Unsaturated Carboxylic Esters

The catalytic asymmetric conjugate addition of phosphorus nucleophiles to unsaturated compounds, catalyzed by metallic or nonmetallic catalysts, has been extensively developed. However, the enantioselective transformations involving α,β-unsaturated carboxylic esters for constructing chiral c-p bonds have been rarely reported, particularly in metal-free processes. In this study, we present a novel metal-free methodology for enantioselective 1,4-addition of diarylphosphine oxides to α,β-unsaturated carboxylic esters using classical chiral oxazaborolidine catalysts. Remarkably high yields and enantioselectivities were obtained for most of the products. Furthermore, these valuable chiral phosphorus esters serve as crucial intermediates that can be transformed into various derivatives including amides, acids, and alcohols in a single step.

The mediating effects of coping styles on the relationship between trait mindfulness and romantic relationship satisfaction

The purpose of the current study was to explore the influence of coping styles and trait mindfulness on the satisfaction of romantic relationships (RRS) among college students. Of the 305 participants, 258 (males: 115, 44.6%) had previously been in, or were presently in a romantic relationship. All participants completed the MAAS, CSQ, and questions about RRS. There was a significant meditating role of mature coping styles in the relationship between trait mindfulness and RRS (indirect effect [95% CI] = 0.021 [0.001, 0.052]). However, the mediating effect of immature coping styles was not significant (indirect effect [95% CI] = 0.038 [-0.020, 0.097]). Mature coping style plays an important mediating role in the relationship between mindfulness and relationship satisfaction.

Semen parameters and sex hormones as affected by SARS-CoV-2 infection: A systematic review

Background

Impaired semen quality and reproductive hormone levels were observed in patients during and after recovery from coronavirus disease 2019 (COVID-19), which raised concerns about negative effects on male fertility. Therefore, this study systematically reviews available data on semen parameters and sex hormones in patients with COVID-19.

Methods

Systematic search was performed on PubMed and Google Scholar until July 18th, 2022. We identified relevant articles that discussed the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on male fertility.

Results

A total number of 1,684 articles were identified by using a suitable keyword search strategy. After screening, 26 articles were considered eligible for inclusion in this study. These articles included a total of 1,960 controls and 2,106 patients. When all studies were considered, the results showed that the semen parameters and sex hormone levels of patients infected with SARS-CoV-2 exhibited some significant differences compared with controls. Fortunately, these differences gradually disappear as patients recover from COVID-19.

Conclusion

While present data show the negative effects of SARS-CoV-2 infection on male fertility, this does not appear to be long-term. Semen quality and hormone levels will gradually increase to normal as patients recover.

Scalable dextran-polypyrrole nano-assemblies with photothermal/photoacoustic dual capabilities and enhanced biocompatibility

Polypyrroles have shown great potential in photoacoustic imaging and photothermal therapy owing to its excellent photothermal conversion capabilities. However, the synthesis of polypyrrole-based nano-assemblies which have colloidal stability in biological buffers requires a number of steps, including the polymerization of pyrrole monomers, self-assembly of polypyrrole-based copolymers, and even an additional step to increase the biocompatibility of the nano-assemblies. Herein, a "polymerization/assembly" two-in-one synthesis is proposed for the first time to achieve the one-step synthesis of a new family of polypyrrole-based nano-assemblies, dextran-polypyrrole nano-assemblies (Dex-PPy NAs), under ambient conditions and in aqueous media. In addition, the approach employs tetravalent cerium ions as initiators which can initiate the polymerization of pyrrole monomers through the initiation of free radicals from dextran molecular chains. The resultant Dex-PPy NAs have a photothermal conversion efficiency reaching as high as 41 % and an excellent photostability. More importantly, the NAs with controllable nanoscale dimensions display no signs of cytotoxicity in both in vitro and in vivo studies owing to their biocompatible dextran "shell". An in vivo study further confirmed that the Dex-PPy NAs have excellent real-time photoacoustic imaging and photothermal therapy capabilities for malignant tumors. Therefore, this study represents an important step towards the scalable synthesis of polypyrrole-based nano-assemblies with photothermal/photoacoustic dual capabilities and enhanced biocompatibility.

Copper-catalyzed ipso-selenation of aromatic carboxylic acids

Study of the synthesis of diaryl and methyl aryl selenides in good to excellent yields, including mechanistic studies and demonstration of the utility of the products in the facile synthesis of 10H-phenoselenazine and 11-methyldibenzo-(b,f)-1,4-selenazepine.

Serious Antimicrobial Resistance Status of Pathogens Causing Hospital-acquired Lower Respiratory Tract Infections in North China

Antimicrobial resistance patterns of pathogens causing hospital-acquired lower respiratory tract infections (LRTIs) in Shandong Province, China were investigated using data collected from January 2002 to December 2006. A total of 10337 isolates were characterized in sputum samples from 39 920 LRTI patients: 68.72% were Gram-negative bacteria, 20.65% were Gram-positive bacteria, and 10.62% were fungi. Organisms most frequently isolated were: Pseudomonas aeruginosa (16.88%), Klebsiella pneumoniae (10.80%), Escherichia coli (10.71%), fungi (10.62%), Staphylococcus aureus (9.68%) and Acinetobacter baumannii (9.03%). Imipenem was the most effective antibiotic against Gram-negative bacteria. Most Gram-positive bacteria were susceptible to vancomycin. Susceptibility to cephalosporins was not optimal and resistance to fluoroquinolones was high. Resistance of Gram-negative bacteria showed a rapid increase over the study period, while resistance of Gram-positive bacteria remained relatively stable. The emergence of resistance to commonly prescribed antimicrobial agents used against LRTI pathogens has compounded the problem of using empirical therapy and created selective pressure on physicians to use certain antibiotics.

[Influence of pavulon on facial nerve monitoring during middle ear-mastoid operation]

OBJECTIVE

To evaluate the influence of pavulon (muscle relaxant) on facial nerve monitoring for patient with middle ear-mastoid operation during general anesthesia.

METHOD

Intraoperative monitoring of the facial nerve (FNM) was done in 45 ears (44 case). For patient with middle ear-mastoid disease, 38 ears underwent inhaled-intravenous anesthesia with muscle relaxant pavulon (group of general anesthesia), 7 ears underwent local anesthesia (group of local anesthesia). Accelography (ACCG) was used in 10 case for testing the correlation between of FNM and the various degree of recovery from ulnar nerve-musculor blockade.

RESULT

FNM could be elicited during different periods of recovery with values of T4/T1 varying from 10%-98%. Pavulon could be used to eliminate muscular vibration from disturbing FNM. Electromyography (EMG) potentials were successfully recorded in 34 ears (89.4%). Anesthesia was uneventful and it may be controled satisfactority.

CONCLUSION

Considering the advantage of pavulon. It can be used for general anesthesia during intraoperative monitoring of the facial nerve for children or adults suffering from local complicated diseases.

[Malignant external otitis: 4 cases report]

OBJECTIVE

To improve the level of diagnosis and treatment of malignant external otitis (MEO).

METHOD

Four cases with MEO were reported.

RESULT

Three in four cases were followed up. One patient was cured, and the others died of intracranial infection.

CONCLUSION

Early diagnosis of MEO is very important for treatment. The patients of MEO with diabetes often died of intracranial infection.

[Facial nerve protection during surgery for congenital malformation of the external and middle ear (review of 519 cases)]

The prevention of facial nerve injury in otoplasty for ear malformation is important. This paper analysed 519 cases of ear malformation collected during 10 years from 1985 to 1995. The hearing of 428 cases was improved, of which the hearing of 221 cases did recover to available level. A long-term follow-up of 198 cases showed that 152 cases had kept the same hearing level as that immediately after surgery. In 130 cases with single middle ear malformation the malformation rate of facial nerve was 60.8%(79/130), and that for chorda tympani 5.4% (7/130). In 75 cases of middle ear malformation with stricture of external acoustic meatus the malformation rate of facial nerve was 60.0% (45/75), and that for chorda tympani 13.3%(10/75). In 314 cases of middle ear malformation with atresia of external acoustic meatus the malformation rate of facial nerve was 42.5%(142/314), and that for chorda tympani nerve 100.0%(314/314). Two cases(0.4%) were of surgical facial nerve paralysis. For protection of facial nerve, it was important to master the anatomy of temporal bone and have a high-resolution computed tomographic scanning to identify facial nerve. It was also important to use electroneurographic monitoring when necessary.

[Simultaneous total ear reconstruction and hearing rehabilitation]

One hundred and fifty-eight patients with congenital microtia and atresia were treated with simultaneous total ear reconstruction and hearing rehabilitation including meatoplasty, tympanoplasty as well as fenestration. Using this operation, the authors have reconstructed 160 auricles and simultaneously restored their auditory function. After the operation, the hearing gain reached 20-45 dB in 132 cases (82.5%). The success rate of the reconstructed ear was 158/160 (98.2%). Most of the reconstructed ears were of excellent appearance.

[Study of relationship between the bacteria in air and the clinic infection]

The Source of infectious bacteria is the first problem in provension of infection considered by the medical workers. In this paper, with the method of bacteria plasmid analysis, chromosome DNA restriction fragment length polymorphism analysis, drug resistance experiment (antibacterial drug, sterilizing drug) and so on. We confirmed that staphylococci of nosocomi is mainly from air; but the gram-negative bacteria is mainly from the patient's pharyngeal portion; and cause hospital infection indirectly. The drug resistance of gram-negative from air was lower than the same gram-negative bacilli's isolated from the patient. Moreover, kill bacteria the infectious strain is same strain in air. Above-mentioed results provided the important basis for control of the hoslpital infection.

[The confounding factor and interaction in studies of pathogenesis--an analysis of the secondary infection of viral hepatitis with corticoid therapy]

A total of 762 cases of viral hepatitis admitted to the two teaching hospitals of the Third Military Medical College were used for study. They were divided into two groups depending upon whether corticoid treatment was given. As the result of cRR = 6.06, chi 2 = 174.16, P < 0.01, it is obvious that the corticoid therapy is a risk factor for the secondary infection in patients suffered from viral hepatitis. For getting rid of the interference of confounding factor and interaction a stratified analysis was performed. These patients were again divided into severe type and moderate type according to the severity of the disease. The results of stratified analysis were aRR (F) = 3.05 and aRR (F) = 1.48, cRR > aRR. These findings demonstrated that the degree of severity of patients played a primary role in the secondary infection of hepatitis and showed that the confounding factor was present. On the other hand, the result of aRR (F) not equal to aRR (F) indicated that the interaction also existed simultaneously. This study suggests that special attention should be paid to maintain and increase the level of immunological defence function in patients with hepatitis. And, it is necessary to restrict the indiscriminate usage of corticoids, particularly in severe patients, for preventing nosocomial infection.

A three-year streptococcal survey among Singapore school children: Part II. Streptococcal infections

The cumulative streptococcal pyoderma and pharyngitis rates of 491 children followed over a period of three years were 19.8 and 15.7% respectively. Streptococcal infections occurred more commonly in Malays, in children from families with monthly household incomes of less than $500/- and in those living in attap/zinc-roofed houses. During the three years, streptococcal pyoderma and pharyngitis rates varied from 1.6-5.3 and 0.4-4.3% respectively. Skin sores occurred most frequently on lower limbs. About one in six acquisitions of streptococci in throats was accompanied by clinical manifestations of respiratory infections. 90.9% of pyoderma cases responded to penicillin therapy. Penicillin was effective in eradicating group A streptococci from the throats of 84.6% of 136 children with previous positive cultures. The treatment schedule implemented for School C did not seem to reduce the streptococcal infection and carrier rates in that school to a great extent.