The influence of laser frequency and groove distance on cell adhesion,cell viability,and antibacterial characteristics of Ti-6Al-4V dental implants treated by modern fiber engraving laser

ObjectiveMicro-nano scale surface modification of Ti-6Al-4V was investigated through the fascinated modern fiber engraving laser method. The process was performed at a high laser speed of 2000 mm/s, under different laser frequencies (20–160 kHz) and groove distances (0.5–50 μm).MethodsTopographic evaluations such as Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FE-SEM) were used to identify the quality and regularity of patterns. The proliferation of human osteoblast-like osteosarcoma cells (MG63) was analyzed by MTT assay for up to 72 h. Also, the plate counting method was used to quantify the viability potential of the modified surface against Escherichia coli bacteria.ResultsThe cellular viability of the sample modified at the laser frequency of 20 kHz and grooving distance of 50 μm increased up to 35 and 10% compared to the non-treated and control samples, respectively. In the case of the surface modification at lower grooving distances range between 0.5–50 μm, the maximum laser frequency (160 kHz) applied leads to lower pulse’s energies and less bacterial adhesion. Otherwise, at groove distances more than 50 μm, the minimum laser frequency (20 kHz) applied reduces the laser pulse overlaps, increases the cell adhesion and antibacterial properties.SignificanceSurface modification by the fiber engraving laser process significantly enhances the cell adhesion on the surface. As a result of such roughness and cell adhesion enhancement, the surface toxicity feature diminished, and its antibacterial properties improved.     

Nonlinear photoresponse of NaYF4:Yb,Er@NaYF4 nanocrystals under green CW excitation: a comprehensive study

One of the efficient and well-known upconverting nanomaterials is NaYF₄:Yb,Er@NaYF₄, which emits photoluminescence at 545 nm and 660 nm under an excitation of 980 nm. Here, the nonlinearity of β-NaYF₄:Yb,Er@NaYF₄ at 532 nm is investigated using three nonlinear approaches. For the first time, the nonlinear optical conjugation of NaYF₄:Yb,Er@NaYF₄ nanocrystals is observed using the degenerate four-wave mixing method. In the optical bistability study, the optical hysteresis of NaYF₄:Yb,Er@NaYF₄ is measured using the Mach–Zehnder interferometer nonlinear ring cavity, and the results of bistability loops show different behaviors at different power regimes. Finally, the Z-scan technique is used for determining the nonlinear absorption and refraction coefficients, which are calculated in the order of 10⁻⁴ (cm W⁻¹) and 10⁻⁸ (cm² W⁻¹), respectively. The results indicate that by increasing incident powers, optical behaviour changes in both optical bistability and Z-scan. Therefore, the results exhibit that the β-NaYF₄:Yb,Er@NaYF₄ nanocrystals have nonlinear photoresponses at both 980 and 532 nm, which could be promising for photonic devices based on NIR light and visible light.

NaYF₄:Yb,Er@NaYF₄ is an efficient and well-known upconverting nanomaterials at 980 nm, also it has strong optical nonlinearity at 532 nm related to energy states of the Yb/Er system which is determined by a unique approach.     

Adsorption performance of M-doped (M = Ti and Cr) gallium nitride nanosheets towards SO2 and NO2: a DFT-D calculation

The structure, adsorption characteristics, electronic properties, and charge transfer of SO₂ and NO₂ molecules on metal-doped gallium nitride nanosheets (M-GaNNSs; M = Ti and Cr) were scrutinized at the Grimme-corrected PBE/double numerical plus polarization (DNP) level of theory. Two types, M_Ga-GaNNSs and M_N-GaNNSs, of doped nanostructures were found. The M_Ga sites are more stable than the M_N sites. The results showed that adsorption of SO₂ and NO₂ molecules on Ti_Ga,N-GaNNSs is energetically more favorable than the corresponding Cr_Ga,N-GaNNSs. The stability order of complexes is energetically predicted to be as NO₂–Ti_Ga-GaNNS > NO₂–Ti_N-GaNNS > SO₂–Ti_Ga-GaNNS > NO₂–Cr_N-GaNNS > SO₂–Ti_N-GaNNS > NO₂–Cr_Ga-GaNNS > SO₂–Cr_N-GaNNS > SO₂–Cr_Ga-GaNNS. The electron population analysis shows that charge is transferred from M_Ga,N-GaNNSs to the adsorbed gases. The Ti_Ga-GaNNS is more sensitive than the other doped nanostructures to NO₂ and SO₂ gases. It is estimated that the sensitivity of Ti_Ga-GaNNS to NO₂ gas is more than to SO₂ gas.

The influences of transition metals (Cr and Ti) doping on the adsorption behavior of SO₂ and NO₂ gases on the metal doped Gallium Nitride Nanosheet (GaNNS) were explored at Grimme-corrected PBE/double numerical plus polarization (DNP) level of theory.     

Chitosan-encapsulated manganese ferrite particles bearing sulfonic acid group catalyzed efficient synthesis of spiro indenoquinoxalines

A simple, highly versatile and efficient synthesis of 5-phenyl-spiro[diindenopyridine-indenoquinoxaline]-diones is achieved through a four-component one pot reaction of ninhydrin, 1,2-diaminobenzene, 1,3-indandione and aniline. This reaction was catalyzed by MnFe₂O₄@CS-Bu-SO₃H MNPs as a very efficient, recyclable heterogeneous catalyst in acetonitrile under reflux conditions. The catalyst can be recovered from the subsequent reaction mixture and reused for at least five cycles without any appreciable loss in its efficiency. The core–shell structure and composition of the produced magnetic nanocatalyst were analyzed using FT-IR, XRD, VSM, SEM, EDX and TGA techniques.

A simply, highly versatile and efficient synthesis of 5-phenyl-spiro [diindeno pyridineindenoquinoxaline]-diones is achieved through five component one pot reaction of ninhydrin, 1,2-diaminobenzene, 1,3-indandione and anilines.     

Long-term bowel disorders following radial cystectomy: an underestimated issue?

Purpose

Patients after radical cystectomy (RC) frequently complain about bowel disorders (BDs). Reports addressing related long-term complications are sparse. This cross-sectional study assessed changes in bowel habits (BH) after RC.

Methods

A total of 89 patients with a minimum follow-up ≥1 year after surgery were evaluated with a questionnaire. Patients with BD prior to surgery were excluded. Symptoms such as diarrhea, constipation, bloating/flatulence, incomplete defecation, uncontrolled stool loss, and impact on quality of life (QoL) were assessed.

Results

A total of 46.1 % of patients reported changes in BH; however, only 25.8 % reported experiencing related dissatisfaction. Primary causes of dissatisfaction were diarrhea and uncontrolled stool loss. The most common complaints were bloating/flatulence and the feeling of incomplete defecation, but these symptoms did not necessarily lead to dissatisfaction or impairment in quality of life. No difference was identified between an orthotopic neobladder and ileal conduit, and even patients without bowel surgery were affected. QoL, health status, and energy level were significantly decreased in unsatisfied patients.

Conclusions

About 25 % of patients complain about BDs after RC. More prospective studies assessing symptoms, comorbidities, and dietary habits are necessary to address this issue and to identify strategies for follow-up recommendations.

     

Clinical outcome and bowel function after surgical treatment in Hirschsprung's disease

Background:

Bowel function has been reported to be adversely affected following surgery in cases of Hirschsprung. We retrospectively studied both the clinical outcome and bowel function status following surgery in patients diagnosed with Hirschprung''s disease (HD). 161 cases, who underwent pull-through operations for HD in Sheikh Pediatric Tertiary Centre, Mashhad, Iran. The specified time bracket spanned between 2006 and 2011.

Materials and Methods:

Data was extracted from Health Information System with the aim of investigating patients for both short and long-term gastrointestinal (GI) complications after surgery bases in addition to the concurrence of any associated anomalies. Three main procedures were analysed in this respect (Swenson, Duhamel and Soave).

Results:

In a study of 96 (59%) boys and 65 (40.3%) girls, mortality rate was reported to be 15.5% (15 males and 10 females). A considerable majority of almost three fourths were detected with both early and late GI complications after surgery. The latter mainly included constipation (30.8%), incontinence (19.8%), enterocolitis (8%), diarrhea (11%) in a declining order of incidence. Down syndrome and others HD-associated anomalies were detected in 3.7% and 24.3% of cases respectively.

Conclusions:

Constipation and foecal incontinence were the most prevalent postoperative complications, which were reported almost as frequent in other studies. Yet, Enterocolitis, was reported slightly less in prevalence. Also mortality rates were considerably higher, compared to developed nations.Key words: Bowel function, constipation, foecal incontinence, Hirschsprung''s disease