Mental nerve shielding from possible injury during mandibular surgical procedures: technical note.

Injuries to the mental nerve are not an uncommon complication in maxillofacial surgeries. Manipulation close to the mental nerve poses a great risk of nerve injury from drills, bone cutting and trimming burs, and oscillating/reciprocating saws. Nerve injuries can be painful and affect the patient's quality of life. The accompanying complication of the nerve injury depends on the severity of the damage inflicted and can range from transient hypoesthesia to neuropathic pain or trigeminal neuralgia. It is considered that direct injury to the nerve may lead to permanent damage and more severe postoperative clinical symptoms than indirect injuries caused by nerve stretching or during endosteal implant fixation. This technical note describes a technique for shielding the mental nerve and protecting it from rotary drill injury during mandibular inferior border recontouring, orthognathic surgeries, and mandibular body fracture fixation.

The way to a man's heart is through his stomach? A unique case report of transient constrictive pericarditis secondary to infarction of herniated omentum following bariatric surgery.

Background: Intrapericardial diaphragmatic hernias are a rare form of diaphragmatic hernia. The presentation is usually acute due to trauma or from iatrogenic causes. In some instances however, these patients can present years later. We describe an unusual case of transient constrictive pericarditis associated with herniation of omentum through a diaphgragmatic hernia extending into the pericardial space, which infarcted following recent bariatric surgery. A multi-disciplinary approach was required with surgical correction of the diaphragmatic defect and removal of omentum from the pericardial space. Case summary: A 38-year-old gentleman with a history of a remote abdominal stab wound and recent laparoscopic gastric sleeve procedure presented with sharp central chest pain radiating to the shoulder. Chest imaging [echocardiography, computed tomography (CT), and cardiac magnetic resonance imaging (MRI)] revealed the presence of an intrapericardial diaphragmatic hernia and herniation of devascularized omentum into the pericardial space. Surgery was undertaken to remove the pericardial omentum. Echocardiography and cardiac MRI revealed changes of pericardial constriction which resolved with anti-inflammatories. Discussion: A multi-disciplinary approach was required in this case with surgical correction of the diaphragmatic defect and removal of omentum from the pericardial space. Multi-modal imaging proved essential in the diagnosis of this rare condition, aiding in timely diagnosis, ongoing management decisions, and for assessing therapeutic response.

Considerations for Pregnant Dental and Health Care Workers amid COVID-19.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is a highly contagious disease that quickly reached pandemic levels. Over 5 million COVID-19 cases and approximately 330,000 deaths have been recorded worldwide. Transmission is primarily spread through direct, indirect (through contaminated objects or surfaces), or close contact with infected people via respiratory droplets, the mouth, and/or nose secretions. Health care professionals (HCPs), including dental HCPs, are recognized to be at considerably high risk for infection due to the close proximity to patients and aerosol-generating procedures. During pregnancy, HCPs may be at even higher risk since pregnancy substantially increases the susceptibility to infectious diseases. OBJECTIVES: Here, we present the posed risks and potential effects of COVID-19 on maternal and fetal health. Current prevention and management strategies for COVID-19 on pregnant dental and HCPs are also discussed. RESULTS: Significant progress is being made in understanding the pathogenesis and clinical consequences of COVID-19. Pregnant women are affected more adversely with viral illnesses, although evidence of vertical transmission of COVID-19 is controversial. Based on the presence of atypical symptoms, the significant numbers of asymptomatic individuals who are COVID-19 positive, and the high susceptibility to viral diseases observed in pregnant women, recommendations have been put forth to limit the exposure of COVID-19-positive or even suspected cases to pregnant HCPs, and these are likely to evolve as new information becomes available. CONCLUSION: Pregnant HCPs require extra caution: not only are they considered a high-risk population, but their work at the frontline in a pandemic may expose them to additional risks. Complete awareness of the effects of COVID-19 on maternal and fetal/infant health, as well as prevention and management guidelines for pregnant HCPs, will allow for a safer work environment. Health care institutional policies aimed at protecting pregnant HCPs should consider avoiding their assignment as first responders, especially if equally trained staff are available. KNOWLEDGE TRANSFER STATEMENT: Dental and health care professionals can use the information in this review to improve their awareness of COVID-19 risks, signs, and symptoms and the associated effects on the health of pregnant health care professionals and their unborn/newborn children.

Stability evaluation of ZnO nanosheet based source-gated transistors.

Semiconducting nanostructures are one of the potential candidates to accomplish low-temperature and solution-based device assembly processes for the fabrication of transistors that offer practical solutions toward realizing low-cost flexible electronics. Meanwhile, it has been shown that by introducing a contact barrier, in a specific transistor configuration, stable device operation can be achieved at much reduced power consumption. In this work, we investigate both one-dimensional ZnO nanowires (NWs) and two-dimensional nanosheets (NSs) for high performance and stable nano-transistors on conventional Si/SiO2 substrates. We have fabricated two variant of transistors based on nanoscale single-crystalline oxide materials: field-effect transistors (FETs) and source-gated transistors (SGTs). Stability tests are performed on both devices with respect to gate bias stress at three different regimes of transistor operation, namely off-state, on-state and sub-threshold state. While in the off-state, FETs shows comparatively better stability than SGTs devices, in both sub-threshold and on-state regimes of transistors, SGTs clearly exhibits better robustness against bias stress variability. The present investigation experimentally demonstrates the potential advantages of SGTs over FETs as driver transistor for AMOLEDs display circuits which require very high stability in OLED driving current.

Photoluminescence Study of the Influence of Additive Ammonium Hydroxide in Hydrothermally Grown ZnO Nanowires.

We report the influence of ammonium hydroxide (NH4OH), as growth additive, on zinc oxide nanomaterial through the optical response obtained by photoluminescence (PL). A low-temperature hydrothermal process is employed for the growth of ZnO nanowires (NWs) on seedless Au surface. A more than two order of magnitude change in ZnO NW density is demonstrated via careful addition of NH4OH in the growth solution. Further, we show by systematic experimental study and PL characterization data that the addition of NH4OH can degrade the optical response of ZnO NWs produced. The increase of growth solution basicity with the addition of NH4OH may slowly degrade the optical response of NWs by slowly etching its surfaces, increasing the point defects in ZnO NWs. The present study demonstrates the importance of growth nutrients to obtain quality controlled density tunable ZnO NWs on seedless conducting substrates.

A facile hydrothermal approach for the density tunable growth of ZnO nanowires and their electrical characterizations.

Controlling properties of one-dimensional (1D) semiconducting nanostructures is essential for the advancement of electronic devices. In this work, we present a low-temperature hydrothermal growth process enabling density control of aligned high aspect ratio ZnO nanowires (NWs) on seedless Au surface. A two order of magnitude change in ZnO NW density is demonstrated via careful control of the ammonium hydroxide concentration (NH4OH) in the solution. Based on the experimental observations, we further, hypothesized the growth mechanism leading to the density controlled growth of ZnO NWs. Moreover, the effect of NH4OH on the electrical properties of ZnO NWs, such as doping and field-effect mobility, is thoroughly investigated by fabricating single nanowire field-effect transistors. The electrical study shows the increase of free charge density while decrease of mobility in ZnO NWs with the increase of NH4OH concentration in the growth solution. These findings show that NH4OH can be used for simultaneous tuning of the NW density and electrical properties of the ZnO NWs grown by hydrothermal approach. The present work will guide the engineers and researchers to produce low-temperature density controlled aligned 1D ZnO NWs over wide range of substrates, including plastics, with tunable electrical properties.

Single-crystalline ZnO sheet Source-Gated Transistors.

Due to their fabrication simplicity, fully compatible with low-cost large-area device assembly strategies, source-gated transistors (SGTs) have received significant research attention in the area of high-performance electronics over large area low-cost substrates. While usually based on either amorphous or polycrystalline silicon (α-Si and poly-Si, respectively) thin-film technologies, the present work demonstrate the assembly of SGTs based on single-crystalline ZnO sheet (ZS) with asymmetric ohmic drain and Schottky source contacts. Electrical transport studies of the fabricated devices show excellent field-effect transport behaviour with abrupt drain current saturation (IDS(SAT)) at low drain voltages well below 2 V, even at very large gate voltages. The performance of a ZS based SGT is compared with a similar device with ohmic source contacts. The ZS SGT is found to exhibit much higher intrinsic gain, comparable on/off ratio and low off currents in the sub-picoamp range. This approach of device assembly may form the technological basis for highly efficient low-power analog and digital electronics using ZnO and/or other semiconducting nanomaterial.

Gaso-transmitter hydrogen sulphide: potential new target in pharmacotherapy.

Research in the last two decades has transformed the way hydrogen sulphide (H2S) is perceived from a noxious gas to a gaso-transmitter with a vast potential in pharmacotherapy. H2S is synthesized in various body-systems using the enzymes cystathionine beta-synthase and cystathionine gamma-lyase; either of these being the predominat enzyme in a particular system. H2S may be one of the physiological modulators of blood pressure in humans. The gas relaxes the vascular smooth muscle cells by opening up K(ATP) channels. Moreover, it suppresses the proliferation of vascular smooth muscle cells. H2S may also be contributing in the protection afforded by ischaemia-preconditioning. Testosterone is thought to be responsible for the higher central nervous system level of H2S in males. In the central nervous system, H2S is implicated in Alzheimer's disease, epilepsy, stroke and Down's syndrome. Insulin secretion is associated with a decrease in the H2S levels. Raised H2S is detrimental in acute pancreatitis as well as in septic shock. Recently, H2S-releasing derivatives of certain drugs have shown promise in protection against gastric ulcer and in inflammatory bowel disease. The beneficial effects of certain sulphur containing herbs like ginseng and garlic may be mediated via H2S. In future, development of specific drugs modulating H2S levels may prove beneficial in varied disorders.

Comparative evaluation of shear bond strength of different bracket base designs in dry and wet environments.

UNLABELLED: One hundred and thirty five extracted premolars were selected and bonded with three types of brackets with different bracket base designs viz. Gemini (foil mesh), Miniature twin (Laser etched) and Mini Dynalocks (Integral base). These brackets were bonded with Transbond XT adhesive using two types of primers viz. Conventional Transbond XT in dry conditions and M.I.P in dry and wet environments. The specimens were tested for SBS using Instron machine at C.I.P.E.T. (Amritsar), Punjab. Results were statistically analyzed. RESULTS AND DISCUSSION: The Miniature twin brackets revealed higher SBS values as compared to Gemini and Mini Dynalock in dry and wet conditions. All the groups showed higher SBS values in dry conditions as compared to wet conditions respectively. The Gemini and Mini Dynalock brackets showed very little difference of SBS values. CONCLUSION: Miniature twin brackets with laser etched bracket base in dry and wet environments have revealed the highest SBS values. All the groups have revealed clinically acceptable SBS value of above 8 MPa in moist conditions.

Linking the Rb and polycomb pathways.

Polycomb group (PcG) proteins associate to form complexes that repress Hox genes, thereby imposing the patterning of Hox expression required for development. However, these proteins have a second Hox-independent role in regulating cell proliferation. Our results suggest that association between Rb and PcG proteins forms a repressor complex that blocks entry of cells into mitosis. Also, we provide evidence that Rb colocalizes with nuclear PcG complexes and is important for association of PcG complexes with nuclear targets. The Rb-PcG complex may provide a means to link cell cycle arrest to differentiation events leading to embryonic pattern formation.

Role of the LXCXE binding site in Rb function.

Oncoproteins from DNA tumor viruses such as adenovirus E1a, simian virus 40 T antigen, and human papillomavirus E7 contain an LXCXE sequence, which they use to bind the retinoblastoma protein (Rb) and inhibit its function. Cellular proteins such as histone deacetylases 1 and 2 (HDAC1 and -2) also contain an LXCXE-like sequence, which they use to interact with Rb. The LXCXE binding site in Rb was mutated to assess its role in Rb function. These mutations inhibited binding to HDAC1 and -2, which each contain an LXCXE-like sequence, but had no effect on binding to HDAC3, which lacks an LXCXE-like sequence. Mutation of the LXCXE binding site inhibited active transcriptional repression by Rb and prevented it from effectively repressing the cyclin E and A gene promoters. In contrast, mutations in the LXCXE binding site did not prevent Rb from binding and inactivating E2F. Thus, the LXCXE mutations appear to separate Rb's ability to bind and inactivate E2F from its ability to efficiently recruit HDAC1 and -2 and actively repress transcription. In transient assays, several of the LXCXE binding site mutants caused an increase in the percentage of cells in G(1) by flow cytometry, suggesting that they can arrest cells. However, this effect was transient, as none of the mutants affected cell proliferation in longer-term assays examining bromodeoxyuridine incorporation or colony formation. Our results then suggest that the LXCXE binding site is important for full Rb function. Mutation of the LXCXE binding site does not inhibit binding of the BRG1 ATPase component of the SWI/SNF nucleosome remodeling complex, which has been shown previously to be important for Rb function. Indeed, overexpression of BRG1 and Rb in cells deficient for the proteins led to stable growth inhibition, suggesting a cooperative role for SWI/SNF and the LXCXE binding site in efficient Rb function.

Exit from G1 and S phase of the cell cycle is regulated by repressor complexes containing HDAC-Rb-hSWI/SNF and Rb-hSWI/SNF.

We present evidence that Rb forms a repressor containing histone deacetylase (HDAC) and the hSWI/SNF nucleosome remodeling complex, which inhibits transcription of genes for cyclins E and A and arrests cells in the G1 phase of the cell cycle. Phosphorylation of Rb by cyclin D/cdk4 disrupts association with HDAC, relieving repression of the cyclin E gene and G1 arrest. However, the Rb-hSWI/SNF complex persists and is sufficient to maintain repression of the cyclin A and cdc2 genes, inhibiting exit from S phase. HDAC-Rb-hSWI/SNF and Rb-hSWI/SNF then appear to maintain the order of cyclin E and A expression during the cell cycle, which in turn regulates exit from G1 and from S phase, respectively.

Maxillary expansion--an interceptive modality in mixed dentition.

Maxillary expansion is a very useful procedure for arch length augmentation, posterior crossbite treatment and removing cross arch interferences. Removable appliances are in the realm of a pedodontist and general dentist. However, one should be aware of the problems arising at an early age of the child, should be able to properly diagnose the condition and if required, a timely referral to a specialist is also expected.

Open reduction and fixation of proximal humeral fractures and fracture-dislocations.

Open reduction and internal fixation was employed in the treatment of 25 severely displaced fractures and fracture-dislocations of the proximal humerus. Our aims were accurate reduction and stable fixation to allow early mobilisation and to achieve full functional recovery. In 15 fractures an AO T-plate was used and in 10 a bent semitubular plate was employed as a blade plate. Excellent or satisfactory results were obtained in all six patients with two-part fractures involving the surgical neck; in four of the five patients with three-part fractures involving the surgical neck and tuberosities; in nine of the 11 patients with fracture-dislocation; and in two of the three patients with split fractures of the humeral head. Overall results were good or satisfactory in 21 of the 25 cases. Unsatisfactory results were associated with rotator cuff damage.