State-of-the-Art Review on Amorphous Carbon Nanotubes: Synthesis, Structure, and Application

Carbon nanotubes (CNTs) have rapidly received increasing attention and great interest as potential materials for energy storage and catalyst fields, which is due to their unique physicochemical and electrical properties. With continuous improvements in fabrication routes, CNTs have been modified with various types of materials, opening up new perspectives for research and state-of-the-art technologies. Amorphous CNTs (aCNTs) are carbon nanostructures that are distinctively different from their well-ordered counterparts, such as single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs, respectively), while the atoms in aCNTs are grouped in a disordered, crystalline/non-crystalline manner. Owing to their unique structure and properties, aCNTs are attractive for energy storage, catalysis, and aerospace applications. In this review, we provide an overview of the synthetic routes of aCNTs, which include chemical vapor deposition, catalytic pyrolysis, and arc discharge. Detailed morphologies of aCNTs and the systematic elucidation of tunable properties are also summarized. Finally, we discuss the future perspectives as well as associated challenges of aCNTs. With this review, we aim to encourage further research for the widespread use of aCNTs in industry.

Flexible Curcumin-Loaded Zn-MOF Hydrogel for Long-Term Drug Release and Antibacterial Activities

Management of chronic inflammation and wounds has always been a key issue in the pharmaceutical and healthcare sectors. Curcumin (CCM) is an active ingredient extracted from turmeric rhizomes with antioxidant, anti-inflammatory, and antibacterial activities, thus showing significant effectiveness toward wound healing. However, its shortcomings, such as poor water solubility, poor chemical stability, and fast metabolic rate, limit its bioavailability and long-term use. In this context, hydrogels appear to be a versatile matrix for carrying and stabilizing drugs due to their biomimetic structure, soft porous microarchitecture, and favorable biomechanical properties. The drug loading/releasing efficiencies can also be controlled via using highly crystalline and porous metal-organic frameworks (MOFs). Herein, a flexible hydrogel composed of a sodium alginate (SA) matrix and CCM-loaded MOFs was constructed for long-term drug release and antibacterial activity. The morphology and physicochemical properties of composite hydrogels were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), Raman spectroscopy, and mechanical property tests. The results showed that the composite hydrogel was highly twistable and bendable to comply with human skin mechanically. The as-prepared hydrogel could capture efficient CCM for slow drug release and effectively kill bacteria. Therefore, such composite hydrogel is expected to provide a new management system for chronic wound dressings.

562 Midline Versus Off Midline Extraction Site in Laparoscopic Left Sided Colorectal Resections for Colorectal Malignancy: A Systematic Review and Meta-Analysis

Method

To evaluate comparative outcomes of off-midline and midline extraction sites in laparoscopic left sided colorectal resections.

Method

A systematic search of electronic databases and bibliographic reference lists was conducted, and a combination of free text and controlled vocabulary search was adapted to thesaurus headings, search operators and limits in electronic databases were applied. Studies comparing the outcomes of Off Midline and Midline incisions for specimen extraction in laparoscopic left sided colorectal resections were included. Incisional hernias, surgical site infections, operative time, estimated blood loss, anastomotic leak and length of hospital stay were the evaluated outcome parameters.

Results

We identified 5 comparative studies reporting a total of 1187 patients comparing outcomes of off-midline (n=486) and midline (n=701) incisions for specimen extraction in laparoscopic left colorectal resections. The off-midline approach was associated with lower post operative surgical site infection (OR 0.71, P=0.68), anastomotic leak (OR 0.76,P=0.66), and incisional hernia (MD: 0.65,P=0.64) compared to midline approach, however it was not statistically significant. There was no significant difference in operative time (MD: 0.10, P=0.99), intra-operative blood loss (MD 2.31, P=0.91), and post-operative hospital stay (MD : 0.78, P=0.18) between the two groups.

Conclusions

Off-midline extraction site for left sided colorectal resections have no significant difference in rates of post operative surgical site infection and incisional hernias when compared to midline extraction site. No significant difference was found in operative time, intra-operative blood loss, anastomotic leak and post operative hospital stay in this study. Future higher-level research is required to further evaluate the clinical outcomes.

Outcome of Mineral Trioxide Aggregate Pulpotomy for Mature Permanent Molars with Symptoms Indicative of Irreversible Pulpitis

Root canal treatment (RCT) is preferred treatment for mature teeth with irreversible pulpitis. But sometimes it is very difficult to perform due to complex pulpal anatomy and the vitality of tooth is completely lost by this procedure. A new hope has been emerged to consider pulpotomy treatment as an effective treatment in mature permanent teeth with irreversible pulpitis as with the new understanding of pulp biology and recent innovation of bioactive material like MTA. The aim of the study was to evaluate the outcome of MTA pulpotomy for mature third molars with symptoms indicative of irreversible pulpitis. This quasi-experimental study was conducted at Department of Conservative Dentistry and Endodontics, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from September 2019 to August 2020. Twenty permanent mandibular third molar teeth with fully developed roots and diagnosed as irreversible pulpitis in 20 patients aged 25-50 years were selected for this study. After informed consent, each tooth was anaesthetized, isolated with dental dam and disinfected with 5% NaOCl before caries excavation; caries was removed, and then, a full pulpotomy was performed. Haemostasis was achieved and MTA (Angelus, Brazil) was placed as the pulpotomy agent over the pulp chamber floor covering the canal orifices and rest of the cavity was sealed with glass-ionomer filling over the set MTA. Clinical and radiographic evaluation was completed at 3 months, 6 months, and 1 year postoperatively. Descriptive statistics were used to assess outcomes. The recall rate ranged from 90% at 3 months to 85% at 1 year, with an overall 100% clinical and radiographic success during the 3 month and 6 month, and 95% success at the end of 1 year. MTA pulpotomy sustained a good success rate over the 1 year follow-up in mature third molar teeth clinically diagnosed with irreversible pulpitis.

g-C3N4: Properties, Pore Modifications, and Photocatalytic Applications

Graphitic carbon nitride (g-C3N4), as a polymeric semiconductor, is promising for ecological and economical photocatalytic applications because of its suitable electronic structures, together with the low cost, facile preparation, and metal-free feature. By modifying porous g-C3N4, its photoelectric behaviors could be facilitated with transport channels for photogenerated carriers, reactive substances, and abundant active sites for redox reactions, thus further improving photocatalytic performance. There are three types of methods to modify the pore structure of g-C3N4: hard-template method, soft-template method, and template-free method. Among them, the hard-template method may produce uniform and tunable pores, but requires toxic and environmentally hazardous chemicals to remove the template. In comparison, the soft templates could be removed at high temperatures during the preparation process without any additional steps. However, the soft-template method cannot strictly control the size and morphology of the pores, so prepared samples are not as orderly as the hard-template method. The template-free method does not involve any template, and the pore structure can be formed by designing precursors and exfoliation from bulk g-C3N4 (BCN). Without template support, there was no significant improvement in specific surface area (SSA). In this review, we first demonstrate the impact of pore structure on photoelectric performance. We then discuss pore modification methods, emphasizing comparison of their advantages and disadvantages. Each method's changing trend and development direction is also summarized in combination with the commonly used functional modification methods. Furthermore, we introduce the application prospects of porous g-C3N4 in the subsequent studies. Overall, porous g-C3N4 as an excellent photocatalyst has a huge development space in photocatalysis in the future.

Genotyping and antibiotic resistance patterns of Campylobacter fetus subsp.venerealis from cattle farms in India

Bovine genital campylobacteriosis caused by Campylobacter fetus subsp. venerealis (Cfv) is of considerable economic importance to the cattle industry worldwide. Cfv causes syndrome of temporary infertility in female cattle, early embryonic mortality, aberrant oestrus cycles, delayed conception, abortions and poor calving rates. In the present study, a total of 200 samples obtained from vaginal swabs, cervicovaginal mucous (CVM), preputial washes and semen straws were investigated that were obtained from organized cattle farm of MLRI, Manasbal and unorganized sectors. Out of a total of 200 samples, 49 (47·57%) vaginal swabs, 1 (3·33%) preputial wash and 8 (25%) carried out CVM samples were positive for Cfv, whereas none of the semen straws were positive for Cfv. A total of eleven isolates of Cfv were recovered. PFGE (Pulse field gel electrophoresis) analysis revealed four different pulsotypes (I-IV) circulating in the screened farms. A common pulsotype circulating among farms could not be established. Insertion element (ISCfe1), a 233 bp amplicon of Cfv, was sequenced and the sequence was deposited in GenBank (accession no: MK475662).

Picosecond 554 nm yellow-green fiber laser source with average power over 1 W

We demonstrate a source of 554 nm pulses with 2.7 ps pulse duration and 1.41 W average power, at a repetition rate of 300 MHz. The yellow-green pulse train is generated from the second harmonic of a 1.11 μm fiber laser source in periodically-poled stoichiometric LiTaO3. A total fundamental power of 2.52 W was used, giving a conversion efficiency of 56%.

An unbalanced half-cryptic translocation involving the 6q subtelomeric region and 2p25.3 in a child with mental retardation: uses and limitations of fluorescence in situ hybridization

We report on a 5-year-old boy with minor anomalies, growth retardation, and developmental delay carrying an extra chromatin material on the terminal band of the long arm of chromosome 6. To determine the origin of this extra material, whole chromosome fluorescence in situ hybridization (FISH) was used initially. Results showed fully painted 6qs, excluding the possibility of a derivative. However, maternal cytogenetic investigation suggested the presence of a possible half-cryptic balanced translocation that was further assessed using specific subtelomeric FISH probes of chromosome 6. Results showed that the 6q subtelomeric region was translocated on an A-group chromosome that was ultimately characterized, using FISH, as chromosome 2. This illustrates the use of specific subtelomeric regions and the limitations of whole chromosome FISH to identify the origin of a subtle chromosomal abnormality.

Stability of neurological soft signs in chronically hospitalized schizophrenic patients

Neurological soft signs (NSS) have been shown to be more prevalent in chronically ill and in acute or never-mediated patients with schizophrenia. If neurological soft signs are trait-like, then NSS scores should be relatively stable over time and should not be related to changes in patients' psychopathology or medication. Chronically hospitalized patients with schizophrenia were rated two or more times over a 5-year period with standard NSS and psychopathology scales. Total NSS scores were highly correlated over time, and changes in NSS scores at two time points were not significantly related to changes in psychopathology scores. Total NSS scores did not change significantly in a subsample rated when they were first treated with a traditional neuroleptic and later with an atypical neuroleptic. The findings suggest total NSS scores may have some characteristics of a trait-like feature in chronically hospitalized patients with schizophrenia.

Campylobacter jejuni enterocolitis in neonates

Campylobacter jejuni is one of the leading bacterial pathogens causing acute gastroenteritis in children. Only a few cases have been described in the world literature about neonatal enterocolitis due to campylobacter and none from Saudi Arabia. We describe six cases of neonatal enterocolitis due to this organism isolated during the period from September 1989 - January 1991 at Suleimania Children's Hospital, Riyadh, Saudi Arabia. All of the patients presented with diarrhea; duration ranging from 1-20 days. Three patients had blood and two had mucus in their stool. In contrast to the findings of other investigators, five neonates presented with fever. One neonate was treated with erythromycin, another received augmentin, and two received other antibiotics because of suspected sepsis. In one patient, previous antibiotics were discontinued and erythromycin was added and two received no antibiotics. Campylobacter infection should be suspected in any neonate presenting with diarrhea accompanied by mucus and blood in the stool.

Management of severe tracheal stenosis caused by repeated endotracheal intubation in a patient of myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction. The disease is characterized by exacerbation and remission of the symptoms from time to time. Myasthenic crisis is a serious complication of MG and is defined as weakness from acquired MG that is severe enough to require intubations [1]. Myasthenic crisis may complicate in 15-20% of patient with MG [2], [3]. Most patients require ventilation for a brief period, usually less than two weeks [4]. Repeated intubations may cause tracheal stenosis. The potential risk factors for post-intubation subglottic stenosis include, the underlying disease requiring endotracheal intubations(EI), the age and body weight, the duration and number of EIs, absence of sedation and the occurance of infections, hypotensive or hypoxic events during the period of EI and traumatic EI [5], [6].Key words: Tracheal stenosis, Repeated intubations, Myasthenia gravis.DOI: 10.3329/pulse.v3i1.6550Pulse Vol.3(1) July 2009 p25-26